Electric stress analysis of a medium voltage cable termination subjected to standard and non-standard lightning impulse voltages

Abstract

In the present work, electric stress analysis is performed on a MV cable termination subjected to transient electric stresses. It is well known that stress cone is used in cable joints and terminations to relief electric stresses at the junction point of insulation and conductor screen. The high electric stress near the screen-cut zone may lead to tracking, partial discharge etc. which eventually jeopardize the operation of a power cable affecting its long-term performance. Moreover, a power cable during its period of operation is subjected to different transient electric stresses in the form of standard and non-standard lightning impulse voltages. Therefore, in this contribution, a comprehensive study of transient electric stresses of a medium voltage cable termination is performed by applying different standard and non standard lightning impulse voltages. For this purpose, a 11kV cable termination is modeled in Comsol Multiphysics Software. The transient electric field analysis is performed using Finite Element method. The stress cone deflector angle and the relative permittivity of the deflector material is also varied to obtain a best possible design that minimizes the electric stress at the insulation-screen junction of a cable termination under the application of impulse voltage stresses.