Protection Platen Status Recognition Based on Wavelet Analysis and Hilbert Transform for Smart Substation

The judgment of closing moment and separating moment are the precondition for status recognition of protection platen in intelligent substation. In this paper, a new method about protection platen status recognition that suitable for on-line monitoring system is proposed based on wavelet analysis and hilbert transform. This method includes three steps, firstly, the interference is removed by wavelet denoising. Secondly, features of platen displacement are emphasized by wavelet decomposition and rebuilding. Lastly, closing moment is obtained through hilbert transform that is used to estimate the status of protection platen. This method is applied to analyze and deal with the protection platen displacement data, and the calculation results of experiment show that the precision is higher. Now, this method has been employed in an online monitoring system for platen condition identification and its stability has been demonstrated.