Partial discharge resulting from internal degradation in underground MV cables: modelling and analysis

A significant cause of underground cable failures is the breakdown of electrical insulation between the conductors due to the internal partial discharge (PD) activity. Failure in cable insulation is generally resulted by a degradation phase which may last several years. Modeling and analysis of medium voltage equipment and partial discharge phenomena are mainly based on electric field analysis. The initiation and propagation of PD activity are subject to the maximum value of electric stress across the degradation of the void. The work presented in this paper considers the electrostatic consequences of the presence of void-defects in MV cables and, in particular, the likelihood of resulting in internal partial discharge. This work is based on online PD method which widely known as an efficient tool for detecting insulation defects, assessing and monitoring the insulation of high voltage equipment to prevent its in service failure.