宽频带油纸绝缘介电响应的全过程谱图提取和定量分析

为深入而全面地解释油纸绝缘材料在宽频带内介电响应的微观机理,基于普适弛豫定律和凝聚态物理经典理论,利用响应谱图受温度影响的频移特性,通过势垒能级这一本征参量建立油纸绝缘材料频域介电谱与热刺激电流曲线在表征同类介电过程时的联系,并进一步以复介电常数实部与虚部关联关系和复介电常数一阶偏微分方程的数据处理手段,形成具有可靠理论依据的宽频带介电过程微观机理综合分析新方法。基于此,依次在宽频带内提取和观察了电荷的各类运动过程。分析结果表明,在较宽温度范围内,油纸绝缘材料的频域介电谱曲线从低频到高频依次包括低频弥散、交流电导和电极极化、界面极化及偶极子转向极化等独立介电过程,并根据相关理论模型和试验数据对上述各独立过程进行定量研究,确定其微观物理机制、频谱函数和发生条件。该研究揭示了油纸绝缘材料在全频域范围的电荷运动规律,为频域介电谱法应用于电力设备绝缘评估提供了新的理论分析思路。

Spectra Extraction and Quantitative Analysis for All Independent Dielectric Processes of Oil-paper Insulation in Broad Frequency Band

In order to explain the microscopic mechanism of oil-paper insulation material’s dielectric response in a sufficiently wide frequency range in depth and comprehensively, the present study considers both the universal relaxation law and classical theoretical model in dielectric physics. By taking full advantage of the thermal characteristics of dielectric processes, barrier height, as an intrinsic parameter, the method was proved to be effective in establishing connection between frequency domain spectroscopy test and thermally stimulated current when observing same dielectric process in the two aspects. Further, with the correlation between the real and imaginary parts of complex permittivity curve as well as the first order partial differential equation of response spectrum data, a synthetical analysis that effectively reveals microscopic mechanisms of dielectric process in frequency domain is established. With this newly developed method, the results illustrate that in a relatively large temperature range, oil-paper’s response curve is generated by independent dielectric processes which are, respectively, low frequency dispersion, conductance, electrode polarization, interfacial polarization and dipole polarization. These processes’ generation mechanisms, function expressions and occurrence conditions are also clarified according to quantitative study. By revealing the charge carriers’ motion law in relatively wide frequency band, the present study contributes to the theory explanation and application of frequency domain spectrum.