Analysis And Application Of Power Supply Unit Reliability In Distribution Network Based On Load Transfer

As the last link between the transmission system and users,the distribution system operation status directly affects the reliable power consumption of users.The continuous improvement of requirements for power quality makes the reliability evaluation of the distribution network increasingly important in the analysis of the power supply capacity of power system.With the introduction of grid,the power grid has divided the power supply area into unit to realize the refined management of the distribution network.The effective reliability evaluation for the power supply unit can find the weak links in the power supply unit in time,guide grid transformation and upgrading of the distribution network,and ensure the reliable power supply capacity of the distribution network.Therefore,it is necessary to study a reliability evaluation method that can be based on the characteristics of the grid structure and conform to the actual operation of the power grid.This paper studies the load recovery process and the reliability evaluation method considering load transfer.The main contents are as follows:(1)Introduce the common wiring of the power supply unit,and establish the topology model of the unit.Then use topology shrinking method to simplify network topology and reduce the search range of transfer paths.Based on this,the topology search methods are introduced,which lays the foundation of the subsequent research on load transfer.(2)Propose a load recovery strategy using heuristic rules for distribution network.Based on the simplified network,heuristic rules are used to search the fault recovery tree to quickly generate an feasible plan for load transfer.In order to obtain the optimal solution that meets both economy and safety,a candidate solution evaluation system based on the G1-Entropy Weight-TOPSIS method is proposed.Five indexes are used to evaluate all transfer plans,which include switching operation frequency,voltage quality,network loss,transformer capacity margin and transformer load change rate.(3)Propose a reliability assessment method of distribution network based on feeder region and parameter transmission.Firstly,divide the network into feeder divisions,use load blocks and node equivalents.The procedure use load blocks replace the load points that need to be analyzed one by one in the traditional method,which reduces the amount of calculation.Secondly,transferred the component parameters of the terminal area upward layer by layer to obtain the reliability parameters of the load block of the uppermost layer,and then superimpose the upstream area parameters on the terminal area layer by layer to realize the whole network transmission of reliability parameters.Combine the minimal path algorithm to simplify the transfer path and analysis process.In order to analyze the influence of the load transfer situation,the reliability evaluation algorithm takes tie line capacity constraints into account,and makes results closer to the actual operation of the distribution network.