• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권4호
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• pp.164-168
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• 2002

The main hazard leading to breakdown in GIS(Gas Insulated Switchgear) comes from free conducting particles, which can cross between tee electrodes and cause dielectric failure under the influence of the electric field. Bouncing height of the particle can be an important factor to evaluate the possibility of breakdown occurrence. In this paper, how to estimate, outside a GIS, the bouncing height of the particle was newly suggested when GIS is in service. Both experimental results using 362 kV test chamber and computer simulation results on estimating the height were presented and compared with each other.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.267-269
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• 1996

In this work, the influence of wire type conducting particles on the insulation reliability of GIS has been systematically investigated when outer electrode was dielectric coated by epoxy resin. For this purpose, coaxial cylinder-type electrode was adopted in 362 kV chamber and various size of Cu conducting particle was used and different gas pressure was applied. To prove the coating effect on the gas insulation, different thickness of epoxy coated outer electrode have been considered and the lift-off voltage and flashover voltage have been analyzed. The results show that the dielectric coated electrode has an remarkable influence on the reducing particle behavior in GIS system and enhancing the GIS insulation reliability.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.311-314
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• 2001

This paper describes the simulation study, conducted on the propagation characteristics of AE signal in the connection of GIS. In the high voltage and large power system, the equipment with SF$\sub$6/ gas insulation which consists of the component part enclosed in the compressed gas has less affected by the environment than with air insulation. When the breakdown in the electric installation occurs, it takes much time to repair them though. Therefore it is very important to diagnose the propagation characteristics of AE signal in the GIS. So, in this investigation, we make a plane model of 362 kV GIS and modal and harmonic analysis to observe the vibro-acoustic property. Through the result of the analysis, we can make a further understanding on the vibro-acoustic characteristics of AE singnal in the connection of GIS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1835-1837
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• 2004

The UHF electromagnetic waves excited by PD pulses propagate along the GIS busbar not only TEM mode, but also TE and TM mode. Generally the waves detected by the UHF sensors are those of high order modes and such waves can only propagate the higher than cut-off frequency. In this paper, computed cut-off frequency of 362[kV] GIS by each modes and simulated electromagnetic field of each propagation modes by FEM(Finite Element Method) program. Frequency band of each TEmn/TMmn modes were determinated by simulation results and were discussed optimal position of UHF sensor from this results.

• 대한전기학회논문지:전력기술부문A
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• 제53권11호
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• pp.624-629
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• 2004

The UHF electromagnetic waves excited by PD pulses propagate along the GIS busbar not only TEM mode, but also TE and TM mode. Generally the waves detected by the UHF sensors are those of high order modes and such waves can only propagate higher than cut-off frequency. In this paper, the cut-off frequency of 362[kV] GIS for each modes is computed and the electromagnetic field of each propagation modes is simulated by FEM(Finite Element Method) program. Frequency band of each TEmn/TMmn modes was determinated by simulation results and was discussed optimal position of UHF sensor from this results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.79-83
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• 2001

This is an investigation on the propagation characteristics of AE signal in GIS. The selection of measuring position and resonant frequency of AE sensor is one of the most important factor to optimize a diagnostic system. And natural frequency and harmonic response characteristics are indispensable to optimize those factors. So, in this investigation, we make a 3D model of 362kV GIS and make a modal and harmonic analysis to survey the vibro-acoustic property. Through the result of the analysis, we can make a further understanding on the vibro-acoustic characteristics of GIS.

• Journal of Electrical Engineering and information Science
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• 제2권3호
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• pp.77-81
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• 1997

In his work, the influence of wire type conducting particles on the insulation reliability of GIS has been systematically investigated when the epoxy resin based dielectric coating was made on he inner side of outer electrode. For this purpose, coaxial cylinder-type electrode was adopted in 362 kV chamber and various sizes of Cu conducting particle were used under different gas pressures. In order to elucidate the coating effect on the gas insulation, different thickness of dielectric coating has been considered and then the lift-off voltage and flashover voltages have been measured. The results shown that the dielectric coating has a remarkable influence by restraining the movement of particle in GIS system, and thus GIS insulation reliability is noticeably improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1574-1576
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• 1994

$SF_6$ gas has become an important insulation medium in modern electric power apparatus, because of its high insulation withstand levels and good arc quenching capability. For the application of $SF_6$ gas in GIS the estimation of insulation properties is a fundamental point. Moreover the reduction of withstand levels in case of inhomogeneous fields caused by particles or fixed protrusions is of special interest. It is known that the presence of free conducting particles in GIS can significantly lower the insulating level of $SF_6$ gas at elevated pressure and also it has been recently shown that dielectric strength is greatly reduced by fast transients such as disconnector surges where metallic particles are involved. In this paper, we have disigned the particle test chamber rated 362kV for the purpose of investigating the discharge characteristics in SF6 gas where inhomogenius fields are caused by metallic particles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1655-1657
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• 2002

Ultra-wide bandwidth (UWB), narrow bandwidth (single frequency), and a combination of both technologies have been studied for the ultra-high frequency (UHF) partial discharge (PD) monitoring system as a detection scheme. We have experimentally compared those detection methods using a mock-up of 362 kV class single phase gas-insulated switchgear (GIS) and a stable PD source. A rolling-ball type PD cell that produces PDs of about 10 pC, is placed at one end of the GIS. An internal UHF PD sensor was attached several meters away from the PD source. The PD spectrum was measured up to 3 GHz. A useable bandwidth of more than 1 GHz was used to measure UWB signals from the PD. To simulate the narrow bandwidth scheme a bandwidth of 100 kHz centered at several different frequencies was used.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.890-893
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• 2002

Since 1970s, varistors using metal-oxide resistors have been applied to Gapless surge arresters for power system. In the paper, the structure of metal-oxide surge arresters without gaps for 362kV GIS which is developed the first in korea has been introduced. And the main evaluation items for the metal-oxide resistors which are reference voltage test, residual voltage test, long duration current impulse withstand test and operating duty test is tested and evaluated.