基于等效电路参数的变压器油中糠醛含量判别法研究

针对油中糠醛仅来自于油纸绝缘变压器绝缘纸的老化,对变压器固体绝缘老化诊断具有重要的指导意义。本文首先对等效电路参数与绝缘老化之间的关系进行理论分析,然后利用改进粒子群算法有效地对3台不同老化状态的变压器等效电路进行参数辨识,最后分析变压器油中糠醛含量与变压器绝缘系统弛豫响应等效电路参数之间的关系。研究结果表明:糠醛含量的变化对等效电路大时间常数支路参数的影响最大,变压器绝缘老化越严重,油中糠醛含量越高,则大时间常数支路的时间常数越小,极化电阻越小,极化电容越大,且糠醛含量与大时间常数支路的时间常数具有良好的函数关系,为变压器油中糠醛含量的定量判定提供新的方法,且当大时间常数支路的时间常数达到134.07s,则变压器绝缘老化严重。

Study on the discrimination method of furfural content in transformer oil based on equivalent circuit parameters

The furfural content in transformer oil only comes from the aging of the insulating paper in oil paper insulation transformer, which has important guiding significance for the aging diagnosis of transformer solid insulation. This paper firstly analyzes the relationship between the equivalent circuit parameters and the insulation aging of the transformer theoretically, uses the improved particle swarm algorithm to effectively identify the equivalent circuit parameters of three transformers with different aging conditions, and finally analyzes the relationship between the furfural content in the transformer oil and the relaxation response equivalent circuit parameters of the transformer insulation system. The research results show that the change of furfural content in transformer oil has the largest effect on the large time constant branch circuit parameters of the equivalent circuit; the more serious the transformer insulation aging is, the higher the furfural content in the oil becomes, the smaller the time constant of the large time constant branch circuit becomes, the smaller the polarization resistance becomes, and the larger the polarization capacitance becomes; and the furfural content has good function relationship with the time constant of the large time constant branch circuit, which provides a new method to quantitatively determine the furfural content in transformer oil. When the time constant of the large time constant branch circuit reaches to 134.07s, the insulation aging of the transformer is serious.