The Research On Software Anti-interference Technology In On-line Detecting System For Transformer

The transformer default is majority caused by the influence of outside factor in operating, which makes the bug of transformer extending, and producing partial discharge. The development of continues and acutely partial discharge leads to partial insulation aging of the transformer. So monitoring the partial discharge is one of the mainly methods on on-line insulation monitoring of the transformer. Accompanying with the transformer discharge, there is the phenomena as electric pulse, electric radiation, ultrasonic, light, and partial over heating etc. And the partial discharge in the oil emits gas and produces the energy wastage. Accordingly many measurements appear, such as the electric pulse measurement, the ultrasonic measurement, the light measures, the infrared measurement, the chemistry measurement, dielectric loss measurement, and the ultra high frequency measurement etc.In engineering application, because of the bad condition which the sensor places at, the range the detecting signals is weak, the spectrum of it is broad, the interference is serious, so the key technique of on-line discharge monitoring of transformer is repress interference. Beginning with the wave shape and spectrum character of interference, this paper detailed and further does research on many kinds of filter arithmetic aiming at certain kind of electromagnetism interference; colligates the reality possibility of the filter arithmetic, the complication degree of program, and every kind of standard for the filtering result; puts forward the best filtering method.Wavelet analysis is more and more applied in filter arithmetic, which has the character of time-frequency localization and the character of "microscope" and "magnifier". This paper introduces the basis wavelet theory combined with multi-resolution analysis, detailed compares and analyzes how to filter the white-noise from partial discharge using wavelet method, and puts forward the conclusion.Finally, apply every kind of filter arithmetic to imitation analysis in the laboratory, and draw a conclusion.