Locating faults before the breaker opens — Adaptive autoreclosing based on the location of the fault

This paper reviews technical, safety, and economical merits of adaptive autoreclosing based on fault location calculated in real time. These applications include preventing reclosing for faults on cable sections of hybrid lines comprising overhead and cable sections, faults located close to large generating stations, faults on line sections crossing densely populated areas or fire-prone terrain, or faults on line sections near airports that receive small airplanes. The paper explains principles of fault locating based on traveling waves and introduces an adaptive autoreclosing control logic to allow or cancel reclosing based on the location of the fault. The paper includes examples that explain and illustrate these principles. The paper also describes several methods of using operational data — internal and external faults as well as switching events — to further improve the fault-locating accuracy of a commissioned fault locator.