• 한국안전학회지
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• 제26권2호
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• pp.20-25
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• 2011

The fire event occurred in fire proof zone often causes serious electrical problems such as shorts, ground faults, or open circuits in nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety related systems and equipments. The fire event can treat the basic design principle that safety systems should keep their functions with redundancy and independency. In case of a multi-core cable fire, operators can not perform their mission properly and can misjudge the situation because of spurious operation, wrong indication or instrument. These would deteriorate the plant capabilities of safety shutdown and make disastrous conditions. In this paper, the characteristic of cable fire is investigated and the heat-flux evaluation for cable fire is studied. Moreover, a diagnostic methodology for degraded cable in nuclear power plants is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1553-1555
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• 1994

In this paper, we describes the research in condenser cone of $SF_6$ gas sealing end for 345KV oil-filled cable. The designed of condenser cone based on the results electric field analysis by electrostatics theory ana FEM. As a results. we have been designed the condenser cone and the inner insulation part of $SF_6$ seating end, the width and length, the number of condenser, the length of stress relief slope, the total length of condenser cone.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.155-157
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• 2006

송전전압이 점차 초고압화되면서 절연체의 유전특성을 개선하여 송전용량을 향상시키고, 절연내력을 높여 케이블 외경을 저감시키려는 시도에 따라 우수한 유전특성 및 절연내력을 갖는 폴리머 절연층과 기계적 특성, 절연유와의 적합성이 우수한 크라프트지의 장점을 혼합시킨 반합성지가 개발되어 전력케이블의 주절연재료로 사용되고 있다. 본 논문은 LS전선이 국내최초로 개발한 400 kV급 반합성지 전력케이블 및 접속함 개발과정 및 이와 관련된 요소기술에 대해 기술하였다. 송전시스템에서 요구되는 유전특성의 반합성지를 설계 제작하여, 기존 크라프트 절연지 대비 유전손실은 50% 수준, 절연내력은 125%이상의 반합성지를 개발하였고, 반합성지 고유의 특성인 팽윤율을 조절하여 케이블을 제조하였다. 반합성지 절연 케이블에 필요한 접속함에서는 보강절연재로 케이블과 동일한 반합성지를 사용하여 전체적인 3기를 감소시키고, 열저항성을 줄이고자 노력하였다. 또한, 접속함 조립공정에 필요한 저온연공법을 개발하여 반합성지에 열적 스트레스를 최소화하였다. 상기 관련기술의 개발 결과로, IEC 60141, AEIC CS2-97 및 NGTS 3.5.1에 근거하여 400 kV급 반합성지 OF 케이블 및 접속함에 대해 국제 공인기관인 KEMA의부터 Type Test을 인증받았다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2206-2210
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• 2007

As a power transmission line supplying power to a densely populated city, the high temperature superconducting (HTS) cable is expected to one of the most effective cables with a compact size because of its high current density. The verification of HTS power cable system have been progressed by KEPRI. A cooling system for a 3-phase 100m HTS power cable with 22.9kV/1.25kA was installed and tested at KEPCO's Gochang power testing center in Korea. The system consists of a liquid nitrogen decompression cooling system with a cooling capacity of 3kW and a closed circulation system of subcooled liquid nitrogen. Several performance tests of the cable system with respect to the cooling such as cooling capacity, heat load and temperature stability, were performed at several temperatures. Thermal cycle test, cool-down to liquid nitrogen temperature and warm-up to room temperature, was also performed to investigate thermal cycle influences. The outline of the installed cooling system and performance test results are presented in this paper.

• Nuclear Engineering and Technology
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• 제48권4호
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• pp.982-996
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• 2016

In this paper, new tethered aerial robots including roaming tethered aerial robots (RTARs) for radioactive material sampling and stationary tethered aerial robots (STARs) for environment monitoring are proposed to meet extremely-long-endurance missions of nuclear power plants. The flight of the proposed tethered aerial robots may last for a few days or even a few months as long as the tethered cable provides continuous power. A high voltage AC or DC power system was newly adopted to reduce the mass of the tethered cable. The RTAR uses a tethered cable spooled from the aerial robot and an aerial tension control system. The aerial tension control system provides the appropriate tension to the tethered cable, which is accordingly laid down on the ground as the RTAR roams. The STAR includes a tethered cable spooled from the ground and a ground tension control system, which enables the STAR to reach high altitudes. Prototypes of the RTAR and STAR were designed and successfully demonstrated in outdoor environments, where the load power, power type, operating frequency, and flight attitude of the RTAR and STAR were: 180 W, AC 100 kHz, and 20 m; and 300 W, AC or DC 100 kHz, and 80 m, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1603-1603
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• 2011

As time goes by these cables make a insulation problems, and ask for a preventive diagnosis method. Cable has very high electrostatic capacity and insulation defects mainly caused by water-tree(WT). Dissipation factor test is very useful for detecting WT but it needs huge power supply. In this paper we presented a cable insulation diagnosis by dissipation factor using low frequency power supply.

• KEPCO Journal on Electric Power and Energy
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• 제2권2호
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• pp.307-310
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• 2016

The operational cost for maintaining the superconductivity of high-temperature superconducting (HTS) cables needs to be reduced for feasible operation. It depends on factors such as AC loss and heat transfer from the outside. Effective operation requires design optimization and suitable operational conditions. Generally, it is known that critical currents increase and AC losses decrease as the operational temperature of liquid nitrogen ($LN_2$) is lowered. However, the cryo-cooler consumes more power to lower the temperature. To determine the effective operational temperature of the HTS cable while considering the critical current and AC loss, critical currents of the HTS cable conductor were measured under various temperature conditions using sub-cooled $LN_2$ by Stirling cryo-cooler. Next, AC losses were measured under the same conditions and their variations were analyzed. We used the results to select suitable operating conditions while considering the cryo-cooler's power consumption. We then recommended the effective operating temperature for the HTS cable system installed in an actual power grid in KEPCO's 154/22.9 kV transformer substation.

• 한국전자통신학회논문지
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• 제17권1호
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• pp.77-84
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• 2022

해저 전력케이블은 수면 아래로 전력을 운송하는 송전케이블이다. 최근 해저케이블은 해상의 재생에너지인 풍력, 파력 및 조류시스템 등의 전력을 육지로 전송하며, 이 케이블이 위치하는 장소에 따라 해저에 매설하거나 해저면에 놓여진다. 전력케이블은 극한 환경에서 이용되어 왔기 때문에 가혹한 조건들과 온도 및 강한 조류를 견디도록 제작되나, 해저조건은 해상케이블에 대해 수 많은 종류의 심각한 손상을 만들기에 충분한 조건을 갖는다. 이러한 원인은 전력전송을 중단시키는 케이블 손상을 가져온다. 본 논문에서는 케이블에 대한 설계기준과 시공절차와 난제 그리고 케이블 전환 접속시스템에 대하여 연구한다. 설계된 해저케이블의 규격은 154kV 기존 케이블 1회선과 신규 케이블 2회선 등 3회선으로 구성되고, 선로당 100MVA 전력용량을 갖는다. 해저케이블 매설깊이를 결정하고 기존 및 신규 케이블을 함께 배치하는 방법을 연구하였다. 지중선로에 대한 해저케이블의 전력용량 허용값을 계산하였고 그 결과 케이블 선로당 100MW 이상의 전력용량을 갖는다는 것을 확인하였다.

• 전기학회논문지
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• 제65권12호
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• pp.2113-2118
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• 2016

The precise detection of electric leakage point of underground power cable is very important to reduce cost and time of maintenance and prevent electric shock accident through expedite repair of electric leakage point. This paper proposes a electric leakage point detection system underground power cable using of half-period modulated transmission waveform and earth electric potential measurement. The developed system is composed of transmitter to generate the wanted pulse waveform, receiver to measure and display earth electric potential by the transmitted pulse in electric leakage point and PC Software program to display of GPS coordinate on detection cable line. The performance of the electric leakage point detection system was tested in the constructed underground cable leakage detection test bed. The test results on signal generation voltage precision of signal transmitter, mean detection earth voltage, mean detection leakage current and electric leakage point detection error showed the developed system can be used in electric leakage point detection underground power cable.

• 한국초전도ㆍ저온공학회논문지
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• 제11권3호
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• pp.31-34
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• 2009

An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.