The ageing kinetic model is regarded as an effective tool to describe the degradation of transformer paper insulation. However, the temperature of the transformer winding is unevenly distributed, and the existing ageing kinetic models only depend on experimental data of accelerated thermal ageing at a constant temperature. Given this issue, this work proposes an improved second-order kinetic model accounting for the non-uniform thermal field. First, oil-paper insulation samples with different ageing stages are prepared under the non-uniform thermal field. Then, the sample's experimental data of moisture dispersion and distribution of degree of polymerisation are collected. On this basis, the improved second-order kinetic model is derived to simulate insulating paper's ageing process subjected to an axial temperature gradient. Further, the relationship of the parameters in the improved second-order kinetic model with the temperature and moisture content at different winding heights is obtained. Finally, the proposed model is validated, and the results show that the proposed model is more scientific than the traditional models to describe the degradation of paper insulation. In that respect, this work illustrates an improved second-order kinetic model to provide a reference for the ageing assessment/life prediction of transformer paper insulation under the non-uniform thermal field.

中文翻译：

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非均匀热场下变压器纸绝缘退化分析的改进二阶动力学模型

老化动力学模型被认为是描述变压器纸绝缘退化的有效工具。然而，变压器绕组的温度分布不均，现有的老化动力学模型仅依赖于恒温下加速热老化的实验数据。鉴于这个问题，这项工作提出了一种改进的二阶动力学模型来解释非均匀热场。首先，在非均匀热场下制备不同老化阶段的油纸绝缘样品。然后，收集样品的水分分散和聚合度分布的实验数据。在此基础上，推导出改进的二阶动力学模型来模拟绝缘纸在轴向温度梯度作用下的老化过程。更远，得到了改进的二级动力学模型中的参数在不同卷绕高度下与温度和含水率的关系。最后对所提出的模型进行了验证，结果表明所提出的模型比传统模型更能科学地描述纸绝缘的退化。在这方面，这项工作说明了改进的二阶动力学模型，为非均匀热场下变压器纸绝缘的老化评估/寿命预测提供参考。结果表明，所提出的模型比传统模型更科学地描述纸绝缘的退化。在这方面，这项工作说明了改进的二阶动力学模型，为非均匀热场下变压器纸绝缘的老化评估/寿命预测提供参考。结果表明，所提出的模型比传统模型更科学地描述纸绝缘的退化。在这方面，这项工作说明了改进的二阶动力学模型，为非均匀热场下变压器纸绝缘的老化评估/寿命预测提供参考。