On the Fairness of PV Curtailment Schemes in Residential Distribution Networks

Active power curtailment of residential PV systems is an effective way to mitigate technical issues in distribution networks. However, existing curtailment schemes can treat households unfairly; e.g., Volt-Watt schemes increasingly being adopted worldwide inherently penalize PV systems at remote locations in radial feeders. Nonetheless, whether fairness is improved or not by alternative curtailment schemes depends on how the impacts on households are considered. In this context, household-centric metrics that quantify PV harvesting, energy export and financial benefit are used along with the Jain's fairness index to assess fairness from different perspectives. To explore the trade-offs brought by schemes that consider fairness differently, four linearized, three-phase Optimal Power Flow (OPF)-based schemes are proposed to determine, periodically, short-term curtailment settings. Using a real Australian 22kV feeder and realistically modelled LV networks with 4,500+ households, a detailed comparison is carried out considering also a Volt-Watt scheme. Results demonstrate that all the schemes that consider fairness are effective in removing locational penalizations. However, in terms of fairness, their performance across the adopted metrics reveals noticeable trade-offs. This highlights the need for decision-makers to determine the metric from which fairness can be based upon in a way that aligns with their respective policies.