Design and realization of online monitoring device for arrester in substation

By analyzing the advantages and disadvantages of several online monitoring methods for lightning arresters, this work uses harmonic analysis to extract characteristic data. This paper introduces the hardware design in detail. As FFT is used for the leakage current signal analysis, the spectrum leakage, fence effect and the sampling deviation caused by the frequency fluctuation of power network is produced. The time shifting phase difference method based on Hanning window is also proposed for correcting the amplitude, phase and frequency of the spectrum of the leakage current signal. The dopting improved wavelet threshold denoising method before the data from the lightning arrester is applied to remove white noise and electromagnetic interference in the environment. Based on Labview2013, the online monitoring system for the upper machine is designed. The test and analysis results for the software module of online monitoring system show that the software module designed in this paper can run stably and display the data accurately.