8-4 C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUALSINGLE-POLE TRIPPING CHAPTER 8: THEORY OF OPERATION8Figure 8-2: Fault locator scheme8.2 Single-pole tripping8.2.1 Overview8.2.1.1 IntroductionSingle pole operations make use of many features of the relay. At minimum, the trip output, recloser, breaker control, openpole detector, and phase selector must be fully programmed and in service; and either protection elements or digitalinputs representing fault detection must be available for successful operation. When single pole trip-and-reclose isrequired overall control within the relay is performed by the trip output element. This element includes interfaces withpilot-aided schemes, the line pickup, breaker control, and breaker failure elements.Single pole operations are based on use of the phase selector to identify the type of the fault, to eliminate incorrect faultidentification that can be made by distance elements in some circumstances and to provide trip initiation from elementsthat are not capable of any fault type identification, such as high-set negative-sequence directional overcurrent element.The scheme is also designed to make use of the advantages provided by communications channels with multiple-bitcapacities for fault identification.
