Study on Interference of Partial Discharge Test of 750kV Shunt Reactor in Substation

In order to judge the state of main insulation and turn-to-turn insulation of 750kV shunt reactors in operation. An on-site partial discharge test method for 750kV shunt reactor based on frequency conversion power supply and series resonance technology was put forward in this paper and used in the field test in Xining 750kV substation. Partial discharge test is the most effective method to detect the insulation status of high voltage equipment. It could help to find the insulation defects timely and increase the reliability of electrical equipment in operation. There is no precedent for the on-site partial discharge test of 750kV shunt reactor before because related test equipment in traditional method is too bulky and heavy to place in substation. Due to the wide application of variable frequency series resonance technology, the on-site partial discharge test of 750kV shunt reactor can be carried out. The test results show that the partial discharge capacity of tested shunt reactor is lower than standard value, but main parts of the PRPD map are filled with interference signals. It is difficult to identify the partial discharge signal from tested reactor because of the bad electromagnetic environment and complex interference in the substation. Therefore, the possible interference factors in the test such as corona discharge of adjacent high voltage transmission lines, higher harmonic interference of power supply and loop coupled interference are analyzed in this paper.