• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.942-946
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• 2006

We simulated insulation defects of stator winding wire on high voltage generator by 5 types. 4 types have one discharge source and other one has multi discharge source by simulation. For accurate decision, measurements used to PRPD pattern to occurred partial discharge source of various types. In this research, when PRPD pattern carried out or analyzed pattern recognition of discharge source, it used to powerful tools. In this result, PRPD Pattern defined to have single discharge source of 4 types by insulation defect. When insulation defect simulated, all the defected winding have not the same result. Errors for a little different can make mistakes from a subtle distinction. The difference between internal and void discharge have magnitude of pulse amplitude of inner discharge bigger than void discharge and have a shape of bisymmetry. But void discharge has a shape of bisymmetry against maximum value on polarity respectively. In cases of slot and surface discharge, we confirmed to show similar results those other researchers. In case of multi-discharge, as a result of we could classify not perfect match with occurred patterns in single discharge eachother. In the future, we will have to recognize and classify with results of multi-discharge.

• 조명전기설비학회논문지
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• 제28권7호
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• pp.62-68
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• 2014

We proposed a series connection-type superconducting fault current limiter(SFCL) using E-I core that can prevent the internal magnetic flux generation of cores during normal operation, and prevent the saturation of cores due to a sudden magnetic flux generation at the initial stage of fault occurrence while limiting the peak current. Through a short-circuit simulation experiment, we analyzed the operating status of the two superconducting elements and limiting characteristics according to the size of the fault current peak before and after the failure. Further, the double peak current limiting characteristics according to the winding directions as well as the current and the voltage of each coil were compared and analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.293-296
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• 2004

This paper proposes a new protective relaying algorithm using ACI(Advanced Computational Intelligence) and wavelet transform. To organize the advanced neuro-fuzzy algorithm, it is important to select target data reflecting various transformer transient states. These data are made of changing-rates of D1 coefficient and RSM value within half cycle after fault occurrence. Subsequently, the advanced neuro-fuzzy algorithm is obtained by converging the target data. As a result of applying the advanced neuro-fuzzy algorithm, discrimination between internal fault and inrush is correctly distinguished within half cycle after fault occurrence. Accordingly, it is evaluated that the proposed algorithm can effectively protect a transformer by correcting discrimination between winding fault and inrushing state.

• Journal of Magnetics
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• 제21권2호
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• pp.249-254
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• 2016

Recently, electric vehicles have got significant attention because it is more eco-friendly and efficient than internal combustion engine vehicles. Instead of an internal combustion engine, the electric vehicle has a motor for propulsion. The permanent magnet synchronous motor which has permanent magnet instead of field winding in the rotor has especially higher efficiency and power density than other types of motor. When the irreversible demagnetization is occurred, drivers are exposed to high risk of accident by the fault operation of motor. Therefore, the irreversible demagnetization of permanent magnet should be detected to reduce the risk of accident. In this study, the demagnetization diagnosis method based on the result of locked rotor test is proposed. Based on short measurement time, the proposed diagnosis method aims to detect the demagnetization fault when an electric vehicle is at a complete standstill. The proposed method is verified through the finite element analysis.

• 정보학연구
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• 제7권1호
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• pp.155-161
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• 2004

정상적인 기계의 동작동안, 부분방전측정이 고전압전동기 고정자권선을 모의하여 터빈제너레이터 분석기(TGA)를 이용하여 실행하였다. 모의한 고정자권선에 인가된 전압은 4.47[kV]와 6.67[kV]을 인가하였다. 모의 고정자권선을 갖는 전동기들은 단자함에 80[pF]용량성 커풀러를 설치하였다. 인가전압 위상각을 고려한 부분방전패턴의 경우 2차원, 3차원적으로 보여주었다. TGA는 정규화된 펄스수(NGN)DHK 부분방전펄스크기(Qm)으로서 두개의 정량화된량을 나타내었다. 결론적으로, 우리는 모의한 고정자권선에 대한 내부방전과 표면방전의 차이를 TGA을 이용하여 식별할 수 있었다. 고정자권선의 결함에 대한 특징을 추출하기 위한 기법으로서 이산웨이블렛 변환기법 및 주파수분석법을 이용하여 결함신호에 대한 특징을 추출할 수 있었다.

• 전기전자학회논문지
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• 제24권1호
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• pp.354-359
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• 2020

전력용 변압기의 결함을 검출하고, 고장을 예방하기 위해 유중가스분석 방법이 정기적으로 수행되고 있다. 유중가스분석방법에 의해 변압기 내부의 과열 또는 방전 현상의 발생은 확인할 수 있지만 결함 부위는 내부점검에 의하여 판별하여야 한다. 하지만, 권선 또는 철심 결함은 내부점검으로 확인할 수 없어 DGA만으로는 조치방안을 수립하기가 불가능하다. 본 논문에서는 변압기 내부점검 보고서를 바탕으로 내부 결함 모드를 분석하여 제시하고, DGA에 의한 판별법을 고려하여 내부 결함을 예측할 수 있도록 하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
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• pp.175-179
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• 2005

The main objective of this paper is to module design and pressure relief test a new type of polymer gapless surge arrester for power distribution line. Metal oxide surge arrester for most electric power system applications, power distribution line and electric train are now being used extensively to protect overvoltage due to lightning. Surge arresters with porcelain housing must not have explosive breakage of the housing to minimize damage to other equipment when subjected to internal high short circuit current. When breakdown of gapless elements in a surge arrester occurs due to flashover, fault short current flows through the arrester and internal pressure of the arrester rises. The pressure rise can usually be limited by fitting a pressure relief diaphragm and transferring the arc from the inside to the outside of the housing. However, there is possibility of porcelain fragmentation caused by the thermal shock, pressure rise, etc. Non-fragmenting of the housing is the most desired way to prevent damage to other equipment. The pressure change which is occurred by flashover become discharge energy. This discharge energy raises to damage arrester housing and arrester housing is dispersed as small fragment. Therefore, the pressure relief design is requested to obstruct housing dispersion.

• 조명전기설비학회논문지
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• 제17권5호
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• pp.43-50
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• 2003

본 논문은 신경회로망을 이용하여 변압기 사고검출 기법을 제안하였다. 계전기 정동작을 위하여 전력용 변압기의 외부사고와 돌입현상은 포화현상이 고려된 EMTP/ATP를 이용하였고, 내부사고는 EMTP/BCTRAN를 이용하여 얻은 전류 데이타를 신경회로망의 사고검출 성능으로 평가하였다. 신경회로망의 입력지수로는 변압기 양단전류를 FFT로 주파수 분석하여 얻은 억제전류와 동작전류의 고조파 비의 크기를 이용하였고, 외부사고 시 억제전류값이 크게 나타나는 것을 이용하기 위해 억제전류를 동작전류로 나눈값을 계전기 입력으로 사용하였고, 학습알고리즘은back-propagation을 사용하였다. 실 계통에 적용하고 있는 변압기 보호용 계전기의 특성을 신경회로망의 검출성능으로 테스트한 결과 제안된 기법이 뛰어남이 확인되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1612-1614
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• 2003

80pF capacitive couplers were connected to six 6.6kV motor model coil terminals. The voltage applied to the coils were 3.81kv, 4.76 kV and 6.6kV, respectively. These stator coils have various types of artificial insulation defects such as large voids, semi-conductive coating damage and strand insulation fault. Digital PD detector(PDD) and turbine generator analyzer(TGA) were used to measure PD activity. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). The PD levels in PD were measured with a conventional digital PD detector. Most of the defect mechanism of large motor stator winding can be associated with PD patterns such as internal and slot discharges. PD patterns coincide with PDD and TGA. These instruments have an input bandwidth of 40-400kHz and 0.1-350MHz. Surge testing detects faults in inter-turn winding of high voltage motor model coils.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.747-748
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• 2006

본 연구에서는 전력계통에서 발생되는 surge나 고장전류에 의해서 변압기의 1차측 코일에 유도되는 전자력의 크기를 유한요소 전자계해석 프로그램(FLUX2D)을 이용하여 해석하였다. 400kVA, 6600/220(V) 단상내철형 변압기의 권선간 전자력계산을 축대칭FEM을 이용하여 각방향의 전자력을 분석하였다. 누설자속분포, 전류유입시 권선 상호간에 작용하는 힘의 변화와 힘의 분포, 전류유입시 권선 상호간에 작용하는 힘의 변화와 힘의 분포, 변압기 내부권선의 정상시와 고장전류시의 전자계비교를 전자계해석을 통하여 변압기에 미치는 영향을 해석하였다. 변압기에 대전류가 유입되는 경우의 전자력 분석결과는 변압기의 절연설계 및 단락기계력에 대한 프레임 구조 설계를 위한 자료로 활용된다.