Wavelet denoising method for partial discharge of DC gas-insulated electrical equipment

Abstract

The invention discloses a wavelet denoising method for partial discharge of DC gas-insulated electrical equipment. The wavelet denoising method comprises the following steps of: (1) acquiring partialdischarge current pulse signals of a typical insulation defect of the DC gas-insulated electrical equipment; (2) selecting an optimal wavelet by using a dynamic time warping method, determining an optimal signal decomposition layer number, carrying out decomposition processing on the partial discharge current pulse signal through discrete wavelet transform, and extracting a wavelet high-frequencycomponent of each layer and a wavelet low-frequency component of the highest layer; (3) processing the wavelet high-frequency components of each layer by using automatic threshold value and intermediate threshold value functions, removing noise components, and reserving partial discharge current pulse signal components; and (4) combining the denoised wavelet high-frequency component of each layerand the original wavelet low-frequency component of the highest layer through inverse discrete wavelet transform, and reconstructing a denoised partial discharge current pulse signal. The wavelet denoising method effectively removes interference in direct-current partial discharge, improves the detection precision and precision, is simple and rapid in calculation, and is easy to implement.

Description

technical field [0001] The invention relates to a wavelet denoising method for partial discharge of DC gas-insulated electrical equipment. Background technique [0002] The rapid development of HVDC power transmission and distribution technology puts forward higher requirements for the safety and stability of related DC gas-insulated electrical equipment. The partial discharge generated at the insulation defect of DC gas-insulated electrical equipment leads to the gradual deterioration of the insulation system of the equipment, which in turn causes secondary accidents such as equipment failure, fire, and casualties. Therefore, detection of partial discharge is an important means for on-line monitoring, risk assessment and asset management of DC gas-insulated electrical equipment, and it is also an effective method to ensure the safe and stable operation of electrical equipment and the entire power system. However, in the on-site partial discharge detection process, white no...

AI Technical Summary

Problems solved by technology

Wavelet denoising technology has been applied to the partial discharge denoising of AC electrical equipment. However, the mechanisms of AC partial discharge and DC partial discharge are different. The wavelet denoising technology of AC partial discharge is not suitable for DC partial discharge denoising. Discharge wavelet denoising technology is still in the initial stage of research

Moreover, the traditional optimal wavelet selection is based on the correlation coefficient method. In order to overcome the problem of different lengths between the partial discharge signal and the wavelet function, this method needs to add steps such as signal standardization, resampling, and displacement, and the calculation process is complex and time-consuming.

Images