GTO circuit breakers

There has been growing interest in the GTO circuit breakers for electric railways. The GTO circuit breaker features high speed interrupting capability and hybrid analog/digital control. This provides short interrupting times when short-circuit faults occur close to the substation and also gives precise overload protection of the circuit breaker itself. The electromagnetic energy trapped in the circuit inductance is dissipated in the energy absorber. A zinc oxide varistor, showing a sharp nonlinear voltage-current characteristic, provides a desirable property as the energy absorber. The author discussed the main features of the GTO circuit breaker