Optimized Adaptive Voltage Control for Distribution Network Using Utility-Scale BESS and PV Systems

The increasing penetration of distributed energy resources (DERs), such as photovoltaic (PV) systems and battery energy storage (BESS), is fundamentally transforming traditional passive distribution networks while creating opportunities to enhance operational efficiency. For instance, BESS can address the intermittent nature of PV output, facilitate peak shaving, and improve the Voltage Profile. Therefore, this paper investigates the operational benefits of PV and BESS to provide additional voltage support, complementing traditional voltage regulation mechanisms such as on-load tap changers (OLTCs). The study is initially conducted on a real medium-voltage (MV) distribution network consisting of 80 nodes operating at 33 kV and 11 kV voltage levels. Two distinct voltage control approaches, local and centralized, are explored. In the local control approach, PV and BESS inverters are operated in either Constant Power Factor (CPF) mode or Voltage-Reactive power (Volt-VAR) mode and their impact is analyzed. Local voltage control often results in sub-optimal utilization of DERs for voltage regulation. To overcome these limitations, a centralized voltage control method is proposed, employing an adaptive optimization algorithm that dynamically adjusts inverter setpoints to enhance voltage performance. The analysis is conducted through both offline and real-time simulations. Offline studies leverage MATLAB and OpenDSS to evaluate the performance of the proposed voltage control strategies using actual measurement data. Real-time validation is carried out using a digital twin setup, where MATLAB/OpenDSS communicates bidirectionally with an OPAL-RT real-time simulator via TCP/IP protocols. This setup facilitates the exchange of network information and execution of control actions, ensuring a robust and realistic evaluation of the proposed schemes. Furthermore, additional testing is performed on a modified IEEE 34-node test system to assess the method's robustness under sudden load drops and partial shading conditions. A detailed comparative analysis with existing voltage control strategies is also presented to highlight the performance advantages of the proposed approach. The results provide valuable insights into the relative effectiveness of local and centralized voltage control methods, demonstrating that the proposed adaptive framework significantly improves voltage profiles and optimizes DER utilization in modern distribution networks.