Power semiconductors-a new method for predicting the on-state characteristic and temperature rise during multicycle fault currents

Abstract

Solid-state switches are being designed for use on AC transmission lines for tighter control of power flow and increased use of transmission capacity in accordance with an advanced concept called "Flexible AC Transmission System" (FACTS). These necessitate using the largest available thyristors and GTOs that must perform under emergency fault conditions with assurance of long term reliability and life expectancy. This paper is concerned with reviewing concepts needed to predict on-state losses incurred at extreme variations of junction temperature and describing an empirical method being used for commercially available 100 mm thyristors.