Contents
1. General provisions
2. Technical measures to prevent the entry of water and air into the transformer
3. Technical measures to prevent the entry of foreign matter into the transformer
4. Technical measures to prevent transformer insulation damage
5. Technical measures to prevent the transformer coil from over-temperature, insulation degradation or burnout
6. Technical measures to prevent over-voltage breakdown accidents
7. Technical measures to prevent insulation deterioration or burnout
6. Technical measures to prevent over-voltage breakdown
7. Technical measures to prevent breakdown under operating voltage
8. Technical measures to prevent false/refusal to operate of protective devices
9. Technical measures to prevent multi-point grounding of the iron core and short-circuit faults
10. Technical measures to prevent casing accidents
11. Technical measures for the prevention of lead wire accidents
12. Technical measures for the prevention of tap changer accidents
13. Technical measures for the prevention of degradation of insulating oil
14. Technical measures for the prevention of short circuit damage to transformers
15. Technical measures for the prevention of fire accidents to transformers
16. Technical measures for the prevention of damage to interconnection sensors
17. Technical measures for the prevention of damage to large transformers and of short circuit damage to transformers
18. 17. Technical measures to prevent damage to large transformers and mutual inductor explosion accidents
1. General rules
(1) In order to improve the reliability of the operation of transformers and mutual inductor equipment (hereinafter referred to as switchgear) of the Guxian hydroelectric power plant, based on the analysis of the accidents and the experience of the regions and departments, the following anti-accident technical measures are put forward, and the personnel of Guxian Hydroelectric Power Plant of all the relevant design, infrastructure, installation, operation, maintenance and testing shall be responsible for the design, infrastructure, installation, operation and testing. Therefore, all relevant design, infrastructure, installation, operation, maintenance and test personnel of the county hydropower plant should be carefully implemented. Each operating unit should also combine the specific conditions and experience of the plant, develop a suitable transformer, transformer equipment to supplement the anti-accident technical measures.
(2) in order to ensure the safe operation of the transformer, transformer, must establish and improve the professional management system, strengthen the technical management of switchgear, each unit should seriously implement and enforce the State Power Corporation issued the "Transformer, Transformer Equipment Management Regulations" and "Transformer, transformer equipment quality supervision and management methods" of the provisions.
(3) Power plant departments at all levels should strengthen the technical training of switchgear installation, operation, overhaul or test personnel, so as to make them familiar with and master the structural performance of the switchgear under their jurisdiction and the technical requirements for installation, operation, overhaul and test.
2, to prevent water and air into the transformer
(1) transformer should be prevented from water and moisture in operation, casing the top of the military cap, the top of the oil storage cabinet, casing elevated sitting and its connecting pipe and other places must be well sealed. If necessary, leakage testing should be carried out, such as insulation has been found to be damp, should take appropriate measures in a timely manner.
(2) the overhaul of the transformer should be developed according to the instructions for vacuum treatment and oil injection, its vacuum vacuum time, oil speed should meet the requirements.
(3) from the oil storage cabinet oil replenishment or charged oil filtration, the oil storage cabinet should first be drained of water, not from the lower part of the transformer into the oil, to prevent moisture. Air or the bottom of the tank impurities into the transformer body.
(4) when the gas relay light gas action signal, should immediately check the gas relay, take gas samples in time to test, in order to determine the gas composition, while taking oil samples for chromatographic analysis in time to identify the cause and exclude.
(5) Should regularly check whether the respirator silicone is normal, to ensure smooth.
(6) Transformer out of service time more than 6 months, before putting into operation again, should be required to carry out the relevant test according to the pre-test procedures.
3. Prevent foreign objects from entering the transformer.
(1) transformer replacement cooler, must use qualified insulating oil repeatedly flushing oil pipeline, cooler, until the flushing oil test qualified and no foreign matter. If more foreign matter is found, it should be further checked and processed.
(2) To prevent the silica gel in the oil purifier device into the transformer. The filter and adsorbent should be checked and replaced periodically.
(5) Enhance regular inspection of the oil flow relay indication is normal. Check whether the oil flow relay baffle plate is damaged off.
4, to prevent transformer insulation damage
(1) maintenance needs to replace the insulation, should be used in line with the manufacturer's requirements, inspection of qualified materials and components, and by drying.
(2) It is strictly prohibited to step on the leads and insulation bracket during the operation and maintenance of the transformer
(3) The insulation of the transformer should be tested regularly.
5, to prevent the transformer coil temperature is too high, insulation deterioration or burn
(1) Transformer overload operation should be in accordance with GB/T15164-94 "oil-immersed power transformer load guidelines" and DL/T572-95 "Power Transformer Operation Regulations".
(2) The hot spot temperature of the transformer in operation shall not exceed the GB/T15164-94 "Oil-immersed Power Transformer Load Guidelines" limits and specific limits.
(3) The air cooler of the transformer is externally flushed with compressed air or water every 1 to 2 years to ensure the cooling effect.
(4) When the transformer is defective or the insulation is abnormal, it shall not run over the specified current, and strengthen the operation monitoring.
(5) regularly check the cooler fan blade should be balanced, regular maintenance to ensure normal operation, vibration, wear and tear of the fan motor should be replaced.
6, to prevent over-voltage breakdown
(1) in the casting of no-load transformer, the neutral point must be reliably grounded
(2) transformer neutral point should be equipped with two and the main grounding network connected to a different location of the grounding lead, and each grounding lead should be in line with the requirements of thermal stability
7, to prevent breakdowns under the working voltage
(1) overhaul replacement of insulating parts or part of the coil and after dry treatment of the transformer should be partial discharge test.
(2) the operation of the transformer oil chromatographic abnormality, suspected equipment discharge failure, partial discharge test.
8, to prevent the protection device error/refusal to act
(1) transformer protection device must be perfect and reliable, prohibit the transformer and transformer high/medium/low-voltage side of the equipment without protection into operation.
(2) The gas relay should be installed and adjusted correctly, regular experiments, to eliminate false activation caused by short-circuiting of the contacts and other factors, such as the installation of rain cover to avoid contact moisture false activation.
(3) The pressure relief valve action signal should be connected to the signal circuit, the winding thermometer and the top oil thermometer action contact should be connected to the signal circuit.
(4) The transformer should be equipped with a fault recorder, the transformer side backup protection should be powered by a different DC power supply, to prevent the loss of DC for any reason, resulting in backup protection all paralyzed for a long time to cut the fault and expand the consequences of the accident.
9. Prevention of core multi-point grounding and short-circuit failure
(1) in the maintenance should be side test core insulation, such as multi-point grounding should be to identify the cause, eliminate the fault.
(2) The insulation of the core bolt should be good, and pay attention to check the iron core screw insulation jacket at both ends of the metal seat cover, to prevent the seat cover is too long to touch the iron core resulting in a short circuit.
(3) coil pressure nail bolts should be tight, to prevent the nut and seat cover loosened down to cause the core short circuit, iron core and iron choke electrostatic shielding leads should be fixed to prevent potential suspension generated discharge.
10. Prevention of casing accidents
(1) regular cleaning of the casing to prevent dirt migration flashover and flashover in heavy rain
(2) regular inspection of the casing oil level is or normal, leakage of oil should be dealt with in a timely manner to prevent the internal moisture and damage.
(3) transformer casing upper oil injection hole bolt pads, should be combined with maintenance inspection and replacement.
11. Prevention of lead accidents
(1) in the overhaul, should check the lead, even ring (ball), wood bracket, glue wood screws, etc. is or have deformation, damage or loose.
(2) In the coil below the horizontal arrangement of the exposed leads, should be wrapped insulation to prevent metal foreign objects touching caused by short circuit.
(3) The cable leads of the transformer casing shall be wrapped with insulating white cloth tape to prevent the bare leads from touching the conduit of the casing and shunt burned leads.
12. Preventing on-load tap-changer accidents
(1) The on-load tap-changer should be connected to the factory instruction manual for maintenance and periodic inspection during operation
(2) The number of times the on-load tap-changer is energized for switching should be mastered, the voltage should be regulated step by step, and the change of voltage and current at the tap-changer should be monitored at the same time, and the adjustment of the voltage and current can only be carried out at the next level of regulation after an interval of one minute or more for every adjustment of a file.
(3) On-load voltage regulator transformer parallel operation, its voltage regulation operation in turn step by step.
13. Prevent degradation of insulating oil
(1) Strengthen oil supervision and management work, regular chromatographic analysis and simplified analysis of insulating oil, to maintain good oil quality.
(2) transformer in the operation of the insulating oil dielectric value exceeds the requirements of the regulations, and affects the insulating properties of the body should be timely to find out the reasons for insulation degradation, and the insulating oil treatment.
14. Prevent transformer short circuit damage accident
(1) Relay protection device action time should be matched with the duration of the transformer short-circuit tolerance test.
(2) Take effective measures to reduce the number of external short-circuit impacts on the transformer, and improve the operating conditions of the transformer.
(3) Strengthen anti-fouling work to prevent the external insulation of the relevant substation equipment from fouling flash
(4) Improve the reliability of the DC power supply to prevent protection refusal due to the loss of DC power supply.
15. Prevent transformer fire accidents
(1) Strengthen the fire prevention of transformers, focusing on preventing the expansion of accidents caused by transformer fires, transformers should be equipped with perfect fire fighting facilities, and strengthen management.
(2) Do a good job in anticipation of transformer fire accidents, strengthen the quality of the casing inspection and operation monitoring, to prevent its operation in the explosion of oil spray caused by the transformer fire.
(3) When drying the transformer on site, should do a good job in advance of the fire release measures to prevent the heating system failure or coil overheating burned.
(4) When welding transformer leads and conducting open flame work around the body, fire prevention measures must be taken in advance.
16, to prevent mutual inductance damage accidents
(1) to prevent mutual inductance damage accidents should be strictly enforced by the State Grid Corporation "to prevent 110 (66) kV ~ 500kV transformer accident measures" (State Grid Biotechnology 2004 641), "110 (66) kV ~ 500kV transformer technical supervision regulations" (State Grid Biotechnology 2005 174) and other relevant provisions, and put forward the following ) and other relevant provisions, and put forward the following key requirements.
(2) Strengthen the whole process of management of transformer equipment from selection, ordering, acceptance to operation, the important transformer should be selected with a longer, good operating experience of the type of transformer and mature manufacturing experience of the manufacturing plant.
(3) Oil-immersed transformers should be selected with metal expander micro-positive pressure structure form, the selected current transformer dynamic thermal stability should meet the installation location of the system short-circuit capacity requirements, pay special attention to the primary winding in series or parallel different performance, capacitive voltage transformer intermediate transformer should not be mounted on the side of the high voltage.
(4) 110k V ~ 500kV transformer in the factory test, should be in accordance with the requirements of the relevant standards and regulations for all factory tests, including high voltage dielectric loss test, partial discharge test, withstand voltage test. Capacitive voltage transformer should require the manufacturer in the factory for 0.8Uln, 1.0Uln, 1.2Uln and 1.5Uln ferromagnetic resonance test (Note: Un refers to the primary phase voltage is the same).
(5) Transformer installation frame should be two places and grounding network reliable connection. Electromagnetic voltage transformer in the handover test and put into operation before, should be 1.5Um / 3 (neutral point effectively grounded system) or 1.9Um / 3 (neutral point is not effectively grounded system) voltage measurement of no-load current, the increment should not be greater than 10% of the factory test value.
(6) Current transformer primary terminals should not be subjected to mechanical force exceeding the permissible value specified by the manufacturer, and its electrical connection should be in good contact to prevent overheating faults, to prevent potential levitation.
(7) The secondary lead terminals of the transformer should have anti-rotation measures to prevent the internal lead from being twisted off by external operation.
(8) The installation of the completed transformer has not been charged for a long time to run (110kv and the following more than half a year; 35kv and the following more than a year), before the commissioning of the precautionary test should be carried out in accordance with the regulations. Accident repair installation of oil-immersed transformers, should ensure that the static time.
(9) overhaul and transformation of the transformer. Oil-immersed transformer overhaul, should strictly implement the "transformer operation and maintenance guidelines" (DL/T727-2000), pay attention to the body of the exposure time shall not exceed the provisions of the back to the installation must be a vacuum injection of oil, in which the insulating oil should be vacuum degassing treatment.
(10) The old type of transformer with diaphragm type and air cushion oil storage cabinet, should be retrofitted with metal expander sealing transformation. On-site sealing transformation should be carried out in good weather. The transformer has not yet been transformed should be in the annual pre-test or outage maintenance, check the top sealing condition, the aging rubber gasket and diaphragm should be replaced. For the diaphragm has water on the transformer, should be its body and insulating oil for the relevant test, the test failed transformer should be withdrawn from operation. Problems with insulation performance of the old transformer, out of operation and no longer be transformed.
(11) The silicone casing and the addition of silicone umbrella skirt of the porcelain sleeve, should always check the silicone surface surface discharge phenomenon, if there is a discharge phenomenon should be dealt with in a timely manner.
(12) Normal inspection of the operator should check the record of the transformer oil level. The operation of the oil seepage of the transformer, should be dealt with according to the situation in a limited period. If necessary, the oil sample analysis, for the water content of the abnormal transformer to strengthen the monitoring or oil treatment.
(13) Oil-immersed transformer serious oil leakage and capacitive voltage transformer capacitor unit oil seepage should immediately stop running. Should be promptly dealt with or replace the confirmed existence of serious defects in the transformer. Suspected defective transformer, should shorten the test cycle for follow-up inspection and analysis to identify the cause.
(14) For fully sealed transformers, gas chromatography analysis of the oil only H2 single exceeds the value of attention, should be tracked and analyzed, pay attention to the rate of gas production, and comprehensive diagnosis. If the gas production rate grows faster, should strengthen the monitoring; such as detection data is stable, it is a non-fault hydrogen exceeds the standard, can be arranged for degassing treatment; when the oil is found to have acetylene is greater than 1x106? L / L, should immediately stop the operation.
(15) The insulating condition of the transformer should be returned to the laboratory to strictly carry out a comprehensive electrical insulation performance test, including partial discharge test. If the operation of the transformer expansion device abnormally long top cover, should be immediately withdrawn from operation. When the transformer abnormal sound should be withdrawn from operation. When the voltage transformer secondary voltage abnormality, should be quick to identify the cause and timely processing.
(16) in the operation mode arrangement and reversing operation should try to avoid the use of the circuit breaker with a capacitor breakers with electromagnetic voltage transformer casting empty bus; when the operation mode can not meet the requirements, should be accident forethought, early development of preventive measures, if necessary, can be installed specifically to eliminate the resonance of such a device.
(17) When the electromagnetic unit is used as a power supply to measure the capacitance and dielectric loss of capacitive voltage transformer capacitor voltage divider C1 and C2, it must be carried out in strict accordance with the manufacturer's instructions.
(18) In order to avoid the expansion of the range of influence in the event of an accident at the bottom of the oil-paper capacitance type current transformer, the secondary winding connected to the differential protection should be located on the L1 side of the primary busbar.
(19) According to the development of the power grid, attention should be paid to check whether the dynamic thermal stability current of the current transformer meets the requirements.
(20) If the short-circuit current of the substation where the transformer is located exceeds the value of dynamic thermal stability current specified in the nameplate of the transformer, the ratio should be changed in time or arranged for replacement.
At least once a year, infrared imaging temperature measurement and other charged monitoring work, and timely discovery of defects in the operation of the transformer.
(21) Strengthen oil quality management. Users can choose the right type of oil according to the operating experience. The new oil arrived at the scene, in the sample test after passing, before being injected into the equipment. The operation of the oil should be strictly enforce the relevant standards. Mixed oil of different oil types should be in accordance with the provisions of GB/T7595-2000.
17. Prevent damage to large transformers and transformer explosion accident measures
(1) start-up variable, the main transformer to increase the partial discharge test items.
(2) Adjust the position of each tap of the on-load voltage regulator tap-changer to verify its correctness when it is first energized.
(3) Avoid commissioning the transformer without any test and inspection after it has experienced an outlet short circuit.
(4) Prevent moisture and air from entering the transformer: the desiccant should be kept dry, and special attention should be paid to removing internal air before commissioning, e.g., the casing elevated seat, the dead zones in the oil piping, and the tops of the coolers should be used several times to remove the residual gas, and the full submersible pump should be started to circulate the oil, so as to allow the residual gas to escape.
(5) to prevent welding slag and copper wire and other debris into the transformer: transformer in the installation should be lifting cover or into the inspection, thoroughly remove debris from the bottom of the box, oil piping, cooler, submersible oil pumps, oil purifier should be thoroughly cleaned before installation and correctly installed.
(6) prevent transformer insulation injury: transformer should be prevented from insulation injury when hanging inspection, in the installation of transformer casing should pay attention to do not make the lead kinking, do not overly force lifting and pulling the lead and make the lead root and winding insulation damage, should tighten the bolts of the clamping pieces, pressure nails, and the bolts of the insulation bracket, to prevent the deformation and damage in the operation of the current impact.
(7) to prevent the winding temperature is too high, insulation deterioration or burned out: transformer cooler failure, the allowable load and time according to the manufacturer's provisions of the operation of the cooling system of the strong oil circulation must have two reliable power supply and can be automatically switched, the signal is complete and reliable.
(8) to prevent breakdown accidents under the operating voltage: 220kV and above when the transformer is put into operation, it is not appropriate to start more than one cooler, but should be started one by one to avoid the occurrence of oil flow charged, the operation of the transformer oil chromatography appeared to be anomalous suspected of having a discharge fault, should be carried out partial discharge test to further determine.
(9) to prevent the protection device error, refused to move: gas protection should be installed and adjusted correctly, the protection of the power supply is reliable, some kind of protection should be deactivated corresponding measures. Transformer outlet or near-area short-circuit should ensure that the switch is correctly tripped to prevent short-circuit time is too long to damage the transformer. Occurred in the export, near-area short-circuit transformer or transportation impulse, according to the specific circumstances of the winding state should be tested and inspected, conditions can be winding deformation measurement, in order to determine the transformer components with or without deformation and damage.
(10) Prevention of core multi-point grounding and short circuit failure: hanging inspection should test the core insulation, such as multi-point grounding should be identified and eliminated, pay attention to check the top of the cover and the core on the clamping pieces of the gap and wear core bolt insulation should be good.
(11) Prevention of casing flashover and explosion: casing should be kept clean to prevent dirt flash and flashover during heavy rain. Pay attention to the oil paper capacitive casing dielectric loss, capacitance and chromatographic analysis results of the trend. During operation, attention should be paid to check the heating of the lead wire terminals and regular infrared detection.
(12) Prevention of lead accidents: installation should pay attention to check the lead, equalizing ring, wood bracket, glue wood screws and other components are deformed, operation is loose, pay attention to remove the burrs on the exposed leads and sharp corners, to prevent the discharge breakdown in operation.
(13) Prevention of on-load tap-changer accidents: Before the transformer is put into operation, the contact resistance of the on-load tap-changer should be confirmed to be qualified, and special attention should be paid to the correctness of the indication position of the actuator.
(14) The sampling period of the dissolved gas chromatography test in the oil of the new transformer should be carried out in accordance with the regulations of the ministry, and should be included in the scope of chromatographic monitoring from the actual energization, and the sampling and testing intervals should be determined according to the actual situation, and the oil samples should be analyzed in a timely manner.
(15) Prevent transformer fire accident: special attention should be paid to the quality of the casing inspection and operation monitoring, to prevent the operation of the explosion of oil spray. Transformer fire prevention facilities should be perfect.
(16) Newly installed domestic transformers, before commissioning should be analyzed for dissolved gases in the oil and trace water measurement in the oil. Current transformer to measure the main insulation and the end of the screen to the ground tgδ and capacitance, if necessary, partial discharge measurement. Electromagnetic voltage transformer to measure the body and insulation bracket tgδ, 220kV and above capacitance voltage transformer partial discharge measurements when necessary, but also for the secondary winding insulation resistance, DC group measurements, and test results and factory values and standard values for comparison, the difference should be analyzed for reasons, unqualified transformer shall not be put into operation.
(17) Transformer in the installation test, before operation should pay attention to check the current transformer capacitance end screen, base grounding, voltage transformer high voltage winding X (or N, B) end and base and other grounding is firm and reliable, it should be directly and obviously grounded, the transformer frame should be one with a reliable connection to the grounding network.
(18) Current transformer primary leads to ensure good contact, the secondary lead terminals should be anti-rotation measures to prevent the internal lead twisted.
(19) In order to prevent the series resonance overvoltage burned voltage transformer, in the system operation mode and reverse operation should be avoided with the fracture capacitance of the circuit breaker casting with electromagnetic voltage transformer of the empty bus, such as operation mode can not meet the requirements, other precautions should be taken.
(20) In order to avoid the current transformer capacitor core bottom breakdown accident to expand the scope of the accident, should pay attention to the primary terminal L1 and L2 installation direction and the polarity of the secondary winding connection should be correct to ensure that the normal operation of the differential protection.