Risk Assessment Of Distribution Network With Distri-buted Generation In Jiujiang

Because of its direct connection with users,distribution network is an important link to provide power for users,and it is becoming more and more widely concerned.According to statistics,80% of the fault accidents occurred in the distribution network,frequent and sudden failure of the outage will inevitably bring irreparable damage to the national economy and people's lives.Therefore,it is very meaningful to study risk assessment strategy for improving power supply reliability of distribution network.Nowadays,with the gradual increase of distributed energy permeability of distribution network,it shortens the time to restore power supply after failure and reduces power loss.On the other hand,the distribution network risk assessment strategy has changed greatly due to the existence of distributed power supply.In this paper,the risk assessment strategy of distributed power distribution system in Jiujiang has been studied,and the main work is as follows:In this paper,the island partitioning strategy in the risk assessment method of distributed power distribution network has been studied.Set up load node importance and line number as parameter index,set up island partition model.The quantum evolutionary algorithm is used to solve the problem,in order to satisfy the radiation constraint of island partition,the quantum chromosome can be trimmed by the depth first search algorithm.An example is used to verify the conclusion that the introduction of line number can further distinguish the importance of load in the same rank,and effectively improve the proportion of important load recovery in the partition scheme of islands.Through the comprehensive study and comparison of common power grid risk assessment methods,this paper uses the Latin hyper-cubic distribution-Monte-Carlo sampling method to obtain the system state for risk assessment by partitioning,sampling and sequencing,and then defines the evaluation index of the fault outage risk size of distribution network by the severity coefficient.On the basis of this,the risk assessment criteria of power distribution network is established.Using the proposed method of distribution network risk assessment,a case study of risk assessment for a DG distribution network in Jiujiang was carried out.Based on the risk assessment model,algorithm and actual data,the risk assessment of the 2016-year initial wind farm connected to the power grid is carried out,and the risk assessment of the wind farm connected with the 2020 is analyzed and compared with the risk level of the fault outage of the medium voltage distribution network in the two different years.It is verified that the increase of distributed power supply can effectively improve the reliability of distribution network.