Fault Location Of Radial Distribution Power Line Based On Double Terminal Traveling Wave Principle

Small current grounding system can be allowed to run for some time when single-phase grounding fault occuring, but called for the fault to be eliminated rapidly, this involves the issue of fault location.Single phase grounding fault occurs in small current grounding system , because of its grounding current being feeble, and no obvious fault features, therefore, single phase fault localization is a great difficulty for many years; As to phase to phase fault, because it often has over-current phenomenon, the fault location relatively being easy, but still difficult to achieve precise and automatic positioning.As transient traveling wave fault location principle has been widely applied to long-distance high-voltage transmission lines, the paper has tried this method to distribution power system , especially for radiation distribution power system structure, and has completed the following main aspects:①Several major principles of traveling wave fault location were summarized, and shows that D-type traveling wave location theory is suitable for the fault location of wires with complex structure.②Analysis of the transient traveling wave characteristics when fault generated and its propagation characteristics in the distribution power system. Analysis shows wave propagation in the distribution wires will bring complex reflection and refraction phenomena; and that both single-phase grounding fault and phase-to-phase faults will have aerial mode components of traveling wave, and the aerial mode components have better stable propagation characteristics, and unrelated to the neutral grounding mode, shows theoretically that traveling wave fault location method applied to transmission wires is feasible for distribution wires.③For structural features of radial distribution power lines, have studied fault line selection technology of small current grounding system.Through the composition of main and auxiliary location system to respond to the traditional double terminal wave theory in the use of this type of the distribution lines caused a large number of cost.④Having studied basic implementation methods of double terminal traveling wave fault location applied to this type distribution power lines, including the selection of traveling wave signal types at both the ends, the choice of the wave modulus, time synchronization, communication problems, and the fault location methods of branch lines and the mixed lines, etc.⑤Using the combine of ratio theory and wavelet transform to identify traveling wave heads,simulation results show it can access to high accuracy.⑥Analyzed the main factors of affecting the precision and reliability about the traveling wave fault location applied to the distribution power lines, were verified by simulation.Theoretical analysis and simulation show that D-type double terminal traveling wave principle is more feasible for fault online location of the radial distribution wires.