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Introduction to Testing and Commissioning of Power System
Chapter 3
Introduction to Testing and Commissioning of Power System 3.1 INTRODUCTION The term “commissioning” refers to a start-up test of the electrical equipment that is undertaken before the initial energization of the equipment.
3.1.1 Precommissioning Procedures Before commencing a commissioning test, some steps must first be undertaken: G G
G
G
Approved design drawing should be on site ready to start the work. Review all wires in the marshaling kiosk, control panels, protection panels, and low voltage switch boards. After review these wires should be highlighted by yellow marker in the schematic drawings. During the wiring review, the tightness of all terminal blocks needs to be confirmed. Low voltage panel bolts tightness torque needs to be reviewed, usually tested at 70 Nm. A panel wires review should be undertaken at local control cubicles (LCC) and in protection panels in the control room. The review should also include transformer boxes, low voltage motor control center, and similar items.
3.1.2 Commissioning Management A commissioning team consists of the commissioning manager and commissioning engineers. The responsibilities of the commissioning manager responsibility are: 1. 2. 3. 4.
Producing the commissioning program. Follow up of the commissioning team. Coordinate with other stakeholders on the project regarding commissioning. Ensure that the project has the required resources to perform the different tests required and all material, facilities, tools are on site.
Practical Power System and Protective Relays Commissioning. DOI: https://doi.org/10.1016/B978-0-12-816858-5.00003-4 © 2019 Elsevier Inc. All rights reserved.
23
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Practical Power System and Protective Relays Commissioning
5. Producing the switching program and coordinate with national control center (NCC) local/state/federal electrical supply company (also called the National Control Center, NCC) during energization. 6. Producing the commissioning file which includes all method statements, single line diagram, site instructions, deviation list and base design comments, various tests, switching program, relay setting calculations, equipments data sheet and specifications, relay manual, relay testing software, and any other required items. 7. Attend commissioning panel meetings on site with other project members. 8. Produce a contingency plan for an emergency should the required circuits be switched off and the situation requires restoration of the operation of one or more circuit during commissioning of existing circuits modification. The responsibilities of the commissioning engineers and technicians are: 1. Confirm all equipment is installed in the correct manner. 2. Confirm all equipment and test tools are on site to start activities as per commissioning program (all with valid calibration certificate for at least one year). 3. Insulation resistance and wiring check for all equipment and panels at site. 4. Safe working environment at site. 5. Confirm that the approved relay setting and approved schematic drawings are at site (last revision). 6. Follow commissioning program steps. 7. Ensure there is a reliable power source without fluctuation at site to perform the testing in reliable manner; the use of nonstable equipment leads to errors in test results. 8. Factory test results, approved test procedures and test sheets should be checked by the commissioning engineer on site. 9. The base and detailed design comments should be checked by the commissioning engineer on site. 10. Produce a punch list (also known as a snags list) that includes the items not completed in any equipment test in the electrical system. 11. Produce a marked up drawing on site. 12. Produce the final commissioning test report.
3.2 POWER TRANSFORMER COMMISSIONING 3.2.1 Visual Check A visual check of all equipment must be undertaken. These checks should including checking of tightness of all bolts by torque wrench tool, nameplate information, all pipe connections, earthing points, tap changers, and fans.
Introduction to Testing and Commissioning of Power System Chapter | 3
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3.2.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4. 5. 6. 7. 8.
Core insulation resistance. Winding insulation resistance. Winding resistance at all taps. Tan δ of the transformer bushing test. Polarity and vector group tests. Turns ratio test. Tap changer local and remote operation test. Fan groups 1 and fan group 2 (Each transformer has a two groups of fans for cooling) running test for rotation and operation test. 9. Bushing current transformer tests. 10. Oil sample breakdown high voltage test. These tests are explained in detail in the following chapters.
3.3 SURGE ARRESTOR TEST Visual checks should include the nameplate, all connections, earthing and all related items as per instruction manual.
3.3.1 Visual Checks Visual checks for nameplate, connections, earthing and all related items as per instruction manual.
3.3.2 Electrical Tests An electrical test can include any of the following: 1. Insulation resistance test. 2. Tan δ test. 3. Leakage current measurement.
3.4 CURRENT TRANSFORMER COMMISSIONING TESTS 3.4.1 Visual Checks Check visually for any damage or craking or oil leakage in the CT.
3.4.2 Commissioning Electrical Tests An electrical test can include any of the following: 1. Insulation resistance test. 2. Winding resistance test.
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Practical Power System and Protective Relays Commissioning
3. 4. 5. 6. 7.
Polarity test. Ratio test by primary injection. Magnetizing current test. Loop resistance burden test. Continuity of secondary circuits. Terminations, shorting links by primary and secondary injection test. 8. High voltage test, which is done during the air insulated substation or gas insulated substation (GIS) high voltage test at the final stages of commissioning tests, but with disconnecting the current transformer (CT) connections to the relays and shorting the CT secondaries during the high voltage test. 9. Demagnetizing the CT cores by connecting the secondaries of the CTs to the ground at the end of all tests. Refer to Chapter 10, Current Transformers, for further details.
3.5 VOLTAGE TRANSFORMER COMMISSIONING TESTS 3.5.1 Visual Checks Check visually for any damage or craking or oil leakage in the VT.
3.5.2 Electrical Commissioning Tests An electrical test can include any of the following: 1. 2. 3. 4. 5.
Winding resistance test. Insulation resistance test. Ratio test. Polarity test. Miniature circuit breakers (MCBs) trips check by secondary injection in voltage transfer secondary circuits. 6. Phasing test. 7. Loop resistance burden test. 8. Tan δ test.
3.6 GAS INSULATED SWITCHGEAR COMMISSIONING TEST 3.6.1 Visual Check and Mechanical Tests Checks should include the nameplate information for all components [e.g., circuit breaker (CB), earthing switch (ES), disconnect switch (DS), voltage transformer (VT), current transformer (CT)], enclosure earthing, gas handling unit, mechanical interlocks, and a dew point test for each gas compartment at rated gas pressure of each compartment.
Introduction to Testing and Commissioning of Power System Chapter | 3
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A gas leakage test for all joints by should be undertaken using gas detectors or a plastic bag test around joints. Testing should include the operation of gas density switch alarms and trip signals and lockout functions, and the operation of CBs, DSs, ESs, and LCCs.
3.6.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4. 5.
6.
7. 8. 9.
10.
Insulation resistance test for all wiring and cables. Interlocking circuit test. Busbar joints resistance tests at 100 Amp D.C. Earth resistance at 100 Amp D.C. Function checks of the LCC including bay control unit, interlocking, alarms and interface circuits between the GIS and protection and control circuits. Circuit breaker tests, timing (close and open) DS (close and open) including the special auxiliary contacts of DS used in busbar protection scheme and a CB mechanism check. VT and CT tests. Heater checks in LCC especially in countries with cold weather. High voltage test of GIS components include CBs and DSs, with VT isolated and CT secondary circuited shorted as per international standard for 1 minute. Partial discharge test measurements; refer to Chapter 14, Gas Insulated System Substation.
3.7 HIGH VOLTAGE CABLES COMMISSIONING TESTS 3.7.1 Visual Checks Checks should include assessing the tightness of connections using a torque wrench tool.
3.7.2 Electrical Tests An electrical test can include any of the following: 1. Phasing test. 2. HV test. 3. Insulation resistance test. Refer to Chapter 6, Transmission Lines, for further details.
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Practical Power System and Protective Relays Commissioning
3.8 PROTECTION AND CONTROL PANELS COMMISSIONING TESTS 3.8.1 Visual Check Check that the panels are built as per the as-built approved drawing. Other checks should include the earthing of each panel, and all external cables to station equipment.
3.8.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Auxiliary relays tests. Secondary injection tests. Primary injection tests. Scheme function tests. On-load tests. Tripping tests. Metering panel tests. Alarm and annunciators tests. Fault recorder panel tests. End-to-end test for line differential protection and distance schemes. Stability of 380 V tests of transformer differential protection. Remote taps-charger panel tests. Bus transfer (ATS) system in 11 kV switchgear. Scada signal operational and alarms test from station to master station.
3.9 FINAL ENERGIZATION COMMISSIONING PROCEDURES Before energization these points should be confirmed: 1. Overcurrent commissioning setting is used on bus coupler temporary which will accelerate the relay operation during first time energization and the energization of any circuit will be through the bus coupler of the station. 2. Remove all CT secondary shorting links. 3. All protection relays are working on their final setting. 4. All VT MCBs are closed and no abnormal alarms exist. 5. No engineers or technicians should be in the switchgear area during energization. 6. No earthing exists in the primary circuits. 7. After energizing the new circuit, a phasing test should be done between the circuit VT secondaries and existing reference circuit VT secondaries.
Introduction to Testing and Commissioning of Power System Chapter | 3
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All of this should be carried out before the loading of the new circuit. After loading of the circuit gradually by the NCC the following should be done: 1. Check the values of each current on each phase for protection relays on each protection panel, including the metering panels. 2. Perform directional tests for directional and distance relays with at least 10% 30% of load current depending on whether it is an electromechanical or digital relay.
3.10 AC DISTRIBUTION PANEL COMMISSIONING TESTS 3.10.1 Visual Checks A visual check should include the tightness of bolts of the low voltage AC busbars with torque wrench tool. Also checking the MCB and CB ratings as per drawings and checking of panel earthing (correct cable cross-section).
3.10.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4.
Insulation resistance tests. Phasing check for cables. Calibration of meters and ampere and voltage meters. Checking of auxiliary relays.
3.11 DC DISTRIBUTION PANELS COMMISSIONING TESTS 3.11.1 Visual Check This check should include the MCB ratings and CB ratings as per drawings, the tightness of bolts of busbars with torque wrench tool and checking of panel earthing (correct cable cross-section) for earthing.
3.11.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4.
Insulation resistance of all busbars and internal wiring in the panel. Polarity check. Operation and trip of MCBs. Checking of earth fault relay on this panel.
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Practical Power System and Protective Relays Commissioning
3.12 BATTERY COMMISSIONING TESTS 3.12.1 Visual Check A visual check should assess the tightness of bolts by torque wrench tool, check for any earth on the battery’s positive and negative lines, the safety equipment in battery room, correct electrolyte specific gravity and liquid level, and the position and working status of the isolation switch of the battery bank.
3.12.2 Electrical Tests An electrical test can include any of the following: 1. Checking of each cell’s voltage. 2. Discharge test. 3. Recharge test.
3.13 BATTERY CHARGER COMMISSIONING TESTS 3.13.1 Visual Checks Ensure that there are no any damage or disconnected wires inside the panel.
3.13.2 Electrical Tests An electrical test can include any of the following: 1. Insulation resistance test for external wires. 2. Checking of fast and floating charge operation during battery commissioning tests.
Introduction to Testing and Commissioning of Power System 3.1 INTRODUCTION The term “commissioning” refers to a start-up test of the electrical equipment that is undertaken before the initial energization of the equipment.
3.1.1 Precommissioning Procedures Before commencing a commissioning test, some steps must first be undertaken: G G
G
G
Approved design drawing should be on site ready to start the work. Review all wires in the marshaling kiosk, control panels, protection panels, and low voltage switch boards. After review these wires should be highlighted by yellow marker in the schematic drawings. During the wiring review, the tightness of all terminal blocks needs to be confirmed. Low voltage panel bolts tightness torque needs to be reviewed, usually tested at 70 Nm. A panel wires review should be undertaken at local control cubicles (LCC) and in protection panels in the control room. The review should also include transformer boxes, low voltage motor control center, and similar items.
3.1.2 Commissioning Management A commissioning team consists of the commissioning manager and commissioning engineers. The responsibilities of the commissioning manager responsibility are: 1. 2. 3. 4.
Producing the commissioning program. Follow up of the commissioning team. Coordinate with other stakeholders on the project regarding commissioning. Ensure that the project has the required resources to perform the different tests required and all material, facilities, tools are on site.
Practical Power System and Protective Relays Commissioning. DOI: https://doi.org/10.1016/B978-0-12-816858-5.00003-4 © 2019 Elsevier Inc. All rights reserved.
23
24
Practical Power System and Protective Relays Commissioning
5. Producing the switching program and coordinate with national control center (NCC) local/state/federal electrical supply company (also called the National Control Center, NCC) during energization. 6. Producing the commissioning file which includes all method statements, single line diagram, site instructions, deviation list and base design comments, various tests, switching program, relay setting calculations, equipments data sheet and specifications, relay manual, relay testing software, and any other required items. 7. Attend commissioning panel meetings on site with other project members. 8. Produce a contingency plan for an emergency should the required circuits be switched off and the situation requires restoration of the operation of one or more circuit during commissioning of existing circuits modification. The responsibilities of the commissioning engineers and technicians are: 1. Confirm all equipment is installed in the correct manner. 2. Confirm all equipment and test tools are on site to start activities as per commissioning program (all with valid calibration certificate for at least one year). 3. Insulation resistance and wiring check for all equipment and panels at site. 4. Safe working environment at site. 5. Confirm that the approved relay setting and approved schematic drawings are at site (last revision). 6. Follow commissioning program steps. 7. Ensure there is a reliable power source without fluctuation at site to perform the testing in reliable manner; the use of nonstable equipment leads to errors in test results. 8. Factory test results, approved test procedures and test sheets should be checked by the commissioning engineer on site. 9. The base and detailed design comments should be checked by the commissioning engineer on site. 10. Produce a punch list (also known as a snags list) that includes the items not completed in any equipment test in the electrical system. 11. Produce a marked up drawing on site. 12. Produce the final commissioning test report.
3.2 POWER TRANSFORMER COMMISSIONING 3.2.1 Visual Check A visual check of all equipment must be undertaken. These checks should including checking of tightness of all bolts by torque wrench tool, nameplate information, all pipe connections, earthing points, tap changers, and fans.
Introduction to Testing and Commissioning of Power System Chapter | 3
25
3.2.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4. 5. 6. 7. 8.
Core insulation resistance. Winding insulation resistance. Winding resistance at all taps. Tan δ of the transformer bushing test. Polarity and vector group tests. Turns ratio test. Tap changer local and remote operation test. Fan groups 1 and fan group 2 (Each transformer has a two groups of fans for cooling) running test for rotation and operation test. 9. Bushing current transformer tests. 10. Oil sample breakdown high voltage test. These tests are explained in detail in the following chapters.
3.3 SURGE ARRESTOR TEST Visual checks should include the nameplate, all connections, earthing and all related items as per instruction manual.
3.3.1 Visual Checks Visual checks for nameplate, connections, earthing and all related items as per instruction manual.
3.3.2 Electrical Tests An electrical test can include any of the following: 1. Insulation resistance test. 2. Tan δ test. 3. Leakage current measurement.
3.4 CURRENT TRANSFORMER COMMISSIONING TESTS 3.4.1 Visual Checks Check visually for any damage or craking or oil leakage in the CT.
3.4.2 Commissioning Electrical Tests An electrical test can include any of the following: 1. Insulation resistance test. 2. Winding resistance test.
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Practical Power System and Protective Relays Commissioning
3. 4. 5. 6. 7.
Polarity test. Ratio test by primary injection. Magnetizing current test. Loop resistance burden test. Continuity of secondary circuits. Terminations, shorting links by primary and secondary injection test. 8. High voltage test, which is done during the air insulated substation or gas insulated substation (GIS) high voltage test at the final stages of commissioning tests, but with disconnecting the current transformer (CT) connections to the relays and shorting the CT secondaries during the high voltage test. 9. Demagnetizing the CT cores by connecting the secondaries of the CTs to the ground at the end of all tests. Refer to Chapter 10, Current Transformers, for further details.
3.5 VOLTAGE TRANSFORMER COMMISSIONING TESTS 3.5.1 Visual Checks Check visually for any damage or craking or oil leakage in the VT.
3.5.2 Electrical Commissioning Tests An electrical test can include any of the following: 1. 2. 3. 4. 5.
Winding resistance test. Insulation resistance test. Ratio test. Polarity test. Miniature circuit breakers (MCBs) trips check by secondary injection in voltage transfer secondary circuits. 6. Phasing test. 7. Loop resistance burden test. 8. Tan δ test.
3.6 GAS INSULATED SWITCHGEAR COMMISSIONING TEST 3.6.1 Visual Check and Mechanical Tests Checks should include the nameplate information for all components [e.g., circuit breaker (CB), earthing switch (ES), disconnect switch (DS), voltage transformer (VT), current transformer (CT)], enclosure earthing, gas handling unit, mechanical interlocks, and a dew point test for each gas compartment at rated gas pressure of each compartment.
Introduction to Testing and Commissioning of Power System Chapter | 3
27
A gas leakage test for all joints by should be undertaken using gas detectors or a plastic bag test around joints. Testing should include the operation of gas density switch alarms and trip signals and lockout functions, and the operation of CBs, DSs, ESs, and LCCs.
3.6.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4. 5.
6.
7. 8. 9.
10.
Insulation resistance test for all wiring and cables. Interlocking circuit test. Busbar joints resistance tests at 100 Amp D.C. Earth resistance at 100 Amp D.C. Function checks of the LCC including bay control unit, interlocking, alarms and interface circuits between the GIS and protection and control circuits. Circuit breaker tests, timing (close and open) DS (close and open) including the special auxiliary contacts of DS used in busbar protection scheme and a CB mechanism check. VT and CT tests. Heater checks in LCC especially in countries with cold weather. High voltage test of GIS components include CBs and DSs, with VT isolated and CT secondary circuited shorted as per international standard for 1 minute. Partial discharge test measurements; refer to Chapter 14, Gas Insulated System Substation.
3.7 HIGH VOLTAGE CABLES COMMISSIONING TESTS 3.7.1 Visual Checks Checks should include assessing the tightness of connections using a torque wrench tool.
3.7.2 Electrical Tests An electrical test can include any of the following: 1. Phasing test. 2. HV test. 3. Insulation resistance test. Refer to Chapter 6, Transmission Lines, for further details.
28
Practical Power System and Protective Relays Commissioning
3.8 PROTECTION AND CONTROL PANELS COMMISSIONING TESTS 3.8.1 Visual Check Check that the panels are built as per the as-built approved drawing. Other checks should include the earthing of each panel, and all external cables to station equipment.
3.8.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Auxiliary relays tests. Secondary injection tests. Primary injection tests. Scheme function tests. On-load tests. Tripping tests. Metering panel tests. Alarm and annunciators tests. Fault recorder panel tests. End-to-end test for line differential protection and distance schemes. Stability of 380 V tests of transformer differential protection. Remote taps-charger panel tests. Bus transfer (ATS) system in 11 kV switchgear. Scada signal operational and alarms test from station to master station.
3.9 FINAL ENERGIZATION COMMISSIONING PROCEDURES Before energization these points should be confirmed: 1. Overcurrent commissioning setting is used on bus coupler temporary which will accelerate the relay operation during first time energization and the energization of any circuit will be through the bus coupler of the station. 2. Remove all CT secondary shorting links. 3. All protection relays are working on their final setting. 4. All VT MCBs are closed and no abnormal alarms exist. 5. No engineers or technicians should be in the switchgear area during energization. 6. No earthing exists in the primary circuits. 7. After energizing the new circuit, a phasing test should be done between the circuit VT secondaries and existing reference circuit VT secondaries.
Introduction to Testing and Commissioning of Power System Chapter | 3
29
All of this should be carried out before the loading of the new circuit. After loading of the circuit gradually by the NCC the following should be done: 1. Check the values of each current on each phase for protection relays on each protection panel, including the metering panels. 2. Perform directional tests for directional and distance relays with at least 10% 30% of load current depending on whether it is an electromechanical or digital relay.
3.10 AC DISTRIBUTION PANEL COMMISSIONING TESTS 3.10.1 Visual Checks A visual check should include the tightness of bolts of the low voltage AC busbars with torque wrench tool. Also checking the MCB and CB ratings as per drawings and checking of panel earthing (correct cable cross-section).
3.10.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4.
Insulation resistance tests. Phasing check for cables. Calibration of meters and ampere and voltage meters. Checking of auxiliary relays.
3.11 DC DISTRIBUTION PANELS COMMISSIONING TESTS 3.11.1 Visual Check This check should include the MCB ratings and CB ratings as per drawings, the tightness of bolts of busbars with torque wrench tool and checking of panel earthing (correct cable cross-section) for earthing.
3.11.2 Electrical Tests An electrical test can include any of the following: 1. 2. 3. 4.
Insulation resistance of all busbars and internal wiring in the panel. Polarity check. Operation and trip of MCBs. Checking of earth fault relay on this panel.
30
Practical Power System and Protective Relays Commissioning
3.12 BATTERY COMMISSIONING TESTS 3.12.1 Visual Check A visual check should assess the tightness of bolts by torque wrench tool, check for any earth on the battery’s positive and negative lines, the safety equipment in battery room, correct electrolyte specific gravity and liquid level, and the position and working status of the isolation switch of the battery bank.
3.12.2 Electrical Tests An electrical test can include any of the following: 1. Checking of each cell’s voltage. 2. Discharge test. 3. Recharge test.
3.13 BATTERY CHARGER COMMISSIONING TESTS 3.13.1 Visual Checks Ensure that there are no any damage or disconnected wires inside the panel.
3.13.2 Electrical Tests An electrical test can include any of the following: 1. Insulation resistance test for external wires. 2. Checking of fast and floating charge operation during battery commissioning tests.