Fault Diagnosis and Analysis of 220kV Capacitance Voltage Transformer Based on Multiple Methods

摘要

Capacitive voltage transformer is prone to failure due to the influence of long operation time, bad operating environment and irregular operation. If it is not repaired in time, it will inevitably have a negative impact on the safe and stable operation of substation. Aiming at the oil leakage defect at the top of the electromagnetic unit box of 220kV capacitive voltage transformer, it is determined that the defect is located in the lower capacitance unit by multiple methods of infrared thermal image detection, insulation resistance, capacitance and dielectric loss test. Through the disassembly and inspection, it is found that the lower section partial pressure capacitor and the electromagnetic unit box are connected with the flange sealing rubber strip for damage, the flange is leaking. Partial capacitor element discharge breakdown is in the weak part of the insulating paper board and the disassembly and inspection condition is consistent with the damage result of the capacitance element obtained by the theoretical calculation. In view of the causes of defects, measures such as eliminating hidden dangers of the same kind of equipment, improving the sealing structure of the equipment and strengthening operation monitoring are worked out, which can effectively ensure the safe and stable operation of the equipment.