Review on voltage regulation techniques via flexible resources in power distribution systems

Distributed generations (DGs), especially rooftop Photovoltaic (PV) generations are widely installed in users’ side in recent years. Meanwhile, electric vehicles (EVs) are getting popular all over the world. With the growing penetration of DGs and EVs, a distribution system's range of voltage variation becomes wider. It will bring more difficulties on voltage regulation issues for distribution system operators (DSOs). Besides the traditional voltage regulation devices, utilizing flexible resources, such as PV, EV, and controllable loads for voltage regulation can supplement DSOs. This paper performs a literature review of the development, impacts, and techniques to deal with the voltage regulation problems. The impact of voltage profile of distribution systems with high penetration of DGs and EVs is first analyzed, and then traditional voltage regulation methods are presented. After that, an overview of voltage regulation methods utilizing flexible resources is introduced.