1. OPERATION OF DRY-TYPE TRANSFORMERS
The safe operation and service life of dry-type transformers largely depend on the safety and reliability of the transformer winding insulation. Winding temperature exceeding the insulation withstand temperature will cause the insulation to age, thereby affecting its service life. It is one of the main reasons that dry-type transformers cannot work normally. Therefore, it is very important to monitor the operating temperature of the transformer and its alarm control.
Dry-type transformers should work under rated capacity and allow short-term overload operation without affecting their life. For indoor transformers, the overload value should not exceed 20%. Under normal circumstances, the load of the transformer should be kept at about 85% of the rated capacity. When the transformer is in overload operation, we must pay attention to monitoring its operating temperature. If the temperature rises to 155°C (an alarm is issued), load shedding measures should be taken (minus some minor loads) to ensure that the insulation of the dry-type transformer is not affected.
2. MAINTENANCE OF DRY-TYPE TRANSFORMERS
Because the operating temperature is directly related to the service life of dry-type transformers, distribution operators should focus on the inspection and maintenance of the fan automatic control system, over-temperature alarm, trip system and temperature display system. Although dry-type transformers are better against moisture, dust in the air will be adsorbed on the insulating surface. Dust reduces the flashover voltage along the surface, and the dust will flashover phenomenon in humid weather. Therefore, dust should be removed regularly and checked for signs of discharge. During the operation of dry-type transformers, please pay attention to check whether there are abnormal noises and whether the bus connecting cables are abnormal. If abnormal phenomena are found, deal with them in time to avoid accidents.