Aging law and reliability analysis of Nomex paper used for dry-type transformer insulation

作者：Wen Minmin^*; Tian Muqin; Song Yuan; Liu Yuan; Lei Zhipeng; Song Jiancheng

来源：High Voltage Engineering, 2014, 40(11): 3430-3437.

DOI：10.13336/j.1003-6520.hve.2014.11.019

• Degradation model
• Degree of polymerization
• Dry-type transformer
• Insulation modeling
• Intrinsic viscosity
• Reliability estimation
• Thermodynamic parameter
• Viscosity properties

Reliability of the Nomex paper is a main influential factor for safe operation of dry-type transformers, thus we designed an interturn insulation model of dry type transformer and simulated its service environment to carry out electrical and thermal combined aging test on the Nomex paper. Then, the viscosity properties of the Nomex/sulfuric solution were measured periodically during the aging test while the relationship between the intrinsic viscosity of the Nomex/sulfuric solution and the degree of polymerization (DP) for Nomex was analyzed. We proposed a degradation model based on DP to analyze the reliability of the Nomex paper, and obtained the thermodynamic parameters of the Nomex through the thermogravimetric analysis (TGA), with which the parameters of the degradation model were calculated. Finally, we estimated the reliability of ten groups of specimens with the established model. Results show that the intrinsic viscosity of the Nomex/sulfuric solution drops with the aging time of the specimens, and the logarithm of intrinsic viscosity is linearly related with the DP, indicating that intrinsic viscosity can reflect the aging degree of the Nomex paper. In addition, the remaining life of the ten groups of specimens corresponds with their reliability analysis results obtained from the degradation model, so that the proposed reliability model can be used for reliability estimation of the Nomex paper.

• 出版日期2014
• 单位太原理工大学