Seismic Qualification of High Voltage Substation Equipment

Earthquake causes simultaneous three dimensional ground shaking. Functioning of electrical equipment during and/or after seismic event is paramount for rescue operation and for safe and reliable power supply. High voltage substation equipment are tall and slender structures with low natural frequency. The natural frequency of high voltage substation equipment lies in the high energy band of earthquake signals, also ceramic insulators used in substation equipment are highly brittle which makes it vulnerable to seismic event. Performance of substation equipment under seismic dynamic loading condition should be evaluated to avoid failures. An electrical substation consists of set of equipment that are interconnected. In addition to design of individual substation equipment for seismic loading, interconnection of equipment should also be designed by considering relative displacement between equipment and dynamic load transfer between equipment. Central Power Research Institute (CPRI) is equipped with state-of-the-art tri-axial shake table facility for simulating true earthquake vibration. Seismic qualification methods, codal provisions and seismic performance evaluation of 245 kV Horizontal double break disconnector by shake table method are discussed in this paper. The seismic stresses at critical locations are presented along with relative displacement at the terminal of disconnector.