A Cascaded D-STATCOM Integrated with a Distribution Transformer for Medium-voltage Reactive Power Compensation

  • Lei, Ertao (School of Electrical and Electronic Engineering, Huazhong University of Science and Technology) ;
  • Yin, Xianggen (School of Electrical and Electronic Engineering, Huazhong University of Science and Technology) ;
  • Chen, Yu (School of Electrical and Electronic Engineering, Huazhong University of Science and Technology) ;
  • Lai, Jinmu (School of Electrical and Electronic Engineering, Huazhong University of Science and Technology)
  • Received : 2016.08.11
  • Accepted : 2016.12.03
  • Published : 2017.03.20


This paper presents a novel integrated structure for a cascaded distribution static compensator (D-STATCOM) and distribution transformer for medium-voltage reactive power compensation. The cascaded multilevel converter is connected to a system via a group of special designed taps on the primary windings of the Dyn11 connection distribution transformer. The three-phase winding taps are symmetrically arranged and the connection point voltage can be decreased to half of the line-to-line voltage at most. Thus, the voltage stress for the D-STATCOM is reduced and a compromise between the voltage rating and the current rating can be achieved. The spare capacity of the distribution transformer can also be fully used. The working mechanism is explained in detail and a modified control strategy is proposed for reactive power compensation. Finally, both simulation and scaled-down prototype experimental results are provided to verify the feasibility and effectiveness of the proposed connection structure and control strategy.


Supported by : National Natural Science of China


  1. F. Shahnia, S. Rajakaruna, and A. Ghosh, Static Compensators (STATCOMS) in Power Systems, Springer, 2015.
  2. O. P. Mahela and A. G. Shaik, "A review of distribution static compensator," Renewable and Sustainable Energy Reviews, Vol. 50, pp. 531-546, Oct. 2015.
  3. K. Sano and M. Takasaki, "A Transformerless D-STATCOM based on a multivoltage cascade converter requiring no dc sources," IEEE Trans. Power Electron., Vol. 27, No. 6, pp. 2783-2795, Mar. 2012.
  4. H. Akagi, H. Fujita, S. Yonetani, and Y. Kondo, "A 6.6-kV transformerless STATCOM based on a five-level diode-clamped PWM converter: System design and experimentation of a 200-V 10-kVar laboratory model," IEEE Trans. Ind. Appl., Vol.44, No.2, pp. 672-680, Mar. 2008.
  5. H. P. Mohammadi and M. T. Bina, "A transformerless medium-voltage STATCOM topology based on extended modular multilevel converters," IEEE Trans. Power Electron., Vol.26, No.5, pp. 1534-1545, May 2011.
  6. H. Akagi, S. Inoue, and T. Yoshii, "Control and performance of a transformerless cascade PWM STATCOM with star configuration," IEEE Trans. Ind. Appl., Vol.43, No.4, pp. 1041-1049, Jun. 2007.
  7. J. I. Y. Ota , Y. Shibano, N. Niimura, and H. Akagi, "A phase-shifted-pwm D-STATCOM using a modular multilevel cascade converter (SSBC)-part I: modeling, analysis, and design of current control," IEEE Trans. Ind. Appl., Vol.51, No.1, pp. 279-288, Jan. 2015.
  8. M. K. Sahu and G. Poddar, "Transformerless hybrid topology for medium-voltage reactive-power compensation," IEEE Trans. Power Electron., Vol. 26, No. 5, pp. 1469-1479, Jun. 2011.
  9. L. Wang, C. S. Lam, and M. C. Wong, "A hybrid-STATCOM with wide compensation range and low DC-Link voltage," IEEE Trans. Ind. Electron., Vol. 63, No. 6, pp. 3333-3343, Jun. 2016.
  10. S. Rahmani, A. Hamadi, K. Al-Haddad, and L. A. Dessaint, "A combination of shunt hybrid power filter and thyristor-controlled reactor for power quality," IEEE Trans. Ind. Electron., Vol.61, No.5, pp. 2152-2164, Oct. 2014.
  11. C. Kumar and M. K. Mishra, "An improved hybrid DSTATCOM topology to compensate reactive and nonlinear loads," IEEE Trans. Ind. Electron., Vol. 61, No. 12, pp. 6517-6527, Dec. 2014.
  12. C. Wang, X. Yin, Z. Zhang, and M. Wen, "A novel compensation technology of static synchronous compensator integrated with distribution transformer," IEEE Trans. Power Del., Vol. 28, No. 2, pp. 1032-1039, Apr. 2013.
  13. B. Gultekin and M. Ermis, "Cascaded multilevel converter-based transmission STATCOM: system design methodology and development of a 12 kV ${\pm}12$ Mvar power stage," IEEE Trans. Power Electron., Vol. 28, No. 11, pp. 4930-4950, Nov. 2013.
  14. C. O. Gercek and M. Ermis, "Elimination of coupling transformer core saturation in cascaded multilevel converter-based T-STATCOM systems," IEEE Trans. Power Electron., Vol. 29, No. 12, pp. 6796-6809, Dec. 2014.
  15. S. X. Chen, Y. S. Foo. Eddy, H. B. Gooi, M. Q. Wang, and S. F. Lu, "A centralized reactive power compensation system for LV distribution networks," IEEE Trans. Power Syst., Vol. 30, No. 1, pp. 274-284, Jan. 2015.
  16. IEC Standard Voltages, IEC 60038, Edition 7.0, 2009-06.
  17. A. C. Franklin and D. P. Franklin, "The J & P Transformer Book: A Practical Technology of the Power Transformer," Elsevier, 2013.
  18. Z. Liu, B. Liu, S. Duan, and Y. Kang, "A novel dc capacitor voltage balance control method for cascade multilevel STATCOM," IEEE Trans. Power Electron., Vol. 27, No. 1, pp. 14-27, Jan. 2012.
  19. L. Maharjan, S. Inoue, and H. Akagi, "A transformerless energy storage system based on a cascade multilevel PWM converter with star configuration," IEEE Trans. Ind. Appl., Vol.44, No.5, pp. 1621-1630, Sep./Oct. 2008.