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软门限小波去噪在变压器冲击试验中的应用研究 总被引:7,自引:6,他引:7
利用基于小波标架的软门限压缩降噪方法,对变压器冲击试验中的中性点电流进行处理。为了验证该方法可以在去噪的同时有效的保留原信号的特征分量,进行了模拟故障试验。结果表明这种去噪方法适用于对衰减快、振荡的信号的处理,能较好地解决保护信号局部特征与抑制噪声之间的矛盾。 相似文献
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直流电压下油纸绝缘的局部放电(partial discharge,PD)关系着换流变压器等关键输变电设备的安全可靠,而计算机技术的迅猛发展则促使PD数值仿真成为了探究PD机理、评估PD威胁的重要手段。文中首先阐述了PD仿真模型的研究现状,综述了abc电容模型、感应电荷概念模型、静电场模型、电流场模型以及迁移—扩散模型的建立机制及优缺点;其次,进一步分析了PD模型在交、直流电压下的主要差异以及目前直流电压下PD仿真的研究进展;最后,从仿真参数的确定以及多物理场的耦合两方面出发,讨论了仿真工况下油纸绝缘PD行为所面临的科学问题。基于上述讨论,期望为直流电压下油纸绝缘PD数值仿真研究提供启发和思路。 相似文献
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Radio interference (RI), as an aftereffect of corona discharge, is an important research topic in the field of electromagnetic compatibility, where excitation function is applied broadly to the prediction of RI level. This paper presents the theory of excitation function method used in the RI level prediction. Then, some practical problems related to this method are discussed. The propagation procedure of corona current is solved by the phase-modal transformation, and the impedance matrix of multi transmission lines is calculated by a double logarithmic approximate model of Carson’s Ground-Return impedance. At the same time, in order to calculate the RI level when total line corona is assumed, an analytical formula is deduced for integral operation. Based on the above solutions, an algorithm is presented and applied to the prediction of RI level of a practical overhead transmission line. Comparison of prediction and measurement results indicates that the algorithm proposed in this paper is effective and feasible. 相似文献
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