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

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-STATCOM) 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.

[1]  M.Manikanta Prasad,et al.  Stability Enhancement of Multi Machine system using a Unified Power Flow Controller , 2016 .

[2]  Li Wang,et al.  Analysis of measured power-quality results of a PV system connected to Peng-Hu power system , 2014, 2014 IEEE Industry Application Society Annual Meeting.

[3]  Robert H. Lasseter,et al.  Statcom controls for operation with unbalanced voltages , 1998 .

[4]  Tzung-Lin Lee,et al.  D-STATCOM With Positive-Sequence Admittance and Negative-Sequence Conductance to Mitigate Voltage Fluctuations in High-Level Penetration of Distributed-Generation Systems , 2013, IEEE Transactions on Industrial Electronics.

[5]  Li Wang,et al.  Load-Tracking Performance of an Autonomous SOFC-Based Hybrid Power Generation/Energy Storage System , 2010, IEEE Transactions on Energy Conversion.

[6]  M. Dilek,et al.  Simultaneous Phase Balancing at Substations and Switches with Time-Varying Load Patterns , 2001, IEEE Power Engineering Review.

[7]  Li Wang,et al.  Evaluation of measured power-quality results of a wind farm connected to Taiwan power system , 2014, 2014 IEEE Industry Application Society Annual Meeting.

[8]  Mo-Yuen Chow,et al.  Phase balancing using mixed-integer programming [distribution feeders] , 1998 .

[9]  Li Wang,et al.  Dynamic Analysis of a Grid-Connected Marine-Current Power Generation System Connected to a Distribution System , 2010, IEEE Transactions on Power Systems.

[10]  George Stavrakakis,et al.  Modeling and identification of diesel-wind turbines systems for wind penetration assessment , 1993 .

[11]  Li Wang,et al.  Integration of Wind Power and Wave Power Generation Systems Using a DC Microgrid , 2015, IEEE Transactions on Industry Applications.

[12]  Jul-Ki Seok,et al.  Control of series active power filters compensating for source voltage unbalance and current harmonics , 2004, IEEE Transactions on Industrial Electronics.

[13]  Reza Iravani,et al.  A unified dynamic model and control for the voltage-sourced converter under unbalanced grid conditions , 2006 .

[14]  Chia-Hung Lin,et al.  Three-phase balancing of distribution feeders using immune algorithm , 2008 .

[15]  Y. M. Lee,et al.  Transformer and feeder load balancing using a heuristic search approach , 1993 .

[16]  Mo-Yuen Chow,et al.  Phase balancing using simulated annealing , 1999 .

[17]  M. J. Hossain,et al.  Dynamic Stability of Three-Phase Grid-Connected Photovoltaic System Using Zero Dynamic Design Approach , 2012, IEEE Journal of Photovoltaics.

[18]  Sheng-Yen Lu,et al.  A preliminary study on total energy-density variations of a Buddhist temple in Taiwan through long-term field measurements of electric-field strength , 2014, 2014 IEEE Industry Application Society Annual Meeting.

[19]  Tsai-Hsiang Chen,et al.  Optimal phase arrangement of distribution transformers connected to a primary feeder for system unbalance improvement and loss reduction using a genetic algorithm , 1999 .

[20]  Li Wang,et al.  Dynamic Stability Analysis of a Tidal Power Generation System Connected to an Onshore Distribution System , 2011, IEEE Transactions on Energy Conversion.

[21]  H. Nikkhajoei,et al.  A matrix converter based micro-turbine distributed generation system , 2005, IEEE Transactions on Power Delivery.

[22]  Pedro Rodriguez,et al.  Voltage quality improvement of microgrids under islanding mode , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[23]  Tsai-Hsiang Chen,et al.  Optimal phase arrangement of distribution transformers connected to a primary feeder for system unbalance improvement and loss reduction using a genetic algorithm , 1999, Proceedings of the 21st International Conference on Power Industry Computer Applications. Connecting Utilities. PICA 99. To the Millennium and Beyond (Cat. No.99CH36351).