Huangbin Liang

Experience from previous earthquakes shows that electrical substations are the most vulnerable components within the power transmission system. Thus, their disaster resilience is essential for providing electric power to communities in earthquake‐prone regions. In this study, a quantitative framework was proposed to assess the seismic resilience of electrical substations. The functionality of a substation was quantified using its maximum allowable transmission capacity that integrates the substation topology, redundancy level, line capacity, and power balance. The network model of the substation was developed to investigate how component damage affects substation's functionality. Substation's recovery was simulated as a time‐stepping process, in which at each time step the substation's ability to provide transmission capacity was conditioned on the functionality state of its components, whose recovery depends on the availability of repair crews and spare parts. The uncertainty of the resilience assessment was quantified by considering the uncertainty in the component‐level vulnerability and recoverability. The impacts of components’ robustness, repair resource constraints, and post‐earthquake recovery scheduling on substation resilience were investigated by modifying components’ seismic fragility curves, available recovery resources, and repair priorities. A case study was conducted on a real‐world 220/110 kV step‐down substation, and a parametric analysis was carried out to investigate the effect of various seismic resilience improvement strategies to demonstrate the applicability of the proposed framework in seismic disaster risk reduction and management.

Electrical substations are crucial components in a power system while substation equipment can be easily damaged in an earthquake. Repairing the damaged equipment as soon as possible is essential to restore the functionality of the substation system and further secure the sustainable power supply of the power grid after the earthquake. However, the damaged equipment cannot be repaired simultaneously due to the limitation of emergency repair resources, and the recovery rate of the substation functionality will vary dramatically depending on the selection of different equipment repair sequences. Therefore, a sensible equipment repair sequence is needed to improve the recovery efficiency of the substation functionality. A resilience-based method was thus proposed in this paper to optimize the equipment repair sequence with the objective of minimizing the resilience index of the substation, which was defined as the post-earthquake overall functionality loss. The heuristic algorithm was incorporated into the systemic resilience assessment framework to find the optimal equipment repair sequence according to different initial damage states of equipment and the limitation of emergency repair resources. A case study was performed on a real-world substation system to illustrate and verify the proposed method, the analysis results can aid decision-makers in the post-earthquake recovery planning.

Electrical substations are critical elements of a power grid, enabling the transmission and distribution of electric power from power generators to the end‐users. Experiences from previous earthquakes have shown that electrical substations can be damaged due to ground shaking, reducing their functionality and potentially preventing the generated electric power from reaching end‐users. To assess the seismic vulnerability of a substation, a modular quantitative assessment method is proposed. In this method, the relation between the functionality state of a substation and the damage state of its components was established through the connection matrix technique. A substation is viewed as a network system, whose topology is defined by the connections among various pieces of electrical equipment (i.e., the components), represented in the connection matrix. The maximum allowable power transmission capacity of the substation after an earthquake is adopted as the system functionality metric, which is jointly determined by the power input, transform, and output capacity of the substation. The seismic vulnerability of an electrical substation is quantified by probabilistically calculating its postearthquake functionality when exposed to various earthquake intensities using Monte Carlo sampling. Finally, the risk of substation functionality loss is quantified by integrating the seismic hazard curve with the seismic vulnerability model of the substation. Two realistic case studies on a distribution substation and a transmission substation, with the same equipment configuration but different power delivery paths, were performed using the proposed method. Furthermore, a sensitivity analysis regarding the equipment fragility parameters is conducted, providing a risk‐informed basis for improving the seismic performance of the substation system.