Commissioning of Protective Relay Systems

Performing tests on individual relays is a common practice for relay engineers and technicians. Most utilities have a wide variety of test plans and practices. However, properly commissioning an entire protection system, not just the individual relays, presents a challenge. This paper suggests a process for performing consistent and thorough commissioning tests through many sources: breaking out relay logic into schematic drawings; using SER, metering, and event reports from relays; simulating performance using end-to-end testing and lab simulations; and utilizing other tools, including synchrophasor measurements. We examine and suggest approaches for commissioning several applications: distribution bus protection, short line protection using communications-aided tripping, main-tie-main scheme, line and transformer differential protection. Finally, we propose that, while 100% commissioning certainty may not be possible, we can approach 100% by integrating event report analysis to validate our commissioning strategy.