• Title, Summary, Keyword: current detection

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Development of the Leakage Current Detection Module for a Concent (콘센트용 누전감지 모듈 개발)

  • Han, Young-Oh
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.3
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    • pp.447-452
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    • 2013
  • In this paper, the leakage current detection and auto shut-off module for a concent has been developed. Existing leakage current detection modules are detecting resistive leakage current, using a resistive leakage current detection chip but the proposed leakage current detection module separates and detects resistive leakage current in the synthesis leakage current by only programming in a power processor MCU(MSP430). The module implemented by proposed method has early detection and auto shut-off feature at more than resistive leakage current 5mA, and has the advantage of easily adjusting resistive leakage current less or more than 5mA, because of resistive leakage current detection function being implemented by a program in MCU.

A Percentage Current Differential Relaying Algorithm for Bus Protection Blocked by a CT Saturation Detection Algorithm (변류기 포화 곤단 알고리즘으로 억제된 모선보호용 비율 전류차동 계전방식)

  • 강용철;윤재성
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.1
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    • pp.44-49
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    • 2003
  • This paper describes a percentage current differential relaying algorithm for bus protection blocked by a CT saturation detection algorithm. The detection algorithm blocks the output of a current differential relay only if a differential current is caused by CT saturation in the case of an external fault. Moreover, if a current differential relay operates faster than the detection algorithm, the blocking signal is not ignited. On the other hand. if the detection algorithm operates faster than a current differential relay, the output of the relay is blocked. The results of the simulation show that the proposed algorithm can discriminate internal faults from external faults ever when a CT is saturated in both cases. This paper concludes by implementing the algorithm into the TMS320C6701 digital signal processor. The results of hardware implementation are also satisfactory The algorithm can not only increase the sensitivity of the current differential relay but Improve the stability of the relay for an external faults.

Switching Signal Patterns to Prevent Short Circuit of AC Choppers (교류초퍼에서 단락사고 방지를 위한 스위칭 신호 패턴)

  • Jang, Do-Hyeon;Yeon, Jae-Eul
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.9
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    • pp.445-452
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    • 2001
  • Two switching signal patterns are proposed to prevent short circuit of PWM ac choppers. The voltage detection method and the current detection method are proposed to execute two switching signal patterns. In the voltage detection method, the dead-time has to be inserted to the switching signals after polarity of input voltage is checked by voltage transducer at input side. In the current detection method, the direction of load current is checked by current transducer at output side, and the dead-time delay is not considered. Controlling circuit built by current detection method is simple because the dead-time delay is considered. The experimental results are presented to prevent short circuit of ac chopper safely.

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A Study of DC Arc Detection Device (DC Arc 검출장치에 대한 연구)

  • Ban, Gi-Jong;Kim, Lark-Kyo;Nam, Moon-Hyun
    • Proceedings of the KIEE Conference
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    • pp.98-100
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    • 2007
  • DC Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, DC arc detection device is designed for the display of DC arc fault current which is occurred in the local electric network with DC Power. This DC arc is one of the main causes of electric fire. Arc fault in electrical network has the characteristics of low current, high impedance and low frequency. DC Arc current detection device is designed for the display of arc fault current which has the modified arc characteristics.

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Frequency analysis based fault detection and isolation of induction motors (주파수 해석을 이용한 유도전동기의 고장 검출 및 분류)

  • 신필재;이인수;전기준
    • 제어로봇시스템학회:학술대회논문집
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    • pp.702-705
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    • 1996
  • Recently, induction motors are used more widely because of their low cost and simple structure. Therefore, the importance of fault detection and isolation of induction motors significantly increases. In most case the line current is used for fault detection and isolation. But in case that an induction motor has an inverter for control, it distorts the information of faulty state included in the line current. This paper proposes a new method for fault detection and isolation of induction motors that is speed controlled by the inverter using frequency analysis of the reference current instead of the line current for fault detection and isolation.

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Method for Detection of Saturation of a Current Transformer (전류변성기의 포화 검출을 위한 알고리즘 개발)

  • Nam, Soon-Ryul;Choi, Joon-Ho;Kang, Sang-Hee;Min, Sang-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.879-884
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    • 2009
  • A Method for detection of saturation of a current transformer(CT) is proposed. The algorithm is initiated when the end point of a saturation period is detected. This detection is achieved by checking the time interval between the adjacent zero-crossing points of the second derivative of the secondary current. Once the end point of the saturation period is detected, the beginning point of the corresponding saturation period is determined by backward examination of the sum of the secondary current from the end point. The performance of the algorithm was evaluated for a-g faults on a 345 kV 100km overhead transmission line. The Electromagnetic Transient Program(EMTP) was used to generate fault current signals for different fault inception angles and different remanent fluxes. The performance evaluation shows that the proposed algorithm successfully detects the saturation period even in the presence of a remanent flux.

On the detection of faults on digital logic circuits using current sensor (전류 센서를 이용한 디지탈 논리회로의 고장 검출)

  • 신재흥;임인칠
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.2
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    • pp.173-183
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    • 1996
  • In this paper, a new structure that can do fault detection and location of digial logic circuits more efficiently using current testing techniques is proposed. In the conventional method, observation point for steady state power supply current was only one, but in the proposed method more fault classes are divided for fault detection and location through the ovservation of steady state power supply current at two points. Also, it is shown that this structure can be easily applied in detection of stuck-open fault which is not easy to do testing with conventional current testing techniques. In the presented mehtod, an extra trasnistor is used, and current path is made compulsorily in the CMOS circuits in which no current path can be established in steady state, then it can be known that stuck-open tault is in the MOS transistor on the considering current path, if this path disappears due to stuck-open fault. The validity and the effectiveness is shwon, thorugh the SPICE simulation of circuits with fault and the current path search experiment using current path search program based on transistor short model wirtten in C language on SUN sparc workstation.

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A Study on Rotor Polarity Detection of SP-PMSM Using Offset Current Based on Current Control (전류 제어 기반 옵셋 전류를 이용한 단상 영구자석 동기 전동기의 회전자 자극 검출에 관한 연구)

  • Park, Jong-Won;Hwang, Seon-Hwan
    • Journal of IKEEE
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    • v.23 no.3
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    • pp.1020-1026
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    • 2019
  • In this paper, a rotor polarity detection algorithm is proposed to control the single-phase permanent magnet synchronous motors(SP-PMSMs) for high speed sensorless operation. Generally, the sensorless control of a SP-PMSM is switched to the sensorless operation in a specific speed region after the open loop startup. As a result, it is necessary to detect the rotor polarity to maintain a constant rotational direction of the SP-PMSM at the starting process. There, this paper presents a novel rotor polarity detection method using a high frequency voltage signal and offset current which is generated by current regulator. The proposed algorithm verified the effectiveness and usefulness of the rotor polarity detection through several experiments.

Islanding Detection Method for Inverter-Based Distributed Generation through Injection of Second Order Harmonic Current

  • Lee, Yoon-Seok;Yang, Won-Mo;Han, Byung-Moon
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1513-1522
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    • 2018
  • This paper proposes a new islanding detection method for inverter-based distributed generators by continuously injecting a negligible amount of 2nd order harmonic current. The proposed method adopts a proportional resonant (PR) controller for the output current control of the inverter, and a PR filter to extract the 2nd order harmonic voltage at the point of common coupling (PCC). The islanding state can be detected by measuring the magnitude ratio of the 2nd order harmonic voltage to the fundamental voltage at the PCC by injecting a 2nd order harmonic current with a 0.8% magnitude. The proposed method provides accurate and fast detection under grid voltage unbalance and load unbalance. The operation of the proposed method has been verified through simulations and experiments with a 5kW hardware set-up, considering the islanding test circuit suggested in UL1741.

Islanding Detection Method for Inverter-based Distributed Generation Systems using a Signal Cross-correlation Scheme

  • Bae, Byung-Yeol;Jeong, Jong-Kyou;Lee, Ji-Heon;Han, Byung-Moon
    • Journal of Power Electronics
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    • v.10 no.6
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    • pp.762-768
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    • 2010
  • This paper describes the development of a new islanding detection method for inverter-based distributed generation systems, which uses a signal cross-correlation scheme between the injected reactive current and the power frequency deviation. The proposed method injects 1% of the reactive current to the rated current which brings about a negligible degradation of the power quality. It discriminates the islanding state, when the calculated cross-correlation index is larger than 0.5. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software and experimental research with a hardware prototype. The proposed method can detect the islanding state without degrading the power quality at the point of common connection. Further study is required to overcome the cancellation of the injected reactive current from multiple distributed generation units interconnected with the utility grid.