• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.244-247
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• 2004

The electrical insulating design is important to realize a HTS power cable because the cable is operated under the high voltage environment. For the insulation design of a HTS power cable, it is necessary to investigate the AC, impulse breakdown and partial discharge(PD) inception stress of liquid nitrogen/LPP composite insulation system. Based on these results, the electrical insulation of a HTS power cable is designed and Mini-model cables are manufactured. The manufactured Mini-model cables are evaluated that AC, impulse withstand voltage, breakdown and partial discharge inception stress and analyzed characteristics insulation of HTS cable bending condition according to this paper. From these tests, the AC, impulse withstand voltage test and partial discharge inception stress is satisfied "standard technical specification of KEPCO" in Korea and the breakdown voltage was 120kV.

• 조명전기설비학회논문지
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• 제22권9호
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• pp.32-39
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• 2008

본 논문은 뇌임펄스전압에 의한 토양의 이온화 현상과 모델접지시스템의 과도적 특성에 관련된 파라미터에 관한 것으로 건조 모래와 습한 모래에 대한 이온화 특성을 치수가 다른 동심원통형 전극계의 실험 용기를 이용하여 연구하였다. 결과로써, 높은 임펄스전압이 인가된 모래의 비선형 전기적 특성은 이온화 과정에 의해 발생하였다. 모래의 과도임피던스는 수분의 함유량과 인가임펄스전압의 크기에 의존하며, 수분의 함유량과 인가전압의 크기의 증가에 따라 접지임피던스는 감소하였다. 본 연구결과는 뇌서지에 대하여 우수한 성능을 가지는 접지시스템의 설계에 유용한 정보가 될 것이다

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1418_1419
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• 2009

This paper presents the transient impedance when high current impulse up to 5 kA is applied to a scaled grounding grid in test field. For a realistic analysis of transient impedance on the high current impulse in the ground systems, grounding electrode installed outdoors and impulse current generator was used. The results were discussed based on its voltage and current trace, impulse impedance and V-I curve.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.698-702
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• 1987

• 한국소음진동공학회논문집
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• 제18권7호
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• pp.783-789
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• 2008

This experimental study describes the noise reduction and the feasibility of short current of a silencer for a high voltage COS(cut out switch) fuse of a transformer. When a high voltage COS fuse becomes a short circuit by the over current, the strong impulse noise over 150 dB(A) is generated. For the purpose of the reduction of impulse noise, in this study, the diffuser type and the reactive type silencers have been designed and tested, respectively. And also the electrical test on the short current is performed. From the experimental results, the well designed reactive type silencer has been shown to have the noise reduction of about 20 dB(A). It has been found that the feasibility of short current for the COS fuse is closely related to the porosity of the silencer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.756-760
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• 1988

The paper presents the measurement results on the parameters affecting the breakdown mechanism of a large air spacing under switching impulse voltages. Measured parameters are the velocities of leader channels, predischarge currents, electric charges injected into the rod-plane air gap and electric field intensities on the plane. For the 3m air gap under switching impulse voltages, the velocities of leader channel have been measured to be of 1cm/${\mu}s$ - 5cm/${\mu}s$, electric field intensity of 2kv/cm, predischarge current of 1.2A - 1.6A, the charges injected into the air gap of 11 - 40 ${\mu}$C for 400-887kV impulse voltages.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.301-304
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• 2008

This paper presents the experimental results on breakdown characteristics in $N_2$ gas under non-uniform electric fields caused by both the positive and negative lightning impulse voltages. $N_2$ gas have an advantage of eco-friendly and cost reduction, and safety aspects. In order to analyze the impulse pre-breakdown processes in $N_2$ gas, we carried out measurements and observations of the impulse breakdown voltages, pre-breakdown current and luminous signals. They were measured by a voltage divider, a shunt and a photo-multiplier tube, respectively. Additionally, the characteristics of discharge channels were observed by high speed cameras. The breakdown voltages in the positive polarity was lower than those in the negative polarity.

• 한국안전학회지
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• 제17권4호
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• pp.101-109
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• 2002

The electrical properties of polyethylene are changed by the superstructure. Such crystalline polymer as polyethylene or polypropylene changes crystallinity and products spherulite or trans-crystal when it is cooled slowly. In this study, after thermal treatment of LDPE at 100[${circ}C$], in silicone oil for an hour, we made specimens in order of slow cooling, water cooling, quenching according to cooling speed. Also, to study the influence of electrical properties due to the superstructure change, we analyzed physical properties and performed dielectric breakdown experiments using DC and impulse voltage Moreover we measured space charges in bulk using Laser Induced Pressure Pulse(LIPP) method. Trap level of specimen is 0.064[eV] at the low temperature region 0.31[eV] at the high temperature region in DC dielectric strength, 0.03[eV] at the low temperature region 0.0925[eV] at the high temperature region in impulse dielectric strength. As its result shows that the quantity of charges induced from the electrode surface increases with applied voltage time, and the distribution of space charges in samples increases the quantity of charges in proportion to applied voltage.

• 전기학회논문지
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• 제58권5호
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• pp.989-993
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• 2009

Triple junction which consists of three media(electrode, insulator, and gas) should be considered in designing of high voltage equipments due to the electric field enhancement. In this paper, positive lightning impulse breakdown voltage is predicted based on the streamer theory for simplified insulator models and 72.5kV spacer with varying the triple junction geometry and gas pressure, and the results are compared to the experimental results. The electric field coefficient concept is also applied in order to evaluate the partial discharge inception voltage and the surface flashover voltage from the streamer inception voltage. The application of this method using the constant electric field coefficient of 1.3 and 0.66 is possible for evaluating the triple-junction insulation of the simplified insulator and the 72.5kV spacer respectively. The error rate is under 10%.

• 한국조명전기설비학회지:조명전기설비
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• 제11권6호
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• pp.96-103
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• 1997

본 논문은 뇌임펄스전압에 대한 누전 차단기의 오동작 특성에 관한 것으로 한국공업규격 KS C 4613의 규정과 서지보호장치를 갖는 모의회로의 조건에서 누전차단기의 부동작 특성을 실험적으로 조사하고 검토하였다. 실험 결과, 본 연구에 사용한 30[A]용 고감도형 누전 차단기인 모든 시료는 증폭회로의 전원부에 설치된 서지보호장치에 의해 입사되는 차동모드의 뇌임펄스전압에 차단되는 성능을 가지고 있었다. 4종의 시료는 KS C 4613에 정의된 뇌임펄스 부동작시험조건을 만족시키지 못하였으며, 그때의 오동작을 유발한 전압은 약 5∼6.5[kV]로 비교적 높았다. 서지보호장치가 설치된 경우를 모의한 시험조건에서는 3종의 누전차단기가 오동작하였으며, 누전차단기가 오동작을 일으키는 전압도 약 3∼5[kV] 정도로 비교적 낮았다.