COORDINATED CONTROL OF DISTRIBUTED ENERGY RESOURCES IN POWER DISTRIBUTION SYSTEM

Abstract

Recent advancements in photovoltaic (PV) and battery technologies, along with significant improvements in the efficiency of power electronic converters, have led to a rapid increase in the penetration of rooftop PV systems and electric vehicles (EVs) within distribution networks. While the integration of these technologies offers substantial economic and environmental benefits and supports the transition toward a more sustainable energy future, it also introduces new operational challenges for power systems. These challenges may include voltage fluctuations, increased system losses, and occurrences of overvoltage or undervoltage, particularly under high PV and EV adoption levels. Traditionally, voltage and reactive power regulation in distribution systems has been managed through Voltage and Var Control (VVC) schemes using equipment such as substation on-load tap changers (OLTCs), voltage regulators, and shunt capacitors. However, with increasing PV and EV penetration, it becomes essential to consider these distributed energy resources in coordination with conventional control devices. This shift necessitates the development of a unified framework for Voltage, Var, and Watt Control (VVWC) to ensure reliable and efficient grid operation. The primary objective of this study is to propose a comprehensive and realistic solution for the coordinated control of PV and EV resources in unbalanced power distribution systems, while considering sustainability and energy justice objectives. To achieve this, a mixed-integer nonlinear multi-objective optimization model is developed, employing a Chebyshev goal programming approach to ensure Pareto-optimal solutions. The model incorporates multiple objectives, including minimizing PV active power curtailment, reducing system losses, flattening the voltage profile, and minimizing unserved demand weighted based on social vulnerability. The formulation accounts for the inherent asymmetries and phase imbalances in distribution systems. To further enhance the study, a seasonal hosting capacity analysis was conducted using correlated hourly sampling, capturing system behavior across different seasons. The proposed VVWC framework is validated through simulations on a modified version of the IEEE 123-bus test feeder, demonstrating its effectiveness in supporting high PV and EV penetration levels while maintaining grid stability and operational efficiency. Most importantly, the study confirms that only through coordinated control strategies can power systems achieve higher integration of distributed energy resources.