Sustainability Metrics for Inverter-based Voltage Regulation Methods in PV-rich Low Voltage Grids

Increasing distributed solar installations in low voltage distribution grids tend to increase the feeder voltage. Rise in voltage is only acceptable to a certain limit, and control strategies are required to keep voltage within defined bounds for equipment safety and system reliability. PV inverter control strategies are effective tools to prevent overvoltage. Different inverter control strategies have different social, economic, and environmental impacts. Three different sustainability metrics are proposed to quantity these impacts for inverter-based voltage control strategies. Five different PV inverter control strategies are implemented in a radial distribution feeder and power flow is analyzed for one year in a one minute resolution to compute and compare the proposed sustainability metrics. It is shown that the use of reactive power improves sustainability compared to just using active power curtailment. The trade-off of the three objectives were compared using multi-objective optimization for the highest solar irradiance day. Results showed that economic and environmental sustainability are positively correlated, and both are negatively correlated with social sustainability, indicating a required trade-off for voltage control strategies.