Cooling system of large oil immersed transformer
Writer： Hengfeng you electric Time：2023-04-03 views：times
When the load current of the common air-cooled oil immersed transformer reaches the specified value, the fan of the oil immersed transformer will be delayed. The automatic control of forced oil circulating air cooling oil immersed transformer is designed according to the following principles. Each cooler has a submersible pump and a plurality of fan motors. The action state of the cooler (action, cut-off, auxiliary and standby) is selected by changing the position of the switch.
If the load of the oil immersed transformer exceeds 75% of the fixed grid capacity or higher oil temperature, the auxiliary cooler operates automatically. When the higher oil temperature of the oil immersed transformer changes up and down at the specified value, in order to avoid frequent switching of the auxiliary cooler, the temperature alarm contact below 5 ℃ of the specified value is set. When the working cooler or auxiliary cooler fails during operation, the self holding circuit is set. The preliminary cooler starts automatically. After troubleshooting, the preliminary cooler exits automatically. When the load of the container drops to the specified value, the auxiliary cooler will cut off automatically. As soon as the oil immersed transformer is disconnected, all coolers will stop. The cooler system is supplied by two AC power supplies. The preparation mode depends on the position of the switch. When the working power supply fails, the standby power supply will start automatically and transmit signals at the same time, delay the oil immersed transformer to disconnect the circuit breaker on each side, and automatically transmit signals when the cooling system fails.
The automatic control of forced oil circulation water-cooled oil immersed transformer shall be designed according to the principles specified in Article 2 to meet the following principles. Before the working cooler is put into operation, the oil pressure must be determined, and the working cooling water solenoid valve must reflect the established oil pressure and the action of the oil flow annunciator and open automatically. The oil pressure during operation is always higher than the water pressure. When the oil pressure drops or rises, the pressure difference of the set value is small, so the pressure difference alarm acts as a fault cooler, puts the preliminary cooler into operation and sends a signal at the same time.
