Performance of 420 kV Instrument Transformers under Earthquake

Abstract

Seismic performance of substation equipment during past earthquakes is poor. In addition, requirement of electric power during post-earthquake led to an increased focus on the earthquake survivability of substation equipment. Equipment installed in the substation is vulnerable to earthquakes by virtue of its geometry and configuration. Interconnection between equipment further aggravates the problem. Failure of substation equipment results in financial loss and considerable time is required to repair/replace the equipment to restore power supply. Earthquake vibration level can be evaluated based on site/location but predicting time of occurrence of earthquake is not possible. High voltage substation equipment shall be designed for seismic loading. Foundation, anchoring, installation and interconnection between equipment also need to be engineered according to the seismic load based on location of installation of equipment. Seismic qualification of various substation equipment as per National and International standard is performed using tri-axial shake table facility of Earthquake Engineering and Vibration Research Centre. Performance of 420kV instrument transformers under earthquake environment is presented in this paper.