Study On Nanosecond Impulse Response Analysis Methods For Detecting Transformers Winding Slight Deformation

Transformer winding deformation can cause transformer insulation defect and expand, while it can lead to mechanical strength of winding decreasing. Therefore, It's has great significance that timely tests and judges the deformation degree of transformer winding for preventing insulation defects and deformation degree aggravating of transformer winding, advancing to prevent accidents, guaranteeing stable operation of power system. This paper studies the nanosecond pulse impulse response method which used to detect transformer winding deformation and developed a nanosecond pulse response detection system for slight deformation of transformer windings detecting based on summarizing and analyzing the current situation of the transformer winding deformation detection method. The main contents of the paper are as follows:â‘ This paper proposes a nanosecond impulse response analysis method for detecting slight deformation of transformer windings against frequency response analysis that widely used to detect transformer winding deformation currently has low sensitivity and slow test speed We choose a suitable incentive pulse waveform and parameters by theoretical analysis and simulation verify the affect of pulse parameters on the high and low frequency signal attenuation. Simulation analysis finds that the response characteristics of transformer windings can reflect the change of state of transformer winding by the voltage pulse exciting.â‘¡This paper proposes a nanosecond impulse response analysis method and detection system applicable to detects different levels of transformer winding deformation for improving the detection sensitivity and measurement speed. The method and system has good high frequency scalability and fast detecting speed, The tested impulse response curves of transformer winding have better repeatability and signal to noise, is less susceptible to interference from external environment and can reflect the actual transmission characteristics of transformer windings. And it's easy to the aid of determine and quantify slight deformation of transformer windings by calculating the correlation coefficient and the Euclidean distance between the curves.â‘¢This paper research the SNR and repeatability of impulse response curve by repeatedly testing with different sampling parameters values. It is found that the sampling frequency and sampling points is higher in test, the measured SNR and reproducibility of pulse response curves is better. It meets on the effect of the impulse response curve denoising and helpful to identify the resonant point changes of impulse response curve and determine the slight deformation of transformer winding by dividing the impulse response curve into different frequency bands according to its distribution of resonance and respectively adjusting the frequency interval of each band. The comparison of experimental results which use frequency response analysis and nanosecond impulse response analysis method to respectively detect the radiation slight deformation of transformer windings shows nanosecond impulse response analysis can reflect the radial changes of winding first side by the changes of impulse response curve in the high frequency part. Its sensitivity is much better than frequency response analysis.The theoretical analysis and experimental results above show that nanosecond impulse response analysis method and detection system researched and proposed by this paper can effectively detect different degrees deformation of transformer windings and the state changes. It has a good applied prospect.