Simulation of the Composite Electric Field on 170 kV Disconnector Using the Finite-Element Method

In this study, the effects in terms of electric stress of composite voltages on a high-voltage disconnector were investigated. The main purpose of this study is to determine and evaluate the effects of the conditions that may occur in real working conditions but out of the type tests. As for the disconnector model, one phase of a center-break disconnector was considered. In order to examine the effects of composite voltages on high-voltage disconnectors, a model is defined in the Comsol Multiphysics program. Different types of voltages such as operating voltage, 50 Hz test voltage, lightning impulse voltage, and composite voltage, were applied to the 170 kV disconnector model separately. After applying a composite voltage consisting of power frequency voltage and lightning impulse voltage to the disconnector, electric potential and electric field distributions were obtained. It has been observed that the maximum electric potential and the maximum electric field strength values on the disconnector are higher when composite voltage is applied than when non- composite voltage is applied to the disconnector. It is observed that the intensity of the electric field lines increases near the contacts of the current-carrying arm and the main contacts of the disconnector.