Research on Reactive Power Optimization Strategy for Voltage Regulation Involving Large-Scale Distributed Photovoltaics in Multi-Time Scales

With the continuous increase in large-scale distributed photovoltaic (PV) integration, issues related to voltage stability and power quality in distribution networks have become increasingly prominent. To address this problem, this paper proposes a multi-time-scale reactive power optimization strategy for voltage regulation based on distributed photovoltaics. The strategy combines day-ahead and intra-day optimization: day-ahead optimization primarily focuses on coordinating the control of capacitors (CB), static var generators (SVG), and on-load tap changers (OLTC), while intra-day optimization dynamically adjusts the reactive power outputs of distributed PVs and SVGs. By constructing multi-objective functions that include network loss minimization, voltage deviation, and PV accommodation, and by balancing these objectives using contribution-based approaches, the overall operational efficiency of PV-integrated distribution networks is improved. Simulation results demonstrate that the proposed strategy effectively suppresses voltage fluctuations, reduces network losses, and enhances the accommodation of distributed PV resources. Meanwhile, it ensures voltage quality in the distribution network and facilitates efficient utilization of distributed PV resources, contributing to the stability and reliable operation of the distribution system.