Due to the low price and convenient maintenance of copper three-phase oil-filled distribution transformers with finned radiators, oil-filled transformers account for more than 80% of the electrical market, much higher than dry-type transformers. However, the failure rate is also very high, so it is necessary to arrange regular inspections. There are three
common accidents in distribution transformers:
I insulation accident.
The insulation damage accident of the three-phase distribution transformer accounts for 70%-80% of the total accidents. It is damaged by mechanical force or overheating. It also has the insulation strength not meet the requirements at the factory or the insulation is damaged and the strength is reduced. Ability requirements.
The main causes of the failure: 1 oil-filled transformer water is damp. Mainly, the end of the casing is not tightly sealed, the water cooler leaks, the explosion-proof cylinder is accumulated, and there is water in the oil storage cabinet. The presence of moisture will reduce the breakdown strength of the transformer insulating oil and cause insulation accidents. The most insulation accidents are windings, leads and screens. The development of creepage leads to inter-turn and inter-layer short circuits. 2 Foreign matter remaining in the distribution transformer. Metal conductors foreign matter and impurities remaining in the transformer body cause partial discharge or wear and tear, causing insulation breakdown damage in the event of an overvoltage or at a normal operating voltage. 3 lightning strikes. The lightning resistance level of the lightning protection of the medium and low voltage side of the three-phase transformer is too low and the insulation structure of the transformer is weak, which causes the grounding short circuit of the transformer during lightning strike.
II Overheating fault. There are overheating caused by abnormal currents, such as overheating caused by circulation and eddy currents, overheating due to increased resistance of the conductive loop, and overheating due to heat dissipation.
III short circuit damage accident. Copper winding transformers suffer from various short-circuit accidents during operation, such as single-phase, two-phase or two-phase, three-phase short circuit, in which the short circuit at the exit is the most serious.
Zhongtian Electric Equipment Co., Ltd. has gathered outstanding talents, excellent assets and core technologies, and has developed into an outstanding enterprise in the industry. ZTELEC has a variety of copper three-phase oil-filled distribution transformers with finned radiators, three-phase epoxy cast-type transformers, and explosion-proof mine dry-type transformers.