backup relay

backup relay

[′bak‚əp ′rē·lā]
(electricity)
A relay designed to protect a power system in case a primary relay fails to operate as desired.
References in periodicals archive ?
where [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] reveal the operation time of the backup relay for the near-end and far-end faults, respectively CTI is the minimum coordination time interval between backup and primary relay; the aim of the time interval is to ensure that circuit breakers clear the fault as directed.
P/B relay pairs Near-end fault current (A) Primary Backup Primary relay Backup relay relay no.
The coordination constraints between the primary and the backup relays are as follows:
main relay protection, HV backup relay protection, together HV backup and MV relay protection and ancillary protection and functions (e.g.
This structure will be implemented by a function on the MatLab software environment, and it will be invoked every time any transmission line suffers any change of state in its own or the backup relays. It is worth mentioning that both for the buses as for the transformers the same implementation procedure described above is used.