Failure Analysis of High Voltage Disconnector Under Seismic Load

A disconnector is a mechanical switch that isolates the essential part of the circuit where the repair/replacement of equipment is planned. High voltage disconnectors used in substations are fragile to earthquake events. Mechanical dynamics of the disconnector switch change with a change in the position of the main and earth-moving contact. Hence seismic performance evaluation of disconnectors is highly complicated, seismic behavior should be evaluated under all possible disconnector positions. High voltage disconnectors located in seismic Zones IV and Zone V of India are vulnerable to seismic events. Seismic performance evaluation of high voltage disconnectors, transformer bushings, instrument transformers, circuit breakers etc., along with interconnection of equipment and anchoring will prevent failure in the event of an earthquake. Hence, demand for safe and uninterrupted electrical service in a post-earthquake environment can be maintained. Tri-axial shaker system of Central Power Research Institute (CPRI) can simulate realistic earthquake vibration simultaneously in two horizontal and one vertical direction. Failure analysis of 245 kV disconnectors subjected to seismic loading by the shake table method is presented in this paper.