Fast Distributed Voltage Control for PV Generation Clusters Based on Approximate Newton Method

Solar power generation is exhibiting a distributed development trend, and has changed conventional characteristics of power supply and consumption. The integration of large-scale distributed photovoltaic (PV) generation forms high-penetration PV clusters in distribution networks, which aims to organize and control geographically scattered resources. However, due to the inherent uncertainty, high-penetration PV clusters are suffering from random disturbances and serious voltage risks. Besides, integrating system via power electronic interfaces, PV generation usually tracks system frequency without any backup and regulation capacity, which poses significant challenges to system operation, and requires greater flexibility of voltage control. In fact, by using appropriate methods, PV inverters can autonomously regulate reactive power output in a distributed manner to improve voltage profiles in clusters. In this article, a distributed voltage control method for PV generation clusters is presented to realize decentralized coordination of PV inverters. Based on matrix splitting and approximate Newton method, it can fast respond to reactive power mismatch and realize voltage profiles optimization. Exhibiting a more efficient, reliable and flexible performance than existing decentralized methods in case studies, the proposed method is demonstrated to effectively organize and control PV cluster to provide corresponding reactive power support and exert friendly effect on system operation.