Definite Trip Alarm; Lockout Of The Auto-Reclose Function; Inverse Definite Minimum Time Characteristics; Technical Reference Manual - Ansi Version - ABB REF610 Technical Reference Manual

REF610 REF610
5.1.4.9.
44
Feeder Protection Relay

Technical Reference Manual - ANSI Version

Definite trip alarm

The AR function generates a definite trip alarm signal after an unsuccessful auto-
reclose sequence, i.e. when no more auto-reclose shots are allowed but the network
fault has not be cleared, the circuit breaker is open and there is no ongoing shot. The
definite trip alarm signal is also be generated in case a protection trips the circuit
breaker while the AR function is disabled.
The definite trip alarm signal is active for 1 second.
The definite trip alarm signal will not be generated if the AR function
has been set out of operation.

Lockout of the auto-reclose function

The lockout signal indicates whether the AR function is ready for shot initiation.
The AR function will be locked out in any of the following situations:
The AR function generates a definite trip alarm
*
The AR function is disabled
*
Circuit-breaker closing fails
*
Manual circuit-breaker closing is detected
*
The lockout signal is reset and the AR function ready for shot initiation on
expiration of the set reclaim time. The set reclaim time starts when the definite trip
alarm signal, the AR disable signal or the CB reclosing failed signal has been
reset or the circuit breaker closed, depending on the reason for the AR function
being locked.

Inverse definite minimum time characteristics

The low-set overcurrent and ground-fault elements can be given an inverse definite
minimum time (IDMT) characteristic. At IDMT characteristic, the operate time of
the element is dependent on the current value: the higher the current value, the
shorter the operate time.
The relay provides nine IDMT characteristics, of which four comply with the IEC
60255-3 and three with the IEEE C37.112 standard. Two are special characteristics
according to ABB praxis and are referred to as RI and RD.
The time/current characteristics can be selected either via the HMI or the SPA bus as
follows:
1MRS755535