• Title/Summary/Keyword: Continuous lightning impulse current test

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A Study on the Microstructure and Electrical Characteristics of ZnO Varistor for d.c. Arrester (소결 조건 변화에 따른 직류 피뢰기용 ZnO 바리스터의 미세구조 및 전기적 성질에 관한 연구)

  • Kim, Seok-Sou;Choi, Ike-Sun;Park, Tae-Gon;Cho, I-Gon;Park, Choon-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.6
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    • pp.683-689
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    • 2004

  • The microstructure and electrical characteristics of A ∼ C's ZnO varistors fabricated according to variable sintering condition, which sintering temperature was 1130 $^{\circ}C$ and speeds of pusher were A: 2 mm/min, B: 4 mm/min, C: 6 mm/min, respectively, were investigated. The experimental results obtained from this study were summarized as follows: The sintering density of A ∼C's ZnO varistors sintered at 1130 $^{\circ}C$ were decreased by sintering keep time to shorten, such as A: 9hour, B: 4.5hour and C: 3hour. A's ZnO varistor exhibited good densification nearly 98 % of theory density. In the microstructure, A∼C's ZnO varistors fabricated variable sintering condition was consisted of ZnO grain(ZnO), spinel phase(Z $n_{2.33}$S $b_{0.67}$ $O_4$), Bi-rich phasc(B $i_2$ $O_3$), wholly. Varistor voltage of A∼C's ZnO varistors sintered at 1130 $^{\circ}C$ increased in order A

  • https://doi.org/10.4313/JKEM.2004.17.6.683 인용 PDF KSCI

Failure Prediction of Metal Oxide Varistor Using Nonlinear Surge Look-up Table Based on Experimental Data

  • Kim, Young Sun
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.6
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    • pp.317-322
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    • 2015

  • The metal oxide varistor (MOV) is a major component of the surge protection devices (SPDs) currently in use. The device is judged to be faulty when fatigue caused by the continuous inflow of lightning accumulates and reaches the damage limit. In many cases, induced lightning resulting from lightning strikes flows in to the device several times per second in succession. Therefore, the frequency or the rate at which the SPD is actually exposed to stress, called a surge, is outside the range of human perception. For this reason, the protective device should be replaced if it actually approaches the end of its life even though it is not faulty at present, currently no basis exists for making the judgment of remaining lifetime. Up to now, the life of an MOV has been predicted solely based on the number of inflow surges, irrespective of the magnitude of the surge current or the amount of energy that has flowed through the device. In this study, nonlinear data that shows the damage to an MOV depending on the count of surge and the amount of input current were collected through a high-voltage test. Then, a failure prediction algorithm was proposed by preparing a look-up table using the results of the test. The proposed method was experimentally verified using an impulse surge generator

  • https://doi.org/10.4313/TEEM.2015.16.6.317 인용 PDF KSCI KPUBS HTML