The effect of over-voltages on SCR are minimized by using.

di/dt protection:

By using a small inductor, called di/dt inductor, in series with the anode circuit.

dv/dt protection:

dv/dt protection can be achieved by using a snubber circuit in parallel with the device.

Overvoltage protection:

- The effect of overvoltages can be minimized by using non-linear resistors called voltage clamping devices like metal oxide varistors

- At the time of normal operation, it offers high impedance and acts as it is not present in the circuit

- But when the voltage exceeds the rated voltage then it serves as a low impedance path to protect SCR

Overcurrent protection: Fast acting current limiting fuse and circuit breakers are used.

Varistors