Automated testing of power system protection relays

Regular testing of protection relays is vital to maintain the integrity of electrical power transmission and distribution systems. Until recently, such testing was time consuming and required a high level of engineering skill. New developments in automatic relay test sets allow more efficient deployment of skilled personnel and permit more frequent testing which will lead to an overall improvement in power-system operational reliability. The authors describe the requirements for automatic test facilities and then go on to discuss hardware, software, and test routines. Test results and field experience are described