Research on a seismic connectivity reliability model of power systems based on the quasi-Monte Carlo method

•In the seismic reliability assessment of power systems, the quasi-Monte Carlo method sampled by a low-discrepancy sequence is applied in reliability evaluation.•A triangle algorithm can reduce the amount of computation in solving transitive closure, is proposed to establish a seismic connectivity reliability model combining low-discrepancy sequence sampling.•The ground motion attenuation model and the magnification effect of site soil were used to perform a seismic hazard analysis of the demonstration area, and the ground motion intensity along with the spatial distribution characteristics of power system were obtained. To improve the speed of the error convergence of the Monte Carlo method in the seismic connectivity reliability assessment of power systems, the quasi-Monte Carlo method sampled by a low-discrepancy sequence is applied in the reliability evaluation. In addition, a triangle algorithm that can reduce the amount of computation in solving connectivity matrix is proposed to establish a seismic connectivity reliability calculation model with low-discrepancy sequence sampling. The ground motion attenuation model and the magnification effect of site soil were used to perform a seismic hazard analysis of the demonstration area, and the peak ground acceleration and the spatial distribution characteristics of the power system were obtained. Based on the results of the fragility analysis of a 110 kV substation and a 330 kV substation in Xi'an, Shaanxi Province, the standard Monte Carlo simulation and the Sobol sequence quasi-Monte Carlo simulation are carried out. The results show that with the same sampling number, the triangle algorithm has higher operational efficiency. Combining the triangle algorithm with the quasi-Monte Carlo method improves not only the accuracy but also the calculation speed.