Fault location on transmission lines

In the 1950s overhead line fault locators were classified into Types A,B,C and D according to their mode of operation-each type being associated with one particular implementation or design and all being based on voltage rather than current waves. The latest travelling wave systems which generally use current waves operate simultaneously in Type A and Type D mode and also include a new Type E mode. Type A and Type D modes rely on the fault to produce one or more travelling wave transients from which the fault location can be determined whereas Type E uses transients produced by circuit breaker operations. The principles of Types A, D and E are briefly outlined. Practical experience of fault location using travelling waves is discussed and an installed system is described.