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Accident detection and measures of line design transformer
- 2019-05-23-

If there is abnormal noise inside the transformer during the design operation of the line . There may be the following reasons for the abnormal sound inside the transformer: severe overload causes a heavy "humming" sound inside the transformer; due to poor internal contact or breakdown points, the inside of the transformer "squeaks" or "cracks" Discharge sound; due to the looseness of individual parts of the transformer top cover connecting shaft bolt, the transformer core is not clamped, causing the silicon steel sheet to vibrate, and strong noise will be emitted; when there is a ground fault or short circuit in the power grid, a large current flows in the winding, Strong noise is emitted; 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 "wowa" noise; due to the resonance of the iron core, the transformer may make coarse and thin noise; the transformer If the primary side voltage is too high or the current is too high, abnormal sound will occur; due to overvoltage, windings or lead wires discharging to the shell, or the iron core ground wire is disconnected, causing the iron core to discharge to the shell, the transformer will emit a discharge sound.
Emergency measures: When abnormal sounds are found from the transformer, the possible causes should be judged based on the above analysis, and emergency measures should be taken in a targeted manner. If the abnormal sound emitted by the transformer is caused by loose parts or breakdown of the winding wires, the power should be immediately processed to prevent the accident from further expanding.
Transformer oil level is too high or too low. Generally, 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 conditions, abnormal oil level changes can also occur due to oil seepage, water seepage, and other faults. Second, changes in oil temperature are related to conditions such as load conditions and ambient temperature. When the oil level changes are not consistent with these factors, it may be a false oil level. Reasons for the false oil level: The oil standard tube is blocked; the explosion-proof tube exhaust hole is blocked. In addition, if the oil level is too high, it will cause oil spill; if the oil level is too low, the internal leads of the transformer and even the coil may be exposed, resulting in internal discharge.
Handling method and emergency measures: If there is a gas relay protection, its trip circuit will be released to prevent accidental trip. On-duty electrical equipment operators should always check the oil level gauge instructions, and when the oil level is too high, they can drain the oil appropriately; when the oil level is too low, they should replenish the oil in time. If it is caused by transformer oil leakage, power failure maintenance and other emergency measures should be taken. When abnormal fuel injection of the oil pillow or explosion-proof pipe is found, the power of the transformer should be cut off immediately to prevent the fault and accident from expanding.
Transformer oil deteriorates or the oil temperature rises suddenly. In working condition, the main role of transformer oil is cooling and insulation. When it is overheated for a long time or the housing is filled with water, it absorbs moisture and deteriorates the oil quality. Observation of the oil mark will reveal that the oil color is abnormally deepened or darkened; sampling analysis can verify that the oil contains carbon particles and water, the acid value increases, the flash point decreases, and the insulation strength decreases. This situation can easily cause a breakdown discharge between the winding and the casing, causing a serious accident. When the transformer is operating normally, if the oil temperature suddenly rises, it is often the cause of overheating inside the transformer. The iron core is on fire, the winding turns are short-circuited, the internal screws are loose, the cooling device is faulty, and the transformer is severely overloaded, which may cause the oil temperature to rise suddenly.
Solution and emergency measures: If the oil color is abnormally deepened or darkened, the insulating oil needs to be regenerated and treated with care; the oil temperature suddenly rises due to load factors, and the load can be appropriately reduced or adjusted; oil caused by other abnormal conditions If the temperature suddenly rises, power should be cut off immediately and the transformer should be overhauled.
The transformer catches fire. When the internal fault of the transformer fails to be handled in time, it may catch fire and cause a fire. When the transformer catches fire, the insulating oil in the fuel tank burns and becomes gas, which causes the fuel tank to burst. The burning insulating oil jets out of the transformer, which will cause equipment damage and property damage. Transformer wires are shorted internally or externally, severe overload, lightning strike, or external fire sources moving into the transformer may cause the transformer to catch fire.
Emergency measures: a. Strengthen the operation management of the transformer, and try to control the oil temperature in the transformer not to exceed 85 ° C; regularly check and test the electrical performance of the transformer, and do the oil degradation test regularly. b. The high- and low-voltage side of the small-capacity transformer should have overcurrent protection links such as fuses; the large-capacity transformer should be equipped with gas protection and differential protection according to regulations. When the high voltage is protected by a fuse, the rated current of the fuse below 100KVA is selected according to 2-3 times the rated current of the transformer. For transformers above 100KVA, the fuse is selected according to 1.5-2 times the rated current. c. The room where the transformer is placed is a Class I fire-resistant building; it should have good ventilation, the maximum exhaust temperature should not exceed 45 ℃, and the temperature difference between inlet and exhaust should be controlled within 15 ℃; ; Do not install two transformers in the same room according to safety requirements. d. Check the transformer load frequently. The load must not exceed the safety management regulations. e. Transformers introduced by overhead wires should be equipped with lightning arresters in accordance with regulations. Lightning protection devices should be checked before the thunderstorm season. f. Set up a special person to maintain the transformer, and have inspection and inspection systems and records. Keep the transformer safe and economical operation and clean the working environment.