Reduction of three-phase voltage unbalance subject to special winding connections of two single-phase distribution transformers of a microgrid system using a designed D-STATCOM controller

• Published in: 2017 IEEE Industry Applications Society Annual Meeting pp. 1 - 9
• Main Authors: Li Wang, Wei-Sheng Liu, Chuan-Chieh Yeh, Chien-Hsiang Yu, Xiu-Yu Lu, Bing-Lin Kuan, Prokhorov, Anton V.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.10.2017
• Subjects: distribution static synchronous compensator; distribution transformer; Iron; microgrid system; U-V/V-V winding connections; Voltage unbalance
• DOI: 10.1109/IAS.2017.8101870

The U-V or V-V winding connections of two single-phase distribution transformers are widely utilized in distribution systems to deliver power to various three-phase and/or single-phase loads. Such special winding connections of distribution transformers can cause three-phase voltage unbalance in distributions systems, which could also lead to unexpected trip of ground relay, extra power losses on distribution-system lines, reduced operating efficiency of induction-motor loads, etc. This paper proposes a distribution static synchronous compensator (D-STASTCOM) to effectively improve the voltage unbalance of a distribution system connected with a microgrid system. The studied microgrid system contains various renewable-energy resources, a diesel-engine generator, and three distribution transformers with U-V and/or V-V winding connections. The simulation results show that the proposed D-STATCOM with the designed controller can effectively reduce voltage unbalance of the distribution system connected with the studied microgrid system when the distribution transformers have U-V and/or V-V winding connections.