Matters that need attention and are about the operation and off-stream of power transformer

  Transformer is outage for one month or put aside and outage for more than 6 months. 

Transformer

What test should be done before it is put into use?

1. If the transformer is outage for one month, we should use the insulation resistance tester 

DC Winding Resistance Meter

to measure insulation before resumption of power.

2. If the transformer is outage for more than 6 months, we should do insulation resistance test and insulation oil pressure test.

3. If the special transformer of drainage and irrigation which is in a dry and cold area, the outage period may be appropriately extended, but not more than eight months.

What are the requirements for transformer operation and outage?

(1) The new transformer must be tested at rated voltage for 5 times, and after the overhaul, the impulse voltage test should be carried out at least 3 times.

500kV25KJ Impulse Voltage Generator 

(2) when the transformer is put into operation, the cooler should be put into use first, and the cooler runs for a period of time (about 15min).

(3) In the 110kV and above neutral grounding system, when the transformer is put into operation and shutdown, the neutral point must be grounded first.Transformer neutral point of the arc suppression coil should be returned and then investted. The neutral point of the two transformers shall not be connected to the neutral bus of an arc suppression coil at the same time.

(4) The power operation, stop the load side of the switch, and then stop switch power supply side (side power from low to high stop); the first pull transformer side switches, pull the bus side gate. Power supply operation is opposite.

(5) Putting into standby transformer should be based on the actual location of the device and meter instructions to determine whether it is carried out the load.  the load has been carried out in order to enable the operation of the transformer power outage. The transformer on the diagonal and the 3/2 connection, although the transformer has been cut off, but the heavy gas and differential protection of the transformer can still cause the closing of the switch. It shauled be based on the actual situation and site regulations to change the location of the gas protection signal or gas out.

(6) The station transformer is not allowed long-term coordination. It can be used to cut the low pressure side of the low voltage side of the circulation with high pressure knife gate cut off the transformer station.