Internal Fault Diagnosis and Analysis of a 1000kV Shunt Reactor with Abnormal Ground Current of Iron Core and Clamp

For a fault case of abnormal grounding current in a 1000kV shunt reactor of a UHV substation, firstly, this paper conducted a preliminary analysis of the fault type based on offline oil chromatography data tracking. Secondly, combined with the high-frequency partial discharge live detection and the monitoring results of the partial discharge intensive care system, it was judged that there is no obvious discharge phenomenon inside the shunt reactor. Finally, according to the ground current test and the circuit modeling analysis, it was judged that there was overlap in ground loop between the iron core and clamp, and the overlap resistance was small. After the current-limiting resistors were installed, the ground current was significantly reduced, but the chromatographic data continued to increase, proving that there were still other lapped hot spots inside. Due to disassembly results returned to the factory, the validity of the ground current test and circuit modeling analysis method of the iron core clamp was verified, which can provide reference for fault diagnosis of internal overlap and abnormal ground current of UHV shunt reactors.