How to judge the transformer accident detection and measures

Abnormal sound inside the transformer. The abnormal sound inside the transformer may be due to the following reasons: severe overload causes heavy "buzzing" sound inside the transformer; Due to poor contact or breakdown points inside, "squeaking" or "crackling" discharge sound occurs inside the transformer; Due to the looseness of some parts of the connecting shaft bolt of the transformer top cover and the fact that the transformer core is not clamped, the silicon steel sheet vibrates and will emit strong noise; when there is a grounding or short-circuit fault in the power grid, a large current flows in the winding, which will emit strong noise. When the transformer is connected with large power equipment or equipment that can generate harmonic current, the operation of the equipment may cause the transformer to make a "wah-wah" sound. Due to the resonance of the iron core, the transformer will have rough and thin noise. Excessive primary voltage and excessive current of the transformer will cause abnormal sound; due to overvoltage, winding or lead wire discharge to the shell, or iron core grounding wire disconnection, resulting in iron core discharge to the shell, all make the transformer discharge sound.

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

Transformer oil level too high or too low. In general, changes in oil temperature can change the oil level. As the oil temperature changes, the oil level also appears to change in a certain range. However, under abnormal circumstances, due to oil leakage, 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, ambient temperature and other conditions. When the oil level change is inconsistent with these factors, it may be a false oil level. Reasons for false oil level: blockage of oil standard pipe; blockage of exhaust hole of explosion-proof pipe. In addition, the oil level is too high will cause oil spill; oil level is too low, it may cause the transformer internal lead wire and even the coil exposed, resulting in internal discharge.

Treatment method and emergency measures: if there is gas relay protection, release the trip circuit to prevent false trip. Operators of electrical equipment on duty should always check the indication of oil level gauge. If the oil level is too high, appropriate amount of oil can be released. When the oil level is too low, oil should be replenished in time. If it is caused by oil leakage of transformer, power outage maintenance and other emergency measures shall be taken. When abnormal fuel injection of the oil conservator or explosion-proof tube is found, the power supply of the transformer should be cut off immediately to prevent the expansion of faults and accidents.

Transformer oil deterioration or oil temperature suddenly increased. In the working state, the main function of transformer oil is cooling and insulation. When the long time overheating operation or shell water, absorb moisture, will make the oil bad. Through the oil mark observation, it will be found that the oil color is abnormally deepened or blackened. Through sampling analysis, it can be detected that the oil contains carbon particles and water, the acid value increases, the flash point decreases, the insulation strength decreases, etc. This situation is prone to breakdown discharge between the winding and the shell, causing serious accidents. When the transformer is running normally, if the oil temperature rises suddenly, it is often the cause of overheating inside the transformer. Iron core fire, winding inter-turn short circuit, internal screw loosening, cooling device failure, transformer serious overload may make the oil temperature suddenly rise.

Solution and emergency measures: if the oil color is abnormally deepened or blackened, the insulating oil needs to be regenerated and overhauled; if the oil temperature suddenly rises due to load factors, the load can be appropriately reduced or adjusted; if the oil temperature suddenly rises due to other abnormal conditions, the power shall be cut off immediately and the transformer shall be comprehensively overhauled.

The transformer caught fire. When the transformer internal failure, and not timely treatment, that may be on fire, resulting in a fire. When the transformer is on fire, the insulating oil in the oil tank burns and turns into gas, causing the oil tank to burst, and the burning insulating oil jets to the outside of the transformer, which will cause equipment damage and property loss. Internal or external short circuit of transformer conductor, serious overload, lightning strike or external fire source moving into transformer may cause transformer fire.

Emergency measures: a. Strengthen the operation and management of the transformer, try to control the oil temperature in the transformer not to exceed 85 ℃; regularly check and test the electrical performance of the transformer, and regularly do the oil deterioration test. B. small capacity transformer high and low voltage side should have fuse and other overcurrent protection link; large capacity transformer should be equipped with gas protection and differential protection according to the provisions. When the high voltage is protected by a fuse, the rated current of the transformer below 100KVA shall be selected by 2-3 times of the rated current of the transformer. For transformers above 100KVA, the fuse is selected according to 1.5-2 times of the rated current. C. the room where the transformer is installed is a class I fire-resistant building; there should be good ventilation, the maximum exhaust temperature should not exceed 45 ℃, and the temperature difference between the air inlet and exhaust should be controlled within 15 ℃; indoor oil blocking facilities and oil storage pits; according to safety requirements, do not install two transformers in the same room. d. Regularly check the transformer load, the load shall not exceed the safety management regulations. e. Lightning arrester shall be installed for transformer introduced by overhead conductor according to regulations. Lightning protection device shall be inspected before thunderstorm season. f. Assign special personnel to maintain the transformer, with inspection and inspection system and records. Keep the normal safe and economic operation of the transformer and the clean working environment.