为了更好地使用好静电示波仪,准确无误地排除各种故障现象,提高工作效率,现将静电示波仪电晕电路的基本功能及工作原理,查找故障及排除的方法进行介绍,以供同行参考。1 基本功能及工作原理1.1 NE 555时基电路各脚的基本功能NE 555时基...为了更好地使用好静电示波仪,准确无误地排除各种故障现象,提高工作效率,现将静电示波仪电晕电路的基本功能及工作原理,查找故障及排除的方法进行介绍,以供同行参考。1 基本功能及工作原理1.1 NE 555时基电路各脚的基本功能NE 555时基电路方框图如图1所示。展开更多
In order to predict the levels of corona noise from high-voltage alternating current （AC） transmission lines, the mechanism of corona noise and the corresponding theoretical prediction model are investigated. On the...In order to predict the levels of corona noise from high-voltage alternating current （AC） transmission lines, the mechanism of corona noise and the corresponding theoretical prediction model are investigated. On the basis of Drnde model, the motion of positive and negative ions produced by high-voltage corona is analyzed, and the mechanism of corona noise is discovered. The theoretical prediction model is put forward by using Kirchhoff formula, which is verified by the well agreement between our result and others＇ , considering the case of three- phase single lines. Moreover, the calculation results show that for both single and bundled lines, the sound pres- sure level of the typical frequency, i.e. twice the power frequency, attenuates slowly and leads to an obviously in- terferential phenomenon near the transmission lines, but the level of the bundled lines is smaller than that of the single ones under the same transmission voltage. Based on the mechanism of corona noise and the prediction model, it is obvious that bundled lines and/or increased line radius can be adopted to reduce corona noise in the practical engineering applications effectively. This model can also provide a theoretical guidance for the high-volt- age AC transmission line design.展开更多
文摘In order to predict the levels of corona noise from high-voltage alternating current （AC） transmission lines, the mechanism of corona noise and the corresponding theoretical prediction model are investigated. On the basis of Drnde model, the motion of positive and negative ions produced by high-voltage corona is analyzed, and the mechanism of corona noise is discovered. The theoretical prediction model is put forward by using Kirchhoff formula, which is verified by the well agreement between our result and others＇ , considering the case of three- phase single lines. Moreover, the calculation results show that for both single and bundled lines, the sound pres- sure level of the typical frequency, i.e. twice the power frequency, attenuates slowly and leads to an obviously in- terferential phenomenon near the transmission lines, but the level of the bundled lines is smaller than that of the single ones under the same transmission voltage. Based on the mechanism of corona noise and the prediction model, it is obvious that bundled lines and/or increased line radius can be adopted to reduce corona noise in the practical engineering applications effectively. This model can also provide a theoretical guidance for the high-volt- age AC transmission line design.
