Application of optimal hardening for improving resilience of integrated power and natural gas system in case of earthquake

Abstract

Growing penetration of natural gas-fired power units in power systems due to their superior characteristics has significantly increased the interaction between power system and natural gas system. In this paper, a robust optimization model is proposed to enhance the resilience of the integrated power and natural gas system (IPGS) against earthquakes. The proposed model is formulated as a tri-level mixed-integer linear program where optimal hardening of power transmission lines and natural gas transmission components (passive pipelines and compressors) is provided in the upper level as an effective preventive measure. A multi-regional uncertainty set is introduced in the middle level to determine the worst damages imposed to the IPGS by earthquake. A discrete uncertainty set is also considered in the middle level to take the intermittency of the wind generation into account. In the lower level that includes operational constraints of the IPGS, the recourse decisions are made to minimize power and natural gas load-loss cost and operation cost. Since there are binary variables in the lower level, the Nested Column and Constraint Generation algorithm is adopted to solve the proposed model. Numerical studies are tested on 6-bus-7-node and 24-bus-20-node IPGSs to validate the effectiveness of the proposed method.