油纸绝缘频域介电谱影响因素研究

Influencing Factors on Frequency-domain Dielectric Spectroscopy of Oil-paper Insulation System

作为一种新型的、非破坏性的试验方法,频域介电谱技术正广泛应用于油纸绝缘型绝缘诊断和评估。但在现场测试时发现,这种方法易受温度、空间电场等干扰因素的影响,从而给设备的绝缘诊断带来困难。为了提高频域介电谱用于油纸绝缘诊断的可靠性和准确性,笔者基于变压器等效XY模型在实验室内制备了典型的油纸绝缘试品,并在控制温度和试品状态的情况下,研究了温度、接线方式和绝缘结构对频域谱的影响规律。结果表明,3因素都对频域谱有特征性的影响,在实际测试中可通过温度校正、合理接线等方式排除这些因素的影响。

As a novel non-destructive test method, frequency-domain dielectric spectroscopy（FDS） has been widely used for diagnosis and assessment of oil-paper insulation systems. However, the measurement of this method is influenced by some factors such as temperature and spaeial electric filed, during on-site test, which leads to difficulty in accurate diagnosis of insulation. To improve the accuracy and reliability of oil-paper insulation diagnosis by FDS, some typical oil-paper insulation samples were prepared by the authors in laboratory based on the equivalent XY model of transformer. The influences of temperature, connection mode and insulation structure on FDS were investigated under controlled temperature and different sample status. Results show that each influencing factor has distinctive effect on FDS, and the effect can be eliminated by temperature correction and proper connection.