• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.126-131
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• 2009

This study was carried out for the reliability of PD(Partial Discharge) pattern recognition. For the pattern recognition, the database for PD was established by use of self-designed insulation defects which occur and were mostly critical in GIS(Gas Insulated Switchgear). The acquired database was analyzed to distinguish patterns by means of PRPD(Phase Resolved Partial Discharge) method and stored to the form with to unite the average amplitude of PD pulse and the number of PD pulse as the input data of neural network. In order to prove the performance of genetic algorithm combined with neural network, the neural networks with trial-and-error method and the neural network with genetic algorithm were trained by same training data and compared to the results of their pattern recognition rate. As a result, the recognition success rate of defects was 93.2% and the neural network train process by use of trial-and-error method was very time consuming. The recognition success rate of defects, on the other hand, was 100% by applying the genetic algorithm at neural network and it took a relatively short time to find the best solution of parameters for optimization. Especially, it could be possible that the scrupulous parameters were obtained by genetic algorithm.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1181-1187
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• 2015

Sulfur hexafluoride (SF₆) gas is used widely in electric power equipment such as Gas Insulated Switchgear (GIS), Gas Insulation transmission Line (GIL), and Gas Circuit Breaker (GCB). But applications of SF₆ should be restricted because SF6 gas is one of the greenhouse effect gases. To reduce use of SF₆ gas, a study on eco-friendly alternative insulation medium is needed. In this paper, we investigated lightning impulse (LI) breakdown of dry-air which is attracting attention as an ecofriendly alternative gas and the LI breakdown of hybrid insulation combined with dry-air and solid insulation (Room-Temperature Vulcanizing Silicone Rubber-RTV SIR) and dry-air in inhomogeneous fields according to gap distance and pressure. The experiment results showed that the LI breakdown strength of hybrid insulation system was higher than that of dry-air insulation system. It was verified that the development of technology related to eco-friendly power apparatus compact such GIS, GCB and GIL can be used as basic research data.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1380-1381
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• 2008

By applying the digital sub-station, the change of various protect and measuring equipments has been applying. This paper is analyzed that the development of GIS partial discharge condition monitoring equipment is suited to the electricity IT technology and digital sub-station. It's constitution apply to be able to suit the data to high rank for GIS partial discharge condition monitoring equipment that is suited digital sub-station and Watch-dog module that be able to monitor the inner communication of the GIS partial discharge equipment. And then it also be able to apply of GIS partial discharge equipment when digital sub-station is applied.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.541-542
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• 2015

초고압 차단기는 개방 또는 투입 기능을 수행시 과도현상에 의한 개폐서지(Switching Surge)가 발생하여 차단기 구성품들에 부담이 가해진다. 초고압 차단기용 개폐제어 장치는 이러한 차단기의 개폐 동작시 차단기 접점의 분리 또는 접촉 순간을 제어하여 개폐서지를 최소화함으로써 접점의 마모와 구성품에 가해지는 스트레스를 감소시키는 장치이다. 즉, 차단기에 인가되는 전압의 위상을 기준으로 원하는 개폐시점에서 개방 및 투입이 일어나도록 제어하는 기기이다. 국외에서는 해외 선진사들이 이미 초고압 차단기용 개폐제어 장치를 상용화하여 현장에 적용하고 있으며, 국내에서는 기술의 검토 단계를 지나서 장치를 개발하고 시험하여 상용화하는 단계로 진입하고 있다. 본 논문에서는 상용화를 위하여 개발된 초고압 차단기용 개폐제어 장치에 대하여 하드웨어 구성을 소개하고, 운영 소프트웨어를 설명하며, 개폐제어 장치의 개폐제어 동작 성능을 자체 모의시험과 GIS(Gas Insulated Switchgear) 차단부와의 연계 시험을 통하여 평가한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.431-432
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• 2015

본 논문은 초고압 가스절연개폐장치의 메인 접점의 압점력에 따른 절연 특성에 대한 연구이다. 차단기 접점의 접촉이 잘 이루어지지 않는 현상이 발생하게 되면 접촉저항이 증가하여 차단기의 투입 및 개방 시에 전류에 의하여 접점에 손상이 발생한다. 그리고 차단기의 접점의 압점력이 커질수록 큰 조작력이 필요하므로 차단기의 동작에도 영향을 미치는 것은 많이 알려져 있다. 그러나 압점력과 절연 특성의 관계에 대한 연구가 미비하므로 이에 대한 연구가 필요하다. 본 연구는 초고압 가스절연개폐장치의 메인 접점의 압점력에 차이에 따른 전계를 해석하고, 고정측 접점의 쉴드 유무에 따른 절연 내력을 비교 및 분석하였다. 전계 해석 결과를 통해서 메인 접점의 압점력과 절연특성과 고정측 접점 쉴드의 영향을 비교함으로써 차단기 인터럽터 내부의 전계 분포를 확인하고, 전계 강도를 확인함으로 가스절연계폐장치의 적절한 절연내력 확보를 목적으로 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.115-121
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• 2007

This paper describes experiments of the breakdown characteristics by temperature change of $SF_6$ gas and Imitation Air(I-Air) in model GIS(Gas Insulated Switchgear). From the results of the experiments, the breakdown characteristics classify the vapor stage of $SF_6$ according to Paschen's law, in which the stage of coexistence for gas & liquid of the voltage value increases. This results in large deviation and the breakdown of the voltage(VB) low stage as the interior of the chamber is filled with a mixture of $SF_6$ that is not liquefacted and remaining air that can not be ventilated. The ability of $SF_6$ liquid($LSF_6$) insulation is higher than high-pressurize $SF_6$ gas. The VB of the I-Air decreases as the temperature drops and the VB also drops. It is considered that the results of this paper are fundamental data for the electric insulation design of superconductor and cryogenic equipment that will be studied and developed in the future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1310-1315
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• 2003

GIS(Gas Insulated Switchgear) is power equipment with excellent dielectric strength and is economy merit in high confidence and stability. But, because of structural characteristics, this is difficult to monitor externally and provide much loss in the event of an accident. Recently, because equipment of GIS is occurring problem of confidence used for a long time, development of diagnosis technique have been importantly recognized. therefore, measurement and analysis of PD much has been generally used for equipment of GIS. But, in case of measurement of PD at field, real trouble signals is difficult to classify noise. Accordingly, a variety of trouble conditions for DS are simulated, and detected signals are analyzed by the application of electrical and mechanical methods. For this analysis, detected signals are accumulated according to phase-magnitude with the application of induction sensor, and then we analyzed the characteristics. For the simulation experiment, we make DS for 170KV GIS and analyze the characteristics of detected signals with the application of neural network algorithm. last, we have measured DS for GIS at field, and then have analyzed detected signals.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.7
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• pp.496-501
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• 2018

In this study, we prepared 40, 45, 50, 55, 60, 65, and 70 wt% content composites filled in epoxy matrix for two micro silica and three micro alumina types for use as a GIS heavy electric machine. As a filler type of epoxy composite, micro silica composites showed excellent AC breakdown strength properties compared to micro alumina composites in the case of electrical properties of micro silica and alumina. The electrical breakdown properties of micro silica composites increased with increasing filler content, whereas those of micro alumina decreased with increasing filler content. In the case of mechanical properties, the micro silica composite showed improved tensile strength and flexural strength compared with the micro alumina composite. In addition, mechanical properties such as tensile strength and flexural strength of micro silica and alumina composites decreased with increasing filler content. This is probably because O-H groups are present on the surface of silica in the case of micro silica but are not present on the surface of alumina in the case of micro alumina.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.485-491
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• 2015

This paper shows the design improvement and test model of FAU (Frequency Analysis Unit) in PDD (Partial Discharge Diagnosis system) for 800kV GIS (Gas Insulated Switchgear). We found some problems during operation of previous FAU, such as the aging of fiber-optic converter that can cause communication error, the malfunction of signal analysis circuit etc. And then we solved those problems by design improvement and verified the performance through type test. To monitor partial discharge, the performance of UHF sensor is important but the performance of frequency analysis unit is also very important. So we solved communication error, the malfunction of signal analysis circuit and then increased the operation reliability of FAU by improving fiber-optic converter and signal analysis circuit. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.8
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• pp.355-360
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• 2005

In this paper the experiments of breakdown characteristics by temperature change of $SF_6$ gas, $SF_6$ liquid ($LSF_6$) and $N_2$ liquid ($LN_2$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, the breakdown voltage of $SF_6$ increases with the drop of temperature and the increase of the inner pressure in model GIS. The ability of $LSF_6$ insulation is higher than high-pressurized $SF_6$ gas and $LN_2$. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machine교 which will be studied and developed in the future.