Domain-based local fairness control guided by voltage sensitivities for high-PV distribution feeders

Overvoltage (OV) events and PV curtailment are increasingly prevalent in distribution feeders with high PV penetration. While Volt-Watt control offers a practical mitigation strategy, “global fairness”—equalizing curtailment across all PV systems—can be ill-posed under heterogeneous electrical conditions and spatially varying irradiance. This study introduces a domain-based local fairness control (LFC) framework that redefines fairness among PV systems by considering only those subject to comparable voltage constraints. The proposed method learns PV-specific voltage-impact characteristics and clusters PVs with similar voltage sensitivity into fairness domains. Within each domain, the LFC enforces intra-domain fairness by equalizing the operational curtailment ratio, while allowing different domains to respond according to their voltage headroom. The effectiveness of the proposed approach was validated using case studies conducted on the IEEE 123-bus feeder with 25 PVs. In Case 1, under an identical OV-free operating condition with a small safety margin, the proposed LFC increases annual harvested PV energy by 986 MWh (+3.61%) compared with the baseline global fairness control, while maintaining zero OV duration throughout the year. The approach also enhances operational fairness based on the curtailment ratios and consistently achieves domain-specific fairness across all identified domains. Case 2 presents an ablation study demonstrating that overall performance depends on the accuracy of voltage sensitivity estimation, highlighting the importance of reliable voltage-impact learning for robust domain formation and stable domain-fairness enforcement. These results indicate that PV curtailment fairness is most effectively defined and enforced locally among electrically comparable PV systems, thereby improving energy harvest without compromising voltage security.