In order to suppress the white noise interference in partial discharge(PD)detection and accurately extract the characteristics of local discharge pulse acoustic signal of transformer under strong noise environment,the...In order to suppress the white noise interference in partial discharge(PD)detection and accurately extract the characteristics of local discharge pulse acoustic signal of transformer under strong noise environment,the adaptive separation and denoising of the discharge pulse acoustic signal were analyzed under low signal-to-noise ratio(SNR)environment.Firstly,the optimal decomposition mode number K of the variational mode decomposition(VMD)was determined based on Spearman correlation coefficient,then the reliability of the proposed Spearman-variational mode decomposition(SVMD)method decomposition was verified by simulated signals,and finally the actual discharge pulse acoustic signal was decomposed and denoised based on the Spearman correlation coefficient averaging threshold method to extract the eigenmode function components of the discharge pulse signal.The results showed that SVMD adaptively solved the unknown defects of VMD mode number,and effectively extracted the modal components of complex signals,and successfully realized the denoising of transformer partial discharge acoustic signals.The proposed method effectively removed white noise interference in the partial discharge acoustic signal and obtained a smooth filtered signal.It retained the integrity of the partial discharge signal to the maximum extent and was beneficial to the subsequent research of partial discharge.The improvement of VMD was helpful to promote its wide use in industrial equipment condition inspection.展开更多
Oil immersed power transformer is the main electrical equipment in power system.Its operation reliability has an important impact on the safe operation of power system.In the process of production,installation and ope...Oil immersed power transformer is the main electrical equipment in power system.Its operation reliability has an important impact on the safe operation of power system.In the process of production,installation and operation,its insulation structure may be damaged,resulting in partial discharge and even breakdown inside the transformer.In this paper,S9-M-100/10 oil immersed distribution transformer is taken as the research object,and the distribution laws of electromagnetic field and temperature field in transformer under normal operation,inter turn short circuit and inter layer short circuit are simulated and analyzed.The simulation results show that under normal conditions,the temperatures at the oil gap between the transformer core and the high and low voltage windings and the middle position of the high-voltage winding are high.When there are inter turn and inter layer short circuit faults,the electromagnetic loss of the fault part of the transformer increases,and the temperature rises suddenly.The influence of the two faults on the internal temperature field of the transformer is different,and the influence of the inter turn short circuit fault on the temperature nearby is obvious.The analysis results can provide reference for the thermal fault interpretation and fault classification of transformer.展开更多
基金supported by State Grid Gansu Electric Power Research Institute(No.52272219000Q).
文摘In order to suppress the white noise interference in partial discharge(PD)detection and accurately extract the characteristics of local discharge pulse acoustic signal of transformer under strong noise environment,the adaptive separation and denoising of the discharge pulse acoustic signal were analyzed under low signal-to-noise ratio(SNR)environment.Firstly,the optimal decomposition mode number K of the variational mode decomposition(VMD)was determined based on Spearman correlation coefficient,then the reliability of the proposed Spearman-variational mode decomposition(SVMD)method decomposition was verified by simulated signals,and finally the actual discharge pulse acoustic signal was decomposed and denoised based on the Spearman correlation coefficient averaging threshold method to extract the eigenmode function components of the discharge pulse signal.The results showed that SVMD adaptively solved the unknown defects of VMD mode number,and effectively extracted the modal components of complex signals,and successfully realized the denoising of transformer partial discharge acoustic signals.The proposed method effectively removed white noise interference in the partial discharge acoustic signal and obtained a smooth filtered signal.It retained the integrity of the partial discharge signal to the maximum extent and was beneficial to the subsequent research of partial discharge.The improvement of VMD was helpful to promote its wide use in industrial equipment condition inspection.
基金Science and Technology Project of State Grid Gansu Electric Power Company(No.52272219000Q)。
文摘Oil immersed power transformer is the main electrical equipment in power system.Its operation reliability has an important impact on the safe operation of power system.In the process of production,installation and operation,its insulation structure may be damaged,resulting in partial discharge and even breakdown inside the transformer.In this paper,S9-M-100/10 oil immersed distribution transformer is taken as the research object,and the distribution laws of electromagnetic field and temperature field in transformer under normal operation,inter turn short circuit and inter layer short circuit are simulated and analyzed.The simulation results show that under normal conditions,the temperatures at the oil gap between the transformer core and the high and low voltage windings and the middle position of the high-voltage winding are high.When there are inter turn and inter layer short circuit faults,the electromagnetic loss of the fault part of the transformer increases,and the temperature rises suddenly.The influence of the two faults on the internal temperature field of the transformer is different,and the influence of the inter turn short circuit fault on the temperature nearby is obvious.The analysis results can provide reference for the thermal fault interpretation and fault classification of transformer.
