Research On The Device Of Fault Line Selection And Location Of High Resistance Grounding System

With the development of distributed power system automation level in our country, the demanding on the reliability of power supply of user is increasingly higher. Nowdays, neutral grounding methods of distribution network mainly uses the non-grounding or by the extinguishing coil.These methods can operate continuously 2 hours with fault when a signle-phase fault takes place, assure the reliability of power supply.The fault line selection and location work can't get an essential breakthrough because of the fault feature of single-phase ground in these systems is undistinguished.Meanwhile,there is only fault line selection device and no-fault location device in small current earth system. telemeter. Furthermore, the accuracy of fault line selection device in market is poor.This article introduces the neutral grounding by high resistance in detail which have decades of experience in developed countries such as USA,then designs a fault selection and location device of high resistance grounding based on DSP which has the advantage of product at home and aboard,it can locate the fault grounding quickly and accurately. It has mainly done the following aspect job in this paper:(1) introduces the characteristic and application field of neutral grounding by high resistance,and analyzes the single-phase fault of high resistance grounding in detail, then presents a new faulty line detection principle of based on the amplitude comparison of zero sequence active current, and set up the simulation model based on MATLAB to prove the accuracy of theoretical analysis. It is helpful to the development of the device.(2) introduces the traditional methods of fault location,then explains the principle of fault location in high resistance system,and analyzes the components of high resistance grounding device,at last gives the demand analysis of its core fault line selection and location device.(3) this paper presents the hardware scheme based on modularized designing then put forward the principle for IC devices selection,the plan for the system designing, and the realization of anti-interference.(4) this paper presents the scheme of the software designing,analyzes every function module in detail,then gives the flowcharts of the software.At last establishes the software debug platform and finishes the module software writing. (5) in the end, a simulation of high resistance grounding system has built in the laboratory.The device of designed can select the fault line correctly and alarm when a simulation of single-phase fault takes place time after times,the pulse signal output correctly, attains to all expectative requirements.