Multi-Hazard Line Hardening with Equity Considerations: A Multi-Objective Optimization Framework

Climate change has increased the frequency and severity of extreme weather events such as wildfires, storms, high winds, and floods. Overhead lines are particularly vulnerable to these hazards, prompting utilities to consider reinforcement solutions through undergrounding overhead lines or structural hardening. However, these mitigation strategies are expensive and should be used selectively, prioritized for areas that are most at risk. This necessitates a framework to concurrently balance cost and resilience. In addition, the adopted reinforcement strategy must consider the consequences of possible outages on communities. This paper presents a multi-objective optimization framework to identify overhead line reinforcement strategies in a distribution system exposed to different hazards. A case study is presented for the city of Greeley, CO, which is prone to both wildfire and flood risks. Undergrounding overhead lines and reinforcing tower structures are considered as possible solutions for wildfire-prone areas and flood-prone areas, respectively. The proposed model is adaptable and can be applied to other hazard types and/or geographic regions. The proposed framework incorporates energy justice by prioritizing vulnerable populations and ensuring equitable distribution of reinforcement benefits. The results indicate that targeted hardening can reduce load shedding, improve outage response, and support equitable resilience planning.