• Title/Summary/Keyword: Short Faults

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Analysis on Air-Gap Magnetic Flux of Synchronous Generator According to Short-Circuit Types in Winding (권선단락 유형별 동기발전기의 공극자속 파형 분석)

  • Bae, Duck-Kweon;Kim, Dong-Hun;Park, Jung-Shin;Lee, Dong-Young;Lee, Sung-Ill
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.929-935
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    • 2009
  • As modem industrialized society progresses, the demand for electric power is increasing rapidly. The electric power system is getting amazingly bigger and complicated, which can easily induce serious troubles from the potential of large fault problems and/or system failure. The monitoring and diagnosis of the electric machine for the fault detection and protection has been important part in the electric power system. Most faults in the generator appear in the winding. This paper presents the air-gap magnetic flux characteristic of a small-scale 2-pole synchronous generator according to the faults in the field winding to protect the generator from the fault. The magnetic flux patterns in air-gap of a generator under various fault conditions as well as a normal state are simulated by using finite element method. These results are successfully applied to the detection and diagnosis of the short-circuit condition in rotor windings of a high capacitor generator.

Fault Diagnosis for Rotating Machinery with Clearance using HHT (HHT를 이용한 간극이 있는 회전체의 고장진단)

  • Lee, Seung-Mock;Choi, Yeon-Sun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.895-902
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    • 2007
  • Rotating machinery has two typical faults with clearance, one is partial rub and the other is looseness. Due to these faults, non-linear and non-stationary signals are occurred. Therefore, time-frequency analysis is necessary for exact fault diagnosis of rotating machinery. In this paper newly developed time-frequency analysis method, HHT(Hilbert-Huang Transform) is applied to fault diagnosis and compared with other method of FFT, SFFT and CWT. The results show that HHT can represent better resolution than any other method. Consequently, the faults of rotating machinery are diagnosed efficiently by using HHT.

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Defect-Limited Yield Difference Model (결함 제한적 수율변화 모델)

  • Lee, Hoong-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1614-1618
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    • 2008
  • This paper propose a novel yield difference model according to layout modification. The difference of average number of faults by layout modification to increase or decrease spaces between geometries is formulated for short faults and open faults. Complex modification including wire bending with jogs is also modeled by dividing patterns into segments and redefining spaces and widths. This model can help to monitor the yield change and to generate a cost function of defect-limited yield quickly.

Faults Analysis and Dynamic Simulation Method for Interior PM Synchronous Motor (매입형 영구자석 동기전동기의 고장해석 및 시뮬레이션방법)

  • Sun, Tao;Lee, Suk-Hee;Hong, Jung-Pyo
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.874-875
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    • 2007
  • This paper introduces major potential faults of IPMSM and their simulation realization methods. The faults of IPMSM, generally, contain single-phase open circuit, single-phase or 3-phase short circuit, and uncontrolled generation. When different fault occurs, the circuit of total system including motor and inverter also will be changed. Therefore, it is necessary to analyze and establish independent model for each kind of fault. In this paper, first, the drive circuit is analyzed as different fault type. Then, the corresponding simulation results solved in Simulink@MATLAB are given. The absence of experiment results leads that the veracity of simulation results can not be verified, but the tendency will be explained by theory analysis.

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Electrical Fire Disaster Prevention Device of Double Protection using a High Precision Current Sensor in Low Voltage Distribution System (고정밀 전류센서를 이용한 저압배전계통 이중 보호용 전기화재 방재장치)

  • Kwak, Dong-Kurl;Jung, Do-Young
    • Fire Science and Engineering
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    • v.23 no.3
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    • pp.40-47
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    • 2009
  • Nowadays the diversity and large-capacity of electric appliances are strong effect on electrical fires augment in an alarming way. But, as the inactive response characteristics of the existing RCD (Residual Current protective Device) used on low voltage power distribution system, so control of overload and electric short circuit faults, major causes of electrical fires, are not enough. Therefore, this paper is confirmed the unreliability of the existing RCD by electrical fault simulator and is proposed a Electrical Fire Disaster Prevention Device (EFDPD) by using a high precision current sensor (namely, reed switch) for the prevention of electrical disasters in low voltage power distribution system caused by overload or electric short circuit faults. The sensitive reed switch in the proposed EFDPD exactly detects the increased magnetic flux with the overload or the short current caused by a number of electrical faults, and the following, the EFDPD has double protection function which operates self circuit breaker or rapidly cuts off the existing RCD. The proposed EFDPD is confirmed the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker through various operation performance analysis. The proposed EFDPD can also prevent electrical disaster, like as electrical fires, which resulted from the malfunction and inactive response characteristics of the existing RCD.

Application of HHT for Online Detection of Inter-Area Short Circuits of Rotor Windings of Turbo-Generators Based on the Thermodynamics Modeling Method

  • Wang, Liguo;Wang, Yi;Xu, Dianguo;Fang, Bo;Liu, Qinghe;Zou, Jing
    • Journal of Power Electronics
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    • v.11 no.5
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    • pp.759-766
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    • 2011
  • This paper focuses on monitoring and predicting the short circuit faults of the rotor windings of large turbo-generator systems. For the purpose of increasing efficiency and decreasing maintenance cost, a method that combines the HHT (Hilbert Huang Transform) with a wavelet has been studied. This method is based on analyzing a classical Albright detecting coil. Due to the Empirical Mode Decomposition (EMD) and the Intrinsic Mode Functions (IMF) of the HHT the exact location of a short circuit of rotor windings may be given. However, a part of the useful information is eliminated by the unreasonable decomposing scale of the wavelet. Based on the thermodynamics modeling method, this study was illustrated with a 50MW turbo-generator system that is installed in Northern China. The analysis results, which have very good agreement with those of a previous study, show that the method of combining the HHT with a wavelet is an effective way to analyze and predict the short circuit faults of the rotor windings of large generators, such as supercritical turbo-generator systems and wind turbo-generator systems. This work can offer a useful reference for analyzing smart grids by improving the power quality of a distribution network that is supplied by a turbo-generator system.

Characteristics of Short-Circuit Protector in Pad-Mounted Transformer (지상변압기의 단락보호장치 특성연구)

  • Kim, K.H.;Lee, W.Y.;Sun, C.H.;Kim, D.M.;Kim, S.J.
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1350-1352
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    • 1995
  • This paper discribed the characteristic of I-t cross-over-point between current limited-fuse and explusion fuse(Bay-O-Net Fuse) and fuse protection in pad-mounted transformer that was generated internal faults and the short circuit of secondary side(load side). In the I-t cross-over-point, current limited fuse was melted when transient recovery voltage was raised rapidly.

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Load Flow Calculation and Short Circuit Faults Transients in Dispersed Generation Systems

  • Hosseini, Seyed Hossein;Shahnia, Farhad;Tizghadam, Saeed
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.800-804
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    • 2005
  • Load flow and short circuit fault transients of a power distribution system with wind turbines as dispersed generation units is presented. Usage of renewable energies such as wind is already a small part of total installed power system in medium and low voltage networks. In this paper, a radial power distribution system with wind turbines is simulated using DIgSILENT PowerFactory software for their influence on load flow and short circuit fault transients. Short fault occurring in dispersed generation systems causes some problems for the system and costumers such as fault level increase or the problems of sudden fluctuations in the current, voltage, power and torque of the double fed induction machine utilized in the wind turbines which have been studied and investigated.

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Development of Digital Fault Detection Systems for Screening Open and Short of Wire Harness (와이어 하네스 단선 단락 선별을 위한 디지털 고장 검출 시스템 개발)

  • A Ran Kim;Jae Wan Park;Ha Seon Kim;Jae Hoon Jeong;Sun Young Kim
    • Journal of Drive and Control
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    • v.20 no.4
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    • pp.140-149
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    • 2023
  • Wire harness is a component for efficient control when electronic parts are required such as construction machinery and electric vehicles. With emerging issues such as autonomous driving and automation in construction, a wire harness composed of multiple cables has become an essential part because more electronic parts are required. However, when a wire harness failure occurs, systems can be stopped, accidents can occur, and economic damage can be significant. Therefore, in this paper, we developed a digital fault screening system that could easily and quickly diagnose faults in the wire harness. The principle of the developed system was to sequentially send pulse signals to the wire harness and use returned signals to perform fault detection. As a result of diagnosing faults using the developed failure detection system, a detection accuracy of 99.9 % was confirmed through the experiments.

The Study of Comparison of the Symmetrical Short Circuit Test Current with ANSI/IE Transformers. (변압기의 단락강도 시험 시 ANSI와 IEC 규격에 의한 시험 전류의 비교 연구)

  • Kim, Sun-Koo;Kim, Won-Man;La, Dae-Ryeol;Roh, Chang-Il;Lee, Dong-Jun;Jeong, Heung-Soo
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.694-696
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    • 2002
  • Transformers together with all equipment and accessories shall be designed and constructed to withstand the mechanical and thermal stresses produced by external short circuit which include three phase, single line-to-ground, double line-to-ground and line-to-line faults etc. Generally the Short Circuit Test of transformers is tested according to the ANSI/IEEE, IEC/JEC, KS etc, in domestic. In this study, it will be showed and compared the difference of symmetrical current for short circuit test of a Pad -mounted transformer according to with ANSI /IEEE and IEC.

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