Application Of Two-stage Resilience Improvement Strategy In Distribution Network

With the increasing frequency of extreme events such as typhoons,earthquakes,and ice disasters,the occurrence of large-scale power outages is not uncommon,causing serious safety and economic impacts on society.The distribution network is located at the end of the power grid,close to various loads at the end,and maintaining its normal operation after extreme events is of great significance.Therefore,the concept of power system elasticity has been proposed to describe the ability of the power system to resist disasters,reduce fault losses,and quickly recover the power grid after extreme events occur.In terms of distribution network elasticity improvement strategies,there are generally two measures based on time scales:planning stage measures and operation stage measures.However,although all reinforcement measures for the line and extensive configuration of energy storage systems can greatly improve the elasticity level of the distribution network,their investment cost is very large,and the low probability of extreme events also leads to low resource utilization rate,making it difficult to promote on a large scale.Therefore,it is necessary to conduct research on the rational allocation of various distribution network elastic resources.Therefore,this article conducts research on the application strategy of two-stage elastic planning in distribution networks.Firstly,the integration of weighted load loss and time axis under extreme events in the distribution network planning model is introduced into the elasticity index.Secondly,based on the impact of extreme disaster typhoons on the distribution network,the line fault rate threshold method is used to effectively analyze the fault status of the distribution line,and a set of line fault states and a reinforcement model of the line are established to obtain emergency operation state scenarios and normal operation state scenarios.Then,a multi resource two-stage planning strategy considering the improvement of distribution network elasticity was proposed.In the first stage of optimization,the goal was to minimize investment costs,taking into account various investment constraints,and optimizing the allocation of energy storage,interconnection switches,and reinforced line resources in the distribution network.In the second stage,in the case of post disaster operation,the operation status of the energy storage system and the interconnection switch is optimized by taking the comprehensive loss of load cost of the post disaster distribution network as the goal and considering various operational constraints.Finally,a two-stage distribution network multi resource multi-objective planning strategy considering elasticity improvement was proposed,which optimizes the allocation of energy storage,interconnection switches,and reinforced line multi resources in the distribution network.This not only improves the elasticity level of the distribution network,but also enhances the economic and reliability benefits during normal operation of the distribution network,achieving the comprehensive benefits of elastic resources,This article conducts simulation analysis on an improved IEEE33 node distribution system example to verify the effectiveness of the proposed method.