变压器油纸绝缘老化诊断方法研究

Study on aging diagnosis method of transformer oil-paper insulation

准确诊断油纸绝缘变压器老化状态,对降低变压器故障率,提高电力系统供电可靠性具有重要意义。提出一种基于等效电路分析的变压器油纸绝缘老化诊断方法。基于回复电压法分析极化谱特征量,构建油纸绝缘变压器扩展德拜等效电路;并通过多台不同老化程度变压器的等效电路参数的比较,研究油纸绝缘老化与等效电路参数之间的内在联系,从而实现油纸绝缘老化程度诊断。研究结果表明,利用等效电路参数可准确、有效的诊断油纸绝缘变压器的老化状态,等效电路中的小时间常数支路反映了弛豫响应速度快的绝缘油的老化情况,大时间常数支路反映弛豫响应速度慢的绝缘纸的老化情况,而中时间常数支路反映油纸绝缘的界面极化现象。

It is important to reduce the faulted rate of transformer and improve the reliability of power supply that the insulation aging condition of transformer oil-paper is diagnosed accurately.An aging diagnosis method of oil-paper insulated transformer based on equivalent circuit was proposed in this paper.Firstly,based on the return voltage method,the characteristics of polarization spectrum was analyzed,and then the extended Debye equivalent circuit of oil-paper insulated transformer was built.By equivalent circuit parameters comparison of multiple transformers with different aging degree,the internal relationships between oil-paper insulated transformer under different aging condition and the parameters of related equivalent circuit was studied.The oil-paper insulated transformer aging diagnosis was thus realized.Research results showed that using the parameters of equivalent circuit could diagnose the transformer oil-paper insulation in aging condition effectively and accurately.The small time constant branches of the equivalent circuit reflect the aging condition of insulated oil which have fast response speed of relaxation,the large time constant branches of the equivalent circuit reflect the aging condition of insulated paper which have low response speed of relaxation,and the medium time constant branches of the equivalent circuit reflect the polarization phenomenon of oil-paper insulation interface.