绝缘材料介电谱测量的接触法和非接触法误差分析

Error Analysis on Contact and Non-contact Methods for Dielectric Spectrum Measurement of Insulating Material

理论分析了几何尺寸测量误差和复电容测量误差对接触法和非接触法介电谱测量误差的影响,并对二者的误差进行了比较,然后对电极间隙距离、试样介电常数对介电谱测量误差的影响进行了仿真分析。基于介电谱仪测量得到高温硫化硅橡胶的介电谱,分析了几何尺寸(试样厚度)测量误差对接触法和非接触法测量结果准确性的影响。结果表明:非接触法受几何尺寸和复电容测量准确性的影响比接触法要大,对仪器测量的准确性要求较高,容易产生比接触法更大的误差。非接触法的相对介电常数测量误差随试样相对介电常数的增加先快速增大然后逐渐稳定;试样相对介电常数不大于5时,随着电极间隙距离的增加,相对介电常数的测量误差快速增大。非接触法适用于几何尺寸和介电常数测量准确性足够高的场合。

The influence of the geometric size and complex capacitance measurement error on the dielectric spectrum measurement errors of contact and non-contact methods was theoretically analyzed,and the two errors were compared.The influence of electrode gap distance and dielectric constant of sample on the dielectric spectrum measurement errors was simulated and analyzed.On the basis of dielectric spectra of high temperature vulcanized silicone rubber obtained by dielectric spectrometer,the influence of measurement errors of the geometric size(sample thickness)on the accuracy of measurement results for contact and non-contact methods was analyzed.The results show that the non-contact method is much more affected by the measurement accuracy of the geometric size and complex capacitance than the contact method,and it has high requirement on the instrument accuracy and is easier to produce significant errors than the contact method.With the increase of relative dielectric constant of the sample,the measurement error of relative dielectric constant by non-contact method dramatically increases and then gradually becomes stable.When the relative dielectric constant of the sample is no more than 5,with the increase of electrode gap distance,the measurement error of the relative dielectric constant dramatically increases.The non-contact method is suitable for the occasion with high measurement accuracy of the geometric size and dielectric constant.