Fault Location Function Of The Line Current Differential Protection

Accurate fault location will lighten the work of seeking for the fault and facilitate quicker repair and restoration to reduce the damages due to stop of power supply, once faults occur on the transmission line. To ensure proper operation of the system, it is of great importance to determine the exact fault location when fault happens. For many years, accurate fault location of transmission line has been paid much attention to on the basis of a lot of predecessors' achievements.The principle of differential current protection is simple, and the differential current protection is immune to power system oscillations, series compensation, mutual inductance, two phase operation and single power supply systems, and it has an instinct for phase selection. So it is suitable for acting main protection of transmission lines.The optical-fiber differential current protection will be adopted widely on transmission line with the development of communication technology and the reduction of the cost for communication device. And this made the methods of transmission line fault location reach a new level.In the case above, the thesis is focus on the research of the optical-fiber differential current protection that has the function of the fault location. At first, some existing methods of transmission line fault location are summarized and those methods' primary merits and disadvantages are analyzed as well; At second, some operation criterions of the differential protection are analyzed theoretically; At last, by the dissertation of the DF3322EA optical-fiber differential current protection , the impedance fault location has been discussed mainly in this thesis, the author presented the algorithms using two-terminal data for locating fault place of transmission line based on the DF3322EA, at the same time, the main protection scheme about DF3322EA line different relay is introduced in detail. Lots of RTDS test results and actual operation show that DF3322EA has high reliability and satisfactory performance, the feasibility and advantage of this scheme has been verified. The device has past the static test and the dynamic analog test in NCQTR, and which has been widely used.