Research On Assessment And Promotion Method Of Distribution Network Resilience Considering Critical Load

In recent years,extreme events with low probability and high impact characteristics in the world have brought serious economic losses to the power system,and increasing attention has been paid to the ability of power systems to withstand extreme events.At the same time,the more mature reliability indicators in the power system cannot accurately measure the impact of extreme events.Therefore,research on the resilience of power systems is of great economic and social significance.In this paper,a method to evaluate and improve the resilience of distribution networks is proposed,focusing on the impact of critical loads under extreme weather events.In view of the impact of extreme events on distribution network,taking the typhoon weather as an example,a model on the line fault rate of distribution network under the typhoon weather is constructed,which lays a foundation for quantifying the impact of extreme events on distribution network.Considering the effects of strong winds and rainfall,a model on the wind-rain combined fault rate of distribution network under typhoon weather is obtained,according to the strong wind and rainfall of line fault models established independently.The simulation results show that the constructed fault rate model can quantify the impact of typhoon weather on distribution network.At the same time,this model can also be applied to the integration of multiple types of disasters under other extreme events.Aiming at the performance of different grades of loads in resisting extreme events and different requirements for reliability of power supply,a method to evaluate the resilience of distribution networks by focusing on the impact of critical loads under extreme weather events is proposed.This method takes into account the different performances of different levels of loads under extreme events and the ability to prevent faulty power outages.The comprehensive load loss after the weight processing of all grades of load buses under extreme events is used to reflect the resilience of distribution network.It considers the loss of system failure during extreme events and the affected time of distribution network.By using this method to evaluate several common methods of resilience improvement,the effectiveness of this method is verified.Focusing on the efficiency problem in the fault repair process,a method for improving the resilience of distribution network considering the fault repair process is proposed.In the case of adequate repair resources,an optimization of line repair time is proposed.According to the impacts of line faults on distribution network,the priority of different lines is determined according to the given weights.And the repair time of the line is optimized according to priority.In the case of repair resources shortage,an optimization of line repair sequence considering load comprehensive loss is proposed,which uses the minimum load comprehensive loss or the maximum resilience of distribution network as optimization target.The simulation results show that the proposed methods can effectively improve the resilience of distribution network,reduce the load loss under extreme events such as typhoon weather and guarantee the rapid recovery of critical loads.In summary,this paper takes the typhoon weather as an example to quantify the impact of extreme events on distribution network and constructs a framework for evaluating the resilience of distribution network.Also,methods for improving the resilience of distribution network considering the process of fault repair is proposed.The effectiveness of the proposed methods has been validated by examples.