Project Title: Development and Demonstration of a Power Electronics Assisted Distribution Voltage Regulator

Project Summary: The purpose of this project is to develop and demonstrate a novel power electronics assisted voltage regulator for the distribution grid. The proposed solution is based on the existing Step Voltage Regulator (SVR) but potentially increases their number of electrical operations by five times. The proposed solution offers arcless operation, fast dynamic response, volt/var control, and voltage sag/swell compensation capability.

The distribution system voltage volatility caused by changing load conditions and penetration of renewable resources presents an increasing challenge in the grid integration of renewables. Utilities are observing greater voltage volatility on the grid. A number of studies have shown that voltage volatility can occur because of high residential PV as well as on systems without significant PV [1-3]. The problem causes today’s distribution voltage regulators to operate more frequently due to changing distributed generations, which results in more maintenance and shorter life time of voltage regulators. The pure power electronics voltage regulation solutions, such as electronic tap changers and solid state transformers, are too expensive and have technical challenges in terms of reliability, basic impulse insulation level (BIL) and fault current protection for utility applications.

The proposed power electronics assisted arcless voltage regulator solution is built on the existing SVR with mechanical tap changing mechanisms. By having an innovate low cost power electronic module, the proposed solution requires minimum changes to the existing SVR, but eliminates the arcing nature of these tap changers to improve the reliability and life time of the voltage regulators. The proposed approach combines voltage regulation and VAR control into one device. With the power converter providing fast compensation, a combination of new features and benefits of SVR, Static Synchronous Compensator (STATCOM), Dynamic Voltage Restoration (DVR) can be achieved to solve today’s increasing challenges in the grid integration of renewables.

University Team Members
Lead: Dr. Tiefu Zhao – UNC Charlotte
Members: Dr. Mesut Baran – NC State University

Industry Advisor: Duke Energy