关键词: 可靠性, 配电网, 弹性, 重要度

Abstract: Due to the increased frequency of extreme weather, the incident rate of widespread power outages in the distribution network has also gradually increased, leading to serious economic losses. Disruption events are inevitable and difficult to predict. After power distribution network suffers from disruptive events, a key step to quickly improving power distribution network resilience with limited resources is to identify the critical nodes that have a high impact on power distribution network resilience improvement.The identification of critical nodes in the power distribution network can help managers to allocate resources scientifically after hazards and quickly restore the power supply capacity of the power distribution network.Due to the unpredictability of disruption events, in addition to the study of the resistance of the power distribution network, the study of how to quickly recover the performance of the power distribution network after natural hazards has also attracted attention.How to combine the importance with the resilience model, calculate the importance of different nodes in the power distribution network after the occurrence of disruption events, and identify the key nodes that have a large impact on the resilience of the power distribution network is still an open research problem. In this paper, the reliability and recovery model of the power distribution network after multi-node failure is investigated.Based on the concept of maximum power supply capacity, combined with the resilience index, the optimal resilience model of the power distribution network is proposed so that the power supply capacity of the distribution system is maximized after disconnection due to partial node failure, when stable operation can be maintained and other nodes are not overloaded.Disruption events may lead to multiple node failures in the power distribution network. When multiple node failures occur, the maintenance strategy focuses on determining the order of maintenance of the failed nodes in order to maximize the recovery capability of the power distribution network, i.e., to the best of its ability within a certain time period.In this paper, we focus on the impact of restoring a single node on the remaining resilience of the distribution network, establish the resilience importance index of the nodes, and perform importance analysis on the faulty nodes, so as to determine the optimal maintenance order of the faulty nodes in a power distribution network with multiple node failures.Finally, the IEEE14 busnode standard test system is used to verify the practicality of the proposed model. The IEEE14 busnode standard test system contains 14 bus nodes and 20 branches, where node S1, node S2, node S3, node S6 and node S8 are generation nodes of the distribution system; node T7 and node T11 are distribution nodes of the distribution system; node D4, node D5, node D9, node D10, node D12, node D13 and node D14 are users in the power distribution system.When the power distribution network is subject to a disruption event, it goes through a resisting phase and then gradually adapts to the impact of the disruption event to reach the stabilization phase, at which nodes S2, S6, T11, T7, D4, D10 and D14 fail. The optimal emergency maintenance strategy needs to be given during the stabilization phase to enable the power distribution network to quickly restore power supply capacity and reduce economic losses. The resilience of the power distribution network is restored to its maximum value when the faulty nodes S6, T7, D4, D10 and D14 are maintained urgently relative to the resilience of the power distribution network after the other faulty node groups are maintained. Therefore, with limited resources and unit emergency maintenance time, only one faulty node can be maintained.Based on the resilience importance, at time 1, the emergency maintenance of the faulty node S6 has the greatest impact on the resilience of the power distribution network; at time 2, the faulty node T7 should be maintained urgently; at time 3, the faulty node D4 should be maintained; finally, the order of maintenance of nodes D10 and D14 has the same impact on the resilience of the network.

Key words: reliability, power distribution network, resilience, importance measure