卷积混合模型分离算法与多局部放电混合信号分离

为了辨识GIS内多绝缘缺陷产生的单一PD信号,对多PD信号在GIS内的传播与混合机理进行深入分析,提出采用卷积混合模型描述其混合过程,并构建分离算法分离多PD信号以获取辨识所需的单一PD信号。结合PD信号的非平稳特性,将各多PD信号在时域空间下划分成短时内平稳的子信号集合,利用Molgedey-Schuste算法在频域内对子信号进行分离,再利用子信号包络线的相关性在频域对分离子信号进行重构,获取各单一PD信号,以实现对非平稳多PD信号的分离。经仿真和实测多PD信号的有效分离,证实了多PD信号在GIS内线性卷积混合特性的假设,同时为用外置UHF检测法获取多绝缘缺陷产生多PD信号的辨识提供了新方法。

Study on separation algorithm of convolutive mixing model and separation of mixing signals of multiple partial discharges

To identify individual partial discharges(PD)signals produced by multiple insulation defects in gas insolated switchgear (GIS),this paper analyses the mechanism of propagation and mixing of multiple PD electromagnetic wave signals in GIS cylinder and proposes the convolutive mixing model to describe it for a separation algorithm to acquire individual PD signals. With the non-stationary property,mixing PD signals are changed at time domain into a set consisting of short-time stationary PD signals and then the Molgedey-Schuster decorrelation approach is employed to separate these stationary PD signals at frequency domain. The correlation of the envelope of separated PD signals in this set is used to reconstruct PD signals to realize the separation of non-stationary UHF PD mixtures. The effective separation of actual UHF PD mixing signals validates the assumption of convolutive mixing process in GIS and also offers a new approach to the identification of mixing PD signals by external ultra-high frequency detection scheme from multiple insulation defects in GIS.