Seismic redundancy quantification of power system: Case study of a substation<bold> </bold>

Power systems play vital roles in emergency response after earthquakes. As the most important component of a power system, the seismic performance of substations must be studied carefully, especially from a functionality perspective. In most studies, either the definition of substation's functionality is incomplete and thus fails to quantify residual serviceability, or substation performance is not fully examined due to its complexity. In this paper, the seismic performance and redundancy of a typical 220-kV substationwas quantitatively assessed using the state tree method, based on reasonably summarized fragility parameters of major 110-220-kV electrical equipment. Standard equations were proposed to define system redundancy and to predict improved seismic capacities considering the redundancy of different components.<bold> </bold>