The complete handbook combines basic electrical fundamentals, detailed descriptions of protective elements, and generic test plans with examples of real-world applications, enabling you to confidently handle nearly any relay testing situation. THEY SHOULD BE GIVEN FIRST LINE MAINTENANCE ATTENTION. ” relay may only need to operate for 0. But failure to operate as intended can result in extensive damage, extended power outages, and loss of life. This problem is worsened by the growing complexity of protection arrangements, application of protection relays with. The protection relay testing procedure is a structured approach to check the operation, accuracy, and reliability of protective relays in power systems. And when those needs change quickly, we have a suitable solution ready for you.