• Title/Summary/Keyword: DC Offset Removal Filter

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Advanced DC Offset Removal Filter of High-order Configuration (고차 구성의 개선된 직류 옵셋 제거 필터)

  • Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.62 no.1
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    • pp.12-17
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    • 2013
  • Fault currents are expressed as a combination of harmonic components and exponentially decaying DC offset components, during the occurrence of fault in power system. The DC offset components are included, when the voltage phase angle of fault inception is closer to $0^{\circ}$ or $180^{\circ}$. The digital protection relay should be detected quickly and accurately during the faults, despite of the distortions of relaying signal by these components. It is very important to implement the robust protection algorithm, that is not affected by DC offset and harmonic components, because most relaying algorithms extract the fundamental frequency component from distorted relaying signal. So, In order to high performance in relaying, advanced DC offset removal filter is required. In this paper, a new DC offset removal filter, which is no need to preset a time constant of power system and accurately estimate the DC offset components with one cycle of data, is proposed, and compared with the other filter. In order to verify performance of the filter, we used collecting the current signals after synchronous machine modeling by ATPDraw5.7p4 software. The results of simulation, the proposed DC offset removal filter do not need any prior information, the phase delay and gain error were not occurred.

Advanced Distance Relaying of on a Double Circuit Transmission Line (병행 2회선 송전선로의 개선된 거리계전기법)

  • Park, Chul-Won
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.8
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    • pp.23-31
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    • 2015
  • This paper proposes an advanced distance relaying based on the DC offset removal filter to minimize the effects of DC offset on a double circuit transmission line. The proposed DC offset removal filter uses only one cycle of data for phasor extraction computation, which does not need to preset the time constant of the DC offset component. This proposed distance relaying uses not only the residual current of the faulted circuit but also mutual current of the healthy adjacent circuit. A series of off-line test results using ATP simulation data show the effectiveness of the an advanced distance relaying.

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)

  • Lee, Hwan;Jung, No-Geon;Kim, Jae-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.6
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    • pp.1108-1114
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    • 2016
  • 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.

Fault Location Algorithm in a Two-ended Sources Transmission Line (양전원 송전선로의 고장점 표정 알고리즘)

  • Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.65 no.1
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    • pp.18-24
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    • 2016
  • In order to service restoration and enhance power system reliability, a number of impedance based fault location algorithms have been developed for fault locating in a transmission line. This paper presents an advanced impedance-based fault location algorithms in a two-ended sources transmission line to reduce the DC offset error effects. This fault location algorithm uses of the GPS time synchronized voltage and current signals from the local and remote terminal. The algorithm uses an advanced DC offset removal filter. A series of test results using ATPdraw simulation data show the performance effectiveness of the proposed algorithm. The proposed algorithm is valid for a two-end sources transmission network.

A Study on Advanced Fault Locating for Short Fault of a Double Circuit Transmission Line (병행 2회선 송전선로의 선간단락시 고장점 표정의 개선에 관한 연구)

  • Park, Yu-Yeong;Park, Chul-Won
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.30 no.1
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    • pp.28-37
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    • 2016
  • Fault locating is an important element to minimize the damage of power system. The computation error of fault locator may occur by the influence of the DC offset component during phasor extraction. In order to minimize the bad effects of DC offset component, this paper presents an improved fault location algorithm based on a DC offset removal filter for short fault in a double circuit transmission line. We have modeled a 154kV double circuit transmission line by the ATP software to demonstrate the effectiveness of the proposed fault locating algorithm. The line to line short faults were simulated and then collected simulation data was used. It can be seen that the error rate of fault locating estimation by the proposed algorithm decreases than the error rate of fault locating estimation by conventional algorithm.

A Study on Digital Fault Locator for Transmission Line (송전선로용 디지털 고장점 표정장치에 관한 연구)

  • Lee, Kyung-Min;Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.4
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    • pp.291-296
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    • 2015
  • Transmission line is exposed to a large area, and then faults are likely to occur than the other component of power system. When a fault occurs on a transmission line, fault locator helps fast recovery of power supply on power system. This paper deals with the design of a digital fault locator for improvement accuracy of the fault distance estimation and a fault occurrence position for transmission line. The algorithm of a fault locator uses a DC offset removal filter and DFT filter. The algorithm utilizes a fault data of GPS time synchronized. The computed fault information is transmitted to the other side substation through communication. The digital fault locator includes MPU module, ADPU module, SIU module, and a power module. The MMI firmware and software of the fault locator was implemented.

Eliminating Method of Estimated Magnetic Flux Offset in Flux based Sensorless Control of PM Synchronous Motor using High Pass filter with Variable Cutoff Frequency (모터 운전 주파수에 동기화된 차단주파수를 갖는 HPF(High pass filter)를 적용한 영구자석 동기전동기의 자속기반 센서리스 제어의 추정 자속 DC offset 제거 기법)

  • Kang, Ji-Hun;Cho, Kwan-Yuhl;Kim, Hag-Wone
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.455-464
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    • 2019
  • The sensorless control based on the flux linkage of PM synchronous motors has excellent position estimation characteristics at low speeds. However, a limitation arises because the integrator of flux estimator is saturated by the DC offset generated during the analog to digital conversion(ADC) process of the measured current. In order to overcome this limitation, HPF with a low cutoff frequency is used. However, the estimation performance is deteriorated (Ed- the verb deteriorate already includes the meaning of 'problem') at high speed due to the low cutoff frequency, and increasing the cutoff frequency of the HPF induces further problems of phase leading and initial starting failure at low speeds. In this paper, the cutoff frequency of HPF was synchronized to the operation frequency of the motor: at low speeds the cutoff frequency was set to low in order to reduce the phase leading of the estimated flux, and at high speeds it was set to high to raise the DC offset removal performance. As a result, the operating range was increased by 200%. Furthermore, a phase compensation algorithm is proposed to reduce the phase leading of the HPF to less than 1.5 degrees over the full operating range. The proposed sensorless control algorithm was verified by experiment with a PM synchronous motor for a washing machine.

Fault Locating Improvement of Transmission Line (송전선로의 고장점 표정 개선)

  • Park, Yu-Yeong;Lee, Jae-Yun;Seok, Kwang-Ho;Kim, Yoon Sang;Park, Chul-Won
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.547-548
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    • 2015
  • In order to reduce error of the distance relay, we propose an improved fault locating scheme using DC offset removal filter. We were modeled 154 kV transmission system using ATP software in order to demonstrate the usefulness of proposed scheme, and applied to the proposed scheme using collected voltage signal and current signal by line-to-ground fault.

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