Definition of static circuit breaker :
The static circuit breaker is basically semiconductor-based circuit. This circuit breaker is capable of providing a fast and also a reliable interruption current.
The static circuit breaker is of two types :
- Static AC circuit breaker
- Static DC circuit breaker
Here this article gives information about two circuit breaker to know more details about circuit breaker.
Static AC circuit breaker :
- A simple arrangement of static ac circuit breaker shown in the figure. The circuit can switch on and switch off by using two thyristors SCR 1 and SCR 2.
- When thyristor SCR 1 is turn on a positive cycle alternative supply when the switch is on condition.
- When SCR 1 is off, the current becomes automatically zero.
- When SCR 2 turn on the negative cycle of alternative supply.
- SCR 1 receives the gate pulse through the diode D2 and SCR 1 receives the gate pulse through the diode D1.
Static DC circuit breaker :
- A simple arrangement of static dc circuit breaker shown in the figure given below. Force commutation is essential for turning off a thyristor device.
- When SCR1 turn on, load voltage becomes equal to supply voltage and capacitor get charge through the circuit source voltage Vs, resistor R, capacitor C and SCR 1.
- When breaking the circuit, SCR 2 is turned on.
- SCR 2 turn on and SCR 1 turn off due to reverse voltage across it.
- The capacitor again charge +Vs to -Vs through the circuit Vs, load C and SCR 2.
- When capacitor C is totally charged to -Vs, a current through load will be zero and the same time current through R will less than the holding current of SCR 2.
- At that time SCR 2 will get turn off naturally, from this the value R can be determined.
