Study On Single-phase Ground Fault Of Non-direct Grounding System

Since the advent of feeder automation(FA)for distribution networks,speed and reliability have always been the goals.In recent years,distributed power sources with many advantages such as excellent power supply complementarity,environmental protection,and flexible operating modes have been connected to the distribution network,which has changed the original flow of the distribution network and further increased the pressure on the self-healing technology of the distribution network.There is an urgent need for a fast and reliable feeder automation to ensure the stable operation and accurate prediction of the distribution network.This paper studies the adaptive method of intelligent distributed feeder automation technology.First of all,the whole fault self-healing process of intelligent distributed feeder automation is studied.According to the fault analysis of the typical grid structure,the working mechanism of distributed FA is summarized.From the distribution network topology identification,fault location,fault isolation mechanism,and completion of non-fault The whole fault self-healing process of regional power supply restoration was researched and analyzed,and an example was verified according to the actual distribution network structure when a fault occurred at different locations.Secondly,it analyzes and studies the impact of distributed generation(DG)infiltration into the distribution network,which is divided into two major aspects.One is to access the distributed power at different locations of the distribution network,and the other is to use the distribution network.Distributed power supplies with different capacities are connected in the system.According to the distribution network structure,build the corresponding simulation model on the software PSCAD/EMTDC,and analyze and explore according to the simulation waveform result diagram.Then,the communication requirements of intelligent distributed FA are given,including its general requirements,fault isolation logic requirements and power supply recovery logic requirements.The information interaction between terminals based on GOOSE service is studied to complete the transmission and processing of messages between terminals.Finally,the process of intelligent distributed feeder automation engineering configuration and terminal configuration are given.According to the information model requirements,the intelligent terminal,GOOSE and distributed DTU are modeled separately.Test conditions.According to the application of the interoperability function,set relevant test parameters to detect the correctness of logic actions in the normal communication state and the abnormal communication state,respectively.