SUBSTATION MAINTENANCE PROCEDURES33KV VACUUM CIRCUIT BREAKERS 125VDC LEAD ACID BATTERY POWER TRANSFORMERS ON - LOAD TAP CHANGERS STRUCTURES & BUSWORK POTENTIAL TRANSFORMERS MV DISCONNECTORS MV SWITCHGEARS GROUNDING FEBRUARY 2009 PREPARED BY: ANSEL GARVEY SUBSTATION MAINTENANCE PROCEDURES TABLE OF CONTENTS 1. 1.1 1.2 1.3 2. 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 3. 3.1 3.2 3.3 3.4 3.5 3.6 4. 4.1 4.2 4.3 4.4 4.5 5. 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 INTRODUCTION ...............................................................................................................1 GENERAL ............................................................................................................................1 DEFINITIONS ......................................................................................................................1 SAFETY................................................................................................................................2 SUBSTATION IN-SERVICE INSPECTION ...................................................................3 INTRODUCTION.................................................................................................................3 INFORMATION, TOOLS AND MATERIALS...................................................................3 SAFETY REQUIREMENTS ................................................................................................3 DISCONNECT SWITCH INSPECTION .............................................................................4 STATION BUS INSPECTION .............................................................................................4 33KV VACUUM BREAKER INSPECTION.......................................................................4 POWER TRANSFORMER INSPECTION ..........................................................................4 ON-LOAD TAP CHANGER INSPECTION........................................................................5 INSTRUMENT TRANSFORMER INSPECTION...............................................................5 STRUCTURE INSPECTION................................................................................................5 INFRARED INSPECTION...................................................................................................5 EQUIPMENT INSPECTION/MINOR MAINTENANCE..............................................7 INTRODUCTION.................................................................................................................7 125 VDC LEAD ACID BATTERY AND CHARGER INSPECTION ................................7 33KV VACUUM CIRCUIT BREAKER ..............................................................................8 POWER TRANSFORMER INSPECTION ..........................................................................10 11KV SWITCHGEAR INSPECTION..................................................................................12 33KV SWITCHGEAR INSPECTION..................................................................................14 EQUIPMENT TESTING....................................................................................................17 SAFETY OF PERSONNEL..................................................................................................17 SAFETY HAZARDS ............................................................................................................17 TRANSFORMER TESTING ................................................................................................18 OIL SAMPLE COLLECTION AND TEST .........................................................................20 CIRCUIT BREAKER TESTING..........................................................................................21 MAJOR MAINTENANCE.................................................................................................23 INTRODUCTION.................................................................................................................23 MAJOR OVERHAULS ON 33KV VACUUM CIRCUIT BREAKERS .............................23 MAJOR OVERHAULS 125 VDC LEAD ACID BATTERIES & CHARGER ...................25 MAJOR OVERHAULS ON POWER TRANSFORMERS ..................................................28 MAJOR OVERHAULS ON ON-LOAD TAP CHANGERS ...............................................31 MAJOR OVERHAULS DISCON SWITCHES AND ASSOCIATED EQUIPMENT ........34 MAJOR OVERHAULS ON INSTRUMENT TRANSFORMERS ......................................36 MAJOR OVERHAULS ON 33KV SWITCHGEAR............................................................37 MAJOR OVERHAULS ON 11KV SWITCHGEAR ...........................................................39 SUBSTATION GROUNDING MAINTENANCE...............................................................41 Page i 6. 6.1 APPENDICES INSPECTION SHEETS 6.1.1 33kv Vacuum Circuit Breakers 6.1.2 125 VDC Lead Acid Batteries & Charger 6.1.3 Power Transformers 6.1.4 On-Load Tap Changers 6.1.5 Structures & Buswork 6.1.6 Instrument Transformers 6.1.7 MV Disconnect Switches 6.1.8 MV Switchgear 6.1.9 Substation Grounding TEST SHEETS SAFETY PROCEDURES 6.2 6.3 Page ii 1. 1.1 INTRODUCTION GENERAL Preventative maintenance is a cycle of planned inspections, tests, minor overhauls and servicing activities designed to keep equipment in good operating condition and to reveal the need for reconditioning or major overhaul in time to prevent breakdowns or failure during operation. This manual contains maintenance standards and procedures for the preventative maintenance program. The maintenance standards and procedures shall be used in conjunction with manufacturer’s manuals. These Maintenance Procedures identify the Works to be carried out for Maintenance on the following equipment: 33kV Vacuum Circuit Breakers 125VDC Lead Acid Batteries & Chargers Power Transformers On-Load Tap Changers Structures and bus work Potential Transformers Medium Voltage Disconnect Switches Medium Voltage Switchgears Grounding This procedure should be used with the attached inspection sheets and test report forms. Ensure all forms are completely filled out and a local field file is maintained on this equipment. 1.2 DEFINITIONS These procedures fall into four categories: Inspections, Minor Overhaul, Major Overhaul and Test Procedures. Inspections are comprised of visual checks and test operating of station equipment. They may require taking readings and making reports on equipment condition. Usually the work can be completed with the equipment in service. Inspections identify when further investigative maintenance is required. Minor Maintenance is usually non-invasive and involves assessment of the equipment condition by a means of inspections, checks, samples and tests etc. Minor maintenance is used to assess the correct functioning of the equipment and to determine further maintenance requirements. This procedure does not cover all eventualities; the crew is also expected to look for and correct defects, which are not anticipated in this procedure. Major Maintenance is the replacement and or refurbishment of an equipment major component or system. Major overhauls are usually performed when a minor overhaul, historical data, modification or system performance deem them necessary. Major overhauls usually include most of the minor overhaul steps. Page 1 Testing/sampling procedures outline the steps required to indicate equipment condition through testing of the equipment or equipment insulation i.e. Oil Samples, Thermovision (Infra-red) Capacitance and Power Factor etc. These tests can be performed outside of the minor or major overhaul procedures. The results of the testing identify when further maintenance is required. 1.3 SAFETY It is the responsibility of every employee to avoid unnecessary risks by following safety rules, approved work procedures and practices. Before undertaking any procedures in this manual, proper work protection must be established as required by GRENLEC Safety Policy and Procedures. In addition, safety hazard identification must be an integral part of everyday work. It is the responsibility of the person in charge of the work and each crewmember to constantly be on the lookout for safety hazards and to take definite steps to eliminate or control the hazards. Safety of Personnel In order to ensure human safety, all personnel involved with the works shall be briefed on all aspects of the work prior to the commencement of any maintenance work or testing, and the following safety procedures adhered to. Particular emphasis should be placed on personnel hazards and the safety precautions associated with these hazards. Work Protection Proper work protection shall be established in accordance with the requirements of GRENLEC Safety Policy and Procedures. Ensure the Controller is notified when a station inspection is being performed. Safety Identification A safety identification exercise and safety basics procedure to identify all hazards shall be performed. Page 2 2. 2.1 2.1.1 SUBSTATION IN-SERVICE INSPECTION INTRODUCTION This Maintenance Procedure details the work to be carried out during Substation Inspections. The maintenance crew is also expected to identify and correct defects, which are not anticipated in this procedure. This procedure is performed to: (i) Assess substation structures, bus work and equipment condition; (ii) Verify the correct functioning of the equipment and determine maintenance requirements. 2.1.2 2.1.3 2.2 2.2.1 The substation inspection should be carried out by trained maintenance personnel and in accordance with this procedure and the manufacturer’s instructions. The Substation Inspection Sheet should be completed during the site inspection. INFORMATION, TOOLS AND MATERIALS Planning In planning the work, refer to: - Manufacturer’s instruction books, technical drawings, etc. - Training lessons - Previous station inspection reports - Copy of any special GRENLEC orders or manufacturers technical bulletins 2.2.2 Special Tools and Materials - Binoculars - Infrared Camera SAFETY REQUIREMENTS During a station inspection and thermovision testing the electrical equipment will be inservice and in an energized state. Proper work clearances must be maintained at all times. Operating and testing of equipment must be approved and coordinated by the controllers. Binoculars should be used for detailed inspection of live equipment. Infrared Camera should be used to check for and record hot joints. All personnel involved shall be briefed on all aspects of the work prior to the start of any maintenance or testing activity. Particular emphasis should be placed on personnel hazards and the safety precautions associated with these hazards. Proper working clearances must be maintained at all times. Make yourself aware of close-by live apparatus while conducting the inspection. 2.3 Page 3 2.4 2.4.1 DISCONNECT SWITCH INSPECTION Visually check that the switches are in their required operating position - either fully closed with blades in proper position or fully open with proper clearances. Check if the insulators are chipped or cracked. Check for signs of flashover, excessive dirt, foreign material, copper splash. Check cementing and fasteners. Check linkages, operating handles for damage and correct positioning. Visually check the motor mechanism for deterioration, corrosion or damage. Check the anti-condensation heater in Motor Control Panel STATION BUS INSPECTION Check bus support insulators for chips, cracks, flashover burns, excessive dirt, foreign material, copper splash, copper wash, correct cementing and fasteners. Check bus connections for damage, deterioration or signs of heating. 33KV VACUUM BREAKER INSPECTION Perform a general inspection in the operating mechanism/control cabinet and around the breaker checking for deterioration, corrosion or damage. Check the anti-condensation heater. POWER TRANSFORMER INSPECTION Check oil levels in tank and tap changer conservators. Check the pressure gauge reading on sealed tank transformers. The gauge should indicate a positive pressure with the unit in service. If the transformer is equipped with a silica gel breather check the color of the silica gel. Blue indicates dry and pink indicates wet. Check valves, gaskets, welds, and fittings for any sign of oil leakage or damage. Perform a general inspection in the control cabinet and inspect the transformer for deterioration, corrosion or damage. Operate the fans to ensure correct operation. Check that the radiators are free from debris that could restrict the flow of air. Check anti condensation heaters Check temperature readings (oil and winding temperature gauges) Page 4 2.4.2 2.4.3 2.4.4 2.4.5 . 2.5 2.5.1 2.5.2 2.6 2.6.1 2.6.2 2.7 2.7.1 2.7.2 2.7.3 2.7.4 2.7.5 2.7.6 2.7.7 2.7.8 2.8 2.8.1 ON LOAD TAP CHANGER INSPECTION Perform a general inspection in the operating mechanism/control cabinet checking for deterioration, corrosion or damage. Operate the tap changer raise and lower one tap. Check for irregular operation, noises, etc. NOTE: Notify controlling authority before operating tap changer. Check the anti-condensation heater (if applicable). INSTRUMENT TRANSFORMER INSPECTION Check valves, gaskets, and fittings for any sign of oil leakage or damage. Perform a general inspection around the instrument transformer checking for deterioration, corrosion or damage. STRUCTURE INSPECTION Check all foundations and structures for cracking, shifting or deterioration. Check all equipment ground connections are secure. INFRARED INSPECTION Scope of Program The objectives of the thermovision testing program are: 1. 2. 3. 4. Detect overheated components in station equipment. Monitor equipment showing signs of deterioration. Examine new installations for improper or faulty connections. Examine the condition of equipment which has been repaired. 2.8.2 2.8.3 2.9 . 2.9.1 2.9.2 2.10 2.10.1 2.10.2 2.11 2.11.1 2.11.2 2.11.2.1 Test Conditions To obtain the most reliable results, it is recommended to arrange station loading so that the equipment being surveyed will be carrying as large a current as possible, for one hour prior to the test. It is recommended that the loading be at least 25% of the equipment rating. Prior to making application for equipment outages and switching required to create the necessary increased loading on components, a switching schedule and test plan should be established for each station. Testing should be carried out with the understanding that equipment may be returned to normal operating position, without notifying the test crew. 2.11.2.2 2.11.2.3 Page 5 2.11.3 Evaluation of Test Results (Current Carrying Components) The thermovision operator will carry out a preliminary evaluation of the test results. Items found to be outside the normal limits of temperature rise outlined in the operators manual shall be reported to the substation group. The thermovision operator will assign priority for further action, as shown below: A – Emergency, arrange repair immediately B – Repair in the immediate future C – Repair in near future possibly with next planned outage D – Repair in regular maintenance, retest at next thermovision inspection 2.11.4 2.11.4.1 Evaluation of Test Results (Non Current Carrying Components) Disconnect Switches (Motor Operated) Scan the motorized mechanism electrical components for signs of overheated terminal strips, connections, relays, contactors and defective heaters. Compare results with other similar mechanisms. 2.11.4.2 Circuit Breakers Scan the operating mechanism/control cabinet’s electrical components for signs of overheated terminal strips, connections, relays, contactors and defective heaters. Compare results with other similar breaker mechanisms. Scan the tanks and interrupter poles of circuit breakers and check for hot spots or variances when compared to other similarly loaded circuit breakers. 2.11.4.3 Transformers and Tap Changers Scan the operating mechanism/control cabinet’s electrical components for signs of overheated terminal strips, connections, relays, contactors and defective heaters. Compare results with other similar transformer mechanisms. Scan the radiator looking for restrictions in the oil flow that may cause variances when compared to other parts of the cooling system or similar transformers. Scan the tap changer compartment looking for variances when compared to other similarly tap changers. Compare the tap changer temperature to the main tank. The tap changer is normally a few degrees cooler than the main tank. Instrument Transformers Scan the tanks of instrument transformers looking for variances when compared to similar instrument transformers. 2.11.4.4 2.11.4.5 Surge Arrestors (Lightning Arrestors) Scan the porcelains of surge arrestors and check for variances when compared to similar surge arrestors. Page 6 3. 3.1 3.1.1 3.1.2 3.1.3 3.1.4 EQUIPMENT INSPECTION/MINOR MAINTENANCE INTRODUCTION Minor maintenance is performed to assess the overall equipment condition, the correct functioning of the equipment and to determine requirements for major maintenance. Maintenance of equipment should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. All appropriate forms should be filled out and a file maintained on the equipment. All personnel involved shall be briefed on all aspects of the work prior to the start of any maintenance or testing activity. Particular emphasis should be placed on personnel hazards and the safety precautions associated with these hazards. Proper working clearances must be maintained at all times. In planning the work, refer to: - Manufacturer’s instruction books, technical drawings, etc. - Training lessons - Substation Inspection Reports - Previous overhaul and trouble reports - Copy of any special GRENLEC orders or manufacturers technical bulletins Make yourself aware of close-by live apparatus while conducting the inspection. 3.1.5 3.1.6 3.2 3.2.1 125VDC BATTERY & CHARGER INSPECTION SPECIAL TOOLS AND MATERIALS Hydrometer, Voltmeter and Ammeter Distilled Water Face Shield Apron Gloves (chemical resistant) 3.2.2 SPECIAL SAFETY HAZARDS Batteries contain sulfuric acid. Do not allow battery fluid to come in contact with eyes or skin. If contact occurs, flush the affected area immediately with water. Batteries generate hydrogen gas, which is flammable and explosive. To reduce the possibility of explosion, never expose the battery to open flame or sparks. Do not smoke near the battery. Tools should be insulated to avoid the chance of sparks. Batteries contain stored energy and may explode if inadvertently shorted. Page 7 3.2.3 3.2.3.1 3.2.3.2 INSPECTION Check to ensure that the battery room temperature is between 20 and 25°C. Record DC voltage reading on the charger voltmeter and note any variation from normal range of values. Record the charger ammeter reading. The normal current drain on the battery should be marked on the meter. Note if the reading is outside the normal range. Check the battery terminals for corrosion or discoloration. Check for leaks. There should be no visible signs of electrolyte on the battery jars, the jar covers or in the trays. Measure and record the corrected specific gravity (S.G.) of the electrolyte in the pilot cell and determine if an equalize charge is required. The pilot cell is one which is used as a convenient means to indicate the condition and state of charge of the whole battery. The pilot cell is the one of poorest quality, lowest specific gravity reading and lowest voltage. Measure and record the voltage of the pilot cell and determine if an equalize charge is required. The pilot cell is the one used to estimate the condition and state of charge of the whole battery. Check the electrolyte level. Add distilled water if the level is below the lower limit. Equalize Battery (periodic application of a controlled overvoltage cycle to battery) 3.2.3.3 3.2.3.4 3.2.3.5 3.2.3.6 3.2.3.7 3.2.3.8 3.2.3.9 3.3 3.3.1 CIRCUIT BREAKER INSPECTION SPECIAL TOOLS AND MATERIALS Multi Meter Clip on Ammeter Foam Spray Recommended lubricants SAFETY OF PERSONNEL Isolate the equipment Carry out a visual check to ensure the equipment is isolated Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the circuit breaker and its mechanisms are disconnected from all power, both high voltage and control voltage before it is inspected. Mark off the work area with signs and easily visible tape. Page 8 3.3.2 The circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure all spring operating systems are fully discharged before working on any mechanism. 3.3.3 SAFETY HAZARDS Some points in the control cabinet may be live. If work is required on a live circuit arrange for isolation at the source end of the circuit. This circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure that all spring operating systems for both closing and opening are fully discharged if work is required in the mechanism. Safety Note: Be aware of near-by live parts before commencing work on the circuit breaker. 3.3.4 3.3.4.1 INSPECTION Verify the operation of the breaker operation counter. Record the counter reading before and after the inspection. Check the bushing for chips, cracks, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Check circuit breaker housing, structures, covers, fittings etc. for any sign of rusting, corrosion or damage to painted surface. Check control and operator mechanism compartments: a. Look for loose, broken, corroded wire/ terminals, loose contactor parts, burnt coils and contacts. Check fuses, connections, contactors. Check for any sign of contact burning and deterioration in insulation of control wire or coils. b. Check for sign of corrosion, moisture, external contamination or damage. Check all cable entrances are properly sealed against rodent. Inspect seals for any sign of external contamination or aging. c. Check the operation of anti-condensation heaters. Inspect the contacts of the auxiliary switches. Check for loose connections and erosion, burning or chattering of contacts. Check also the auxiliary switch linkage alignment for wear & lubrication. Clean or adjust, if required. Check the condition of the contacts on all the relays. Check the condition of the following items: Mechanism bearings, Linkages, springs and shafts. Check springs for defects, cracks and tightness of fittings. 3.3.4.2 3.3.4.3 3.3.4.4 3.3.4.5 3.3.4.6 3.3.4.7 Page 9 3.3.4.8 Operating mechanism Inspect operating mechanism. Check lubrication. Check for smooth operation during manual operation. Clean and lubricate the operating mechanism/ linkage as per manufacturer’s instructions. Note the condition of the parts. Use recommended lubricant only. 3.3.4.9 3.3.4.10 3.3.4.11 Verify the operation of position indicator (open/close) to ensure it is indicating correctly. Check the charging spring indicator in both the charged and discharged position. Record Contact wear 3.4 POWER TRANSFORMER INSPECTION Minor overhaul on the transformer shall be conducted with the transformer energized and in service. 3.4.1 SPECIAL TOOLS AND MATERIALS This procedure should be used with the attached inspection report form. Ensure all forms are completely filled out. A copy of the completed inspection form should be sent to the Distribution Department. Tools and Materials - Volt / Ohm Meter - Foam Spray - Recommended Lubricants Oil Sample & Test - Approved, Clean, Oil Sample Jars and Syringes - Labels, GRENLEC and Laboratory Forms and Shipping Information - Clean PVC Hoses, Fittings and Wipers - Bucket and Waste Oil Container 3.4.2 SAFETY OF PERSONNEL The maintenance of transformers should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Some points in the control cabinet may be live even with all the control switches open. If work is required on a live circuit arrange for isolation at the source end of the circuit. Safety Note: Make yourself aware of close-by live apparatus before starting to work on the transformer. Page 10 3.4.3 3.4.3.1 3.4.3.2 3.4.3.3 3.4.3.4 TRANSFORMER INSPECTION (IN-SERVICE) Listen for any abnormal sounds that may indicate loose windings, blocking or other mechanical problems. Check the oil level in the main tank on transformers equipped with conservator tanks. The gauge should show a normal level, adjusted for temperature. Check the pressure gauge reading on sealed (no conservator) type transformers. The gauge should indicate a positive pressure. Check the bushing condition. Look for broken, chipped or cracked bushings, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Check pressure relief vent for signs of damage or oil leakage. Check for signs of relief vent diaphragm operation, cracked diaphragm and visible evidence of oil around relief area. For transformers equipped with a silica gel breather check the color of the silica gel. Check to ensure the breather vent is not plugged with debris or insects. Check valves, gaskets and fittings for any sign of oil leakage or damage. Check panels, structures, covers, valves, fittings for signs corrosion or damage. Check the control cabinet for broken or corroded wire/terminals, loose contactor parts, burnt coils and contacts. Check fuses, connections. Check conductors and coils for deterioration in insulation. Inspect the control cabinet for signs of corrosion, moisture, external damage or contamination. Ensure cable entrances are properly sealed against rodents. Inspect seals for signs of external contamination or aging. Check the door. Check the operation of anti-condensation heaters. Check and record the maximum and existing oil and winding temperatures. Check the temperature gauges for correct functioning - upper drag hand limit is not excessive, drag hands indicate reasonable temperature range. Reset. Operate the fans. Check that all fans are operating properly and turning in the correct direction, there is no audible indication of bearing trouble, fan guards are fixed in place and there is no damage to blades and wiring is in good condition. Check the radiators. Remove any bird nests, bird excrement, or other foreign debris that will restrict the flow of air or cause corrosion or damage to the units. Take an oil sample from the tank. Perform a dielectric test. Results of the Dielectric test should be used to assess the transformer condition. Record and compare the results with previous tests and ANSI recommended values. Check Buchholz Relay for flammable gas. Check pressure relief device for normal condition. 3.4.3.5 3.4.3.6 3.4.3.7 3.4.3.8 3.4.3.9 3.4.3.10 3.4.3.11 3.4.3.12 3.4.3.13 3.4.3.14 3.4.3.15 3.4.3.16 3.4.3.17 Page 11 3.4.4 3.4.4.1 ON-LOAD TAP CHANGER IN-SERVICE INSPECTION Operate the Tap changer (raise/lower) a) Check the tap changer operation counter is operating properly. b) Check the tap position indicator is operating correctly c) Check for irregular operation, noises, etc. d) Record final reading Check the gear lubricant levels and refill if necessary, using manufacturer’s recommended lubricant. Check linkages for correct operation. Lubricate drive gears according to manufacturer recommendations Check the mechanical and electrical limits by operating the tap changer through its complete range of taps and attempt to overdrive (mechanically and electrically) at both ends of the tap range. NOTE: The limits must be checked manually first. 3.4.4.2 3.4.4.3 3.4.4.4 3.4.4.5 3.4.4.6 Test the Buchholz relays. Check for flammable gases. Take an oil sample from the tap changer. Perform a dielectric test. Results of the Dielectric test should be used to assess the tap changer condition. Record and compare the results with previous tests, and ANSI recommended values. Check pressure relief device for normal condition. 3.4.5.7 3.5 3.5.1 11KV SWITCHGEAR INSPECTION SPECIAL TOOLS AND MATERIALS Multi Meter Clip on Ammeter Foam Spray Recommended lubricants Vacuum Cleaner SAFETY OF PERSONNEL De-energize the equipment Carry out a visual check to ensure the equipment is isolated; where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the circuit breaker and its mechanisms are disconnected from all power, both high voltage and control voltage before it is inspected. Page 12 3.5.2 The circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure all spring operating systems are fully discharged before performing an inspection or maintenance. De-energize control power to the circuit breaker by removal of the fuse holder or by opening the molded case circuit breaker. Perform the spring discharge test before removing or inserting the circuit breaker. See Instruction Manual for procedure. Ensure circuit breaker door is closed before racking. See Instruction Manual for racking procedures. 3.5.3 SAFETY HAZARDS Some points in the control cabinet may be live. If work is required on a live circuit arrange for isolation at the source end of the circuit. This circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure that all spring operating systems for both closing and opening are fully discharged if work is required in the mechanism. Safety Note: Be aware of near-by live parts before commencing work on the circuit breaker. 3.5.4 3.5.4.1 INSPECTION A general visual inspection of the switchgear and a check on accessories shall be conducted every year. A more detailed inspection shall be carried out every five (5) years. Inspect general condition of the switchgear installation. Check housing, structures, covers, fittings etc. for any sign of rusting, corrosion or damage to painted surface. Check the bushing for chips, cracks, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Verify the operation of the breaker operation counter. Record the counter reading before and after the inspection. Inspect switchgear interior for accumulation of dust, dirt or foreign matter. Clean panels and check connections Check control and circuit breaker compartments: a. Look for loose, broken, corroded wire/ terminals, loose contactor parts, burnt coils, contacts and terminal blocks. Check fuses, connections, contactors. Check for any sign of contact burning and deterioration in insulation of control wire or coils. b. Check for sign of corrosion, moisture, external contamination or damage. Check all cable entrances are properly sealed against rodent. Inspect seals for any sign of external contamination or aging. c. Check the operation of anti-condensation heaters. d. Examine indicating lamps and replace as required Page 13 3.5.4.2 3.5.4.3 3.5.4.4 3.5.4.5 3.5.4.6 3.5.4.7 3.5.4.8 Inspect the contacts of the auxiliary switches. Check for loose connections and erosion, burning or chattering of contacts. Check also the auxiliary switch linkage alignment for wear & lubrication. Clean or adjust, if required. Check the condition of the contacts on all the relays. Check the condition of the following items: Mechanism bearings, Linkages, springs and shafts. Check springs for defects, cracks and tightness of fittings. Operating mechanism Inspect operating mechanism. Check lubrication. Check for smooth operation during manual operation. Clean and lubricate the operating mechanism/ linkage as per manufacturer’s instructions. Note the condition of the parts. Use recommended lubricant only. 3.5.4.9 3.5.4.10 3.5.4.11 3.5.4.12 3.5.4.13 3.5.4.14 3.5.4.15 3.5.4.16 3.5.4.17 3.5.4.18 Verify the operation of position indicator (open/close) to ensure it is indicating correctly. Check the charging spring indicator in both the charged and discharged position. Record Contact-wear while checking spring Check for proper condition of instrument transformers. Replace burned out fuses. Check primary and secondary connections. Insert the draw-out section into the panel Check out all the necessary functions and interlocking Replace reassemble, re-insulate, return all items to proper operating conditions and remove grounds prior to energizing. 33KV SWITCHGEAR INSPECTION SPECIAL TOOLS AND MATERIALS Multi Meter Clip on Ammeter Foam Spray Recommended lubricants Vacuum Cleaner SAFETY OF PERSONNEL De-energize the equipment Carry out a visual check to ensure the equipment is isolated; where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the circuit breaker and its mechanisms are disconnected from all power, both high voltage and control voltage before it is inspected. Page 14 3.6 3.6.1 3.6.2 The circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure all spring operating systems are fully discharged before performing an inspection or maintenance. De-energize control power to the circuit breaker by removal of the fuse holder or by opening the molded case circuit breaker. Perform the spring discharge test before removing or inserting the circuit breaker. See Instruction Manual for procedure. Ensure circuit breaker door is closed before racking. See Instruction Manual for racking procedures. 3.6.3 SAFETY HAZARDS Some points in the control cabinet may be live. If work is required on a live circuit arrange for isolation at the source end of the circuit. This circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure that all spring operating systems for both closing and opening are fully discharged if work is required in the mechanism. Safety Note: Be aware of near-by live parts before commencing work on the circuit breaker. 3.6.4 3.6.4.1 INSPECTION A general visual inspection of the switchgear and a check on accessories shall be conducted every year. A more detailed inspection shall be carried out every five (5) years. Inspect general condition of the switchgear installation. Check housing, structures, covers, fittings etc. for any sign of rusting, corrosion or damage to painted surface. Check the bushing for chips, cracks, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Verify the operation of the breaker operation counter. Record the counter reading before and after the inspection. Inspect switchgear interior for accumulation of dust, dirt or foreign matter. Clean panels and check connections Check control and circuit breaker compartments: a. Look for loose, broken, corroded wire/ terminals, loose contactor parts, burnt coils, contacts and terminal blocks. Check fuses, connections, contactors. Check for any sign of contact burning and deterioration in insulation of control wire or coils. b. Check for sign of corrosion, moisture, external contamination or damage. Check all cable entrances are properly sealed against rodent. Inspect seals for any sign of external contamination or aging. c. Check the operation of anti-condensation heaters. d. Examine indicating lamps and replace as required Page 15 3.6.4.2 3.6.4.3 3.6.4.4 3.6.4.5 3.6.4.6 3.6.4.7 3.6.4.8 Inspect the contacts of the auxiliary switches. Check for loose connections and erosion, burning or chattering of contacts. Check also the auxiliary switch linkage alignment for wear & lubrication. Clean or adjust, if required. Check the condition of the contacts on all the relays. Check the condition of the following items: Mechanism bearings, Linkages, springs and shafts. Check springs for defects, cracks and tightness of fittings. Operating mechanism Inspect operating mechanism. Check lubrication. Check for smooth operation during manual operation. Clean and lubricate the operating mechanism/ linkage as per manufacturer’s instructions. Note the condition of the parts. Use recommended lubricant only. 3.6.4.9 3.6.4.10 3.6.4.11 3.6.4.12 3.6.4.13 3.6.4.14 3.6.4.15 3.6.4.16 3.6.4.17 3.6.4.18 Verify the operation of position indicator (open/close) to ensure it is indicating correctly. Check the charging spring indicator in both the charged and discharged position. Record Contact-wear while checking spring Check for proper condition of instrument transformers. Replace burned out fuses. Check primary and secondary connections. Insert the draw-out section into the panel Check out all the necessary functions and interlocking Replace reassemble, re-insulate, return all items to proper operating conditions and remove grounds prior to energizing. Page 16 4. 4.1 4.1.1 4.1.2 4.1.3 4.1.4 EQUIPMENT TESTING INTRODUCTION Equipment testing is performed to assess the overall equipment condition and to determine requirements for major maintenance. Testing of equipment should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. All appropriate forms should be filled out and a file maintained on the equipment. All personnel involved shall be briefed on all aspects of the work prior to the start of any testing activity. Particular emphasis should be placed on personnel hazards and the safety precautions associated with these hazards. Proper working clearances must be maintained at all times. In planning the work, refer to: - Manufacturer’s instruction books, technical drawings, etc. - Training lessons - Relevant IEEE Standards - Copy of any special GRENLEC orders or manufacturers technical bulletins 4.1.5 4.2 SAFETY OF PERSONNEL Prior to performing any test of power apparatus, there should be a meeting of all people who will be involved or affected by the test. The test procedure should be discussed so there is a clear understanding of all aspects of the work to be performed. Consideration of safety in electrical testing applies not only to personnel but also to the test equipment and equipment under test. Particular emphasis should be placed on personnel hazards and the safety precautions associated with these hazards. 4.3 SAFETY HAZARDS Insulation tests in the field present a hazard to personnel unless suitable precautions are taken. Equipment to be tested shall be disconnected from the power system. A visual check of the disconnection should be carried out. When this is not possible, check with a voltage indicator. Grounds are then applied. Personnel shall be instructed to treat all ungrounded apparatus as energized. Ground Connection Use of working grounds should comply with established company guidelines. Warning Signs and Barriers The test area may be marked off with signs and easily visible tape. Page 17 4.4 4.4.1 TRANSFORMER TESTING SAFETY OF PERSONNEL Isolate the equipment Carry out a visual check to ensure the equipment is isolated Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the transformer and its controls are disconnected from all power, both high voltage and control voltage before it is inspected. Mark off the work area with signs and easily visible tape. 4.4.2 SAFETY HAZARDS Some points in the control cabinet may be live. If work is required on a live circuit arrange for isolation at the source end of the circuit. Be aware of near-by live parts before commencing work on the transformer. Under no conditions shall tests be performed on a transformer under vacuum because under these conditions the dielectric strength of the system is significantly reduced. 4.4.3 TEMPERATURE INDICATOR TEST Test the alarm points, cooling operation and correct indication of the temperature indicators by removing the temperature sensor bulb from the transformer and putting it in a oil heater and slowly raise and lower the temperature. 4.4.4 MEGGER TEST Perform a MEGGER test on the windings and core. Test HV to LV, HV and LV to ground and the core to ground (if core is accessible). If a core ground resistor is installed check its value. Record the results 4.4.5 WINDING RESISTANCE TEST Objective - Check for abnormalities, due to loose connections, broken strands and high contact resistance in tap changers. Interpretation of results is usually based on a comparison of measurements made separately on each phase in the case of a wye-connected winding or between pairs of terminals on a delta-connected winding. Comparison may also be made with original data measured in the factory. Variations of up to 5 % for any of the above comparisons is satisfactory. Resistance measurements are converted to values corresponding to the reference temperature in the transformer test report by the following formula: RS = RM * TS + TK TM +TK Page 18 Where: RS = Resistance at desired temperature Ts RM = Measured resistance TS = Desired reference temperature (C) TM = Temperature at which resistance was measured (C) TK = 234.5 C (copper)) = 225 C (Aluminum)) Note: The value of Tk may be as high as 230 for Alloyed Aluminum. 4.4.6 POWER FACTOR TEST This test is carried out to determine deterioration of, contamination of, or physical damage to the insulation Test voltages for typical field test sets range from below 100v to as high as 12 kV. Temperature correction should be made during the measurements. Interpretation Power Factor Less than 0.5% 0.5%-1.0% Above 1.0% Insulation condition Good Acceptable Questionable One of the most useful methods of evaluating test results is by comparison to previous test results on the same equipment. 4.4.7 TRANSFORMER TURNS RATIO TEST (TTR) The turns’ ratios should be determined for all taps. The turns’ ratio tolerance should be within 0.5 % of the nameplate specifications for all windings. For three-phase Y connected windings this tolerance applies to the phase-to-neutral voltage. Out-of-tolerance ratio measurements may be symptomatic of shorted turns, especially if there is an associated high excitation current. Open turns in the excited winding will be indicated by low exciting current and no output voltage. Open turns in the output winding will be indicated by normal levels of exciting current, but no or very low levels of unstable output voltage. The turn ratio test may also detect high-resistance connection in the lead circuitry or high contact resistance in tap changer by higher excitation current. Page 19 4.5 4.5.1 OIL SAMPLE COLLECTION AND TEST SAFETY PRECAUTION The oil sampling of electrical equipment should be carried out by trained maintenance personnel and in accordance with this procedure If the transformer is suspected to be developing internal problems avoid area of transformer explosion vent discharge when sampling the equipment. Personnel sensitive to Transformer Oil should wear latex gloves to avoid skin contact. 4.5.2 GATHER SAMPLES Setup Connect sample hose to bottom sampling valve. Note: Special tests may call for top oil samples. Flush Flush oil through the valve, fittings and hose to clean and dry them and to ensure the sample is representative of the oil in the equipment, not just in the valve and piping. Using a clear jar check the oil being flushed for water and debris. When satisfied that sampling can begin reduce oil flow and maintain the same rate throughout sample collection as opening and closing the sample valve may release unwanted debris. Fill Sample Jars and Syringes Jars: rinse Jar 3 times, put PVC hose to bottom of Jar (to avoid aeration) and fill almost completely with final sample. Label Jar and place in container to protect it from breakage and sunlight. Syringes: hold Syringe vertical with its valve at top and rinse Syringe 3 times and manipulate to expel air bubbles. Fill slightly above full mark with final sample. Tilt Syringe and inspect for air bubbles. If any bubbles are detected repeat final fill and inspect again. Repeat if necessary until a bubble free sample is obtained. Note that if a bubble appears later this is a result of the sample cooling and evolving gas: this bubble must not be expelled. Record syringe serial number and store it in its protective container away from sunlight. Complete Sample Information Fill in all information requested on the sample forms completely and accurately equipment data, sampling point, oil temperature(s), ambient temperature, humidity, purpose of sample, date, crew name(s), etc. Local Dielectric Testing Ensure that the Oil Tester is set up to perform tests according to the proper ANSI Standard. Note - Compare results to previous test results to establish if there is a ‘Trend’ Page 20 4.6 4.6.1 CIRCUIT BREAKER TESTING SAFETY OF PERSONNEL Isolate the equipment and carry out a visual check to ensure the equipment is isolated Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the breaker and its controls are disconnected from all power, both high voltage and control voltage before it is inspected. Mark off the work area with signs and easily visible tape. 4.6.2 SAFETY HAZARDS Some points in the control cabinet may be live. If work is required on a live circuit arrange for isolation at the source end of the circuit. Safety Note: Be aware of near-by live parts before commencing work. 4.6.3 MICRO-OHM TEST Measure and record the micro-ohm readings of each phase with the breaker closed. Test leads should be placed between the power leads on the bushing terminals. Be sure that both the power leads and test leads are making a good connection with the bushing terminal. Sources of high micro-ohm readings could be poor connection of test leads, bushing caps, bushing adapter & interrupter and contact block. 4.6.4 TIME/ TRAVEL TEST Perform a circuit breaker timing test using an approved circuit breaker timer and compare the results with the recommended values provided in the manufacturer’s instruction manual. The results for the following tests should be recorded. 1. Opening time 2. Open spread (difference between poles) 3. Closing time 4. Close spread (difference between poles) 5. Close/trip time 6. Slow operating speed could be an indication of weak opening or closing springs or binding in the mechanism. 7. Investigate any readings, which exceed the maximum values given by the manufacturer. DC HI-POT TEST The high pot test should be carried with the following values: 11kV Breakers 33kV Breakers Circuit Breaker Open: Connect high-voltage lead to pole 1 and ground all other poles. Repeat all other poles. Circuit Breaker Closed: Connect high-voltage lead to Pole 1 with either pole of phase 2 and 3 grounded. 4.6.5 Page 21 4.6.6 VACUUM BOTTLE TEST With the circuit breaker open conduct test on each phase. For each phase connect highvoltage lead to pole 1 with other pole grounded. 4.6.7 4.6.8 LOW DC VOLTAGE TEST Perform low voltage close and trip test at 80% of the rated control voltage. SPRING CHARGING SYSTEM CHECK After normal close operation, measure and record the spring recharging time. Measure and record the charging motor current. FUNCTION TESTS Perform the breaker function tests: seal-in, anti-slam and anti-pump. 4.6.9 5. 5.1 MAJOR MAINTENANCE INTRODUCTION Major overhauls are an internal or more in depth analysis of the equipment to determine if replacement or overhaul of parts is required and if required carry out the necessary part replacement or refurbishment. Equipment maintenance in the field presents a hazard to personnel unless suitable precautions are taken. Equipment to be maintained shall be disconnected from the power system. A visual check of the disconnection should be carried out. When this is not possible, check with a voltage indicator. Grounds are then applied. Personnel shall be instructed to treat all ungrounded apparatus as energized. 5.2 5.2.1 MAJOR OVERHAUL ON 33KV VACUUM CIRCUIT BREAKERS SPECIAL TOOLS AND MATERIALS - Micro-ohm Tester - Circuit Breaker Timing Tester - Volt / Ohm Meter - Clip on Ammeter - Minimum Voltage Tester - Hi-Pot Tester - Foam Spray - Recommended lubricants Page 22 5.2.2 SAFETY OF PERSONNEL The maintenance of vacuum circuit breakers should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Isolate the equipment and carry out a visual check to ensure the equipment is isolated Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the circuit breaker and its mechanisms are disconnected from all power, both high voltage and control voltage before it is overhauled. Mark off the work area with signs and easily visible tape. The circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure all spring operating systems are fully discharged before working on any mechanism. Follow the manufacturer’s recommendation to protect against radiation hazard while carrying out HI POT tests. 5.2.3 5.2.3.1 CIRCUIT BREAKER MAINTENANCE Check the breaker operation counter is operating. Record the counter reading before and after the overhaul. Check the bushing condition. Look for broken, chipped or cracked bushings, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Check operating mechanism/control cabinets, structures, covers, fittings etc. for any sign of rusting, corrosion or damage. Check the general condition of the operating mechanism/control panel. Look for loose, broken, corroded wire/ terminals, loose contactor parts, burnt coils and contacts. Check fuses, connections, contactors for signs of contact burning, and control wire and coils for sign of deterioration in insulation. Inspect the operating mechanism/control panel for any sign of corrosion, moisture, external contamination or damage. Check all cable entrances are properly sealed against rodents and check for signs of external contamination or aging. Check the door fits properly. Check the operation of anti-condensation heaters. Inspect auxiliary switch contact - check for loose connections and erosion, burning or chattering of contacts. Check also the auxiliary switch linkage alignment for wear & lubrication. Clean or adjust as required. Check the condition of the contacts on all the relays. Page 23 5.2.3.2 5.2.3.3 5.2.3.4 5.2.3.5 5.2.3.6 5.2.3.7 5.2.3.8 5.2.3.9 Check the condition of the following items: Mechanism bearings, Rollers, Linkages, springs and shafts for defects, cracks and tightness of fittings. 5.2.3.10 Clean and lubricate the operating mechanism as per manufacturer’s instructions. Note the condition of the parts. Use only the recommended lubricant. 5.2.3.11 Check the operation of open/close position indicator/ linkage to ensure it is indicating correctly. 5.2.3.12 Check the charging spring indicator in both the charged and discharged position to ensure it is indicating correctly. 5.2.3.13 Check the mechanism measurement specifications as per the manufacturer’s instruction manual. 5.2.3.14 Check and record the measurements of the contact wear indicator as per the manufacturer instruction manual. 5.3 5.3.1 125VDC LEAD ACID BATTERIES AND CHARGER SPECIAL TOOLS AND MATERIALS Hydrometer Voltmeter Ammeter Distilled Water Impedance Tester Cleaning Solution (baking soda) Durable Wipers Face Shield Apron Gloves (chemical resistant) 5.3.2 SPECIAL SAFETY HAZARDS Batteries contain sulfuric acid. Do not allow the battery fluid to contact eyes or skin. If contact occurs, flush the affected area immediately with water. Batteries generate hydrogen gas, which is flammable and explosive. To reduce the possibility of explosion, never expose the battery to open flame or sparks. Do not smoke near the battery. Tools should be insulated to avoid the chance of sparks. Batteries contain a large amount of stored energy and may explode if inadvertently shorted during the overhaul. Page 24 5.3.3 5.3.3.1 CHARGER INSPECTION Calibrate the charger voltmeter for correct float and equalize voltages. The calibration should be done using an accurate portable voltmeter. Calibrate the charger ammeter reading. The calibration should be done using an accurate portable ammeter. Remove dust and contamination from all the components and surfaces in and on the charger. Check the contacts on timing devices, relays, and switches for signs of burning, heating or deterioration. Check the calibration of the under-voltage and over-voltage alarms as per manufacturer instructions. 5.3.3.2 5.3.3.3 5.3.3.4 5.3.3.5 5.3.4 5.3.4.1 5.3.4.2 BATTERY INSPECTION Check to ensure that the battery room temperature is between 20 to 25 Deg. C. Battery cells: a) Check for signs of deterioration. Check plates for buckling, sulfating or plate growth. Check inter-plate spacers for signs of charring; check bottom of cell for excessive sedimentation, or active material fallen from plates. b) Check outside of the batteries for cracked cells or acid attack on inter-cell connections c) Check for corrosion or discoloration on battery cell terminals on connections d) Check for leaks. There should be no visible signs of electrolyte on the battery jars, the jar covers or in the trays e) Clean the outside of the cells to remove any conductive salt deposits or dust deposits. Use a baking soda solution to neutralize the acid. Do not allow any cleaning solution to enter the cells. f) Replace defective cell as per instructions outlined in Section 4.3.5. Measure and record the corrected relative density (specific gravity) of the electrolyte in the pilot cell. Measure and record the voltage of the pilot cell. Measure and record the corrected relative density (specific gravity) of the electrolyte in all the cells. Measure and record the voltage of all the cells. Choose the new pilot cell (lowest reading). The pilot cell is one, which is used as a convenient means to indicate the condition and state of charge of the whole battery. The pilot cell is generally the poorest cell, determined by the specific gravity reading and the cell with the lowest voltage. 5.3.4.3 5.3.4.4 5.3.4.5 Page 25 5.3.4.6 Shut off the battery charger and test the ability of the battery to supply typical peak load, e.g., breaker closing current. With the charger shut off for 90 minutes; test the capacity of the battery to supply a steady load while maintaining the voltage. Record the results Perform an Impedance test on all the battery cells. Compare with previous test results. Check the percent change of each cell and percent deviation from the average cell. Check the electrolyte level. Add distilled water if required Place batteries on equalize. 5.3.4.7 5.3.4.8 5.3.4.9 5.3.4.10 5.3.5 5.3.5.1 BATTERY CELL CHANGE OUT Special Tools and Materials Standby battery of same voltage and enough capacity for short term use Suitably sized temporary cables and connectors for battery connections Micro-ohmmeter, insulated tools, cleaning materials and suitable connection corrosion inhibitor for inter-cell/block connectors 5.3.5.2 Special Safety Hazards The change out of defective batteries should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Batteries contain sulfuric acid. Do not allow the battery fluid to contact eyes or skin. Personal protective equipment must be worn. If contact occurs, flush the affected area immediately with water. Batteries generate hydrogen gas, which is flammable and explosive. To reduce the possibility of explosion, never expose the battery to open flame or sparks. Do not smoke near the battery. Tools should be insulated to avoid the chance of sparks or shorts. Personnel should touch a grounded surface prior to touching the battery to drain any static charge. Batteries contain large amounts of stored energy and can cause high energy DC arcs and cell explosion if shorts are created. Extreme care and thorough job planning must be employed to avoid these hazards. Rubber gloves and flash goggles should be used while making and breaking the parallel connections. 5.3.5.3 5.3.5.3.1 Battery Change-out Procedure Ensure that the replacement battery is of the same voltage as the one to be replaced, is in a similar state of charge and has adequate capacity to meet the minimal needs of the DC Network during the time of the Works. Check that the battery area is well ventilated in order to prevent build up of explosive gasses. Page 26 5.3.5.3.2 If required, ground or insulate the replacement battery rack/carrier as required to match the setup of the battery to be replaced. Check to ensure that the replacement batteries intercell/block connections are secure. Securely connect the negative of the replacement battery to the negative of the battery to be replaced using adequately sized cable. Use two-hole terminal lugs at the load bus better facilitates replacement battery connections without disturbing the normal connections. Connect the positive side cable to the positive of the replacement battery. Check with a DC voltmeter to ensure minimal voltage between the positive cable and the positive of the battery to be replaced. A 100W light bulb in a ‘pigtail lamp holder’ can be temporarily connected across the two positives to allow the two batteries to equalize their charges and prevent any appreciable spark when the final connection is made-up. When it is safe to do so, connect the positive cable to the positive of the battery to be replaced. This now puts the two batteries in parallel. Disconnect the replaced battery at both negative and positive side so as to fully isolate it. Proceed with repairs as required on the replaced battery. Note that inter-cell/block connections can be checked with a Micro-ohmmeter to determine resistance and any need to dismantle for cleaning and re-greasing. The above procedure may be used to replace a few cells if the work allows this but great care must be exercised with polarities, number of cells replaced/paralleled, minimal voltage difference and connection security before the parallel is completed. It is usually safer to replace the whole battery. When the work is completed, the original battery can be returned to service and the temporary battery can be removed, using the same step-by-step procedure outlined above. 5.3.5.3.3 5.3.5.3.4 5.3.5.3.5 5.3.5.3.6 5.3.5.3.7 5.3.5.3.8 5.4 5.4.1 MAJOR OVERHAULS ON POWER TRANSFORMERS SPECIAL TOOLS AND MATERIALS Volt / Ohm Meter Transformer Test Equipment Oil Sample Equipment Processed transformer oil for top up Temperature Control Oil Heater Thermometer Foam Spray Recommended lubricants 5.4.2 SAFETY OF PERSONNEL Isolate the equipment Carry out a visual check to ensure the equipment is isolated Page 27 5.4.3 Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the transformer and its controls are disconnected from all power, both high voltage and control voltage before it is inspected. Mark off the work area with signs and easily visible tape. SAFETY HAZARDS Some points in the control cabinet may be alive even with all the control switches open. If work is required on a live circuit, then it may be necessary to arrange for isolation at the source end of the circuit. Safety Note: Be aware of near-by live parts before commencing work. 5.4.4 5.4.4.1 TRANSFORMER INSPECTION Prior to isolating the transformer listen for any abnormal sounds that may indicate loose windings, blocking or other mechanical problems. Check the oil level in the main tank on transformers equipped with conservator tanks. The gauge should show a normal level, adjusted for temperature. For transformers equipped with a conservator tank drain the conservator tank to remove condensation. Check the pressure gauge reading on sealed (no conservator) type transformers. The gauge should indicate a positive pressure. Check the bushing / porcelain condition. Look for broken, chipped or cracked bushings/ porcelain, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Check the relief vent and/or the self-resetting pressure relief vent for signs of damage or oil leakage. Check for signs of past relief vent diaphragm operation; cracked/broken diaphragm, self resetting pressure relief vent indicator operated, visible evidence of oil around relief area. If the transformer is equipped with a silica gel breather check the colour of the silica gel. Blue indicates dry and pink indicates wet. Check to ensure the breather vent is not plugged with debris or insects. Check valves, gaskets, packing, and fittings for any sign of oil leakage or damage. Check control cabinet, structures, covers, valves, fittings piping etc. for any sign of rusting, corrosion or damage. 5.4.4.2 5.4.4.3 5.4.4.4 5.4.4.5 5.4.4.6 5.4.4.7 5.4.4.8 5.4.4.9 Page 28 5.4.4.10 Check the general condition of the control cabinet. Look for loose, broken, corroded wire/ terminals, loose contactor parts, burnt coils and contacts. Check fuses, connections, contactors, any sign of contact burning, any sign of deterioration in insulation of control wire or coils. Inspect the control cabinet for any sign of corrosion, moisture, external contamination or damage. Check all cable entrances are properly sealed against rodents. Inspect weather/ rodent seals for any sign of external contamination or aging. Check the door fits properly and hardware keeps the door secure. Check the operation of anti-condensation heaters. Check and record the maximum and existing oil temperature and winding temperature. Check that the temperature gauge is functioning properly; upper drag hand limit is not excessive, upper and lower drag hands indicate a reasonable temperature range and reset properly. In addition record the maximum current. Operate the fans. Check that all fans are operating properly and turning in the correct direction. No audible indication of mounting/bearing trouble, fan guards are fixed in place and there is no damage to blades. Wiring is in good condition. Operate the pumps. Check that all pumps are operating properly with no audible indication of trouble and that the flow indicators are working. Wiring is in good condition. Check the radiators/coolers. Remove any bird nests, bird excrement, or other foreign debris that will restrict the flow of air or cause corrosion or damage to the units. Take an oil sample from the tank. Perform a dielectric test. Results of the Dielectric test should be used to assess the transformer condition. Record and compare the results with previous tests, GRENLEC specifications and the manufacturer’s specifications. An oil sample should also be taken from the tap changer if it is not scheduled for maintenance 5.4.4.11 5.4.4.12 5.4.4.13 5.4.4.14 5.4.4.15 5.4.4.16 5.4.4.17 5.5 5.5.1 MAJOR OVERHAUL ON ON-LOAD TAP CHANGERS SPECIAL TOOLS AND MATERIALS Volt / Ohm Meter Ratiometer Winding Resistance Tester Oil Sample Equipment Dielectric Test Set Oil Filter/Handling Equipment New Filtered Oil Oil Pails Durable Wipers/Cloths (Lint Free) Filtered transformer oil Manufacturer Recommended Tools Page 29 - Lifting Rig (Crane) Lifting Equipment (slings & rope-blocks) Foam Spray Recommended lubricants 5.5.2 SPECIAL SAFETY HAZARDS The maintenance of under load tap changers should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Some points in the control cabinet may be alive even with all the control switches open. If work is required on a live circuit, then it may be necessary to have the Protection Department arrange for isolation at the source end of the circuit. The ULTC consists of mechanical components, which will be set in motion to observe their performance during the overhaul. Safety Note: Make yourself aware of close-by live apparatus before starting to work on the tap changer. 5.5.3 TAP CHANGER OVERHAUL Prior to opening the tap changer ensure all tools and foreign material from workers pockets etc. are prevented from falling into the tap changer compartment. 5.5.3.1 Check the tap changer operation counter is operating. Record the counter reading before and after the overhaul. Operate the tap changer manually one tap position in both directions (raise and lower). Check the operation of mechanism and linkages for any undue mechanical restriction, binding, irregular operation, noises, etc. Operate the tap changer by raising and lowering it one tap position. Check for irregular operation, noises, etc. Check the winding resistance on each of these three positions. Operate the ULTC through the neutral position, stop at the next tap and again check the winding resistance. This process will check the diverter and reversing switches prior to the overhaul. NOTE: Refer to the manufacturer manual to ensure the tap changer is on the recommended tap position before beginning the overhaul. Do not change the diverter switch position after it has been disengaged from the drive linkage. Ensure the oil handling equipment is clean, dry and there is a supply of approved insulating oil. Connect the oil handling equipment and slowly remove the oil from the tap changer. Open the bleeder valve in the tap changer cover. After the oil is removed, open the cover as per manufacturer recommendation. Flush (using the tube flush device) the insert with filtered oil, inserting the flushing nozzle down into the openings in the top casting to flush down the arcing chamber. Disconnect and remove the insert from the transformer following the manufacturer recommendations. Continue to flush Page 30 5.5.3.2 5.5.3.3 5.5.3.4 5.5.3.5 as it is being lifted, paying particular attention to the center, interphase drive tube both inside and out. When the flushing is complete, drain the remaining oil from the tap changer. 5.5.3.6 Remove any remaining carbon from the insert and the housing using clean durable lint free wipers. Check the support cylinder and internal insulating components. Inspect all insulation for signs of deterioration including tracking, overheating and cracking. Check the mechanical condition of the shafts, gearboxes and pivot points for signs of wear or misalignment. Measure the contact thickness of the moving and stationery contacts as per the manufacturer recommendations. Compare the readings with the recommended measurements. Inspect the flexible shunts, contacts and joints for signs of fraying, heating or deterioration. Measure the diverter resistors resistance values as per the manufacturer recommendation. Compare the results with the recommended values. Re-install the tap changer insert into the transformer following the manufacturer instructions. Fill the tap changer compartment with new filtered oil and perform recommended bleeding procedures. Operate the tap changer manually one tap position in both directions (raise and lower). Check the operation of mechanism and linkages for any undue mechanical restriction, binding, irregular operation, noises, etc. Perform any other checks recommended by the manufacturer to ensure the tap changer has been assembled and installed correctly. Check the gear lubricant levels and refill if necessary, using manufacturer’s recommended lubricant. Check the mechanism / linkages for correct operation. Lubricate drive gears according to manufacturer recommendations Check that the tap position indicator/linkage operates correctly. Check the mechanical and electrical limits by operating the tap changer through its complete range of taps and attempt to overdrive (mechanically and electrically) at both ends of the tap range. NOTE: The limits must be checked manually first. Test the RS 1000/2000 Bucholtz protective device. Page 31 5.5.3.7 5.5.3.8 5.5.3.9 5.5.3.10 5.5.3.11 5.5.3.12 5.5.3.13 5.5.3.14 5.5.3.15 5.5.3.16 5.5.3.17 5.5.3.18 5.5.3.19 5.5.3.20 5.5.3.21 Take an oil sample from the tap changer after it has been refilled. Perform a dielectric test to ensure the installed oil is of acceptable quality. Compare the results with the manufacturer’s and GRENLEC’s recommended specifications. Perform a ratio test on 5 tap positions - top, bottom, neutral, and both sides of neutral positions. Record the results. 5.5.3.22 5.6 5.6.1 MAJOR OVERHAULS ON DISCONNECTS & ASSOCIATED EQUIPMENT SPECIAL TOOLS AND MATERIALS Micro-ohm Tester Volt / Ohm Meter Clip on Ammeter Recommended lubricants 5.6.2 SPECIAL SAFETY HAZARDS Some points in the control cabinet of motor operated disconnect may be live even with all control switches open. If work is required on a live circuit, it may be necessary to arrange for isolation at the source end of the circuit. 5.6.3 5.6.3.1 5.6.3.2 5.6.3.3 5.6.3.4 5.6.3.5 5.6.3.6 5.6.3.7 5.6.3.8 5.6.3.9 5.6.3.10 5.6.3.11 5.6.3.12 5.6.3.13 DISCONNECT SWITCH INSPECTION Manually operate the switch and check: contact alignment, toggles, stops, linkage, undue insulator movement and general ease of operation Check porcelain for chips or cracks, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the porcelains if they are contaminated. Check contact pressure. Check jaw for correct compression. Observe jaw spread as blade closes into jaw. Check contacts for burning, erosion or deterioration. Check the wiping contacts for burning, erosion or deterioration. Clean and lubricate the contacts with recommended lubricants. Clean and lubricate the linkages with recommended lubricants. Remove gearbox covers and inspect the gears, linkages, bearings, shafts and pins. Lubricate if necessary with approved lubricant. Check that all the connections to the switch are tight with no signs of burning, damage, or discoloration indicating heating. Check that there is no undue stress on the insulator stacks Check the switch grounding connections are tight and undamaged. Clean and paint corroded spots on linkages, mechanism or gearbox. Operate the switch manually and electrically where so equipped. Page 32 5.6.3.14 Perform a micro-ohm test on switches that are in highly contaminated or corrosive environments. The readings on all three phases should be comparable. Measure and record the micro-ohm readings of each phase with the switch closed. Test leads should be placed between the power leads on the connection terminals. Be sure that both the power leads and test leads are making a good connection with the connection terminal. 5.6.4 5.6.4.1 MOTOR MECHANISM INSPECTION Check the general condition of the operating mechanism. Look for loose, broken, corroded wire/ terminals, loose contactor parts, burnt coils and contacts. Check fuses, connections, contactors (for signs of contact burning), insulation of control wire or (coils for signs of deterioration). Inspect the operating mechanism box for signs of corrosion, moisture, or damage. Check cable entrances are properly sealed. Inspect seals for signs of contamination or aging. Check the door fits properly and the door secure. Check the operation of anti-condensation heaters. Inspect the contacts of the auxiliary switches. Check for loose connections and erosion, burning or chattering of contacts. Check also the auxiliary switch linkage alignment for wear & lubrication. Clean or adjust, if required. Clean and lubricate the operating mechanism as per manufacturer’s instruction. Oil the bearings in the operating mechanism. Use recommended lubricant. Inspect motor commutator and brushes for wear. Check interlock switches and locking devices for proper operation. Measure and record motor current during open and close operation. STATION BUS INSPECTION Check the porcelain condition. Look for broken, chipped or cracked porcelain, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the porcelains if they are contaminated with dirt, dust or other pollutants. Check that all the connections to the bus are tight with no signs of burning, damage, or discoloration indicating heating. Ensure all locking washers are secure and not damaged. Check welded connections for cracks. Check expansion connections for fraying, binding or damage to shunts. Check that there is no undue stress on insulator stacks. SURGE ARRESTORS (LIGHTNING ARRESTORS) Check the porcelain for chips or cracks, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean porcelains if contaminated. Check that all the line and ground connections to the arrestor are tight with no signs of burning, damage, or discoloration. Page 33 5.6.4.2 5.6.4.3 5.6.4.4 5.6.4.5 5.6.4.6 5.6.4.7 5.6.4.8 5.6.5 5.6.5.1 5.6.5.2 5.6.5.3 5.6.5.4 5.6.6 5.6.6.1 5.6.6.2 5.7 5.7.1 MAJOR OVERHAULS ON INSTRUMENT TRANSFRMERS SPECIAL TOOLS AND MATERIALS Oil Sample Equipment Dielectric Test Set Durable Wipers/Cloths 5.7.2 SPECIAL SAFETY HAZARDS The maintenance of Instrument Transformers should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Some points in the junction/connection box may be live even with all the control switches open. If work is required on a live circuit arrange for isolation at the source end of the circuit. Safety Note: Make yourself aware of close-by live apparatus before starting to work on the instrument transformers. 5.7.3 5.7.3.1 INSTRUMENT TRANSFORMERS INSPECTION Check the bushing / porcelain condition. Look for broken, chipped or cracked bushings/ porcelain, flashover burns, copper splash, copper wash, correct cementing and fasteners. Clean the bushings if they are contaminated. Check valves, gaskets, packing, and fittings for any sign of oil leakage. Check the oil level of the tank, adjusted to the temperature. Check main tank, fittings, etc. for any sign of rusting, corrosion or damage. Check the general condition of the junction/connection box. Look for loose, broken, corroded wire/ terminals. Check fuses and connections for any sign of burning and insulation of control wire for signs deterioration. Inspect the junction/connection box for any sign of corrosion, moisture, external contamination or damage. Check all cable entrances are properly sealed against rodents. Inspect weather/ rodent seals for any sign of external contamination or aging. Check the cover fits properly and hardware keeps the cover secure. 5.7.3.2 5.7.3.3 5.7.3.4 5.7.3.5 5.7.3.6 Page 34 5.8 5.8.1 MAJOR OVERHAUL ON 33KV SWITCHGEAR SPECIAL TOOLS AND MATERIALS - Micro-ohm Tester - Circuit Breaker Timing Tester - Volt / Ohm Meter - Clip on Ammeter - Minimum Voltage Tester - Hi-Pot Tester - Foam Spray - Recommended lubricants SAFETY OF PERSONNEL The maintenance of vacuum circuit breakers should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Isolate the equipment and carry out a visual check to ensure the equipment is isolated Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the circuit breaker and its mechanisms are disconnected from all power, both high voltage and control voltage before it is overhauled. Mark off the work area with signs and easily visible tape. The circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure all spring operating systems are fully discharged before working on any mechanism. Follow the manufacturer’s recommendation to protect against radiation hazard while carrying out HI POT tests. 5.8.2 5.8.3 5.8.3.1 5.8.3.2 33KV SWITCHGEAR MAINTENANCE Record the counter reading before and after the overhaul. Check the bushing condition. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Inspect auxiliary switch contact - tighten loose connections. Check the auxiliary switch linkage alignment for wear & lubrication. Clean, lubricate or adjust as required. Clean and lubricate the operating mechanism as per manufacturer’s instructions. Note the condition of the parts. Use only the recommended lubricant. Check the operation of open/close position indicator/ linkage to ensure it is indicating correctly. Page 35 5.8.3.3 5.8.3.4 5.8.3.5 5.8.3.6 Check the charging spring indicator in both the charged and discharged position to ensure it is indicating correctly. Check the mechanism measurement specifications as per the manufacturer’s instruction manual. Check and record the measurements of the contact wear indicator as per the manufacturer instruction manual. 5.8.3.7 5.8.3.8 5.9 5.9.1 MAJOR OVERHAUL ON 11KV SWITCHGEAR SPECIAL TOOLS AND MATERIALS - Micro-ohm Tester - Circuit Breaker Timing Tester - Volt / Ohm Meter - Clip on Ammeter - Minimum Voltage Tester - Hi-Pot Tester - Foam Spray - Recommended lubricants SAFETY OF PERSONNEL The maintenance of vacuum circuit breakers should be carried out by trained maintenance personnel and in accordance with this procedure and specific manufacturer’s instructions. Isolate the equipment and carry out a visual check to ensure the equipment is isolated Where visual check is not possible carry out checks with an approved voltage indicator to ensure the equipment is fully isolated. Ground the equipment Ensure the circuit breaker and its mechanisms are disconnected from all power, both high voltage and control voltage before it is overhauled. Mark off the work area with signs and easily visible tape. The circuit breaker is composed of many mechanical devices, which may be under spring loading regardless of the operating position. Ensure all spring operating systems are fully discharged before working on any mechanism. Follow the manufacturer’s recommendation to protect against radiation hazard while carrying out HI POT tests. 5.9.2 Page 36 5.9.3 5.9.3.1 5.9.3.2 11KV SWITCHGEAR MAINTENANCE Record the counter reading before and after the overhaul. Check the bushing condition. Clean the bushings if they are contaminated with dirt, dust or other pollutants. Inspect auxiliary switch contact - tighten loose connections. Check the auxiliary switch linkage alignment for wear & lubrication. Clean, lubricate or adjust as required. Clean and lubricate the operating mechanism as per manufacturer’s instructions. Note the condition of the parts. Use only the recommended lubricant. Check the operation of open/close position indicator/ linkage to ensure it is indicating correctly. Check the charging spring indicator in both the charged and discharged position to ensure it is indicating correctly. Check the mechanism measurement specifications as per the manufacturer’s instruction manual. Check and record the measurements of the contact wear indicator as per the manufacturer instruction manual. 5.9.3.3 5.9.3.4 5.9.3.5 5.9.3.6 5.9.3.7 5.9.3.8 5.10 STATION GROUND MAINTENANCE This procedure should be used with the attached inspection report form plus copies of the Station Ground Network Drawing. Complete the report form and mark drawings to reflect the connections, test points used, the test results. 5.10.1 SPECIAL TOOLS AND MATERIALS Ground/Earth Resistance Tester Micro-ohmmeter Bonding Jumpers and Portable Grounds 5.10.2 SPECIAL SAFETY HAZARDS The maintenance inspection of Station Ground Networks should be carried out by trained maintenance personnel and in accordance with this procedure. A system fault may occur during a test. The use of Rubber Gloves is recommended. Proper work clearances must be maintained at all times. Jumper ground connections requiring repairs to prevent electrocution if system conditions create a current flow while the connection is insecure. Page 37 5.10.3 5.10.3.1 GROUND NETWORK INSPECTION Visual Inspection (above ground) Inspect all station ground connections, cable and cable securing clips on equipment and structures. Spot check bolted connectors for tightness. Note the location of any problems on drawing. 5.10.3.2 Visual Inspection (below ground) Dig down and expose 10% of the buried cable and ground rod connections. Use care not to separate any connections during the digging as lethal voltages could develop. Inspect and note on the drawing which connections were exposed and any suspected faults. Refer to this record before future inspections to ensure that different connections are exposed during each inspection. Where numerous defects are found more sections must be dug up for further inspection. 5.10.3.3 Repairs Repairs in an energized station are hazardous and must be carried out during periods of good weather with no equipment switching. Suitably sized bonds/ jumpers with clean, tight connections must be used to bypass any connection to be opened. Bolted connections must be cleaned, greased and properly tightened and Cadweld joints re-welded. Repair activities must be noted in the report. 5.10.4 GROUND NETWORK TESTS Refer to the original commissioning test and subsequent maintenance test results to plan and execute a repetitive test scenario. Use the same test equipment and test method as on previous jobs. Compare current results to previous ones. Note recent weather patterns, particularly rainfall, as this can affect the test result. Page 38 APPENDIX 6.1 INSPECTION SHEETS Page 39 SUBSTATION IN SERVICE INSPECTION SHEET Substation/Location: Inspection Date: Item No. 1 1.1 1.2 1.3 1.4 1.5 2 2.1 2.2 3 3.1 3.2 4 4.1 4.2 4.3 4.4. 4.5 4.6 4.7 4.8 5 5.1 5.2 6 6.1 6.2 Descriptions (Inspection/Checks) Disconnect Switch Inspection Switch (properly closed/opened & in req. op. position) Porcelain Condition (dirt, chips, flashover) Linkages,Operating Handles, (damage & correct positioning) Motor Mechanism (damage, corrosion) Anti Condensation Heaters (working) Station Bus & Surge Arrester Inspection Porcelain Condition (Chip, flashover, burns, dirt) Bus Connections (Discoloration, damage, heating/burning, tightness) Vacuum Circuit Breaker Operating Mechanism/Control Cabinet, Tank (damage/corrosion/deterioration) Anti Condensation Heaters (working) Transformer & Tap Changer Inspection Main tank/tap-changer oil levels Pressure gauges on sealed tanks (+ve pressure) Silica gel - Main Tank/Tap Changer (Dry/Wet) Valves, welds, gaskets (damage/leakage) Control Cabinet/Tank/Tap Changer operating mechanism (deterioration, corrosion, damage) Fan operation (correct rotation, radiators free of debri) Anti Condensation Unit (working) Oil & Winding Temperatures (Normal Readings) Instrument Transformers Tank (deterioration, corrosion, damage, leakage) Marshalling Boxes (Corrosion, damage) Structure Inspection Foundation (Cracks, shifting, deterioration) Structures (deterioration, corrosion) Observations/Readings Corrections Carried out Date Description Engineer: TRANSFORMER IN SERVICE INSPECTION SHEET Substation/Location: Inspection Date: Transformer S.N.: MVA Rating Manufacturer: Year of Manufacture Voltage Rating HV/LV: Item No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Descriptions (Inspection/Checks) Test Dielectric Str. kV* Hydran, ppm T.C. Sensing Volts Auxiliary Volts Ambient Temp. Deg. C Humidity Observation/Readings Date Test Equipment Result Corrections Carried out Description Painted Surface Bushing Condition Fans (Check operation/current) Motors (Check operation/current) Transformer tank, fittings - general condition Radiator/Cooler Condition Pressure Relief Device - Tank Pressure Relief Device - Diverter Sw. Winding Temperature Deg. C. (Cur./Max) Oil Temperature Deg. C (Cur./ Max.) Oil Level - Tap Changer Oil Level - Main Tank Pressure (gauge) reading Valves, Gaskets (Leaks - gas or oil) Silica gel - Tap Changer Silica gel - Main Tank No. of Tap Changer Operations (Found/Left) Tap Changer Position Min/Present/Max Electrical Connections - Infrared 20 Noise/Vibration 21 Buchholz Ralay & Gas Catcher Divice 22 Temperature Indication Test (Cooling/Alarm/Trip) 23 Control Cabinet: 23.1 Moisture, seals, contamination, Cable entrances 23.2 Anti Condensation Heaters 23.3 Wiring, contactors, coils, connections, insulation Engineer: 12/17/2012 Appendix 6.1 Inspection Sheets TAP CHANGER INSPECTION SHEET Substation: Date: Transformer Serial # Tap Changer Manufacturer Tap Changer Serial # # of Tap Changer Op Found # of Tap Changer Op Left Measurements Ambient Temperature Deg C Humidity Oil Temperature Reading Deg. C Winding temperature Reading Deg C Oil Dielectric Test, kV Contact Thickness, mm Contact Resistance Values, Ohms Observations/Readings Remarks Compare with Manufacturer Values Corrective Actions Carried Out Date Description Item No. 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 2 3 4 4.1 4.2 4.3 4.4 4.5 5 6 7 8 9 10 Descriptions (Inspections/Checks) Contacts Pitting Burning Allignment Freedom of movement Spring Pressure Arc resistance material Heating in current carrying parts Support Cylinder and Insulating Components (Check for tracking, cracking, wear and misalignment) Flexible Shunts, connections and Joints - Check for fraying, heating and deterioration Fasteners Operating Mechanism Do manual operation and check for binding, mechanical restriction, noise and irregular operation Mechanical & Electrical Limits Mechanical linkages operation & lubrication Belt Gear Box Lubricant Level Tap Position Indicator Liquid level indicator operation Buchholz Relay Pressure relief valve - exhaust screen Control wire connections tightness Voltage relay time delay Setting (0.5-1s req.) Engineer: BUSWORK & INSULATOR INSPECTION SHEET (QUEENS PARK) Bus Insulators, Surge Arresters, Instrument Transformers, Substation/Location: Queens Park Inspection Date: Item No. 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Test Equipment Binoculars Infrared Camera Manufacturer Decsription Observation/Readings (Inspections/Checks) Identify equipment: Bus Insulator Porcelain Condition Line 1 Line 2 Line 3 Line 4 Transformer T1 Transformer T2 Transformer T3 Transformer T4 Surge Arresters & Potential Transformers, Disconnect Switch, Porcelain Condition Line 1 Line 2 Line 3 Line 4 Transformer T1 Transformer T2 Transformer T3 Transformer T4 Conductors & Connectors, Transformer, PTS, RATING A B C Disconnector (Thermovision). Line 1 Line 2 Line 3 Line 4 Transformer T1 Transformer T2 Transformer T3 Transformer T4 Corrections Carried out Date Description D Engineer: BUSWORK & INSULATOR INSPECTION SHEET (GRAND ANSE) Bus Insulators, Surge Arresters, Instrument Transformers, Substation/Location: Grand Anse Inspection Date: Item No. 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Test Equipment Binoculars Infrared Camera Observations/Readings Date Manufacturer Description (Inspection/Checks) Identify equipment with Defects: Bus Insulator Porcelain Condition 33kV Bay 1 33kV Bay 2 33kV Bay 3 33kV Bay 4 33kV Bay 5 Transformer T1 & 11kV Bay Transformer T2 & 11kV Bay Surge Arresters & Potential Transformers, Disconnect Switch, Porcelain Condition 33kV Bay 1 33kV Bay 2 33kV Bay 3 33kV Bay 4 33kV Bay 5 Transformer T1 & 11kV Bay Transformer T2 & 11kV Bay Conductors & Connectors, Transformer, PTS, Disconnector (Thermovision). 33kV Bay 1 33kV Bay 2 33kV Bay 3 33kV Bay 4 33kV Bay 5 Transformer T1 & 11kV Bay Transformer T2 & 11kV Bay - Corrections Carried out Description RATING A B C D Engineer: STRUCTURE AND FOUNDATION INSPECTION SHEET Substation/Location: Inspection Date: Test Thermovision Test Equipment Item No. 1 2 3 4 5 6 7 7.1 7.2 7.3 7.4 7.5 7.6 Description (Inspections/Checks) Foundation (Cracking, shifting, deterioration) Steel Support Structures (Peeling, corrosion) Circuit Breaker & Switchgear Structures (Corrosion) Structure Grounding Secure Equipment (Circuit Breakers, Switchgears, Marshalling Kiosk, Disconnects) Grounding Secure Fencing (deterioration, ground connection) Junction Boxes, PT Marshalling Boxes (Moisture, contaminations, seals, wiring, connections, insulation) Observations/ Readings Date Corrections Carried out Description PT Marshalling Boxes Marshalling Kiosk PT Junction Box Disconnect Switch Auxiliary Switch (proper functioning) Disconnect Switch Motor Box Disconnect Switch Interlocking device Engineer: CIRCUIT BREAKER INSPECTION SHEET Substation/Location: Inspection Date: Circuit Breaker S.N.: Ampere Rating Manufacturer: Year of Manufacture Voltage Rating: Item No. 1 2 3 3.1 Description (Inspection/Checks) Test/Measurement Contact Wear Phase A, mm Contact Wear Phase B, mm Contact Wear Phase C, mm Auxiliary Volts, VAC/VDC Ambient Temp. Deg. C Humidity Observation/Readings Date Result Test # of Operation # of operation left Result Corrections Carried out Description Equipment structure & painted Surface (condition) Bushing/Porcelain Condition (dirt, chips, burns, fastners) Control & Operator Mechanism Compartments: Compartment General Condition (Moisture, contamination, rusting, corrosion or damage, weather, & rodent seals) 3.2 Compartment Control Circuits (Wiring, contactors, coils, connections, insulation, fuses) 3.3 Anti Condensation Heaters (operation) 4 Motors (Check operation/measure current) 5 Operating mechanism (etc. bearings, linkages, lubrication, cleansliness, smooth manual operation); Clean & lubricate 6 Position Indicator (trip & close and check operation) 7 Charging Spring (check indication in both charged and discharged pos., defects, tightness, cracks) 8 Auxiliary switches (check contacts, check alignment and lubrication of linkages) 9 Relay Condition (contacts) 10 Electrical Connections (Infrared test) 11 Trip/Close Operation (Noise/Vibration, Counter) 12 Vacuum Bottle (contact erosion, note wear) 13 Counter Operation (operate/note counter reading) Engineer: SWITCHGEAR INSPECTION SHEET Substation/Location: Inspection Date: Circuit Breaker S.N.: Ampere Rating Manufacturer: Year of Manufacture Voltage Rating: Item No. 1 2 3 3.1 Description (Inspection/Checks) Test/Measurement Contact Wear Phase A, mm Contact Wear Phase B, mm Contact Wear Phase C, mm Auxiliary Volts, VAC/VDC Ambient Temp. Deg. C Humidity Observation/Readings Date Result Test # of Operation found # of operation left Result Corrections Carried out Description Equipment structure & painted Surface (condition) Bushing Condition (dirt, chips, burns, fastners) Control & Operator Mechanism Compartments: Compartment General Condition (Moisture, contamination, rusting, corrosion or damage, weather, & rodent seals) 3.2 Compartment Control Circuits (Wiring, contactors, coils, connections, insulation, fuses) 3.3 Anti Condensation Heaters (operation) 4 Motors (Check operation/measure current) 5 Operating mechanism (etc. bearings, linkages, lubrication, cleansliness, smooth manual operation); Clean & lubricate 6 Position Indicator (trip & close and check operation) 7 Charging Spring (check indication in both charged and discharged pos., defects, tightness, cracks) 8 Auxiliary switches (check contacts, check alignment and lubrication of linkages) 9 Relay Condition (contacts) 10 Electrical Connections (Infrared test) 11 Trip/Close Operation (Noise/Vibration, Counter) 12 Vacuum Bottle (contact erosion, note wear) Engineer: DISCONNECT SWITCH INSPECTION SHEET Substation/Location: Inspection Date: Disconnect Switch S.N. Type/Model: Manufacturer/Year: Operating Position Voltage/Current Rating: Mechanism Type: Item No. 1 2 3 3.1 3.2 3.3 4 5 6 7 8 9 10 11 12 12.1 12.2 12.3 13 14 15 16 17 18 19 20 21 Test/Measurements Contact Resistance Thermovision Reading Auxiliary Volts (Motor Ambient Temp. Deg. C Equipment Result Description (Inspections/Checks) Manual Operation (alignment, toggles, linkages) Porcelain Condition (chips, dirt, burns) Contact (Pressure/Compression) (Burning, erosion, deterioration) Lubricate Contacts Hinge End Shunt (Burning, erosion, deterioration) Lubricate linkages Gear Box (gears, linkages, bearings and pins) lubricate if necessary. Connections (tightness, burning, damage, discoloration) Insulator Stacks (Undue stress) Grounding Connections (tightness) Clean and paint corroded linkages and mechanisms Test operate disconnect switch Contact Resistance Conection to Connection Phase A, μΩ Conection to Connection Phase B, μΩ Conection to Connection Phase C, μΩ Motor Mechanism Inspection Mechanism Cabinet (Wiring, Contactors, coils, connections, insulation (Corrosion, moisture, contamination, cable entrances, seals) Anti Condensation Heaters (operation) Auxiliary switches (contacts, alignment and linkages Lubricate operateing mechanism Motor comutator brushes Interlock switches & locking devices Observations/Readings Corrections Carried Out Date Description Engineer: SUBSTATION GROUND GRID INSPECTION SHEET Substation/Location: Inspection Date: Grounding Layout Drawing # Area of Ground Grid, m2 Test/Measurement Recent Weather Conditions Item No. 1 2 3 Description (Inspection/Checks) Joints Structure Connections Connection Problem Observation/Readings Date Correction Carried out Description Engineer: 125 VDC BATTERY CELL CHANGE OUT SHEET Substation/Location: Inspection Date: Date Battery Installed: Manufacturer: Year of Manufacture Rated Ampere Hour: Voltage Rating VDC: Battery Type: Battery Cell Changed (#) Reason for Change Measurements: Ambient Temperature: Battery Room Temp: Humidity: Comments Engineer/Supervisor: BATTERY AND CHARGER INSPECTION SHEET Substation/Location: Inspection Date: Date Battery & Charger Installed: Battery: Battery Manufacturer/Year: Rated Ampere Hour: Voltage Rating VDC: Battery Type: Item No. 1.0 1.1 1.2 1.3 1.4 2.0 2.1 2.2 3.0 3.1 3.2 3.3 3.4 3.5 4.0 4.1 4.2 4.3 4.4 4.5 5.0 5.1 5.2 6.0 6.1 Description/ (Inspection/Checks) Battery Cell (Inspection) Deterioration (Buckling, charring, sedimentation plate growth) Deterioration (Cracked cells, acid attack) Connections/terminals (corrosion, discoloration) Battery jar & covers (leaks) Pilot cell (Measurements) Relative density/specific gravity (if charge is required) Pilot Cell Voltage, Volts Battery Tests Peak Load Test (ability to supply peak load) Steady Load Test (capacity to supply steady load) Impedance Test Electrolyte Level Equalize Batteries Charger Inspection Calibrate Voltmeter Calibrate Ammeter Clean Charger (dust, contamination) Contacts, timers, relays (burning, heating, deterioration) Calibration (under-voltage/over-voltage alarms) Meter Readings DC Voltage, VDC (deviation from normal range) Amp Readings, A (deviation from normal range) Environment: Battery Room Temperature (20 - 25Deg C) Engineer/Supervisor: Observations/ Readings Charger: Charger Manufacturer/Year: Charger Type: Ambient Temperature, Deg. C Corrections Carried Out Descriptions Date APPENDIX 6.2 TEST SHEETS TURNS RATIO TEST (TTR) Substation: Date: Transformer S.N.: Manufacturer: Year of Manufacturer: Voltage Rating HV/LV: Humidity Ambient Temperature kV Tap Changer Manufacturer Year of manufacture Serial No. Type No. of Operations Item No. Connections Ratio Tap Positions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Voltage Design Ratio 1 1.1 1.2 1.3 1.4 1.5 2 2.1 2.2 2.3 2.4 2.5 Star - Delta (Ynd-1) Phase A (H1-Ho:X1-X2) Phase B (H2-Ho:X2-X3) Phase C (H3-Ho:X3-X1) Maximum Variation (%) Max Current mA Delta - Star (Dyn1) Phase A (H1-H3:X1-Xo) Phase B (H2-H1:X2-Xo) Phase C(H3-H2:X3-Xo) Maximum Variation (%) Max Current mA Max allowed = 0.5% Notes 1. Perform Null & Unity Ratio checks 2. Check winding polarity 3. Do not change connection until the test set is deenergised Engineer/Supervisor Date: Page 1 12/17/2012 Appendix 6.2 Test Sheets INSULATION RESISTANCE (IR) TEST SHEET Substation/Location: Date: Transformer S.N.: MVA Rating Manufacturer: Voltage Rating HV/LV, kV: Ambient Temperature: Deg C Temperature Correction Humidity: Test Equipment Manufacturer Model Winding Temp, Deg. C Oil Temp, Deg. C Item No. 1 1.1 1.2 1.3 2 2.1 Test Megger - Insulation HV to LV and Ground LV to HV and Ground HV to LV Core Insulation Res. Core ground strap tank ground Polarization Index Absorption Index Test Volts 5 KV 15s 30s 1m 2m 3m Resistance Readings - M Ohms 4m 5m 6m 7m 8m 9m 10m A.I. P.I. 500V P.I. A.I. 10m reading/1m Reading 1m reading/30s Reading Date: Date: Tested by: Approved: WINDING RESISTANCE TEST SHEET Substation: Date: Transformer S.N.: MVA Rating Manufacturer: Voltage Rating HV/LV: Connection Item No. 1 Description Tap Position Tester (Manufacturer/Model Ambient Temp Winding Temp Readings Deg. C Deg. C Dial Position I % Winding Unit Dial Position I % Winding Unit Dial Position I % Winding Unit Ohms Amps Res. Ohms Amps Res. Ohms Amps Res. 2 2.1 2.2 2.3 2.4 2.5 3 3.1 3.2 3.3 3.4 3.5 TM TS TK Wye with Neutral RAY (RAN) (H1-H0/X1-X0) RBY (RBN) (H2-H0/X2-X0) RCY (RCN) (H3-H0/X3-X0) RT =RAN + RBN + RCN RTC = RT * (TS +TK)/(TM + TK) Delta RAD (RAB)(H1-H2/X1-X2) RBD (RBC)(H2-H3/X2-X3) RCD (RCA)(H3-H1/X3-X1) RT = 3/2*(RAB + RBC + RCA) RTC = RT * (TS +TK)/(TM + TK) Measured temperature Reference temperature (Temp rise + 30 deg. C.) 234.5 (for Cu) Tested by: Approved Date: Date: EXCITATION CURRENT TEST SHEET Substation: Date: Transformer S.N.: MVA Rating Manufacturer: Voltage Rating HV/LV: Tester: Ambient Temperature: Temperature Correction Factor: Humidity: Item No. Test Volts 1 1.1 1.1.1 1.1.2 1.1.3 Excitation Current Test Method I Phase A Phase B Phase C Readings Amps Deviation (%) Remarks Excitation Current Test Method I Test Voltage = 10% phase voltage (lower voltages may be used). Engineer: 125 VDC BATTERY TEST SHEET Substation/Location: Inspection Date: Date Battery Installed: Manufacturer: Year of Manufacture Rated Ampere Hour: Voltage Rating VDC: Battery Type: Cell # Prior to load test Relativ e density Cell Volts Voltage readings load test 30 min 60 min 90 min Cell # Measurements: Ambient Temperature: Battery Room Temp: Humidity: Before Load Test Voltage readings load test Relativ e density Cell Volts 30 min 60 min 90 min 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Engineer: VACUUM BREAKER TEST SHEET Substation: Date: Circuit Breaker S.N. Voltage/Current Rating, kV/kA Manufacturer: BIL, KV Description Micro-ohm Testing Bushing to Bushing Phase A, μΩ Bushing to Bushing Phase B, μΩ Bushing to Bushing Phase C, μΩ Time/Travel Test Opening Time, ms Opening Spread, ms Closing Time, ms Closing Spread, ms Close/Trip Time, ms Dielectric Test: Phase A - Phase B, μA Phase A - Phase C, μA Phase B - Phase C, μA Phases (A, B, C) to Ground, μA Vacuum Integrity Charging Spring: Spring Charging Time, s Charging Motor Current, Amps Function Tests Seal-In Anti-Slam Anti-Pump Tested By: Approved By: Test Equip (Manufacturer/Model) Ohm Meter Dielectric Test Set Ambient Temperature, Deg C Humidity, % Test Results Comments Date: Date: APPENDIX 6.3 HIGH VOLTAGE ELECTRICITY SYSTEM SAFETY RULES HIGH VOLTAGE ELECTRICITY SYSTEM SAFETY RULES 1. INTRODUCTION These Safety Rules shall be read in conjunction with the Occupational Health and Safety Administration Manual. These Safety Rules state the basic safety requirements for work on the Cement Company 24kV and 3.3kV Distribution System. These rules are designed to: Ensure the works are carried out to recognized industry standards Provide maximum protection to persons working on plant or equipment. Provide a guide to safe working on or within the vicinity of high voltage electrical systems. Provide Controls and responsibilities for individuals operating on or working in the vicinity of high voltage plant and equipment. It is the responsibility of individuals to be familiar with respect to these rules before operating on the distribution system. The Person-in-Charge of the works shall be a Competent Person. 2. BASIC REQUIREMENTS No person shall: Enter a substation without a Permit-to-Work. Interfere with any item of electrical equipment without first having been given instructions to do so by the Authorized Engineer. Commence work until they fully understand their instructions and are conversant with the nature and extent of the work to be carried out. Instructions shall not be exceeded. Enter a confined space until instructed to do so by the Authorized Engineer following a job specific Risk Assessment, after all necessary safety precautions have been taken. 3. GENERAL PROVISIONS These rules apply to the Cement Company 24/3.3kV: All High Voltage substation, plant and equipment. All High Voltage distribution cables. All Low Voltage equipment under the control of Estates Services. 4. INFORMATION, INSTRUCTION AND TRAINING Arrangements shall be made by the CCC to ensure that all persons with access to the above equipment are adequately informed of: Risks to their Health and Safety Preventive and protective measures to be taken Procedure in the event of serious or imminent danger The risks arising from other activities in the workplace Those with access to operate equipment are aware of the consequences of operations carried out. Other people who may be exposed to danger by the operations or works receive adequate information and where necessary instruction. The capabilities of persons are taken into account in allocating tasks. Persons are provided with adequate Health and Safety training and re-training. 5. ISSUE OF SAFETY RULES A copy of these rules shall be issued as determined by the Document Owner. Each copy issued will carry the signature of the holder. The recipient shall be responsible for keeping them to hand for reference as necessary when work is being carried out under these rules. 6. VARIATION OF SAFETY RULES In special circumstances these safety rules may be varied to such an extent as is necessary and approved by the Document Owner. Approval may be given only if safety requirements are satisfied in another way. These variations must be documented and held as a permanent record. 7. OBJECTIONS ON SAFETY GROUNDS When any person has concerns regarding the operation of or work upon the system, they shall refer them to the person issuing instructions or to a higher authority. The matter shall be investigated, and reviewed before proceeding. 8. TREATMENT FOR ELECTRIC SHOCK All persons who may be in charge of or control of any operation or work on the system shall be trained and conversant with the treatment for electric shock. 9. 9.1 9.2 9.3 DEFINITIONS A CAUTION NOTICE is a notice conveying a warning against interference. CIRCUIT MAIN EARTH means the earthing equipment applied before the issue of, and at a position recorded in a Safety Document. DANGER means a risk to health or of bodily injury. Page 43 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 DANGER NOTICE is a notice reading 'DANGER', warning of electrical or physical danger. DEAD means an electrical potential at or about zero voltage and disconnected from any Live System. DOCUMENT OWNER is the person appointed to be responsible for the application of these safety rules. EARTH means the conductive mass of the earth. EARTHED means that the system or equipment being worked upon is connected to EARTH through switchgear or by adequately rated earth leads. ISOLATED means disconnected from associated plant, equipment and conductors by an isolating device in the isolating position, or by adequate physical separation, or sufficient gap. LIVE means electrically charged. A COMPETENT PERSON is a person recognized as having sufficient technical knowledge and/or experience to enable him/her to avoid danger and who may be nominated to receive and clear specified An AUTHORISED PERSON is a Competent Person, over the age of 18 years, who has been appointed in writing by the Senior Authorized Person. An Authorized Person is authorized to carry out specified duties, which may include, subject to the permission of the Control Engineer, the issuing and cancelling of Safety Documents. A SENIOR AUTHORISED PERSON is an Authorized Person who has been appointed in writing to carry out specified duties, including the issue and cancellation of Safety Documents. The Senior Authorized Person is also responsible for the day-to-day management of Authorized Persons. A CONTROL ENGINEER is an Authorized Person or a Senior Authorized Person specifically nominated in writing by an Authorized Person or a Senior Authorized Person to exercise the function of control of the system. LIMITATION-OF-ACCESS - Instructions which define the limitations and nature of work, which may be carried out when verbal instructions are not considered sufficient for that purpose, and where a Permit-to-Work or Permit-to-Test is not applicable. PERMIT-TO-WORK A permit to work specifies the high voltage equipment which has been made safe to work on, the safety precautions applied to ensure continued safety and the work which is to be carried out. PERMIT-TO-TEST specifies the high voltage equipment which has been made safe for testing to proceed and the conditions under which the testing is to be carried out. A SAFETY LOCK is a lock that has a unique key, being different from all other standard locks used on the system. IMMEDIATE SUPERVISION means supervision by a person, having adequate technical knowledge or experience, who is continuously available at the location where work or testing is in progress. PERSONAL SUPERVISION means supervision by a person, having adequate technical knowledge or experience, who is at all times in the presence of the person being supervised. Page 44 9.12 9.13 9.14 9.15 9.16 9.17 9.18 9.19 9.20 9.21 SWITCHING - Switching is the operation of circuit breakers, isolators, fuses or other methods of making or breaking an electrical circuit and/or the application and removal of Circuit Main Earths. LOW VOLTAGE (LV) is a voltage not exceeding 1000 volts HIGH VOLTAGE (HV) is a voltage exceeding 1000 volts HAZARDOUS ENERGY: Electrical, mechanical, hydraulic, pneumatic, vacuum, Flywheels, springs, elevated parts that could fall, capacitors, batteries, or other energy present in or capable of being emitted from circuit or equipment. SANCTION FOR TEST: A form of declaration signed and given by an Authorized Person to a competent person in charge of functional testing or performing test on distribution equipment or apparatus for the purpose of making known to such person exactly what equipment/apparatus is to be functional tested. GENERAL PRECAUTIONS General Safety (a) In addition to the requirements specified in these Safety Rules the safety of all persons at work shall be achieved by maintaining general in the vicinity of the work place. (b) The Competent Person must ensure that arrangements are maintained to ensure that other work areas are not adversely affected by the activities for which he is responsible. 9.22 9.23 9.23 9.24 10. 10.1 10.2 Access to and Work in Substations (a) Only Competent Persons, Authorized Person and Senior Authorized Persons have authority to access substations. (b) Persons not classified as above may gain access or work on the system provided they are under the supervision of, at minimum, a Competent Person. (c) Access doors and gates shall normally be kept lock. Keys are to be issued only by an Authorized Person. 10.3 Access to High Voltage Equipment and Conductors. (a) Barriers, doors, or gates preventing access to live equipment shall be kept locked. (b) Keys shall be accessible only to Authorized Persons. 11. 11.1 HIGH VOLTAGE SWITCHING High voltage switching shall be carried out only by an Authorized Persons or a Competent Person under the personal supervision of an Authorized Person. Switching shall be carried out only with the authority of the System Control Engineer. It is forbidden to undertake switching operations by signal or prearranged understanding after an agreed time interval. Any concerns over switching, or where switchgear shows signs of distress, must be communicated to the Control Engineer who will investigate before continuing. Page 45 11.2 11.3 12. RECORDS Verbal instructions shall be recorded and repeated back to the sender, to ensure that it has been accurately received. The Authorized Person actually carrying out switching shall ensure a record is made of the time and particulars of any switching. USE OF VOLTAGE TESTING DEVICES Where voltage testing devices are used, they shall be tested immediately before and after use as a check on functionality. 13. 14. 14.1 SAFETY PRECAUTIONS FOR WORK ON OR NEAR HIGH VOLTAGE SYSTEMS General Requirements Safe access to live conductors can only be achieved after the following steps have been completed. The section of the system to which access is required must be:(a) Dead (b) Isolated, and all practical steps taken to lock off from all points of supply, including voltage transformers, auxiliary transformers, common neutral earthing equipment and other sources of supply from which the section of the system can be made LIVE. (c) Caution Notices must be fixed at all points of isolation. (d) Earthed at all points of disconnection of HIGH VOLTAGE supply. (e) Screened where necessary to prevent DANGER from other LIVE parts of the system. (f) Danger Notices to be attached to adjacent live equipment. (g) Identified at the point of work. (i) Released for work by issue of appropriate Safety Document which shall not be issued unless the recipient is fully conversant with the part of the system to be worked on and the nature and extent of the work to be done. (j) Where the design of equipment inhibits compliance with the above steps, the work will be carried out under instruction of the Senior Authorized Person after agreement with the Control Engineer. The instructions shall be documented in writing and signed by the Senior Authorized Person. Page 46 14.2. Isolation of Equipment and Conductors (a) Isolation and re-connection can only be completed with the authority of the Control Engineer. (b) Safety Locks shall be used to lock open all switchgear at points of isolation. (c) Keys shall be kept in a key safe or in the possession of the Senior Authorized Person. (d) Fuses, links (and carriers) that control circuit to be worked on shall be removed and kept in the custody of the person issuing the Safety Document. (e) Caution Notices shall be fixed at all points of isolation. 14.3. Earthing (a) Where practical, earthing shall be provided by use of a circuit breaker or earthing switch. (b) The trip feature shall normally be rendered inoperative before closing. This renders the switch inoperative whilst it remains a Circuit Main Earth. (c) After closing, the breaker or switch shall be locked in the EARTH position. (d) Circuit Main Earths can only be applied or removed with the authority of the Control Engineer who shall record the time of application and removal. (e) Circuit Main Earths shall be recorded on the Safety Documentation. 14.4 Permit-to-Work 14.4.1 Authority to issue (a) Before any work can commence on the high voltage systems a Permit-to-Work must be issued. (b) A Permit-to-Work can only be issued by a Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. 14.4.2 Procedure for Issue and Receipt (a) A Permit-to-Work can only be received by a Competent Person who shall retain the permit in their possession. (b) It will be explained by the issuer and the contents read back by the Competent Person who must confirm understanding of the permit, the nature and extent of the work to be done before signing its receipt. (c) Where there is more than one working party, each working party must have a separate permit. The Permits-to-Work should be cross-referenced. 14.4.3 Procedure for Clearance and Cancellation (a) The recipient shall sign the permit to clear it and hand to a Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. Indicating that the work is 'complete' or 'incomplete' and that all gear and tools 'have' or 'have not' been removed. Page 47 (b) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall cancel it and inform the Control Engineer. (c) Circuit Main Earths shall be removed only when all Permits-to-Work associated with the earths have been cancelled. 14.5 Permit-to-Test 14.5.1 Authority to issue (a) Before any testing can commence on the high voltage system, a Permit-to-Test must be issued. (b) A Permit-to-Test can only be issued by a Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. 14.5.2 Procedure for Issue and Receipt (a) A Permit-to-Test can only be received by an Authorized Person who shall retain the Permit-to-Test in their possession at all times during testing. (b) It will be explained and the Authorized Person, who after reading the contents back to the issuer, must confirm understanding of the PERM1T-TO- TEST, the nature and extent of the testing to be carried out before signing its receipt. 14.5.3 Procedure for Clearance and Cancellation (a) The recipient shall sign the document to clear it and hand to a Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. Indicting that testing is 'complete' or 'incomplete', all equipment 'has' or 'has not' been removed and the operational state of the equipment. (b) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall cancel it and inform the Control Engineer. 14.6. Limitation-Of-Access 14.6.1 General (a) A LIMITATION-OF-ACCESS shall be issued when it is considered necessary to have written instruction to avoid danger and other Safety Documentation is not applicable. (b) Authority to issue - Only a Senior Authorized Person or an Authorized Person with specific authority to do so may issue a LIMITATION-OF-ACCESS. 14.6.2 Procedure for Issue and Receipt (a) A LIMITATION-OF-ACCESS shall be explained and issued to the PERSON in direct charge of the work, who after reading the contents to the person issuing it and confirming that he understands it and is conversant with the nature and extent of the work to be done shall sign the receipt. (b) The recipient shall retain the limitation in their possession at all times when work is being carried out. Page 48 14.6.3 Procedure for Clearance and Cancellation (a) The recipient shall sign the LIMITATION-OF-ACCESS to clear it and hand to a Senior Authorized Person, or Authorized Person. (b) The Senior Authorized Person, or Authorized Person, with specific authority to do so, shall cancel it. 15. 15.1 PROCEDURES FOR WORK ON PARTICULAR ITEMS OF PLANT, EQUIPMENT AND CONDUCTORS General Requirements (a) All high voltage equipment within the zone of work are connected to Circuit Main Earths at the time when the specified equipment is released for work or testing by the issue of a Safety Document. (b) In these circumstances the recipient of the Safety Document may, in the course of work or testing, disconnect from the Circuit Main Earths as required any equipment within the zone of work. (c) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall, at the time of issue of the Safety Document, demonstrate to the recipient that the equipment and/or conductor are dead. (d) The equipment and conductors shall be re-connected to the Circuit Main Earths before the Safety Document is cleared. (e) Precautions shall be taken to prevent danger from potential differences arising from remote earth points by bonding and earthing at a point as near as possible to the point of work. Work on Ring Main Equipment when an LV system back feed is available (a) When work is to be carried out on HIGH VOLTAGE contacts or connections of Ring Main Equipment where there is a known or potential back feed to the substation, the Low Voltage switch or links shall be isolated, screened and a CAUTION NOTICE applied. (b) Where facilities exist to lock open switches or secure LV control panels a safety lock shall be applied. (c) The remote ends of all High Voltage in-feeds must be Isolated, Safety Locked, Caution Notices applied and Earthed. (d) A Permit-to-Work must be issued for work on the Ring Main Equipment. 15.3. With-Drawable Equipment (a) All spout shutters not required to be opened for immediate work or operation shall be locked shut, if not otherwise made inaccessible. (b) Withdrawn equipment shall be discharged to earth, but need not remain connected to earth. (c) Work on withdrawn equipment that remains within the immediate area shall be completed under a Limitation-of-Access. 15.2 Page 49 15.4 Busbar Spouts, Busbars and Busbar connections of Multi-panel Switchboards When work is carried out on the above, isolation shall be carried out as follows (a) The section on which work is to be carried out shall be ISOLATED from all points from which it can be made LIVE. (b) Isolation arrangements shall be locked. (c) Where practicable, the shutters of LIVE spouts shall be locked shut. (d) Caution Notices shall be attached, at all points where the busbar can be made LIVE. (e) Danger Notices shall be attached on adjacent LIVE equipment. (f) EARTHING - Where practicable, the section of busbar will be verified as not LIVE by use of a testing device, typically on the panel where the Circuit Main Earth is to be applied. (g) The Circuit Main Earth is to be applied at a panel other than that at which work is to take place, on the ISOLATED section of busbars. (h) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall satisfy himself that the recipient of the Permit-to-Work is aware of the location of adjacent live circuits before issuing the permit. (i) Work on busbar spouts will be carried out under the PERSONAL SUPERVISION of the Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. This will include: Identifying spout to be worked on, Provide access by removing shutter locks and Proving spout is not live using a voltage testing device. (j) Work on busbars or busbar connections shall be completed as follows: (k) Access shall be identified by the Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. (l) Access shall be made by the removal of appropriate cover plates under the PERSONAL SUPERVISION of the Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, where practicable each busbar or connection should be proved not LIVE by the use of a voltage testing device. (m) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall remain on site until he is satisfied that no further access is required to complete the work. 15.5 Feeder Spouts and Connections, Voltage Transformer Spouts and Connections and Single Panel Busbar Spouts and connections Isolation shall be carried out as follows: (b) The spouts or connections on which work is to be carried out shall be ISOLATED from all points from which it can be made LIVE. (c) Isolation arrangements shall be locked. Page 50 (d) The shutters of LIVE spouts shall be locked shut. (e) Caution Notices shall be attached, at all points where the circuit can be made LIVE. (f) Danger Notices shall be attached where applicable on adjacent LIVE equipment. (g) Earthing - Where practicable, the spout contacts or connections shall be verified as not LIVE by use of a voltage testing device, typically on the panel where the Circuit Main Earth is to be applied. (h) The circuit shall be EARTHED at the point of work and, where reasonably practicable, at all points of isolation. (i) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall satisfy himself that the recipient of the Permit-to-Work is aware of the location of adjacent live circuits before issuing the permit. (j) Work on the feeder, voltage transformer or busbar spouts on a single panel unit will be carried out under the personal supervision of the Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. (k) This will include: Identifying spout to be worked on, Provide access by removing shutter locks, (l) Where necessary the Circuit Main Earth may be removed to provide access and (m) Prove each spout is NOT LIVE using a voltage-testing device. (n) No other work shall be carried out on the circuit whilst earths are disconnected. (o) Work on feeder or voltage transformer connections and single panel busbar or connections shall be completed as follows: (p) Access shall be identified by the Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. (q) Access shall be made by the removal of appropriate cover plates under the PERSONAL SUPERVISION of the Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer. (r) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall remain on site until he is satisfied that no further access is required to complete the work. (s) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall take appropriate action to prove that each connection or busbar in the work area is NOT LIVE by using a voltage testing device 15.6. Transformers (a) When work is to be carried out on the connections to, or the windings of, a transformer, the switchgear or fuse gear controlling all windings shall be opened. (b) Additionally, to prevent the possibility of the transformer being made LIVE by back-feed, all LOW VOLTAGE fuses or links on associated voltage or auxiliary transformers shall Page 51 be withdrawn and, where practicable, the voltage and auxiliary transformers shall be ISOLATED. (c) When work is to be carried out on a High Voltage or Low Voltage transformer and the Low Voltage windings of the transformer are controlled by a switch or isolator, the switch or isolator shall be secured open. In other cases, arrangements shall be made to ensure that the Low Voltage windings are ISOLATED from all sources of Low Voltage supply. (d) The transformer shall be ISOLATED from all common neutral earthing equipment from which it may become LIVE. (e) Caution Notices shall be attached at all points of isolation, including those of Low Voltage. (f) The transformer shall be EARTHED at all points of isolation from High Voltage supply. (g) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall identify the transformer to be worked on at the point of work before issuing Safety Documentation. 15.7. High Voltage Cables (a) Conductors must be Dead, Isolated and Earthed before the insulation can be interfered with. (b) The Senior Authorized Person, or an Authorized Person with the permission of the Control Engineer, shall identify and spike the cable at the point of work. Spiking may be omitted if the cable is visible along its entire length from the point of work back to an earthed switch. (c) The Control Engineer will be informed before and after any cable is spiked. (d) Precautions shall be taken to prevent Danger from induced or sheath voltage. 16. SAFETY PRECAUTIONS FOR TESTING OF HIGH VOLTAGE EQUIPMENT Testing under a Permit to Test Equipment cannot be connected to the System until it has passed the appropriate test. (a) Connection can only be made with the sanction of the Control Engineer. (b) The recipient of the Permit-to-Test shall: Be responsible for coordinating the all testing, Ensure that the equipment, test leads and test equipment are suitably protected to prevent Danger, Ensure that 'Danger High Voltage Testing' notices are suitably displayed and discharge all cables and capacitors before and after the application of test voltages. (c) The recipient has the authority to: Remove and replace earths to complete testing without the further reference to the Control Engineer. Make LIVE from a testing supply. Page 52 Where practical, Circuit Main Earths shall be replaced before the Permit-to-Test is cancelled. 17. 17.1. RESPONSIBILITIES OF PERSONS General All persons concerned with work on or in the vicinity of equipment or plant to which these safety rules apply have a duty to comply with these rules. 17.2. Competent Persons - may: (a) Be nominated to be responsible for a working party. (b) Receive and retain a Permit-to-Work or Limitation-of-Access confirming they are fully conversant with the nature and extent of the work to be carried out. (c) Provide immediate or Personal Supervision as required. (d) Implement all necessary measures to establish general safety. (e) Give authority for work under the safety document they hold. (f) Clear Safety Documentation, ensuring that all persons are aware that the safety document has been withdrawn and all tools and equipment removed. 17.3. An Authorized Person may in addition to the responsibilities of a Competent Person: (a) Be authorized for Switching on the System. (b) Be authorized to receive a Permit-to-Test. (c) Be authorized to issue and cancel a Limitation-of-Access. (d) Be authorized to issue and cancel a Permit-to-Work with the permission of the Control Engineer. 17.4. Senior Authorized Person may in addition to the responsibilities of an Authorized Person; (a) Issue and cancel a Permit-to-Work or Permit-to-Test. Ensuring that the recipient fully understands the nature and extent of the work or testing to be done. (b) Provide immediate or Personal Supervision on work specified as requiring a Senior Authorized Person, (c) Take on the responsibilities of a Control Engineer for specified sections of a system. 17.5. Control Engineer has responsibility for and authority to: (a) Release equipment or plant from service. (b) Give authority for all High Voltage Switching. (c) Give authority for the issue of and acknowledge cancellation of Safety Documentation. (d) Maintain a written record of all operations and the issue and cancellation of Safety Documents on the system. Page 53 18. 18.1. THE KEY SAFETY RULES Switching Employees/Contractors must always verify isolation/blocking points and test a circuit and/or equipment to be sure if it is de-energized. Contractors must never perform an un-authorized operation of a circuit or a piece of equipment. Confined Space Work Employees/Contractors entering confined workspaces are responsible for knowing the potential hazards associated with these spaces and for complying fully with the company’s safe work procedures for confined spaces. 18.2. 18.3. 18.4. Fall Protection: Employees must utilize fall protection in situations that require it. Grounding: Employees/Contractors must verify that any circuit requiring grounding is properly grounded before commencing work and work outside the minimum approach distance of an exposed energized circuit or parts of equipment unless properly protected. 18.5. Personal Protective Equipment Employees/Contractors are responsible for knowing the potential hazards associated with the work they are performing, for selecting and using appropriate personal protective equipment (PPE) for this work, and for otherwise complying with the company’s procedures for the use and care of personal protective equipment. 18.6. Shoring and Trench Wall ProtectionEmployees/Contractors must exercise care and take appropriate precautions when entering trenches or excavated areas. They must also ensure that such areas have proper shoring and safe way out before entering. Page 54 REFERENCES 1. These Safety Rules are based on the High Voltage Electricity System Safety Rules and Associated Safety Guidance for Loughborough University Estates Services Health and Safety Policy National Electrical Code, 1990 Electric Safety Manual, by John Cadick, Mary Capelli-Schellpfeffer, Dennis Neitzel Occupational Safety and Health Administration (OSHA) JPS Safety Manual 2. 3. 4. 5. APPENDIX Extract From OSHA (Pages 386 -387) – Section (u) Substations Page 55