How to judge the transformer accident detection and measures?

There is an abnormal sound inside the transformer. Abnormal sound inside the transformer may have the following reasons: serious overload makes the transformer inside the heavy "buzzing" sound; Due to poor internal contact or breakdown point, "squeaking" or "crackling" discharge sound occurs inside the transformer; Because some parts of the connecting shaft bolt of the transformer top cover are loose, the transformer core is not clamped, resulting in vibration of the silicon steel sheet and strong noise; When there is a grounding or short circuit fault in the power grid, the winding flows through a large current, which will give out strong noise; When the transformer is connected with large power equipment or equipment that can produce harmonic current, the operation of the equipment may cause the transformer to emit a "wah-wah" cry; Because of the resonance of the iron core, the noise of the transformer is coarse and thin. The primary side voltage of the transformer is too high and the current is too high. The transformer emits a discharge sound due to overvoltage, winding or lead wire discharge to the housing, or core ground wire disconnection, resulting in core discharge to the housing.

Emergency measures: When the transformer is found to emit abnormal sound, the possible causes should be determined according to the above analysis, and emergency measures should be taken in a targeted manner. If the abnormal sound emitted inside the transformer is caused by loose parts or breakdown of winding wires, power should be immediately cut off to avoid further expansion of the accident.

The transformer oil level is too high or too low. In general, changes in oil temperature can change the oil level. With the change of oil temperature, the oil level also appears a certain range of changes. However, under abnormal circumstances, due to oil seepage, water seepage and other failures and other accidents will also cause abnormal changes in the oil level. Secondly, the change of oil temperature is related to the load condition, environmental temperature and other conditions. When the oil level changes are inconsistent with these factors, it may be a false oil level. The cause of false oil level: oil label tube blockage; Explosion-proof tube vent blocked. In addition, the oil level is too high will cause oil spill; If the oil level is too low, it may cause the internal lead line and even the coil of the transformer to be exposed, resulting in internal discharge.

Treatment methods and emergency measures: with gas relay protection, the trip circuit is lifted to prevent false trip. When the electrical equipment operator should check the oil level indicator frequently and find that the oil level is too high, the appropriate amount of oil can be discharged; Replenish oil when the oil level is too low. If it is caused by transformer oil leakage, power outage maintenance and other emergency measures should be taken. When the oil pillow or explosion-proof pipe is found to be abnormal oil injection, the power supply of the transformer should be cut off immediately to prevent the expansion of failures and accidents.

Transformer oil quality deteriorates or oil temperature rises suddenly. In the working state, the main role of transformer oil is cooling and insulation. When the prolonged overheating operation or the housing water, absorb moisture, will make the oil quality bad. The oil color will be abnormally deepened or blackened by observing the oil label. After sampling analysis, it can be tested that the oil contains carbon particles and water, the acid value is increased, the flash point is reduced, and the insulation strength is reduced. This situation is very easy to occur between the winding and the shell breakdown discharge, resulting in serious accidents. When the transformer is in normal operation, a sudden rise in the oil temperature is often the cause of overheating inside the transformer. Iron core fire, winding turn short circuit, loose internal screws, cooling device failure, transformer serious overload may cause the oil temperature to rise suddenly.

Solution and emergency measures: if the oil color is abnormally deepened or blackened, the insulation oil needs to be regenerated and overstressed; Due to the sudden increase in oil temperature caused by load factors, the load can be appropriately reduced or adjusted; If the oil temperature rises suddenly due to other abnormal conditions, the power should be cut off immediately and the transformer should be comprehensively overhauled.

The transformer is on fire. When there is a fault inside the transformer and it is not handled in time, it may catch fire and cause a fire. When the transformer is on fire, the insulating oil in the fuel tank burns and turns into gas, causing the fuel tank to burst, and the burning insulating oil jets out of the transformer, which will cause equipment damage and property losses. Internal or external short circuits of transformer wires, severe overload, lightning strikes, or external fire sources moving into the transformer may lead to transformer fire.

Emergency measures: a. Strengthen the operation management of the transformer, try to control the oil temperature in the transformer does not exceed 85℃; Check and test the electrical performance of the transformer regularly, and do the deterioration test of the oil regularly. b. The high and low voltage side of small capacity transformer should have overcurrent protection links such as fuse; Large-capacity transformers should be equipped with gas protection and differential protection as required. When the high voltage is protected by a fuse, the rated current of the transformer below 100KVA is selected by 2-3 times the rated current of the transformer. For transformers above 100KVA, the fuse is selected by 1.5-2 times of the rated current. c. The room where the transformer is placed is a first-class fire-resistant building; There should be good ventilation, the maximum exhaust air temperature should not exceed 45 ° C, and the temperature difference between air intake and exhaust air should be controlled within 15 ° C; There should be oil retaining facilities and oil storage pits in the room; Do not install two transformers in the same room according to safety requirements. d. Check the transformer load frequently, and the load shall not exceed the safety management regulations. e. The transformer introduced by the overhead wire shall be equipped with lightning arresters according to the regulations, and the lightning protection devices shall be checked before the thunderstorm season. f. Special personnel are set up to maintain the transformer, and there are inspection and inspection systems and records. Keep the transformer safe and economical operation and the working environment clean.