The Transactions of the Korean Institute of Power Electronics (전력전자학회논문지)

The Korean Institute of Power Electronics (전력전자학회)
권호 표지
DOI QR코드

DOI QR Code

Power Compensator Control for Improving Unbalanced Power of AC Electric Railway

교류전기철도 불평형 전력 개선을 위한 전력보상장치 제어

  • Woo, Jehun (Dept. of Electrical Engineering, Chungnam National University) ;
  • Jo, Jongmin (Dept. of Electrical Engineering, Chungnam National University) ;
  • Lee, Tae-Hoon (Railroad Research Institute, KORAIL) ;
  • Cha, Hanju (Dept. of Electrical Engineering, Chungnam National University)
  • Received : 2019.11.29
  • Accepted : 2020.02.20
  • Published : 2020.06.20
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, we propose a control algorithm to reduce the unbalanced characteristics of a three-phase system power caused by the unbalanced load of the AC electric railway. Then, we verify its performance through the design of a power compensator and experiments applying it. Like electric railway systems, a Scott transformer is applied, and the load and single-phase back-to-back converters are connected to the M-phase and T-phase outputs. The back-to-back converter monitors the difference in active power between the unbalanced loads in real-time and compensates for the power by using bidirectional characteristics. The active power is performed through PI control in the synchronous coordinate system, and DC link overall voltage and voltage balancing control are controlled jointly by M-phase and T-phase converters to improve the responsiveness of the system. To verify the performance of the proposed power compensation device, an experiment was performed under the condition that M-phase 5 kW and T-phase 1 kW unbalanced load. As a result of the experiment, the unbalance rate of the three-phase current after the operation of the power compensator decreases by 58.66% from 65.04% to 6.38%, and the excellent performance of the power compensator proposed in this study is verified.

Keywords

References

  1. J. C. Kim, Feeding System Analysis and Understanding of Korean Railway Electricity, Gidari, 2008.
  2. G. H. Son, K. H. Choi, S. I. Kim, and H. S. Jung, "A study on unbalance compensation using SVC in Electric railway feeding system," in Annual Conference of Korean Society for Railway, pp. 3124-3132, Oct. 2011.
  3. A. V. Jouanne and B. B. Banerjee, “Assessment of voltage unbalance,” IEEE Trans. on Power Delivery, Vol. 16, No. 4, pp. 782-790, Oct. 2001.
  4. I. Beom, S. Choi, and S. Beak, "Study on development of technology to improve electric power quality in AC railway," in Annual Conference of Korean Society for Railway, pp. 248-249, Oct. 2018.
  5. K. Shishime, "Practical application of the railway static power conditioner (RPC) for conventional railways," Meiden Review, No. 3, pp. 38-41, 2012.
  6. R. Grunbaum, "SVC light: a powerful means for dynamic voltage and power quality control in industry and distribution," in Proc. of 8th International Power Electronics and Variable Speed Drives Conference on, No. 475, pp. 404-409, Sep. 2000.
  7. S. Tamai, "Novel power electronics application in traction power supply system in Japan," in Proc. of 16th International Power Electronics and Motion Control Conference and Exposition, pp. 701-706, Sep. 2014.
  8. G. P. Kim and J. O. Kim, "Analysis and compensation of the current unbalance considering dynamic characteristic of feeding traction loads," Journal of the KIIEE, pp. 54-60, Jan. 2013.