绝缘油老化程度对变压器绝缘系统极化谱参数影响规律的研究

The Influence of Insulating Oil Aging Degree on Polarization Spectrum in Oil-paper Insulation System of the Transformer

油浸式电力变压器在运行过程中绝缘油不断地老化,严重影响其运行寿命,因此评估变压器绝缘油老化程度对确保变压器安全可靠运行具有重要意义。基于回复电压的极化谱方法是一种无损的绝缘诊断方法,可以方便地对变压器的绝缘状态进行现场诊断,已经被用来评估变压器的绝缘状态。通过对由三种不同老化程度的绝缘油和普通纤维素绝缘纸组成的绝缘系统进行的回复电压测试,研究了回复电压极化谱在不同老化程度绝缘油下的变化规律。结果表明:绝缘油老化程度对中心时间常数的影响最为明显,对峰值电压和初始斜率的影响则不大,初步建议用中心时间常数来判断绝缘油的老化程度,将峰值电压和初始斜率作为参考。

Insulating oil become an aging in Oil-immersed power transformer while operation, and the operational life will be seriously influenced. Therefore, the assessment of aging degree of insulating oil in transformer makes great sense for the safe and reliable operation of transformer. As a non-destructive insulation diagnostic technique, the polarization spectral method which is based on RVM（ recovery voltage measurement） has been employed to assess the state of insulation in transformer. In this paper, RVMs were conducted for the insulating system composed of three types of insulating oil with different aging degrees and kraft paper, and the changing regularities of polarization spectrum based on return volt- age measurement were obtained. The result shows that insulating oil aging effecting on the central time constant is most obvious, but not on the initial slope and the peak voltage, so it is suggested preliminarily to use central time constant to diagnose the aging degree of insulating oil, and initial slope and peak voltage as a reference.