Application of Probability and Topological Metrics for Resilience Assessment of District Heating Networks

The concept of resilience is essential for reducing the effects of high-impact and low-probability (HILP) events, such as extreme weather variations, geopolitical conflicts, and cyberattacks. District heating systems are particularly susceptible to HILP events given their age and hard-to-access nature, however, they are often overlooked, while power systems receive more attention. This research proposes a novel composite resilience evaluation framework for district heating systems based on key resilience metrics: robustness, resourcefulness, and recovery. Each metric comprises several graph topology-based metrics, normalized to ensure positive increments, and aggregated into resilience blocks. Resilience building blocks are combined into a single composite, weighted resilience index, with values ranging from zero to one for easier interpretation. The proposed index is tested on a couple of experimental networks with basic and advanced topologies and later used to evaluate a district heating system in a mid-sized city in Lithuania. Future research goals for expanding resilience-building blocks, including technical aspects of the network, thermal-hydraulic simulation, and network optimization, are described at the end of the article.

Keywords: Resilience, Safety, Robustness, Resourcefulness, Recovery, District heating, Graph theory, Network topology.