Oil Distribution Transformer Oil Level Abnormal Processing Method
The abnormal oil level of the oil distribution transformer is a problem that occurs from time to time in the daily operation of the transformer. Once the problem is not solved in time, it will cause great obstacles to the daily power supply.
In order to monitor the oil level of the transformer, the oil pillow of the transformer is equipped with a glass tube oil level gauge or a magnetic needle oil level gauge. The oil pillow adopts a glass tube oil level meter, and the oil pillow is marked with an oil level monitoring line, which indicates the normal oil level of the transformer when the ambient temperature is -20, +20, and +40 °C; if the magnetic needle oil level meter is used, in different environments At temperature, the position where the pointer should rest is determined by the curve provided by the manufacturer. When the transformer is running, under normal circumstances, the oil level of the transformer changes with the temperature, and the temperature depends on the load of the transformer, the ambient temperature and the operation of the cooling system.
The abnormal transformer oil level has the following three manifestations:
(1) The oil level is too high. The oil level is higher than the maximum oil level line due to the rise in oil temperature, and sometimes the oil level reaches the top and the oil level cannot be seen.
The reason for the high oil level is: the transformer cooler does not operate normally, which increases the oil temperature of the transformer, and the oil expands when heated, causing the oil level to rise; the oil level is much higher when the oil distribution transformer is refueled, and once the ambient temperature rises significantly, the oil level will be too high. high. If the oil level is too high due to the abnormal operation of the cooler, check whether there is dust accumulation on the surface of the cooler, whether the upper and lower valves of the oil pipe are open, whether the pipeline is blocked, whether the fan and submersible pump are operating normally and reasonably, and whether the cooling medium Whether the temperature is appropriate and the flow is sufficient. If the oil level is too high due to excessive refueling, the oil should be drained to an appropriate height. If the oil level cannot be seen, it should be judged that the oil level is indeed higher than the maximum oil level line, and then the oil should be drained to an appropriate height.
(2) The oil level is too low. When the oil level of the transformer is significantly lower than the oil level corresponding to the oil temperature at that time, and the oil level is below the minimum oil level line or cannot be seen, it should be judged that the oil level is too low.
The reasons for the low oil level are: transformer oil leakage; the original oil level of the transformer is not high, when the oil distribution transformer load suddenly drops or the external ambient temperature drops significantly, the oil level is too low; the time when the strong oil water-cooled transformer oil flows into the oil cooler Longer, will also make the oil level too low. If the oil level is too low, it will cause light gas protection action, and if it is a float relay, it will also cause heavy gas protection to trip.
When there is a serious shortage of oil, the transformer core and winding will be exposed to the air, which will not only be easily damped and reduce the insulation capacity, but may also cause insulation breakdown. Therefore, if the oil level of the transformer is too low or the oil level is obviously lowered, the oil should be replenished to the normal oil level as soon as possible. If the oil level is significantly lowered due to serious oil leakage, it is forbidden to change the gas protection from trip to signal to eliminate oil leakage and restore the oil level to normal. If a large amount of oil leaks, the oil level drops below the gas relay or continues to drop, the transformer should be stopped immediately.
