中文摘要：

为将频域介电谱法更好地应用于油纸绝缘设备老化状态的无损检测,通过对比有限元法与XY模型法对变压器油纸绝缘系统的频域介电特性的求解结果,探讨了两种方法的准确性与局限性。研究结果表明：XY模型在计算过程中忽略了油纸交界面附近由于材料不连续效应所产生的电场畸变,由此引入了模型误差。对于电场分布较均匀,畸变效应不明显的主绝缘结构,当油电导率γ〈1.0×10^-11S/m时,XY模型求解结果较准确,但是当油电导率γ〉1.0×10^-11S/m时,随着油电导率的继续增大,其准确度会降低;有限元法建立的仿真模型与实际模型更接近,其突出的优势还在于考虑了电场畸变等因素对频域介电谱计算的影响。因此,相比于XY模型法,有限元法准确度更高,能够求解复杂结构的频域介电谱,具有更广阔的应用前景。

英文摘要：

In order to apply frequency domain spectroscopy（FDS） in nondestructive diagnosis of the aging state of oil-paper insulating equipment more effectually, we simulated and calculated the frequency domain dielectric response characteristics of main insulation structure in transformers by using the finite element method and XY model. On the basis of comparing the results, we investigated the accuracy and limitation of the two methods. It is showed that the main problem of the XY model is that it neglects the electric field distortion because of the discontinuous effect near the interface of oil and paper. As for the main insulation structure, whose electric field is comparatively uniform and distortion is not obvious, the error of the XY model is relatively small under the condition that the oil conductivity is less than 1.0×10^-11S/m. But when the oil conductivity is more than 1.0×10^-11S/m, the error increases as the oil conductivity rises. The model established by FEM is closer to the real model. Its prominent advantage is that the influence of the distortion on the calculation of frequency domain dielectric spectroscopy characteristics is also taken into consideration. Compared with XY model, FEM is more accurate and can be used as the solution to analyze the characteristics of frequency domain dielectric spectroscopy with complex structures. So the potential application of FEM is broad and promising.