Evaluation of Oil-Paper Insulation Condition Based on Correlation Analysis of Isothermal Relaxation Current and Breakdown Characteristics

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Transactions on Dielectrics and Electrical Insulation Pub Date : 2026-10-01 Epub Date: 2026-07-03 DOI:10.1109/TDEI.2026.3709802

Haotian Shen;Jiandong Wu;Jiabei Zhu;Qiaohua Wang;Yi Yin;Feng Liu

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引用次数: 0

Abstract

This article analyzes the correlation between the isothermal relaxation current (IRC), dielectric strength, and physicochemical properties of oil-paper insulation during the aging process. It explores a calculation method and evaluation criteria for aging factors based on IRC response. The samples used for testing consist of insulating oil and insulating paper used in 500-kV power equipment, which were subjected to accelerated thermal aging at

$130~^{\circ }$

C for 50 days. The results indicate that the relaxation current of the oil-paper insulation can be fit using a three-exponential model. During the aging process, the DC component I₀, the relaxation time constant

$\tau _{{1}}$

, and the relaxation polarization intensity a_i all show a clear increasing trend. However, the relaxation time constants

$\tau _{{2}}$

and

$\tau _{{3}}$

increase significantly before 20 days of aging, while they decrease markedly after 20 days. The charge amounts Q₁–Q₃ released within the three relaxation time constants all increase with aging time. The traditional cable insulation aging factor A_cable, based on the charge amount ratio, does not show a monotonic increase after aging, primarily due to the neglect of the DC component I₀ and Q₁. The improved charge ratio-based aging factor A_op exhibits a monotonic increase with aging time, and it shows a positive correlation with breakdown field strength, residual life, and the degradation trend of polymerization degree. Finally, an evaluation criterion for the aging factor A_op is proposed based on the residual life during the aging process of oil-paper insulation.

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基于等温松弛电流与击穿特性相关性分析的油纸绝缘状态评价

分析了油纸绝缘在老化过程中的等温弛豫电流（IRC）与介电强度及理化性能之间的关系。探讨了基于IRC响应的老化因子的计算方法和评价标准。试验所用样品为500kv电力设备用绝缘油和绝缘纸，在130~^{\circ}$ C条件下加速热老化50天。结果表明，油纸绝缘的弛豫电流可以用三指数模型拟合。时效过程中，直流分量I0、弛豫时间常数$\tau _{{1}}$、弛豫极化强度ai均呈现明显的增大趋势。而松弛时间常数$\tau _{{2}}$和$\tau _{{3}}$在老化20 d前显著升高，20 d后显著降低。在三个弛豫时间常数范围内释放的电荷量q1 ~ q3均随老化时间的增加而增加。传统的电缆绝缘老化系数Acable，基于电荷量比，老化后不呈现单调增加，主要是由于忽略了直流分量I0和Q1。改进的电荷比老化因子Aop随老化时间单调增加，与击穿场强、剩余寿命和聚合度的降解趋势呈正相关。最后，基于油纸绝缘老化过程中的剩余寿命，提出了老化因子Aop的评价准则。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

IEEE Transactions on Dielectrics and Electrical Insulation 工程技术-工程：电子与电气

CiteScore

6.00

自引率

22.60%

发文量

309

审稿时长

5.2 months

期刊介绍： Topics that are concerned with dielectric phenomena and measurements, with development and characterization of gaseous, vacuum, liquid and solid electrical insulating materials and systems; and with utilization of these materials in circuits and systems under condition of use.