• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.289-292
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• 2008

This paper describes the electrical characteristics of the ZnO surge arrester according to the variation of surrounding conditions. To investigate the characteristics of degraded ZnO surge arrester, 8/20 [${\mu$s], 2.5 [kA] impulse currents were applied to the ZnO surge arrester to be test. To present the effect of the surrounding con야tions, the leakage currents of ZnO surge arrester were measured to the surrounding temperature and wet conditions. As a result, the increase of ambient temperature causes the increase of resistive leakage current of ZnO surge arrester. Also, in the wet test, the outside leakage current through the ZnO surge arrester housing is much larger than the intrinsic leakage current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1305-1306
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• 2008

In this work, in order to investigate the effect of lightning impulse currents on ZnO surge arrester. and the deterioration characteristics of ZnO surge arrester, 8/20 [${\mu}s$], 2.5 [kA] impulse currents were applied to the ZnO surge arrester under test. The leakage currents of ZnO surge arrester were measured and ZnO element was analyzed by X-ray photoelectron spectroscopy. As a result, the resistive leakage current of ZnO surge arrester was increased with the injection number of lightning impulse currents.

• 조명전기설비학회논문지
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• 제27권3호
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• pp.79-86
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• 2013

In order to analyze the electrical performance of ZnO surge arresters stressed by the combined DC and AC voltages that are generated in DC/AC converter systems, the leakage current properties of ZnO surge arrester blocks deteriorated by impulse currents were investigated. The test specimens were deteriorated by the 8/$20{\mu}s$ impulse current of 2.5kA and the leakage currents flowing into the deteriorated zinc oxide(ZnO) arrester blocks subjected to the combined DC and power frequency AC voltages are measured. As a result, the leakage currents flowing through deteriorated ZnO surge arrester blocks were higher than those flowing through the fine ZnO surge arrester blocks and the larger the injection number of 8/$20{\mu}s$ impulse current of 2.5kA is, the greater the leakage current is. The leakage current-voltage curves(I-V curves) of the fine and deteriorated ZnO surge arrester blocks stressed by the combined DC and AC voltages show significant difference in the low conduction region. Also the cross-over phenomenon is observed at the voltage close to the knee of conduction on plots of I-V curves.

• 조명전기설비학회논문지
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• 제23권4호
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• pp.79-85
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• 2009

이 논문은 피임펄스전류의 입사에 따른 ZnO 피뢰기의 열화 특성에 대하여 기술하였다. 뇌서지에 의한 ZnO 피뢰기의 열화특성을 분석하기 위해 시료 ZnO 피뢰기에 8/20[${\mu}s$], 2.5[kA]의 표준뇌임펄스전류를 인가하였다. 뇌임펄스전류를 인가한 것과 인가하지 않은 ZnO 피뢰기에 흐르는 상용주파수 AC 및 DC 누설전류를 측정하였다. 그 결과 임펄스전류의 인가횟수가 증가함에 따라 누설전류는 증가하였고 AC전압에서 누설전류의 비 대칭성은 뚜렷하게 나타났다. 뇌임펄스전류를 인가하지 않은 ZnO 피뢰기의 ZnO 입자는 균일한데 반해 뇌임펄스전류를 인가한 ZnO 피뢰기의 ZnO 입자는 불균일하게 변형되었다. 또한 뇌임펄스전류 인가에 따른 $Bi_2O_3$의 감소가 입계층의 결핍을 발생시키며 입계층의 결핍에 의한 전류의 집중이 ZnO 피뢰기 소자의 비선형 특성의 열화에 대한 중요한 요인으로 작용한 것으로 밝혀졌다.

• 조명전기설비학회논문지
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• 제22권9호
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• pp.62-68
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• 2008

이 논문은 ZnO 피뢰기의 외부환경 변화에 따른 전기적 특성을 기술하였다. 뇌임펄스전류에 의한 ZnO 피뢰기의 열화특성을 분석하기 위해 8/20[${\mu}s$], 2.5[kA]의 임펄스전류를 시료에 인가하였다. ZnO 피뢰기의 누설전류를 다양한 외부 온도와 주수 상태에서 상용 주파수 교류 전압을 인가하여 측정하였다. 그 결과 임펄스전류의 인가횟수와 외부 온도가 증가함에 따라 누설전류가 증가하였고, 누설전류의 비대칭성도 뚜렷하였다. 또한 주수 시험에서 ZnO 피뢰기의 외피를 통하여 흐르는 전류는 피뢰기 소자의 누설전류보다 크게 나타났다. 본 연구의 결과는 피뢰기의 감시시스템 성능과 신뢰성 향상의 요소로 적용할 수 있다.

• 조명전기설비학회논문지
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• 제26권4호
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• pp.41-47
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• 2012

This paper deals with the electrical characteristics related to power loss, equivalent resistance, and leakage currents flowing through new and deteriorated zinc oxide(ZnO) arrester elements subjected to the mixed DC and 60[Hz] AC voltages. The test specimens were deteriorated by 8/20[${\mu}s$] impulse current of 2.5[kA]. The leakage current-applied voltage($I-V$) characteristic curves of ZnO surge arrester elements were measured as a parameter of the ratio of the peak of 60[Hz] AC voltage to the peak of total voltage. As a consequence of test results, in case of the same applied voltage, the leakage currents flowing through the deteriorated ZnO arrester elements were higher than those flowing through the new ZnO surge arrester elements. The cross-over phenomenon in $I-V$ curves of ZnO surge arrester elements measured as a parameter of the mixed ratio of DC and AC voltages was observed at the low current domain. The effect of DC voltage on the leakage current flowing through ZnO surge arrester elements is pronounced at the same magnitude of test voltages. In addition, the larger the applied number of 8/20[${\mu}s$] impulse current of 2.5[kA] is, the greater the power loss is, in particular, the more severe the power loss increases at higher applied voltages.

• 조명전기설비학회논문지
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• 제21권10호
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• pp.66-72
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• 2007

이 논문은 직류+60[Hz] 교류 중첩전압에서 신품과 노후된 18[kV] 산화아연 서지피뢰기의 누설전류와 전력손실에 대하여 기술하였다. 최대 50[kV]의 직류+60[Hz] 교류를 발생시킬 수 있는 중첩전압발생장치가 설계되고 제작되었다. 피뢰기의 I-V 특성곡선은 전압중첩률 K의 함수로 측정된다. DC와 AC 전압이 중첩된 I-V, R-V 특성곡선은 순수한 직류와 교류곡선 사이에 있고 저전류 영역에서 교차현상이 나타난다. 그 결과 중첩 전압에서 직류 성분의 증가는 ZnO 피뢰기의 전체 누설전류의 저항성분의 증가를 유발한다. 또한 같은 인가전압에서 피뢰기를 통해 흐르는 누설전류는 상용전원에서 장시간 스트레스 받은 피뢰기가 신품 피뢰기에 비해서 높게 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.383-386
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• 1999

Surge arrestor is used for protection of facilities and lines. Recently lots of arresters fatted prematurely In the distribution lines. It is important to know that what the cause of the failures is. This paper presents characteristics of the aged and new 18kV surge arrester. In order to analyse characteristics, we measured leakage current using specialty made leakage current measurement system and also investigated Tan $\delta$ of the arrester and microstructure of the elements. Through the investigation we found that the characteristics among the ZnO elements in an arrester were a little different, It means that the surge arreste can have non-uniform electric field due to the characteristic difference of The each element. Owing to this concentration of the electric field, the localized aging might be proceeded.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.212-216
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• 2000

ZnO varistors for distribution surge arrester (18kV, 5kA) were developed and tested microstructure and electrical characteristics. Microstructure of ZnO varistor was consisted of ZnO grain, spinel phase and Bi-rich phase. Average grain size of ZnO varistor was $\mu\textrm{m}$ Reference voltage and lightning impulse residual voltage of ZnO varistor exhibited a good haracteristics above 5.5kV and below 11.56kV, respectively. Consequently, discharge capacity which is the most important characteristics of ZnO varistor for surge arrester exhibited excellent properties above 70kA at twice high-current impulse test. Moreover, variation rate of reference voltage and lightning impulse residual voltage showed below 5% and 2% after high-current impulse test, respectively. Leakage current and watt loss of ZnO varistor will not increase during accelerated aging test at stress condition, such as 3.213kV/$115^{\circ}C$/1000h.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1142-1145
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• 2004

ZnO surge arresters continuously endure the operating voltages during the operation course, and in the mean time, which need to withstand occasionally transient voltages of lightning and switching overvoltages. Under these voltages, the ZnO varistors inside arresters would have aging phenomena, one important result of aging phenomena is the increasing of resistive currents of varistors, which leads to the increasing of power losses of varistors. And the operating voltage is continuously applied on the ZnO varistors, there is a degradation phenomenon existing in ZnO varistors. When the degradation reaches a certain degree, then the arrester must stop operation. The degradation is related to the applied voltage ratio, the applied voltage ratio is high, the degradation is quickly. When the power loss is higher than the thermal dispersion ability of house of arrester, then the arrester will thermally breakdown. In this study the thermal stability characteristics of surge arresters for high power wil be discussed on the view point of watt losses and thermal breakdown.