Trip circuit supervision

The trip circuit supervision continuously monitors the availability

and operation of the trip circuit. It provides two open-circuit

monitoring functions that can be used to monitor the circuit

breaker’s control signal circuits. It also detects loss of circuit

breaker control voltage.

Self-supervision

The relay’s built-in self-supervision system continuously

monitors the state of the relay hardware and the operation of

the relay software. Any fault or malfunction detected is used for

alerting the operator.

A permanent relay fault blocks the protection functions to

prevent incorrect operation.

The relay has the capacity to store the records of the 128 latest

fault events. The records can be used to analyze the power

system events. Each record includes, for example, current,

residual voltage and angle values, start times of the protection

blocks and a time stamp. The fault recording can be triggered

by the start or the trip signal of a protection block, or by both.