The Study of Noise-rejection by Using Pulse Time-delay Identification Method and the Analysis of PD Data Obtained in the Field

Based on the mechanism of partial discharges occurring in the stator winding insulations of generators, a set of on-line PD measurement with double sensors is developed in this paper. After comparing the different types of measurement, the noise suppressing method is focused on the technique of "pulse time-delay identification" which is based on installing double sensors for every phase. The principle of the method is introduced in this paper. The software program designed by Labview provides the power frequency graph, N-Q and N- Φ two dimension diagram, three dimension diagram and maximum quantity of PD and NQN tendency diagram to make a further analysis of the PD data. In addition, the dada obtained in the field is analyzed here, including an insulation fault detected in a plant successfully.