The stable operation of the transformer is related to the stability of the entire power grid. The temperature of the transformer is too high and the heat dissipation is not timely but often occurs. The oil temperature at the top of the oil-immersed transformer is generally adjusted at 85 °C. If it exceeds 85 °C, the reason should be analyzed: 1. If the room temperature is too high, the load is too heavy, etc., and it can continue to run above 85 °C, but the maximum can not exceed 95. °C (At this time, the center core or winding of the transformer is 105 °C, which will seriously damage the insulation, shorten the service life or burn the transformer); 2. When the transformer exceeds 85 °C, the temperature difference between the oil temperature at the top of the transformer and the room temperature should not exceed 55 °C, if it exceeds It may be severe overload, low voltage, excessive current, internal faults, etc. Continued operation will seriously damage the insulation, shorten the service life or burn the transformer. The oil-immersed transformer is operating at high load. Once the critical temperature is exceeded, the transformer will start the “self-protection” program and automatically trip. If the transformer is still running, it will cause damage, resulting in a large-scale blackout. Once such an accident occurs, it is difficult to repair in a short time. At this point, it is necessary to actively cool the main transformer.
1), load shedding
When the temperature of the substation transformer is close to or exceeds the maximum temperature allowed by the operating regulations, and the heat dissipation of the transformer itself is limited, the usual practice is to stop the load, stop the industrial users and special users and the transformer is shut down to cool down.
2), open the main sprinkler system
The repeated high power load has caused a great burden on the power supply equipment, and the substation equipment also needs to be cooled. In order to ensure the normal operation of the equipment, the main change sprinkler system is turned on for the main transformer with overload and high temperature, and the main transformer is subjected to the charged water flushing work by manual means to improve the heat dissipation effect of the transformer. Flushing a live transformer with water is a professional task in the power system. Flushing the live transformer with water is extremely demanding. In addition to requiring the operator to have the appropriate professional skills, the operator should wear professional protective equipment such as insulating gloves and insulated boots during the flushing process. Moreover, the staff only flushes the heat sink of the transformer, not the live part of the flushing transformer.
3), transformer ventilation
Strengthening the ventilation of the transformer can achieve the purpose of cooling, so the solid door of the transformer is changed into a mesh door for ventilation, which is used to alleviate the overheating caused by poor ventilation. If necessary, you can also use a giant fan to assist in cooling.
4), transformer auxiliary cooling car
When using a transformer-assisted cooling car, fill the water tank with water, move it to the working position, and fix the nozzle to the appropriate position of the transformer through the fixing piece. When the control device collects the temperature sensor signal value exceeding the set value, the water pump is started to work for a short period of time. At this time, the water pump presses the water into the plenum, compresses the air inside the plenum, and increases the internal pressure of the plenum. Then open the solenoid valve for the water spray operation. The transformer auxiliary cooling car of the invention can work automatically only after the worker sets the nozzle and the control device, and does not need the worker to operate for a long time, and can work conveniently in the place of no water source.
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