Network Hardening and Optimal Placement of Microgrids to Improve Transmission System Resilience: A Two-stage Linear Program

This paper aims to develop a linear two-stage optimization problem based on an attacker-defender resilient planning (AD-RP) model to improve the power system's operational and infrastructural resilience in the face of low-probability high-impact events. In the developed model, attackers are natural phenomena that can cause the most severe damage to system performance, and defenders are actions that minimize system vulnerabilities. In the first stage, a stochastic model depending on Monte-Carlo simulation is developed to present a new index for selecting the most vulnerable transmission system components. This index is designed based on combining the worst possible case of attack, disaster statistical analysis, system structure and fragility curves. In the second stage, as defense operations, the hardening of vulnerable lines and microgrids placement in the proper places are carried out considering investment budget constraints. Minimizing load shedding and ensuring the resilience of the transmission network are the main objectives behind the second stage. In this regard, a comprehensive metric for the evaluation of the transmission system resilience is introduced. Thanks to a mixed-integer programming problem, the effectiveness of the proposed AD-RP model in increasing system resilience is demonstrated in the IEEE 30-bus and 118-bus test systems.