Fairness-Aware Distributed Energy Coordination for Voltage Regulation in Power Distribution Systems

The accelerating deployment of solar photovoltaics into low-voltage distribution networks can cause reverse power flow and overvoltage problems. However, if coordinated properly, the real and reactive power flexibility of these resources enables distribution operators to manage their networks more efficiently. Existing literature is rich in droop-based control (Volt-Watt and Volt-VAr) and optimization-based distributed energy coordination for four-quadrant control of photovoltaics to prevent overvoltage issues. While optimal coordination can effectively mitigate overvoltage, it treats resources at sensitive parts of the grid unfairly. To address this concern, we propose a distributed optimal power flow formulation that incorporates fairness in curtailing photovoltaic generation and utilizes the reactive power capability of smart inverters. Fair curtailment of photovoltaic systems is studied with aggregation at each of two layers in a distribution network: 1) area-level fairness and 2) feeder-level fairness to demonstrate the flexibility of the proposed approach in resource aggregation. To explore the trade-off, the fairness-aware control actions are compared against the performance of a centralized controller that aims to maximize the aggregate PV generation without incorporating fairness. Simulation results show that introducing area-level fairness increased curtailment by 1.11 percentage points, and feeder-level fairness increased curtailment by 4.7 percentage points compared to a fairness-agnostic control.