• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2038-2040
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• 2000

The main objective of this paper is to design and test a new type of polymer ZnO surge arrester for AC power system of railroad vehicles. Metal oxide surge arrester for most electric power system applications, electric train and subway 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 ZnO elements in a surge arrester occurs due to flashover, fault short current flows through the arrestor 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. The main research works are focused on the structure design by finite element method, pressure relief of module, and studies of performance of surge arrester for electric railway vehicle.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.66-72
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• 2007

This paper describes the characteristics of power loss and leakage currents flowing through new and used 18[kV] zinc oxide(ZnO) surge arrester under the mixed DC and AC voltages. The mixed DC and AC voltage generator of 50[kV] peak was designed and fabricated. The I-V curves of ZnO surge arrester were measured as a function of the voltage ratio K. The I-V curves under the mixed DC and AC voltages lay between the pure DC and AC characteristics, and the cross-over phenomenon in both I-V curves and R-V curves was observed at the low current region. As a result, the increase of DC component in the mixed voltages causes the increase of resistive component of total leakage current of ZnO surge arrester. Also, in the case of same applied voltage, the leakage current flowing through the used ZnO surge arrester was higher than that of the new ZnO surge arrester.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.79-85
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• 2009

This paper describes the degradation properties of ZnO surge arresters impressed by lightning impulse currents. To investigate the deterioration behaviors of ZnO surge arresters due to lightning surges, the 8/20[${\mu}s$], 2.5[kA] standard lightning impulse currents were injected to the ZnO surge arrester under test. The power frequency AC and DC leakage currents flowing through the ZnO surge arresters with and without the injection of lightning impulse currents were measured. As a result, the leakage currents are increased and the asymmetry of the AC leakage current is pronounced as the number of injection of the impulse current increases. The ZnO grain of the surge arrester without the injection of lightning surges are uniform but the ZnO grain of the ZnO surge arrester with the injection of lightning impulse currents are deformed. Also, it was found that the decrease of the $Bi_2O_3$ due to the lightning impulse current leads to the lack of grain boundary layer and the current concentrated by the lack of grain boundary layer play an important role to degrade nonlinear property of ZnO surge arrester blocks.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.273-280
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• 2007

In this paper, the ZnO surge arrester performance of power distribution class has been studied under different manufacturing conditions such as housing materials(polymeric, porcelain), interface sealants and one-body molding type. In the recent years, the polymeric ZnO surge arresters have been developed and put into operations based on their excellent characteristics. For polymeric surge arresters, the inner gas volume is extremely small, especially in solid insulation polymeric arresters there are not any gas volume inside arresters in the structure due to polymeric materials are filled into the internal gas volume. The sealing integrity is related to safe operation of surge arrester, the prime failure reason of porcelain housed arresters is moisture ingress. In this paper, the sealing integrity of polymeric surge arresters is investigated with moisture multi-aging test and ingress test. The evaluation techniques are used to inspect the sealing integrity of polymeric arresters, including leakage current, surface temperature, reference voltage and dissipation factor.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.357-361
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• 2006

This paper dealt with the performance evaluation and the diagnostic techniques of lightning arresters for DC electric traction vehicle. Field Measurements on the protective operation of lightning arresters against surge currents were carried out on running vehicles to acquire the data necessary for the diagnosis. The frequency and the magnitude of surge events were analyzed. Surge currents of $1\sim3$ times were recorded in one running service route and their magnitudes were ranges of $150A\sim2kA$. Also, an acceleration experiment on a lightning arrester by the standard lightning impulse current of 8/20 us and 5 kA was performed to know the aging characteristics. After the surge current application of 3,000 times, the reference voltage decreased by 4.5 %, and the leakage current was below 10 uA at the continuous operating voltage and about 50 uA at the rated voltage. From the experimental results, we propose a decision level of leakage current for the arrester used in this paper and designed an arrester tester which analyzes arrester condition by the magnitude of leakage current.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.62-68
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• 2008

This paper describes the electrical characteristics of ZnO surge arresters associated with the variation of surrounding conditions. To investigate the deterioration behaviors of ZnO surge arresters due to lightning surges, 8/20[${\mu}s$], 2.5[kA] impulse currents were injected to the ZnO surge arrester under test. The leakage currents of ZnO surge arrester subject to power frequency AC voltage were measured in different surrounding temperature and wet conditions. As a result, it was found that the leakage current is increased and its asymmetry is pronounced as the number of injection of the impulse current and the ambient temperature increase. Also, in the wet test the outside leakage current flowing through the housing surface of the ZnO surge arrester is much larger than the intrinsic leakage current of ZnO surge arrester element. The results obtained in this work can be a lied as factors of improving the reliability and performance of monitoring system for surge arresters.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.503-505
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• 1995

The surge arrester plays a vital role in the protection of substation against transient overvoltages resulting from lightning surges and system switching operations. The proper selection and application of the surge arrester is an integral part of the process of substation equipment insulation level selection. The paper outlines the basic consideration in modeling the lightning stroke, the surge arrester, and the system to be protected. The paper discusses the results of various cases simulated using the alternative transient computer program to evaluate the separation effects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.326-327
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• 2006

The paper describes the development of arrester for 154kV class power station and substation. The arrester employs silicone insulating materials for Its housing, instead of the conventional porcelain housing. The sealing integrity is related to safe operation of surge arrester, the prime failure reason of porcelain housed arresters is moisture ingress. In this paper, the sealing integrity of polymeric surge arresters for ultra high voltage is investigated with moisture ingress test. The diagnostic techniques are discusses, including watt loss, partial discharge, AC leakage current, 1mA DC voltage and residual voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.546-547
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• 2005

This study aims to evaluate the properties and the performance of the newly designed disconnector for surge arrester. This disconnector was verified with the performance in long-duration current impulse test and high current impulse test. And time-current characteristic test was done at 20A, 200A and 800A(3points) for simulating the internal fault condition of the arrester. The results of this test was very good. Consequently, the newly designed disconnector was, evaluated that it is possible to be used for surge arrester in distribution line system.