The maintenance activities for protection relays can be categorized into three main areas: visual inspection, functional testing, and calibration. During visual inspection, the relay should be checked for any signs of damage, such as physical wear and tear, loose connections, or. Protection systems play a key role in ensuring the safe and reliable operation of the entire electrical grid including generation, transmission, and distribution for utility and industrial applications. These devices spend years in standby mode, waiting to isolate faults in milliseconds when called upon. On such products, intensive testing is desired to prove its characteristics and to gain information about it. (ii) On relay types which have been used earlier, only minimum necessary checks should. 5a. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. This guide is intended to bring the Western Electricity Coordinating Council (WECC) into compliance with the North American Electric Reliability Council (NERC) Planning Standards (Reference 3) regarding installation and maintenance of protection systems. This guide is applicable to all “main grid”. The recommendations and guidelines in this document are based on the experience and judgment of WECC members and include criteria for developing protection system best practices that, when implemented and used consistently, result in dependable, secure protection systems.