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.

Trip circuit supervision

The trip circuit supervision continuously monitors the availability

and operability of the trip circuit. It provides open-circuit

monitoring both when the circuit breaker is in closed and in

open position. It also detects loss of circuit-breaker control voltage.

The recordable quantities include

currents, voltages, power and power factor values. The

recording time depends on a settable demand interval

parameter and the amount of quantities selected. The

quantities’ type and amount to be recorded are determined in

the application configuration. The recorded quantities are

stored in the COMTRADE format.