Numerical modelling, simulation and experimental validation of partial discharge in cross‐linked polyethylene cables

Abstract

A clear understanding of the partial discharge (PD) phenomena occurring in cavities at various radial locations in the insulation is essential for proper monitoring of cables. This work presents a comparison of finite element method (FEM) model and capacitive model for simulation of PD in the insulation and an attempt to identify reliable parameters for monitoring the condition of cable insulation is done. A three-dimensional FEM-based model of the cable is developed in ANSYS software by including the effects of surface charge accumulation and propagation along with the phenomena of charge decay at the void surface. The induced charge concept which is correlated with changes in capacitance is employed to model a capacitive model for simulation of PD by considering the free electron availability for simulation of PDs in cables in EMTP software. The experimental validation of developed models is done by PD measurement on 11 kV cross-linked polyethylene cables. Analysis of the simulation results recommends the relevance of the capacitive model to be employed for condition assessment of cable insulation in view of its simplicity and appropriateness in the estimation of model parameters from actual cable measurements.