Development of a damage simulator for probabilistic seismic vulnerability assessment of electrical installations

Recent earthquakes have revealed the vulnerability of electric power networks to seismic events. To assess their susceptibility to seismic shaking, a user-friendly damage simulator is developed. It consists of two major components: seismic hazard and damage calculation, whereas the inventory of the exposed transmission towers and substations and their vulnerability are provided by the user. The application uses open-source software without any financial costs to users. The computation starts with selection and calculation of either probabilistic or user-defined seismic hazard scenarios including the local site effects. Spectral accelerations at the fundamental vibration period of transmission towers and the peak ground accelerations for substations are considered as intensity measures (IMs) of the transitory seismic shaking. The probabilistic damage assessment incorporates uncertainties in the site parameters and vulnerability of electric installations. The epistemic uncertainty is considered through the logic tree approach introduced in the latest seismic hazard of the National Building Code of Canada, aleatory uncertainty is captured with the Monte Carlo analysis option, whereas the inherent uncertainty related to the structural dynamic response and damage assessment is accounted for with a set of fragility curves describing different damage states. An example of the seismic site characterization, hazard assessment and vulnerability analysis of Hydro-Quebec electrical installations in the Saguenay region, Canada, is presented to illustrate the capacity of the developed software to predict potential damage. Results indicate the resistance of transmission towers and the relatively high vulnerability of substations to seismic shaking.