【作者】 肖文章；

【导师】 刘骥；

【作者基本信息】 哈尔滨理工大学 ， 高电压与绝缘技术， 2011， 硕士

【摘要】 介电响应法是一种非破坏性的绝缘状态诊断方法,这种方法通过时域测量绝缘的极化去极化电流,计算得到其低频特性,反映绝缘系统的状态。由于常规的绝缘诊断方法具有一定的局限性,论文提出了介电响应法并阐述该方法的测量方法和研究现状,然后详细介绍了介电响应法的基本理论和时频域关系。论文证实了傅里叶变换在介电响应法频域分析中通过测量时域电流信号替代低频段频域测量的可行性和正确性。由于测量低频介电特性需要花费大量的时间,而时域测量极化去极化电流时间较短,因此,我们可以通过傅里叶变换将时域测量的电流信号变到频域,获得介质的低频特性,代替直接用频域法进行测量,这样可大大减少测量的时间,有利于更快的进行绝缘状态诊断。最后,通过实验测量了绝缘纸板在不同电压和极化时间下的极化去极化电流,表明更充分的极化时间能获得更多的绝缘内部信息。由于水分是绝缘老化的产物,论文研究了水分对极化去极化电流的影响,含有水分时电流幅值变大,在曲线的后半段衰减缓慢。在此基础上,将干燥和吸潮纸板的去极化电流通过傅里叶变换计算得到其在低频段的复电容和损耗因数曲线,从损耗因数曲线图可以发现,水分的存在使得损耗因数值变大而且随着频率的增加曲线也变得平缓。实验结果证实了介电响应法的有效性。更多还原

【Abstract】 Dielectric response is a non-destructive insulation diagnosis method, which measures the polarization and depolarization current of the insulation in time domain, and then calculates its low-frequency characteristics to reflect the condition of the insulation system.Because of the limitations of conventional insulation diagnosis methods, this thesis has proposed the dielectric response method and described its measurement methods and research status, and then detailed of the basic theory of the dielectric response and the relationship between time and frequency domain. This thesis has verified the feasibility and validity of the Fourier transform in frequency domain analysis of dielectric response through measuring the time current signal instead of low-frequency measurement. Since the measurement of low-frequency dielectric properties requires a lot of time, and the time domain of measuring the polarization and depolarization current is shorter, so we can transform the measured time domain current signal to frequency domain to obtain low-frequency characteristics of the dielectric through the Fourier transform, in place of directly measuring by the frequency domain method, this can greatly reduce the measurement time and diagnose the insulation condition faster.Finally, experimentally measuring the the polarization and depolarization current of the insulation paperboard under different voltage and polarization time has indicated that more polarization time may get more insulation interior information. Because water is a product of insulation aging, this thesis has discussed the influence of water on the polarization and depolarization current,the result shows the current amplitude becomes larger and the depolarization current curve decays slowly when the paperboard contains water. On this basis, this thesis transforms the depolarization current of dry and moisture absorption paperboard to calculate the low-frequency complex capacitance and dissipation factor, it can be found from the loss factor curve that the moisture makes the dissipation factor value larger and the curve becomes gentle along with the increasing frequency. The experimental results have verified the availability of the dielectric response in this thesis.更多还原