• Title, Summary, Keyword: cable sheath

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A study or Metallic sheath for Extra-high voltage XLPE cable (초고압 XLPE 케이블 금속 차폐층 고찰)

  • Choi, C.S.;Lee, K.J.;Chung, M.Y.;Kwon, B.I.
    • Proceedings of the KIEE Conference
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    • pp.1652-1654
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    • 1994
  • The Extra-high voltage XLPE cable is characterized by low transmission loss, large capacity, and high reliability. Conventionally, for XLPE cables of l54kV and above, aluminium sheath was used to be moisture barrier (thus preventing water tree deterioration of the insulation) and to protect cable core from physical stresses. However, as transmission capacity of the cable increases, so does the cable diameter and the corresponding aluminium sheath outer diameter and thickness. As a result, eddy-current loss in the sheath is increased, limiting the maximum current capacity of the cable itself. As an alternative to aluminium sheath, we have adopted stainless steel sheath with non-magnetic properties and a large resistivity, The new XLPE cable with stainless-steel sheath (CSZV cable) has drastically reduced eddy-current loss in the sheath.

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A Study on the Reduction Methods of Sheath Circulating Current using the Reduction Equipment in Underground Transmission Systems (지중송전계통에서 저감장치를 이용한 시스 순환전류 저감방안에 관한 연구)

  • Gang, Ji-Won;Yang, Hae-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.9
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    • pp.474-481
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    • 2002
  • Sheath circulating current is increased in the change of sheath mutual impedance which is caused by unbalanced cable system, and different section length between joint boxes. If excessive current flows in sheath, sheath loss which is reduced the transmission capacity is produced. Recently, excessive sheath circulating current was partially measured in underground cable systems of KEPCO. Accordingly, actual schemes to reduce excessive sheath circulating current are urgently required for installed cable system as well as newly-installing cable systems. This paper describes the relation analysis of sheath circulating current and burying types. And also, various schemes to reduce excessive circulating current using EMTP/ATPDraw and applicable schemes are proposed through a detailed analysis regarding cable systems by considering various electrical and environmental factors. It is evaluated that the proposed reduction schemes can be effectively applied to reduce the excessive sheath circulating current with the minimized electrical problems. And reduction effect is Proved with sheath circulating current reduction equipment.

Sheath Circulating Current Analysis of a Crossbonded Power Cable Systems

  • Jung, Chae-Kyun;Lee, Jong-Beom;Kang, Ji-Won
    • Journal of Electrical Engineering and Technology
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    • v.2 no.3
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    • pp.320-328
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    • 2007
  • The sheath in underground power cables serves as a layer to prevent moisture ingress into the insulation layer and provide a path for earth return current. Nowadays, owing to the maturity of manufacturing technologies, there are normally no problems for the quality of the sheath itself. However, after the cable is laid in the cable tunnel and is operating as part of the transmission network, due to network construction and some unexpected factors, some problems may be caused to the sheath. One of them is the high sheath circulating current. In a power cable system, the uniform configuration of the cables between sections is sometimes difficult to achieve because of the geometrical limitation. This will cause the increase of sheath circulating current, which results in the increase of sheath loss and the decrease of permissible current. This paper will study the various characteristics and effects of sheath circulating current, and then will prove why the sheath current rises on the underground power cable system. A newly designed device known as the Power Cable Current Analyser, as well as ATP simulation and calculation equation are used for this analysis.

A Study on the Reduction of Sheath Circulating Current in Underground Transmission Systems (지중송전계통의 시스순환전류 저감에 관한 연구)

  • Jung, C.K.;Hong, D.S.;Lee, J.B.;Kang, J.W.;Yu, C.H.;Kang, W.T.
    • Proceedings of the KIEE Conference
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    • pp.29-33
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    • 2001
  • Sheath circulating current results from the change of sheath mutual impedance which is caused by unbalanced cable system, and different section length between joint boxes. If circulating over current flows in sheath, it produces much sheath loss which reduces the transmission capacity. And also such large sheath current influences severely on the operator. Recently, large sheath circulating current was partially measured in underground cable system of KEPCO. Accordingly, actual schemes to reduce sheath circulating over current is urgently required for installed cable system as well as newly-constructing cable system. This paper describes the analysis of sheath circulating current and various schemes to reduce the large circulating current in case of operating cable system using EMTP/ATPDraw. And also, possible schemes are proposed through a detailed analysis regarding cable systems by considering various electrical and environmental factors. It is evaluated that the proposed reduction schemes can be effectively applied to reduce the large sheath circulating over current with the minimized electrical problems.

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Development of Restraining-unit of Sheath Circulating Current and Its Electrical Characteristics (시스 순환전류 저감장치의 개발 및 전기적 특성 검토)

  • Ha C. W.;Kim J. N.;Kim D. W.;Kang J. W.;Kim J. S.
    • Proceedings of the KIEE Conference
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    • pp.394-396
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    • 2004
  • In order to reduce the sheath circulating current, same arrangement and balanced length of cable are required for the underground cable system. But practically, changing the whole arrange of cable which is already constructed is impossible. Therefore, It is necessary to apply the restraining-unit of sheath circulating current at the cross-bonding wire of insulated joint because the impedance of restraining-unit is able to reduce sheath circulating current at a normal condition. Even at a transient state, the restraining-unit must maintain electrical and mechanical characteristics. In this paper, the features of restraining-unit developed by LG Cable as well as the electrical test results are described. It proves that the restraining-unit is applicable to the underground cable system where sheath circulating current rises.

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Analysis on the Effects of the Induced Noise Voltage with the Grounded or Non-grounded Cable Sheath in the Power Inducting Situation (전력 유도 발생 시 케이블 쉬스 접지 여부에 따른 유도 잡음 전압 영향 분석)

  • Lee, Sang-Mu;Choi, Mun-Hwan;Cho, Pyoung-Dong
    • 한국정보통신설비학회:학술대회논문집
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    • pp.285-288
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    • 2007
  • This article presents the change characteristics of induced noise whether the sheath layer of the cable is grounded or not. As what affects the induced noise, there are power influence or longitudinal transverse voltages and its weighted filtered voltage. The sheath ground is basicaly predicted to have the effects of alleviation on the power influence. But practically the effects may not happen in the case of common cable's sheath layer. Rather there are cases that the ground of sheath affects so that the noise level could increase. So we need to scrutinize the effects of the sheath gorund in the measures for the protection against electromagnetic induction by powerline or traction line system. And the evaluation of using the designated shielding purpose cable is needed.

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Underground Transmission Cable Sheath Voltage Analysis Using EMTP (EMTP를 이용한 송전케이블 시스전압 분석)

  • Oh, Dong-Soo
    • Proceedings of the KIEE Conference
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    • pp.428-430
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    • 2000
  • This paper describes under-ground transmission cable sheath voltage by using EMTP and proposes a new design method for calculating cable sheath voltage in steady state. The cross bonding system of power cable is modeled on ${\pi}$ equivalent circuit and the sheath voltage(current) of cable can be analyzed with comparing to conventional method.

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Analysis of Sheath Induced Voltage and CCPU Operating Characteristic in Underground Transmission Cable (지중송전계통에서 시스유기전압 및 CCPU 동작 특성 해석)

  • Jin, Hye-Young;Lee, Jong-Beom;Kim, Young;Cho, Han-Koo
    • Proceedings of the KIEE Conference
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    • pp.494-496
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    • 2001
  • This paper describes sheath induced voltage and operating characteristic of cable cover protection unit(CCPU) in underground transmission cable. Real cable system operating by 154kV XLPE cable was modelled for simulation. Sheath induced voltage and operating characteristic of CCPU were analyzed. In particular, sheath induced voltage was analyzed in case of individual grounding and common grounding, respectively, and operating characteristics of CCPU were compared each other.

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Analysis of Induced Voltage on Sheath of Transmission Power Cable Connected with Surge Arrester (피뢰기 적용에 따른 지중송전케이블 시스 유기전압 해석)

  • Lee, Jun-Sung;Lee, Jong-Beom;Kim, Young
    • Proceedings of the KIEE Conference
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    • pp.1391-1393
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    • 1999
  • This paper have analyzed sheath induced voltage in underground transmission cable system which will be operated with cable cover protection unit(CCPU). Simulation was carried out to analyze sheath induced voltage using on real cable system in the case with and without CCPU. Sheath induced voltage was also analyzed according to grounding method, fault resistance and fault angle. Simulation was performed using EMTP and ATP Draw, the simulation results represent whether the arrester is necessary or not in cable system.

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A Study on the Characteristic and Rising Cause of Sheath Circulating Current by Analysis and Measurement (해석 및 측정을 통한 시스순환전류 특성 및 상승원인 검토)

  • Gang, Ji-Won;Yang, Hae-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.10
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    • pp.525-533
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    • 2002
  • It is common to install multiple lines in the same route. Recently, excessive sheath circulating current was partially measured in underground cable systems of KEPCO. Especially, the installation type, unbalance section length between joint boxes and zero sequence current by distribution cable have an effect on the rising of sheath circulating current in the underground transmission system. If excessive current flows in sheath, sheath loss which is reduced the transmission capacity is produced. This paper describes the relation analysis of sheath circulating current and burying types. And also, a detailed analysis on rising cause and characteristic of sheath circulating current by considering various unbalanced conditions presents using analysis and measurement regarding cable systems which have the problem of excessive sheath circulation current.