Study On Fault Positioning Technology Of Small Current Grounding System

When the system fails, the current is relatively small, it can keep the running time under fault conditions, and will not have an impact on the continuous power load. Currently used for low-voltage distribution networks generally use a small current neutral grounding (including three types of methods:not grounded, Petersen coil impedance grounding and by ground); and because there may be a fault current is small, the arc becomes unstable, etc., therefore, when a small current grounding system detects ground faults way there will be some difficulties, and the lack of effective fault line selection method, this is an important issue in power system protection exist in the work. In recent years, with the gradual start-up and development of distribution automation technology, making in the event of line failure, the use of automatic devices can quickly and accurately determine that these failures, it is particularly important.Firstly, the neutral point of the various power system wiring method gives a brief introduction and comprehensive comparison of operating parameters partial wiring (which is mainly for the small current grounding system in the presence of three neutral wiring schematic knowledge and operating characteristics). In further consideration of the amount of steady and static electrical fault,which is occured in the small current grounding system, the program, which is commonly used to explain the basic principles of line selection and the limitations, is reviewed. Tthe zero-sequence comparison exercises, injecting signal, the fifth harmonic, zero-sequence current amplitude method than four methods to analyze the fault location principle is discussed, and its advantages is derived, there are still problems and engineering applications. And on this basis, the common fault location methods are introduced and analyzed. Finally, the small current grounding system single-phase ground fault line selection is simulated, and the first practical fault localization model is established.