Life cycle resilience quantification and enhancement of power distribution systems: A risk-based approach

Abstract

Distribution systems in the US are commonly supported by wood utility poles. Since wood poles may experience substantial decay rates, current standards specify a strength-based maintenance program for pole replacement regardless of the poles’ vulnerability and importance in the system. While state-of-the-art methods have developed risk-based metrics to guide system hardening decisions, such metrics are analyzed for the current conditions of the system. In this context, the potential of a stochastic series of hazards over extended horizons and the subsequent effects on the resilience of systems have been largely neglected. To address these limitations, a risk-based methodology is proposed for quantifying the life cycle resilience of power distribution systems. To project pole vulnerability, a recursive approach is developed that captures the stochasticity of precedent failures and subsequent corrective actions over extended horizons. Furthermore, a risk-based replacement index called Expected Outage Reduction (EOR) is introduced that estimates the expected power outage reduction if an existing pole is replaced by a new pole. The application of the proposed method for life cycle resilience analysis and management of a realistic distribution system subjected to stochastic hurricanes indicates that EOR can improve the cumulative life cycle resilience by up to 22.3% over 70 years.