Probability-based seismic reliability assessment method for substation systems

Power systems play a key role in emergency rescue after an earthquake. Substations are among the most important components of a power system, so it is necessary to study their seismic reliability after an earthquake. Most studies, however, have focused on the seismic behavior of major electrical equipment or the reliability of the substation under ordinary operational conditions. The seismic reliability of substations as a system has not been thoroughly studied. This study proposes a new probability-based method to evaluate the seismic reliability of complex engineering systems such as substations. The proposed method developed the state tree to construct a greatly simplified system model that enables the failure probability to be calculated for the whole system, with explicit consideration of correlations among various components. A typical 220/110/10-kV substation was studied with this method, and the most critical components were identified.