Simulation Study on the Electric Field of Three-Phase Three-Post Insulators Under Typical Defects

In three-phase three-post insulators, air gaps and crack defects are important sources of partial discharge and surface flashover. Using finite element analysis software, this study created a three-dimensional simulation model to investigate the effect of these defects on electric field distribution. The effects of crack defects and air gaps of different sizes and locations on the electric field distribution were then methodically investigated. According to the results, the most significant electric field distortion is caused by air gap defects close to the phase A conductor, and the distortion is exacerbated by shorter air gap lengths. Air gap length has much less effect on the electric field in the phase B conductor. There is no obvious change in electric field strength with the radius of air gap defects (0.1–2 mm). The electric field strength is negatively correlated with crack height; greater height reduces distortion, while crack width and depth are positively correlated with the surrounding field strength; greater dimensions increase distortion.