Development And Research On Technology Of Fault Line Selection Based On Medium Resistance Switching In Small Current Neutral Grounding System

Power distribution systems are mostly small current grounding systems. The biggest problem, which plagued the operating personnel, is the line fault, especially the single-phase ground fault monitoring, location and isolation. Despite the small current grounding system does not affect the operation of the grid when the single-phase ground fault, but it might end up to a great threat caused by over-voltage wiring insulation, and thus quickly identify the fault line is of great significance for improving the reliability of power supply.The distribution network to 35kV in our country mostly used large capacity ground operation mode. The class system of single-phase ground fault occurs, because the inductive current, which generated Petersen coil system, will promptly compensate capacitive current. In order to reducing points of failure fault current, the tiny ground-fault current mixed in various disturbances, making distribution network fault verification, and very difficult to find, so a small current grounding system fault line selection problem over the years has not been solved. In view of this, we propose the use of switching shunt resistor method for rapid line selection technology. Based on the research and analysis of both domestic and foreign existing small current grounding system ground fault method, this paper focus on the small current grounding system throws hit resistance method of fault line. This study selects principles and analyzes its effects and feasibility, and the establishment of after simulation model Petersen coil grounded 35kV system to verify the accuracy of the method of switching shunt resistance line selection through a series of simulation. This paper Launched a small current grounding system design cast hit resistance method of fault line selection of complete sets of equipment, analyzed the construction of the system’s software and hardware monitoring platform, so as to develop a prototype device system complete line selection, and select 220kV substation 35kV side were actual line selection sets on-site installation and testing of the device. The results of this paper show that both the occurrence of metal ground fault circuit or ground fault through the transition resistance, arc suppression coil resistance line selection device in the correct line selection can prove the validity of the election to vote quickly hit resistance line technology and feasibility.