12 - Testing

Abstract

The importance of maintenance and testing of protective gear assumes importance when one considers its role in the power system. It is different from all other equipment in that it is operative for a limited period of time. It is, therefore, most important that it functions correctly when operation is required. To ensure this, regular maintenance and testing of the relay and its associated equipment are required. It is not possible to specify the frequency of testing, which depends on the location and the importance of the equipment. An important piece of equipment with protection mounted in a location where conditions are poor would require some attention every 12 months, or maybe more often in the light of experience, whereas a less important unit with protection in a good location would require testing every 4 years. For site testing, it is necessary to consider the tests to which a relay is subjected in the manufacturers' works. During the development stage of a relay or protection scheme, many tests are performed to achieve the desired characteristics and performance. When development is completed, the equipment is subjected to a type test, which is in two parts—the tests that are common to every relay, impact, vibration, insulation tests, etc.; and the tests that are particular to the relay to prove its characteristics, speed of operation, stability level, CT requirements, etc.