Cover Story

Redundancy - Considerations for Protective Relay Systems

The basic concept of redundancy is simple. Instead of relying on a single piece of equipment, there are duplicate or triplicate sets that perform the same function. Consequently, if one piece of equipment fails, the function will still be performed by a redundant device. Redundancy of components plays a major role in elevating the reliability of protection systems. The impact on the power system when a protection device is not functioning when required is much less severe when there is a redundant device that takes over the job. If the redundant devices are of equal performance, there should be no detrimental effect at all on power system operations, and a non- functioning device would just need to be repaired or replaced.

While local redundancy is generally applied, it is not the only mitigation that can be used to improve the  reliability. Remote protection systems may provide adequate protection system reliability in some situations, provided that remote protection can detect faults and provide clearing times that meet performance requirements.More

BeijingSifang June 2016