Transformer can normal operation not only depends on the transformer structure design and manufacturing process, but also with the daily operation, maintenance management and other aspects have a great relationship, transformer failure occurs, will greatly affect the normal operation of the power plant, oil-immersed transformer failure on the operation of the power grid system is extremely dangerous, in order to avoid accidents, should strengthen the daily operation of inspection management and the development of effective maintenance measures to ensure that the transformer Safe and stable operation. Strengthen the regular maintenance of the transformer, take effective measures to prevent the occurrence of transformer failure, to ensure the safe and stable operation of the transformer has important significance.

　　1, transformer operation in the analysis of common faults and handling measures

　　(1) Transformer fire is also a dangerous accident. Due to the transformer bushing breakage or flashover, so that the oil in the oil pillow oil pressure out, and in the transformer top cover burning; transformer internal failure, so that the oil burning and make the shell rupture, etc.. Because the transformer has many combustible materials, not timely handling may cause an explosion or make the fire expand. When such accidents occur, the transformer protection should act to make the circuit breaker disconnect. If for some reason the circuit breaker is not disconnected, the circuit breaker should be manually disconnected immediately, pull the isolation switch that may lead to the transformer power supply, and quickly put in the backup change, restore power supply, stop the operation of cooling equipment, fire. Transformer fire, it is best to use foam fire extinguishers or dry powder fire extinguishers, if necessary, sand fire.

　　(2) tap changer failure. Transformer on-load tap-changer is one of the common transformer failures. As the switch is contacted by pressure for a long time, there will be insufficient spring pressure, so that the effective contact area of the connecting part of the switch is reduced, as well as the contact part of the silver-plated layer wear off, causing the tap changer in operation heat damage. Poor contact with the on-load tap-changer can not withstand the impact of the short-circuit current and cause the on-load tap-changer to burn out and malfunction; in the on-load tap-changer transformer, the on-load tap-changer tank and transformer tank are generally not connected to each other. If the on-load tap-changer tank is seriously short of oil, the on-load tap-changer in the switching will occur in the short-circuit fault, so that the on-load tap-changer burned.

　　(3) automatic tripping of the transformer processing. When the transformer side of the circuit breaker automatically tripped, first of all, the control switch of the tripping circuit breaker operated to the position after the trip, and quickly put into the spare transformer, adjust the mode of operation and load distribution, maintain the operating system and equipment in a normal state. Then check the protection action and carry out external inspection. After inspection is not an internal fault but due to external faults or personnel errors caused by the action, then without internal inspection can be put into power supply. If it is a differential, heavy gas, speed break and other main protection action, the equipment within the scope of the protection should be fully checked. In the absence of a clear cause, the transformer is prohibited to put into operation.

　　(4) winding of the main insulation and inter-turn insulation failure. The main insulation and inter-turn insulation of the oil-immersed transformer winding are the parts prone to failure. The main reasons are: due to long-term overload operation, or poor heat dissipation conditions, or the use of long years, so that the transformer winding insulation aging brittle cracking, electrical strength greatly reduced; transformer repeatedly short-circuit impact, so that the winding deformation, hidden insulation defects, once encountered voltage fluctuations may be insulation breakdown; transformer oil into the water so that the insulation strength is greatly reduced and can not withstand the allowable voltage, resulting in insulation Breakdown; in the high-voltage winding strengthening section or low-voltage winding parts, due to insulation expansion, so that the oil channel blockage, affecting the heat dissipation, so that the winding insulation due to overheating and aging, a breakdown short circuit; due to imperfect lightning protection facilities, in the atmosphere under the action of overvoltage, insulation breakdown occurs.

　　(5) core insulation failure. Transformer core is made of silicon steel sheets stacked, silicon steel sheets have insulating paint film between. Due to poor fastening of silicon steel sheet, so that the film damage vortex current and local overheating occurs. Similarly, the clamping of the core through the core screw, pressure iron and other components, if the insulation damage will also occur overheating phenomenon. In addition, if the transformer residual iron chips or welding slag, so that the core of two or more points of grounding, will cause core failure.

　　(6) gas protection failure. Gas protection is the main protection of the transformer, light gas act on the signal, heavy gas act on the trip. The following analysis of the causes of gas protection action and handling: First, the light gas protection action after the signal. The reason is: transformer internal minor fault; transformer internal air; secondary circuit failure, etc.. Operating personnel should immediately check, if no abnormalities are found, gas sampling analysis should be carried out. Second, when the gas protection action trips, it may produce a serious fault inside the transformer, causing the oil to decompose a large amount of gas, and may also secondary circuit failure. When the gas protection action trips, you should first cast the standby transformer, and then carry out external inspection. Check the oil pillow explosion-proof door, whether the welding seam is cracked, and whether the transformer shell is deformed; finally, check the flammability of the gas.

　　(7) Transformer casing failure. Mainly casing flashover and explosion, transformer high-voltage side generally use capacitor casing, due to poor casing porcelain or trachoma and cracks, casing sealing is not tight, there is oil leakage; casing accumulation of too much scale, etc. may cause flashover and explosion.