Static relay for circuit breaker using thyristor switching - includes two thyristors providing switching, with third additional thyristor providing control to protect against excess voltage

摘要

The static relay, such as a static circuit breaker (1') for an alternating network includes two static interrupters (5, 6) connected in a half-bridge of diodes (10, 11). Two varistors (12A, 12B) which are practically identical, have an operating voltage (VBR) less than the maximum voltage of the network. They are connected in series between the terminals (13, 14) of the circuit breaker (1'). A third static interruptor (15) is connected between the junction (16) of the varistors (12A, 12B) and the junction (17) of the static interruptors. This is controlled to close when one or other of the two interruptors is open. ADVANTAGE - Improved protection against over-voltage.