An advanced method for testing of distance relay operating characteristic

This paper describes a test method for distance relays using an advanced open-loop digital simulator. Derivation of test signals during prefault and fault, and test procedure are introduced. It is demonstrated that the method of generating test signals and the procedure of applying them to a relay under test directly affect test results. Prefault voltage and current are also a very important factor. The decaying dc offset is considered as well. Test results for five different relays using this new method are presented in this paper. The results demonstrate practical benefits of the test method.