Test run of power transformer factory

Many people may not know much about the power transformer. In fact, the transformer can be electrified for trial operation after careful inspection before it is put into operation.  During trial operation, special attention must be paid to check the following points.  There is no abnormal sound, noise and vibration.  There is no coke odor and other abnormal odor.  There is no local overheating caused by discoloration.  Is ventilation good?  In addition, the following points should be noted.

First, although dry transformer moisture resistance is strong, but because it is generally open structure, or susceptible to moisture, especially the dry transformer insulation level is low (lower insulation level).  Therefore, dry transformer can be operated in relative humidity below 70% to obtain higher reliability.  Dry transformer should also avoid long-term outage, so as not to be seriously damp.  When the insulation resistance value is lower than 1000/V(operating voltage), it indicates that the transformer is seriously damp, and the trial operation should be stopped.

Second, the dry transformer used for boosting the power station is different from the oil-immersed transformer. It is forbidden to operate the low-voltage side open-circuit, so as not to break down the insulation of the dry transformer due to the over-voltage occurring on the grid side or the line being struck by lightning.  In order to prevent transmission overvoltage hazards, a set of overvoltage protection arresters (such as Y5CS zinc oxide arresters) should be installed on the voltage busbar side of dry transformer.