Analysis of Transformer GSB Bushing Fault Causes Based on Finite Element Simulation

Abstract

In response to a sudden explosion and fire fault during the operation of a GSB dry-type transformer bushing in a certain power grid company, based on the structural parameters of the bushing measured by the supplier and on-site, a reverse design of the capacitor core was carried out on the faulty bushing. Based on the measured parameters and reverse design results, a finite element simulation model of the bushing electric field and structural force field was established. Calculate the electric field distribution of the casing under normal operation, 60s power frequency withstand voltage, lightning impulse, operation impulse, and other operating conditions; Conduct finite element simulation of structural mechanics to calculate the stress distribution of the casing under conditions such as cantilever load and short circuit impact; Based on the discharge traces discovered during disassembly, simulation calculations were conducted by assuming the defect situation of the casing, and the electric field distribution of the casing under different defect types was quantitatively analyzed. The simulation calculation results of the electric field under various working conditions have verified that the occurrence of this fault is the result of multiple defects working together, providing quantitative support for fault analysis and providing a certain reference for the operation and maintenance of similar casings.