Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

Mathematical Modeling and Analysis for Water_Tree of Underground Cables

지중 케이블의 수트리에 대한 수학적 모델링 및 분석

  • Lee, Jung-Woo (Department of Electrical Engineering, Korea University of Technology and Education) ;
  • Oh, Yong-Taek (Department of Electrical Engineering, Korea University of Technology and Education)
  • 이정우 (한국기술교육대학교 전기공학과) ;
  • 오용택 (한국기술교육대학교 전기공학과)
  • Received : 2020.01.30
  • Accepted : 2020.05.08
  • Published : 2020.05.31
Download PDF
⟨ Previous Next ⟩

Abstract

Water trees can cause considerable damage to the performance of underground cables. Theymay formwithin the dielectric used in buried or water-immersed high voltage cables. They grow in a bush-like or tree-like form, often taking decades before causing damage to a cable's performance. They are usually found on very old underground cables, often in an inaccessible place. It is costly and time-consuming to detect watertrees in underground cables. Tree detection technology, including mathematical modeling,can reduce the maintenance cost and time necessary for detecting these trees.To simulate detection of water trees in this study, a mathematical model ofan XLPE cable and a water tree were developed. The complex water tree structure was simplified, based on two identified patterns of aventedtree. A Matlab simulation was performed to calculate and analyze the capacitance and resistance of a cable insulation layer,based on growth of a watertree. Capacitance size increased about 0.025×10-13[Farads/mm] compared to normal when the tree area of the cable was advanced to 95% of the insulation layer. The resistance value decreased by about 0.5×1016[ohm/m]. These changesand changesshowninaBurkes paper physical modeling simulation are similar.The value of mathematical modeling for detecting water trees and damage to underground cables has been demonstrated.

수트리의 진행과정은 십수년이 걸리며 보통 매우 오래된 지중케이블에서 발견된다. 이러한 지중케이블들은 이미 접근이 어려운 곳에 있어 수트리를 검출하기 위해서는 많은 비용과 시간이 소요된다. 이러한 지중케이블의 유지보수 비용과 시간을 절감하기 위해서는 수트리가 진행된 지중케이블이 전력망에 미치는 영향을 분석할 수 있는 수학적 모델링이 필요하고, 이를 이용한 수트리 탐지 기술개발이 매우 필요한 실정이다. 본 논문에서는 수트리가 포함된 XLPE 케이블 대한 수학적 모델링을 하고자 수트리의 복잡한 구조를 Vented tree의 확인된 특정 패턴 2가지를 기준으로 가정하여 단순화 하였다. 그리고 수트리의 발달에 따른 케이블 절연층의 캐패시턴스 및 레지스턴스를 계산 및 분석하기 위해 matlab으로 시뮬레이션을 실시하였으며, 모델링의 유용성을 검증하기 위해서 참고문헌 Burkes 논문의 케이블 데이터를 동일하게 적용하였다. 시뮬레이션 결과, 캐패시턴스 크기의 변화는 케이블에 수트리 영역이 절연층에 95%까지 진행되었을 때 정상대비 약 0.025×10-13[Farads/mm] 증가됨을 확인하였다. 레지스턴스 값의 경우 정상대비 약 0.5×1016[ohm/m] 정도 감소되는 것을 확인하였다. 따라서, Burkes 논문의 물리적 모델링 시뮬레이션 결과와 비교하였을 때 그 변화값이 매우 유사하여 본 논문에서 제시한 수학적 모델링의 유용성을 검증하였다.

Keywords

References

  1. HS. Yoon, "A Study on the Water Tree Argeing Analysis of Undergrounding Cable and Application of New Method to Efficiency Restoration", Master's thesis, Seoul National University of Science & Technology, Seoul, Korea, pp.1, 2000.
  2. YH. Beak, "Rational Direction of Cable Underground Project", Technical Report, Korea Industrial Development Institute, Korea, pp.1-3.
  3. Korea Electric Power Corporation, "Analysis and Countermeasures of the Fault on Underground Distribution Line", 1999
  4. Hwang, B.K. (1990) A New Water Tree Retardant XLPE. IEEE Transactions on Power Delivery, 5, 1617-1627. DOI: http://dx.doi.org/10.1109/61.58008
  5. L. Bayan, "Water Tree in XLPE Cable," Penang, Malaysia, Dec. 28, 2009.
  6. S. Mohammadi, R. K. Far, "Failures detection in high voltage line by image processing," World Academy of Science, Engineering and Technology 2012, pp. 2055-2057, 2012.
  7. Z. Wang, P. Marcolongo, J. A. Lemberg, B. Panganiban, J. W. Evans, R. O. Ritchie, P. K. Wright, "Mechanical fatigue as a mechanism of water tree propagation in TRXLPE," IEEE Transactions on Dielectrics and Electrical Insulation, vol.19, no.1, pp.321-330, February 2012. https://doi.org/10.1109/TDEI.2012.6148534
  8. M. Y. Chen, "A nonlinear frequency analysis based approach for power cable insulation fault detection", COMPEL, vol. 31, no. 2, pp. 369-386, 2012. https://doi.org/10.1108/03321641211200482
  9. K. W. Burkes, E. Makram, and R. Hadidi, Proceedings of the 2016 COMSOL Conference in Boston, 2016.
  10. M. Alsharif, P. A. Wallace, D. M. Hepburn, and C. Zhou, Proceedings of the 2012 COMSOL Conference in Milan, 2012.
  11. Catalog of PRYSMIAN, "5-35kV 1/C TRXLE MV-90 POWER (Tape Shield), Medium Voltage Commercial & Industrial Cables", B111 2013-07-10 (2013)
  12. Q. Chen, "Capacitance of Water Tree Modeling in Underground Cables", Journal of Power and Energy Engineering, 2014, 2, 9-18 DOI: http://dx.doi.org/10.4236/jpee.2014.211002
  13. K. W. Burkes, "Modeling the Effect of a Water Tree Inside a Tape Shield and Concentric Neutral Cables", Excerpt from the Proceedings of the 2014 COMSOL Conference in Boston, 2014.