A Study on DC Offset Removal using Low-Pass Filter in AT Feeder System for Electric Railway

전기철도 AT급전계통에 Low-Pass Filter를 이용한 직류옵셋 제거에 관한 연구

  • Received : 2016.02.09
  • Accepted : 2016.04.06
  • Published : 2016.06.01


The cause of failure in the AT feeding system is divided into grounding, short-circuit of feeding circuit and internal faults of the railway substation. Since the fault current is very high, real-time current is detected and the failure must be immediately removed. In this paper, a new DC offset elimination filter that can remove component to decrease in the form of exponential function using low-pass filter was proposed in order to extract the fundamental wave from distorted fault current. In order to confirm the performance of the proposed filter method, AT feeder system was modelled by simulation tool and simulations were performed under various conditions such as fault location, fault resistance and fault voltage phase angle in case of trolley-rail short-circuit fault. When applying the proposed DC-offset removal method, it can be seen that the phase delay and gain error did not appear.


AT feeder system;Fault current;DC offset;Low-pass Filter


  1. Sung-IL Kwon et al, "Development of Integrated Protection Relay for AC Railway System with Time Synchronization Function", R&D Plan Report, 2014. 7.
  2. No-Geon Jung, Ho-Sung Jung, Kyung-Wan Koo, Jae-Moon Kim, "The Analysis of Short Current on Actual System through Power Analysis of AT Feeder System for Electric", The Transactions of KIEE, Vol. 63, No. 11, pp. 1582-1587, 2014. 10.
  3. Sang-Hee Kang, Jong-Keun Park, "A New Ultra High Speed Distance Relaying Method Using Travelling Wave Technique", The Transactions of KIEE, Vol. 40, No. 12, pp. 1203-1210, 1991. 12.
  4. Chul-Won Park, "Advanced DC Offset Removal Filter of High-order Configuration", The Transactions of KIEE, Vol. 62P, No. 1, pp. 12-17, 2013. 1.
  5. Jae-Moon Kim, "The Voltage Drop Compensation of Electric Railway Feeding system using a Fuelcell System", The Transactions of KIEE, Vol. 64, No. 2, pp. 342-348, 2015. 2.
  6. Sang-Hee Kang, Jong-Keun Park, "A New Digital Distance Relaying Algorithm Based on Fast Haar Transformation Techniques with Half acycle Offset Free Data", The Transactions of KIEE, Vol. 41, No. 9, pp. 973-983, 1992. 9.
  7. Yang-Su Kim et al, "Wonju-gangneung AC Feeder Simulation Report", 2014


Grant : 철도 핵심부품 및 장치 기술개발 2단계(철도부품창의연구센터)

Supported by : 국토교통과학기술진흥원