Important Considerations for Testing and Commissioning Digital Protective Relays: Avoid Misoperations

The proven advantages of digital technology for power system protective relays are now commonplace in the power producing and delivery industry. Digital relays provide unsurpassed reliability and extended capabilities at an economical cost. Keeping pace with the testing and commissioning requirements of these devices has proven to be a challenge for both protective relay engineers and technicians. Although testing procedures have been well defined for single-function electromechanical (EM) protection devices, modern relay test procedures have been left to the utility to develop, creating possible shortcuts that may compromise the protection system operation.