• 조명전기설비학회논문지
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• 제19권3호
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• pp.44-50
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• 2005

본 논문에서는 산화아연(이하 ZnO) 피뢰기 열화진행의 한 요인으로 예측되는 전극과 ZnO소자 사이에서 발생하는 방전광 현상에 관한 연구를 수행하였다. 이를 위해 $8/20[{\mu}s]$, 최대 10[kA]의 뇌임펄스전류를 발생시키는 뇌임펄스전류 발생장치를 설계${\cdot} $제작하였다. 실험결과, 상${\cdot}$하부의 전극 부근에서 발생하는 방전광의 형상은 인가되는 뇌임펄스의 극성에 따라 다르게 나타났으며 상대적으로 (-)극의 전극부근에서 방전광이 더 강하고 활발하게 발생하는 것으로 관찰되었다. 또한 전극의 면적에 따른 방전광의 세기는 전극의 면적이 증가할수록 감소하는 것으로 관측되었다. 동시에 전극과 소자의 접촉상태도 방전광의 발생과 매우 밀접한 관계가 있는 것으로 확인되었다. 따라서 배전급 ZnO피뢰기의 기존 전극구조는 보완이 필요하며 ZnO피뢰기 제품의 성능향상 및 지속적인 성능유지를 위해서는 환형구조 대신 내부면적이 있는 원판구조로 교체하는 것이 바람직하다고 판단된다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.335-338
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• 2009

In this study, in order to investigate the thermal and electrical properties of ZnO arrester block against 60[Hz] AC voltage, the changes in leakage current were measured. The temperature distribution appearing on the ZnO arrester blocks was observed using a forward looking infrared camera. In particular, the correlation between the thermal and electrical properties of a ZnO arrester block was analyzed experimentally. From this analysis, the thermal phenomena resulting from the heat generation and dissipation of the ZnO arrester block were interpreted. The degradation and thermal runaway phenomena of ZnO arrester block are closely related to the temperature limit of the ZnO arrester block. The installation of an additional metal electrode has resulted in the decrease of the leakage current due to the heat dissipation.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.303-306
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• 2005

This paper presents the frequency-dependent characteristics of leakage currents flowing through ZnO surge arrester block. The leakage current-voltage (I-V) characteristic curves of the commercial ZnO surge arrester blocks were measured. The resistive leakage current was found to increase with increasing frequency in the low conduction region. The capacitance of ZnO block was independent of the magnitude and frequency of the applied voltage. The power losses of ZnO block increase as the frequency of applied voltage increases, because of the dielectric loss related to the frequency of the test voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1869-1871
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• 2004

The primary role of ZnO arresters is to protect transmission and distribution equipments against lightning surges. The extremely nonlinear V-I characteristics of the ZnO arrester obviates the need for isolation gaps and consequently it is continuously connected to line voltage. For this reason, ZnO arresters are degraded with increasing with time in actual power systems. In this work, the characteristics of the luminous events between the ZnO block and electrodes were investigated. As a result, the luminous events were effected by the impulse and the near polarity of the luminous event was intense near the grounded electrode. Also the luminous event may cause the degradation of ZnO arrester block.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.26-28
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• 2004

The primary role of ZnO arresters is to protect transmission and distribution equipments against lightning surges. The extremely nonlinear V-I characteristics of the ZnO arrester obviates the need for isolation gaps and consequently it is continuously connected to line voltage. For this reason, ZnO arresters are degraded with time in actual power systems. In this work, the characteristics of the luminous events caused between the ZnO block and electrodes according to the electrode area were investigated. As a result, the luminous events were effected by electrode area and the longer electrode areas were increased, the more luminous events were decreased. Also the reduction of luminous events was fumed up to the degraded ZnO arrester block.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.353-356
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• 2007

This paper presents the thermal and electrical characteristics of ZnO arrester blocks under the AC voltages. The leakage currents of ZnO arrester blocks were measured as a function of time. The temperature distributions of ZnO arrester blocks were observed by the forward looking infrared camera The degradation and thermal runaway of ZnO arrester blocks were closely related with the temperature limit of ZnO arrester blocks which decided heat generation and dissipation As a result, the degradation and thermal runaway of ZnO arrester blocks depend on the temperature and leakage current of ZnO arrester blocks.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.458-459
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• 2007

This paper describes the characteristics of lightning impulse current of ZnO block for transmission line arrester with external gap. The ageing parameters of lightning arresters are impulse current, moisture ingress, temperature ageing and so on. Especially it is important to estimate the change of electrical characteristics by impulse current. Total energy applied to the ZnO arrester each time is $4/10{\mu}s$, 30kA and $2/20{\mu}s$, 10kA impulse current. Before and After the test, the residual voltage variation of varistors passed was below 5%. According to the test, it is thought that the ZnO arrester shows good stability with impulse current test.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권7호
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• pp.550-555
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• 1999

This paper deals with the effect of lightning impulse current on electrical characteristics of ZnO blocks used in distribution lightning arrester. The electrical characteristics of ZnO blocks are degraded by overtime impulse current, and the degraded ZnO block is brought to a thermal runaway and finally destroyed. It is therefore important to estimate the change of electrical characteristics of ZnO blocks. In this study, an impulse current generator which can produce 8/20$[\mus]$, 3[㎄] and 4/10$[\mus]$, 5[㎄] waveform is designed and fabricated to simulate the lightning impulse current of power systems. Total energy applied to the ZnO blocks at each time is 739[J] in 8/20$[\mus]$, and 523[J] in 4/10$[\mus]$, impulse current, respectively. From the experimental results, the 3rd harmonic of the leakage current increases continuously with the number of applied impulse current, but no significant changes in residual voltage and in reference voltage are observed until the ZnO block is destroyed. Also, it is confirmed that the main factor on degradation of ZnO blocks is rather the total energy applied to ZnO blocks than the peak value of the impulse current.

• 한국세라믹학회지
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• 제31권1호
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• pp.62-68
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• 1994

It is compared the structures of the S-block in the Ba-Co-Zn Y-type hexagonal ferrites (Ba2Co2-xZnxFe12O22, x=0~2) and the Co-Zn spinel ferrites (Co1-xZnxFe2O4, x=0~1) expressed by a hexagonal axis system (space group R3m). The structures have been refined with a Rietveld analysis of the powder X-ray diffraction pattern with high precision (Rwp<0.13, RI<0.03). The overal dimension of the S-block is slightly different from the 1/3 of a hexagonal spinel unit cell as follow: 1.6~2.0% longer c-axis, 1.3~1.6% shorter a-axis and about 1% smaller volume. Upto Zn:Co=1:1 in the Ba-Co-Zn Y-type hexagonal ferrites, the zinc substitute primarily the tetrahedral sites in the S-block. Beyond that the zinc seems to go into the T-block as well.

• 한국자기학회지
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• 제6권2호
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• pp.73-79
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• 1996

Y형 육방정 산화철$(Ba_{2}Me_{2}Fe_{12}O_{22}:Me=천이금속)$은 천이 금속으로 Co와 Zn가 포함된 경우 양호한 고주파 특성을 보이는 것으로 알려져 있다. 따라서, 결정 구조 내에 이들의 분포 상태를 파악하는 것이 중요하다. 본 논문에서는 엄밀한 성분 분석, X-선 회절 분석, 자기 특성 분석을 통하여 확인된 $Co_{2}Y$와 $Co_{1.6}Zn_{0.4}Y$시료에 대한 $M\"{o}ssbauer$ 분광 분석 결과로부터 다음과 같은 결론을 제시하였다. (1) Co는 주로 육방정 산화철의 S-block에 위치한 4배위 자리 $(6c_{IV})$와 S-, T-block 경계의 6배위자리(18h VI)에 들어간다. (2) Co의 일부를 Zn으로 치환하여도, Fe의 분포에는 큰 영향을 미치지 않는다.