Mock-up Experiment and Numerical Analysis Simulating a Ground Fault in a Power Cable Termination

Abstract

A method for estimating the internal pressure rise when ground fault occur inside power cable terminations has not been established yet because the pressure rise due to a ground fault is a fast phenomenon that occur within a few milliseconds. In this study, a mock-up experiment was conducted in order to reproduce the first peak of the pressure rise when a ground fault occurs, by burning explosives in the insulators used in 110kV class cable terminations. The experimental results were compared with numerical analysis result, which was solved by the equation of state considering the generation of shock waves. The maximum pressure at the mock-up experiment was 11.4MPa at 2.2ms. Compared to a numerical result with an initial pressure of 10MPa in the combustion gas region, the maximum pressure of the numerical analysis was 25% higher and the time was 0.27ms faster than the result of the mock-up experiment. The local pressure rise could be reproduced approximately by this analysis method. If the strain of the sample and fluid leakage could be reproduced in the model, more accurate analytical results could be obtained.