Question

what is the relation between shunt trip and lockout relay and reverse relay and how they all function with each other

Answer 1

Reverse power relay

It is a directional protective relay that prevents the power flow in reverse direction and isolate the devices from supply.

Shunt trip

It is a secondary or optional protection provided in circuit breaker .it initiates the operation while failure in primary or automatic operation for trips the coil.

Shunt trip coil needs the external source to operate.

Lockout relay

It is a electromechanical device used for protection which is closed its contact when it is in set condition.Locking out means the circuit cannot normalized until and unless this realy is reset.

The relationship between these parameters are ,

When the reverse power flow occurs reverse relay senses fault and it sends signal to lockout realy which sets the lockout relay will be initiated the contact will be set to open the contacts.The opening contact is done by shunt trip coil. when the fault will clear the lockout relay is resets and supply continuity is enabled