The Research Of Digital Anti-interference Technique In Partial Discharge On-line Measurement In The Power Transformer

Partial discharge measurement is one of important instrument for keeping power equipment run on an even keel. Partial discharge on-line monitoring is confronted with intensity interferences. The paper mostly introduce the application of digital anti-interference technique in partial discharge on-line monitoring in power transformer. Firstly, the development process of PD measurement, key technique and application of PD on-line monitoring are summarized in this thesis. And then the paper design the system of PD on-line monitoring and explain the trait of the measurement and functionof'management software. Based on the analysis of various interference in PD on-linemonitoring, the thesis put forward a new digital filtering technique based on thetransversal inhibition effect of MAXNET for rejecting communication interference, a new method using wavelet packet for restraining white noise and identification of periodic pulse interference based on cluster analysis. Later on, a new pulse direction identifying method based on wavelet is proposed to distinguish external discharges from internal discharges. According to the above-mentioned introduction, the author has designed a multi-layer synthetic handling model which adopts different digital signal processing technique for suppressing different interference. The imitation and on-site test results show its strong ability of suppressing interference and picking up the PD signal.