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Analysis for Insulating Degradation Characteristics with Aging Time for Oil-filled Transformers and/or Correlation between using Linear Regression Method

유입식 변압기의 열화시간에 따른 절연 열화특성 및 선형회귀법을 이용한 상관관계 분석

  • 이승민 (충남대학교 사범대학 전기전자통신 공학교육과)
  • Received : 2010.02.18
  • Accepted : 2010.03.15
  • Published : 2010.04.01

Abstract

General transformer's life is known as paper insulation' life. If a transformer is degraded by these aging factors, it is known that electrical, mechanical and chemical characteristics for transformer's oil-paper are changed. When the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. The paper breakdown is accompanied by an increase in the content of furanic compounds within the dielectric liquid. In this paper it is aimed at analysis on correlation between aging characteristics for insulating diagnosis of thermally aged paper. For investigating the accelerated aging process of oil-paper samples accelerating aging cell was manufactured for estimating variation of paper insulation during 500 hours at $140^{\circ}C$ temperature. To derive the results, it was performed analysis such as tensile strength(TS), depolymerization(DP), dielectric strength(DS), relative permittivity, water content(WC) and furan compound(FC) for aged paper. Also for analyzing correlation between insulating degradation characteristics, we used linear regression method. As as results of linear regression analysis, there was a close correlation between TS and DP. WC, FC. But dielectric strength was a weak correlation with aging time.

Keywords

Oil-filled transformer;Tensile Strength;HPLC;Correlation;Linear Regression

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