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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.

Wall bushings that connect converter valves within hall buildings and other electric facilities in a direct current (DC) field are indispensable in substations but vulnerable to earthquakes. A finite element model was developed to evaluate the seismic performance of a real ultra-high-voltage (UHV) DC wall bushing. The numerical results show that the maximum stress of the wall bushing during seismic activity does not satisfy the strength safety factor provisions within Chinese regulations. To improve the seismic performance of the wall bushing, an energy dissipation device composed of eight friction ring spring dampers (FRSDs) was proposed to be installed between the connection plate on which the bushing is mounted and a steel wall frame. In addition, optimum parameters of the FRSDs were researched and determined, then the seismic responses of the wall bushing with and without the FRSDs were compared to evaluate the energy dissipation effects. Full-scale shaking table tests were conducted on a wall bushing with the designed energy dissipation device. The validity of the numerical simulations and effectiveness of the proposed energy dissipation device of the wall bushing were verified by the experimental results in terms of seismic response mitigation.

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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.