基于SPDMD算法的XLPE电缆介质响应参数辨识

Parameters Identification for Dielectric Response of XLPE Cable Insulation Based on SPDMD Algorithm

为进一步解析获取表征交联聚乙烯(cross-linked polyethylene,XLPE)电缆绝缘介质内部弛豫、电导过程的特征参数,从而定量评估其绝缘状态,该研究以极化电流谱线为研究对象,提出一种基于稀疏增强动态模态分解(sparsity-promoting dynamic mode decomposition,SPDMD)的介质扩展Debye等效电路模型参数辨识计算方法。首先,从采集极化电流中计算得出增强稀疏幅值向量;随后利用介质响应真实模态对应向量元素非零的特征,辨识得出扩展Debye模型支路数量;最后实现对支路元件参数进行计算。结果表明,该方法相较于传统方法辨识精度更高;此外,根据极化/去极化电流测试的自身特性,相较于传统针对去极化电流进行参数辨识的方式,将极化电流作为辨识对象更为准确可靠,这一观点也在仿真及实测结果中得到验证。

To further analyze and obtain the parameters which characterize the relaxation and conduction processes of the cross-linked polyethylene(XLPE)cables,thus to quantitatively evaluate the insulation status,we take the polarization current spectrum as the identified object,and introduce the Sparsity-promoting dynamic mode decomposition algorithm,which is used to identify the equivalent circuit parameters of the extended Debye model.First,we need to calculate the sparsity-promoting amplitude vector with the polarization current.Then,we can identify the number of branches of the extended Debye model,and utilize the non-zero elements of the vector corresponding to the dielectric response true mode.Finally,the parameter identification of the equivalent circuit branch components is realized.The results show that this method has higher identification accuracy than the conventional method.In addition,according to the features of the po-larization/depolarization current measurement,compared with the depolarization current,the identified results of parameters utilizing the polarization current is more accurate and reliable.This viewpoint has also been verified by the simulation and experiment results in the study.