Enhancing the voltage stability of distribution network during PV ramping conditions with variable speed drive loads. (15th April 2020)

• Record Type: Journal Article
• Authors: Maharjan, Salish; Sampath Kumar, Dhivya; Khambadkone, Ashwin M.
• Is Part Of: Applied energy. Volume 264(2020)
• Publication Date: 2020-04-15
• Subjects: Voltage stability -- PV ramping -- Distribution network -- Variable Speed Drives -- Q-V analysis -- DigSILENT; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2020.114733
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Severe PV ramping at high penetration could cause voltage instability in presence of Induction motor loads. Replacement of Induction motor by Variable Speed Drive (VSD) loads enhances voltage stability of distribution network. Enhanced stability with VSD is studied theoretically with Q-V analysis and with time simulations. Minimum IM replacement by VSD is determined for realistic distribution network at various PV penetration levels. Abstract: The Photovoltaic (PV) sources have become the most popular renewable energy resources as it is modular and are deployed quickly. However, the distributed PVs are highly volatile and can have high ramping characteristics where the ramping can go up to 90% of its capacity in about 20 s due to events such as the passing of fast-moving clouds. This kind of PV ramps with high magnitudes can lead to voltage instability in distribution networks that are usually dominated by Induction motor (IM) loads. This paper explains the mechanism of such an instability analytically using Q-V analysis with distribution feeder and IM load characteristics. Highlighting the gradual replacement of IM loads by Variable Speed Drive (VSD) loads due to energy efficiency policies, the paper demonstrates the enhanced voltage stability under VSD loads by both time simulation and analytical approach. Furthermore, the analysis is extended to a realistic distribution network namely, United Kingdom General Distribution System (UKGDS) and extensive case studies are conducted to analyze the voltage stability during PV ramping events at various load compositions of IMs and VSDs. Moreover, the minimum VSD penetration level required to avert the voltage instability at various PV penetration levels have also been determined.