Research On Ultrasonic Detection And Noise Reduction Method Of Partial Discharge In Power Equipment

Whether the power equipment can operate safely and reliably in the power system determines the stable operation of the power system.During the manufacture and operation of power equipment,the insulation may be defective,and partial discharge may occur at the defective part during the operation.Long-term partial discharge will expand the scope of insulation defects,accelerate insulation aging,and lead to insulation breakdown of power equipment in severe cases.Therefore,it is of practical value to carry out research on partial discharge detection methods and signal denoising methods for power equipment insulation.The research on the mechanism of partial discharge generation was carried out,and the partial discharge laws and characteristics of three partial discharge models were studied,the ultrasonic signal generated when the partial discharge was simulated by the needle plate discharge model was determined,the measured ultrasonic signal was used as the follow-up analysis and processing base support.Design of partial discharge ultrasonic signal detection system design.Including the frequency of the ultrasonic signal generated by the discharge model of the needle plate,the PXR15 MRH ultrasonic sensor of Pengxiang Technology was selected.According to the characteristics of the output signal of the sensor,a dynamic adjustment amplifier was designed to realize the gain adjustment of the output signal of the sensor.In order to eliminate the environmental noise on site In order to reduce the interference of power supply noise,a linear power supply is designed to supply power to the measurement system.The signal is finally collected by the oscilloscope output.In order to completely eliminate the interference in the partial discharge signal received by the detection system,a model signal containing noise interference is constructed on the basis of analyzing the characteristics of the interference signal in the partial discharge signal.The singular value measurement quantization method is used to eliminate narrow-band noise and some white noise.For the residual noise of the signal,the EMD-like method is used to denoise the noise,and the results show that the denoising effect of a single-type EMD method is not ideal.The measurement quantification is combined with the CEEMDAN threshold layered denoising method to continue processing.The simulation results show that the denoising effect of the layered denoising method is obvious,the signal-to-noise ratio can reach 5.69 d B,and the partial discharge signal can be better preserved.Finally,this paper also applies the denoising method to denoise the partial discharge signal received by the detection system and filtered by the filter circuit.Through analysis,it is found that the method in this paper still has a good denoising effect on the noise contained in the measured signal.