OPTIMAL RC PROTECTION OF THYRISTORS

Abstract

Thyristors are susceptible to the increase rate of anode voltage, recovery overvoltage and current increase rate. They are therefore protected by means of supplementary circuits. Sometimes a protection circuit that has been designed to attenuate a certain transient process is not optimal for the attenuation of some other process, therefore a compromise solution is needed. In this paper, the optimal operating conditions of the thyristor protection are analyzed, where the thyristor parameters that are characteristic for the turn-on and turn-off period have been taken into consideration. The analysis has been performed in a normized form, which assures its general applicability.