A Faulty Line Selection Method And The Corresponding Equipment Of Non-effectively Grounded System Single-phase-to-ground Fault Based On The Fuzzy Theory

The single-phase-to-ground fault is the most familiar fault which affects the operation reliability of distribution networks. Many methods of faulty line selection and the corresponding equipments are researched all of the world in order to find out the faulty feeder as quickly as possible. There are many different kinds of faulty line selection principles, and almost all the principles are discussed in the thesis, which are simply summarized into three sorts: stable-components analysis method, transient-components analysis method and signal injection tracking method. But only use single faulty line selection method cannot obtain a satisfied result, therefore using a comprehensive faulty line selection method is necessary.On the basis of the general analysis of the faulty line selection methods and the phenomenon of single-phase-to-ground fault, a new method which fusing the advantages of several complementary methods by using the fuzzy theory is proposed in this thesis. According to the different faulty situation and data reliability, some fault measurement membership functions and criterion weight coefficient membership functions are defined. The new faulty line selection method is constructed by these functions.The defining and calculating method of these membership functions is introduced in detail in the thesis. Many times of different stimulation are done to verify the correct rate of the new faulty line selection method.Finally, a novel faulty line selection equipment is developed on the basis of the new faulty line selection method. The details of software and hardware development are also introduced in the thesis.The results of dynamic physical simulation verified the correction of the method, and indicate that the equipment has a high selection reliability and an anti-interference ability.