1、General principles of accident handling

When an accident occurs on the equipment in the charge of the operator on duty or within its jurisdiction, the operator on duty can eliminate the accident in the following order:

1. In case of transformer accident, the operator on duty shall pay close attention to the instructions of the meter and signal. Among the operators on duty in the main control room, someone must record the execution time (especially the sequence) of various operations and the phenomena related to the accident, and judge the overall situation of the accident according to the instructions of the meter and the external signs of the action of the automatic device for equipment protection.

2. In case of an accident, the dispatcher on duty shall be notified immediately. The dispatcher on duty is the commander to deal with the accident. The operation attendant of the substation shall quickly and indisputably execute all orders of the dispatcher on duty. If the Substation Operator on duty thinks that there is an error in the command of the dispatcher on duty, he shall point out it in time and give a simple explanation to the other party. When the dispatcher on duty determines that his command is correct, the Substation Operator on duty shall implement it immediately. If the order of the dispatcher on duty directly threatens the safety of personnel or equipment, it can be refused.

3. When receiving the order to deal with the accident, the operator on duty of the substation must repeat it to the sender. If the order is unclear or does not understand it, he shall ask again. The operator on duty can handle the accident only after receiving the order to deal with the accident from the leader or dispatching department he is familiar with. The leader who issues the order or the dispatcher on duty shall be familiar with the person who receives the order and ask the person who receives the order to repeat his order. If the next order to deal with the accident must be determined according to the execution of the previous order, it shall wait for the personal return of the receiver, shall not be communicated through a third party, and it is not allowed to judge the execution of the order according to the instructions of the meter.

4. After the accident, the operation personnel on duty shall quickly carry out inspection and test to determine the nature, location and scope of the fault. For the faulty equipment, necessary repair shall be carried out after determining the fault part and nature. If the operator on duty cannot handle the damaged equipment with his own strength, he shall immediately notify the dispatcher on duty or relevant leaders. Before the maintenance personnel arrive, the operation personnel on duty shall make preparations for the work site (such as cutting off the power supply, installing the grounding wire, hanging the warning board, etc.).

5. When dealing with the accident, we must be quick and correct, and should not panic. Hasty or thoughtless handling will often expand the accident. In some cases, in order to prevent the expansion of the accident, some emergency operations must be carried out. These operations can be carried out by the operator on duty of the substation first, and then reported to the dispatcher on duty. In any case, the following operations can be performed by the watchman of the substation without waiting for the order of the dispatcher on duty:

1) Power off the equipment that directly threatens people's lives; And rescue the electric shock personnel.

2) Quickly limit the development of accidents, and stop and isolate the damaged transformer equipment;

3) When the equipment in operation is threatened with damage, it shall be isolated according to the regulations of on-site accident handling procedures;

4) When the bus voltage disappears, open the switch connected to the bus;

5) Restore the power supply when the station power is completely or partially cut off;

6) In order to prevent the accident from expanding, each stage of accident handling must be reported to the dispatching department or the direct superior leader quickly and correctly. Otherwise, even if it is not a serious accident, the whole substation may be chaotic due to the lack of correct cooperation.

2、Treatment after tripping of transformer circuit breaker

After the transformer circuit breaker trips, if there is a standby transformer, the personnel on duty shall put it into operation immediately under the command of the dispatcher to restore the power supply to the user, and then find out the tripping cause of the faulty transformer. If there is no standby transformer, only find out what kind of protection action according to the sign dropping indication as soon as possible. While finding out the cause of transformer tripping, check whether there are obvious abnormalities, such as external short circuit, line fault, overload, obvious fire, strange sound, oil injection, etc. If it is proved that the tripping of circuit breakers on both sides of the transformer is not caused by internal fault, but by overload, external short circuit or misoperation of secondary circuit of protection device, the transformer can be put into operation again without external inspection. If the internal cause of the transformer trip cannot be determined. Mainly check the insulation resistance and DC resistance. When it is judged that there is no internal fault in the transformer through inspection, it shall be confirmed that the gas protection is put into the tripping position, and the transformer shall be reclosed once. The whole process shall be handled with caution. If it is judged that the transformer has internal fault through insulation resistance and DC resistance inspection, AC withstand voltage test and hanging core inspection shall be carried out for the transformer.

3、Treatment after transformer gas protection action

In case of local heating during transformer operation, in many cases, it does not show electrical abnormalities, but the first is the abnormality of oil-gas decomposition, that is, the oil decomposes into gas under the action of local high temperature, and gradually accumulates in the upper end of transformer top cover and gas relay. To distinguish the speed of gas generation and the size of gas production is actually to distinguish the size of overheating fault.

1. Treatment after light gas action. After the light gas action sends a signal, first stop the audio signal, check the amount of gas in the gas relay and determine the reason. Non transformer fault causes. For example, air intrudes into the transformer (after oil filtering); The oil level drops below the gas relay (float type gas relay) or the oil level drops sharply (baffle type gas relay); Secondary circuit fault of gas protection (such as water inflow in junction box of gas relay, short circuit of terminal strip or secondary cable, etc.). If it is determined that the action is caused by external reasons, the transformer can continue to operate after the signal is restored. If it cannot be determined that the gas signal action is caused by external reasons and no other abnormalities are found, it is necessary to confirm that the gas protection tripping circuit is in the input state, strengthen the monitoring of the transformer and carefully observe its development and changes.

2. Treatment after heavy gas protection action. If the transformer in operation trips due to gas protection action, or the gas signal and gas trip act at the same time, the possibility of internal fault of the transformer shall be considered first. This kind of transformer should be handled with great caution. The gas generated in the fault transformer is due to the different parts in the transformer. It is very important to identify the nature of the gas in the gas relay, the quantity and speed of gas accumulation. Caused by different forms of overheating. Therefore, it is very important to judge the nature and severity of transformer fault. If the accumulated gas is colorless, tasteless and nonflammable, the gas action is caused by the air separated from the oil. At this time, it can be determined that it is not the fault cause of the transformer. The transformer can continue to operate. If the gas is combustible, it is most likely caused by the internal fault of the transformer. Such transformers are not allowed to be put into operation until they have been inspected and passed the test. Transformer gas protection action is a precursor of an internal accident, or itself is an internal accident. Therefore, special care should be taken for forced transmission, trial transmission and supervision operation of such transformers. Forced transmission is not allowed until the cause of the accident is found out.

4、Treatment after transformer differential protection action

The same with gas protection is that these two kinds of protection actions are sensitive and rapid, and they are the main protection of transformer itself. Different from gas protection, gas protection mainly reflects the fault of oil-gas separation caused by overheating in the transformer, while differential protection reflects the internal electrical fault of the transformer within the scope of differential protection. If the differential protection action causes the circuit breaker to trip, the operator shall take the following measures: first, open the knife switch on each side of the transformer, and carefully check the transformer body, such as oil temperature, oil color, explosion-proof glass, porcelain bushing, etc., to determine whether there are obvious abnormalities. Secondly, check all primary equipment within the transformer differential protection area, that is, check all equipment, leads and buses between the circuit breakers on the high-voltage side and low-voltage side of the transformer, and measure the external infrared temperature of the transformer to judge whether there is fault inside the transformer, so as to find out whether there is abnormality in the differential protection area. Third, check the differential protection circuit of transformer to see whether there is short circuit, breakdown and accidental touch. After the inspection of the above steps, if it is determined that the differential protection is due to external reasons, such as protection MIS touch, misoperation caused by through fault, etc., the transformer can be put into trial operation when the heavy gas protection is put into the tripping position. If the external cause cannot be judged, further measurement and analysis shall be carried out for the transformer, such as measuring DC resistance, simplified analysis of oil, or chromatographic analysis of oil, so as to determine the nature of fault and the cause of differential protection action. If it is found that there are characteristics of internal faults, the hanging core inspection and AC voltage withstand test shall be carried out for further inspection.

1、General principles of accident handling

When an accident occurs on the equipment in the charge of the operator on duty or within its jurisdiction, the operator on duty can eliminate the accident in the following order:

1. In case of transformer accident, the operator on duty shall pay close attention to the instructions of the meter and signal. Among the operators on duty in the main control room, someone must record the execution time (especially the sequence) of various operations and the phenomena related to the accident, and judge the overall situation of the accident according to the instructions of the meter and the external signs of the action of the automatic device for equipment protection.

2. In case of an accident, the dispatcher on duty shall be notified immediately. The dispatcher on duty is the commander to deal with the accident. The operation attendant of the substation shall quickly and indisputably execute all orders of the dispatcher on duty. If the Substation Operator on duty thinks that there is an error in the command of the dispatcher on duty, he shall point out it in time and give a simple explanation to the other party. When the dispatcher on duty determines that his command is correct, the operator on duty of the substation shall execute it immediately. If the order of the dispatcher on duty directly threatens the safety of personnel or equipment, it can be refused.

3. When receiving the order to deal with the accident, the operator on duty of the substation must repeat it to the sender. If the order is unclear or does not understand it, he shall ask again. The operator on duty can handle the accident only after receiving the order to deal with the accident from the leader or dispatching department he is familiar with. The leader who issues the order or the dispatcher on duty shall be familiar with the person who receives the order and ask the person who receives the order to repeat his order. If the next order to deal with the accident must be determined according to the execution of the previous order, it shall wait for the personal return of the receiver, shall not be communicated through a third party, and it is not allowed to judge the execution of the order according to the instructions of the meter.

4. After the accident, the operation personnel on duty shall quickly carry out inspection and test to determine the nature, location and scope of the fault. For the faulty equipment, necessary repair shall be carried out after determining the fault part and nature. If the operator on duty cannot handle the damaged equipment with his own strength, he shall immediately notify the dispatcher on duty or relevant leaders. Before the maintenance personnel arrive, the operation personnel on duty shall make preparations for the work site (such as cutting off the power supply, installing the grounding wire, hanging the warning board, etc.).

5. When dealing with the accident, we must be quick and correct, and should not panic. Hasty or thoughtless handling will often expand the accident. In some cases, in order to prevent the expansion of the accident, some emergency operations must be carried out. These operations can be carried out by the operator on duty of the substation first, and then reported to the dispatcher on duty. In any case, the following operations can be performed by the watchman of the substation without waiting for the order of the dispatcher on duty:

1) Power off the equipment that directly threatens people's lives; And rescue the electric shock personnel.

2) Quickly limit the development of accidents, and stop and isolate the damaged transformer equipment;

3) When the equipment in operation is threatened with damage, it shall be isolated according to the regulations of on-site accident handling procedures;

4) When the bus voltage disappears, open the switch connected to the bus;

5) Restore the power supply when the station power is completely or partially cut off;

6) In order to prevent the accident from expanding, each stage of accident handling must be reported to the dispatching department or the direct superior leader quickly and correctly. Otherwise, even if it is not a serious accident, the whole substation may be chaotic due to the lack of correct cooperation.

2、Treatment after tripping of transformer circuit breaker

After the transformer circuit breaker trips, if there is a standby transformer, the personnel on duty shall put it into operation immediately under the command of the dispatcher to restore the power supply to the user, and then find out the tripping cause of the faulty transformer. If there is no standby transformer, only find out what kind of protection action according to the sign dropping indication as soon as possible. While finding out the cause of transformer tripping, check whether there are obvious abnormalities, such as external short circuit, line fault, overload, obvious fire, strange sound, oil injection, etc. If it is proved that the tripping of circuit breakers on both sides of the transformer is not caused by internal fault, but by overload, external short circuit or misoperation of secondary circuit of protection device, the transformer can be put into operation again without external inspection. If it cannot be determined that the transformer trip is caused by the above external reasons, the transformer must be internally inspected. Mainly check the insulation resistance and DC resistance. When it is judged that there is no internal fault in the transformer through inspection, it shall be confirmed that the gas protection is put into the tripping position, and the transformer shall be reclosed once. The whole process shall be handled with caution. If it is judged that the transformer has internal fault through insulation resistance and DC resistance inspection, AC withstand voltage test and hanging core inspection shall be carried out for the transformer.

3、Treatment after transformer gas protection action

In case of local heating during transformer operation, in many cases, it does not show electrical abnormalities, but the first is the abnormality of oil-gas decomposition, that is, the oil decomposes into gas under the action of local high temperature, and gradually accumulates in the upper end of transformer top cover and gas relay. To distinguish the speed of gas generation and the size of gas production is actually to distinguish the size of overheating fault.

1. Treatment after light gas action. After the light gas action sends a signal, first stop the audio signal, check the amount of gas in the gas relay and determine the reason. Non transformer fault causes. For example, air intrudes into the transformer (after oil filtering); The oil level drops below the gas relay (float type gas relay) or the oil level drops sharply (baffle type gas relay); Secondary circuit fault of gas protection (such as water inflow in junction box of gas relay, short circuit of terminal strip or secondary cable, etc.). If it is determined that the action is caused by external reasons, the transformer can continue to operate after the signal is restored. If it cannot be determined that the gas signal action is caused by external reasons and no other abnormalities are found, it is necessary to confirm that the gas protection tripping circuit is in the input state, strengthen the monitoring of the transformer and carefully observe its development and changes.

2. Treatment after heavy gas protection action. If the transformer in operation trips due to gas protection action, or the gas signal and gas trip act at the same time, the possibility of internal fault of the transformer shall be considered first. The treatment of this kind of transformer should be very careful