Analysis for Typical Fault of 12.5 kV Cabinet Bushing Based on Electro-Thermal Coupling Simulation
摘要
The cases of transformer outlet short circuit caused by the failure of cabinet bushing in the GIS are relatively common in the operation of the power grid. This article establishes an electro-thermal coupling finite element analysis model for the 12.5 kV cabinet bushing fault event of the No.1 main transformer in a 220 kV substation. The electric field distribution and temperature characteristics of the bushing about the fault are obtained by simulating the air gap defect inside the bushing, and the combination of the FEM and Townsend discharge Theory. And it was found that the partial discharge in the internal air gap of the bushing gradually caused the insulation degradation. The temperature rise effect of the bushing under the influence of short-circuit current further accelerates the occurrence of the faults.