SEISMIC RELIABILITY OF ELECTRICAL-POWER TRANSMISSION-SYSTEMS

The reliability of electric power transmission systems is important fo r the probabilistic safety assessment of nuclear power plants under a given earthquake loading as it relates to the loss of off-site power t o the nuclear power plants. Here, a comprehensive model to evaluate th e seismic reliability of electric power transmission systems is presen ted. The model provides probabilistic assessments of structural damage and abnormal power flow that can lead to power interruption in a tran smission system under a given earthquake. With the proposed methodolog y seismic capacities of electrical equipment are determined on the bas is of available test data and simple modeling from which fragility fun ctions of specific substations are developed. Earthquake ground motion s are defined as stochastic processes. Probabilities of network discon nectivity and abnormal power flow are assessed through Monte Carlo sim ulations. The proposed model is applied to the electric power network in San Francisco and vicinity under the 1989 Loma Prieta earthquake, a nd the probabilities of power interruption are contrasted with the act ual power failures observed during that earthquake.