Application of Intelligent Current Protection of Zero Time Limit in Radial Distribution Network

For problems that traditional current protection in multistage radial distribution network cannot meet selectivity and speed requirements at the same time and has protection dead zone, principle and application examples of an intelligent current protection scheme of zero time limit were introduced. Optical fiber is used to achieve information exchange between current protections at the lower and upper levels, which solves the problem of protection coordination. Delay time of quick break protection of protection devices at all levels are set to 0 s so that quick break protection of incoming line can be the main protection of bus fault at the same time, which solves the problem of protection dead zone. The application result shows that the scheme can block underground override trip successfully.