An Analytical Method for Resilience Evaluation of Distribution System Based on Instantaneous Availability Increment and Probability Density Evolution

Distribution system resilience evaluation can guide distribution network planning and operation to improve system resilience against extreme events. In this paper, an analytical method for resilience evaluation of distribution systems under wind storms is proposed based on instantaneous availability increment and discrete probability density evolution, considering interconnection switches (ISs), distributed generations (DGs) and repair strategy. This approach eliminates the need for a large number of sampling and optimization solutions required by simulation method, thus enhancing evaluation efficiency. The evaluation process is divided into two processes: outage process and restoration process. A comprehensive resilience evaluation index system is developed. In the outage process, a spatio-temporal grid model of the distribution system and a time-varying failure rate model of components are developed. The instantaneous availability increment and conditional instantaneous availability are proposed to assess the instantaneous availability of nodes. In the restoration process, a component importance index is proposed and the component repair strategy is developed accordingly. The discrete probability density evolution method is used to calculate the resilience indices. Finally, the proposed method is applied to the IEEE 123-node system, IEEE 37-node system and a 361-node real system to demonstrate its correctness and efficiency.