• KIEE International Transactions on Power Engineering
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• 제4A권1호
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• pp.11-17
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• 2004

It becomes difficult and high in cost to construct new ducts and/or tunnels for power cables in domestic areas. This paper presents possible strategy of an HTS distribution cables for distributing electric power in local areas as niche marketing. Reflected were its important distinction such as system configuration, rationale, establishment of strategy and considerably high economical efficiency compared with present underground cables. In this paper, applicable important items by using HTS distribution cables in water pumping powerhouse and distribution substation as example objective regions were reviewed. Based on this, the following items on distribution HTS system are examined. (I)A review of constructing a model system to introduce high temperature superconducting distribution cables to objective areas is presented. (2)The strategy to capture HTS distribution cable in water pumping powerhouse and distribution substation as niche marketing regions were reviewed. (3)In concrete, system configuration, rationale, establishment of strategy and considerably high economical efficiency are reviewed between existing cable and HTS one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1569-1571
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• 1999

In this work, we have performed the application experiment for real distribution line to diagnose the underground power cables using DC voltage decay measurement system. We have also performed the Isothermal Relaxation Current test for the same distribution line using KDA-l. We could confirmed possibility of grading the insulation aging state of underground power cables. Therefore, we conclude that it is possible to apply DC voltage decay method to the real distribution line.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.21-27
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• 2015

The goal of this study is the size and distribution of the electromagnetic force generated by the current flowing through the second underground line of 154kV power transmission cables by using electromagnetic finite element analysis. So we interpret how mutually electromagnetic force has an effect on the comparable judgement of Trefoil, Duct and Flat, which shows in a numerical arrangement. 154kV OF 1200SQ Cable 1.281km not only is applicable to modeling for underground transmission cable but also examine the effect of line to line, phase to phase and size and direction of the electromagnetic force preparing for the occurrence of normal state and single-phase earth fault, which are arranged in trefoil, duct and flat formation between sections. As showing how the trajectory, and size distribution of the electromagnetic force translate as the arrangement of the cables when a steady-state current and a fault current flows on the underground cables, I hope that when Underground transmission is designed, this data will be useful information.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.628-634
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• 2014

This paper investigates the transient characteristics of grounding systems used in under-ground distribution power cables. Recently, two kinds of grounding system are used for underground distribution cables in Korea. The first one is conventional multi-point grounding system, the other is newly proposed non-bundled common grounding system. The non-bundled common grounding system has an advantage the decreasing the power loss due to decrease of the shield circulation current. In this paper, the lightning overvoltage induced in neutral wire (in case of non-bundled common grounding system, overvoltage between opened neural wires and grounding in each phase) of these two kinds of grounding systems are estimated and compared by field tests and EMTP simulations. The EMTP simulation methods are firstly verified by comparison of measurement and simulation. Finally, the insulation level against lightning is expected by EMTP simulation results using verified model.

• 조명전기설비학회논문지
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• 제12권3호
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• pp.45-50
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• 1998

본 논문은 기존의 지중배전케이블의 준공시험으로 사용되고 있는 DC시험을 대체 하기 위한 초저주파 전원의 적용결과로서, 실험실에서 제작한 5m 길이의 실제 케이블의 칼흠집 결함과 침결함에 대해 초저주파 전원의 결함검출 능력을 평가하였다. 이 시험에서 초저주파 시험은 케이블 절연체 내부에 존재하는 결함부위에서 전기트리 개시는 어렵지만, 일단 전기트리가 개시되면 트리의 진전이 매우 빠르고 내부결함이 검출되지 않는 경우, 시험으로 인한 새로운 결함이 형성되거나 결함이 더 확대되지 않는 것으로 나타났다. 따라서 초저주파전원은 지중배전선로의 현장시험용으로 적용되기보다는 제조업체의 품질검사 확인용으로 사용하는 것이 효과적이라 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.270-272
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• 2001

This paper proposes an algorithm of analyzing the conductor temperature distribution of underground power cables buried ill ducts. This algorithm used an equation of the permissible current-carrying capability of power cables. The algorithm will be given to an operator an ability to operate the underground power system in comfort.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.497-501
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• 2004

The primary failure causes of underground distribution power cables are water penetration in insulation layer and stress enhancement at inner semi-conductive layer. Accordingly, it is needed to improve the materials and the structure of power cables for extending lifetime and preventing failure. We uses non-flaming PE materials instead of PVC as a covering material and encapsulating structure. We also use super smooth class material as a inner semi-conductive layer. The newly developed cables are improved in AC breakdown voltage after ageing tests.

• 한국전기전자재료학회논문지
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• 제33권1호
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• pp.1-5
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• 2020

In this study, the objective is to improve the criteria used for statistical comparison of the VLF tanδ (TD) database and failure rate according to water-tree degradation in underground distribution power cables. The aging condition of the KEPCO criteria is divided into 6 levels using the Weibull distribution, and the "failure imminent" condition is quantified by using the statistical end-point of the lifetime parameter of the VLF big-data group obtained from KEPCO. Moreover, new criteria with a 2-dimensional combination of TD, DTD, and a statistical normalized factor are suggested. These criteria exhibit high reproducibility for the detection of cables in an imminent failure state. Consequently, it is expected that the adoption of the extended VLF-2019 criteria will reduce the asset management cost of cable replacement compared to the VLF-2012 criteria of KEPCO.

• 조명전기설비학회논문지
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• 제22권2호
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• pp.107-113
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• 2008

22.9[kV]-y 배전 방식은 지중 케이블로 전력을 공급하고 있으며 선로 운영상 배전케이블 선로의 동심중성선을 케이블 접속 구간마다 3선 일괄 접지하는 다중 접지방식을 채택하고 있다. 그러나 지중 배전 선로에서 각 상의 부하가 평형일 경우에도 동심중성선에는 부하 전류의 약 40[%](전력구)${\sim}$50[%](관로)의 동심중성선 순환 전류가 발생되고 있기 때문에, 순환전류로 인한 손실이 도체 손실의 76[%]에 달한다. 이러한 손실 전력으로 케이블의 내부온도가 상승되어 케이블의 허용전류 용량이 관로의 경우 20[%] 정도 감소하게 된다. 본 논문은 이와 같은 문제점을 해결하기 위하여 새로운 동심중성선 접지방식을 제안하고 있다. 새로운 방법은 동심중성선의 순환전류를 효과적으로 제거하고 있으며, 그 방안을 직접 계통망에서 적용시켜서 실측하여 본 결과, 그 타당성과 유용성을 확인하였다.

• 전기학회논문지
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• 제61권8호
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• pp.1091-1098
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• 2012

This paper describes frequency response and propagation characteristics considering semiconducting screen in distribution cables. In CIGRE WG 21-05, Simplified Approach(SA) and Rigorous Approach(RA) which can revise the permittivity considering semiconducting screen propose for more detailed EMTP model and frequency dependant analysis. In this paper, the frequency dependent characteristics of complex permittivity are variously analysed by cole-cole function of RA. The attenuation, propagation velocity and surge impedance according to frequency range(1 kHz to 500 MHz) and cable length are also analysed by SA and EMTP simulation in distribution cables. The propagation velocity considering semiconducting screen is slower, and it is saturated over the range of 1 MHz. The signal is significantly attenuated as frequency range is high.