Based on classical circuit theory, this article develops a general analytic solution of the telegrapher’s equations, in which the length of the cable is explicitly contained as a freely adjustable parameter. For this...Based on classical circuit theory, this article develops a general analytic solution of the telegrapher’s equations, in which the length of the cable is explicitly contained as a freely adjustable parameter. For this reason, the solution is also applicable to electrically short cables. Such a model has become indispensable because a few months ago, it was experimentally shown that voltage fluctuations in ordinary but electrically short copper lines move at signal velocities that are significantly higher than the speed of light in a vacuum. This finding contradicts the statements of the special theory of relativity but not, as is shown here, the fundamental principles of electrical engineering. Based on the general transfer function of a transmission line, the article shows mathematically that an unterminated, electrically short cable has the characteristics of an ideal delay element, meaning that an input signal appears at the output with a slight delay but remains otherwise unchanged. Even for conventional cables, the time constants can be so small that the corresponding signal velocities can significantly exceed the speed of light in a vacuum. The article also analyses the technical means with which this effect can be conveyed to very long cables.展开更多
Model of an atom by analogy with the transmission line is derived using Maxwell’s equations and Lorentz’ theory of electrons. To be realistic such a model requires that the product of the structural coefficient of L...Model of an atom by analogy with the transmission line is derived using Maxwell’s equations and Lorentz’ theory of electrons. To be realistic such a model requires that the product of the structural coefficient of Lecher’s transmission lines σ and atomic number Z is constant. It was calculated that this electromechanical constant is 8.27756, and we call it structural constant. This constant builds the fine-structure constant 1/α = 137.036, and with permeability μ, permittivity ε and elementary charge e builds Plank’s constant h. This suggests the electromagnetic character of Planck’s constant. The relations of energy, frequency, wavelength and momentum of electromagnetic wave in an atom are also derived. Finally, an equation, similar to Schrodinger’s equation, was derived, with a clear meaning of the wave function, which represents the electric or magnetic field strength of the observed electromagnetic wave.展开更多
多源数据是一种综合多个信息源的复杂数据类型,其主要特点是不同的信息源从不同的角度刻画了样本以及样本之间的关系(具体到配电网领域,不同量测系统针对同一节点所得到的数据是不同的,甚至存在较大差异)。提出了一种适用于配电网线损...多源数据是一种综合多个信息源的复杂数据类型,其主要特点是不同的信息源从不同的角度刻画了样本以及样本之间的关系(具体到配电网领域,不同量测系统针对同一节点所得到的数据是不同的,甚至存在较大差异)。提出了一种适用于配电网线损计算的多源数据综合利用方法,为便于数据融合,对多源量测数据进行转换;为保证量测时间断面一致性,选择同步相量测量单元(phasor measurement unit,PMU)某一量测时刻作为基准,对数据采集与监视控制(supervisory control and data acquistion,SCADA)系统数据进行时间配准与数据填充操作,对智能电表数据采用“量测值+预测值”方式进行时标对齐;对时序数据进行滤波,获得较为准确的配电网数据;基于登普斯特-沙夫特(dempster-shafter,D-S)证据理论法实现多源数据融合。以某10 kV配电网为算例分析计算了配电网线损,结果表明,所提方法可较好地完成多源数据的综合利用,提高配电网线损计算的准确性。展开更多
文摘Based on classical circuit theory, this article develops a general analytic solution of the telegrapher’s equations, in which the length of the cable is explicitly contained as a freely adjustable parameter. For this reason, the solution is also applicable to electrically short cables. Such a model has become indispensable because a few months ago, it was experimentally shown that voltage fluctuations in ordinary but electrically short copper lines move at signal velocities that are significantly higher than the speed of light in a vacuum. This finding contradicts the statements of the special theory of relativity but not, as is shown here, the fundamental principles of electrical engineering. Based on the general transfer function of a transmission line, the article shows mathematically that an unterminated, electrically short cable has the characteristics of an ideal delay element, meaning that an input signal appears at the output with a slight delay but remains otherwise unchanged. Even for conventional cables, the time constants can be so small that the corresponding signal velocities can significantly exceed the speed of light in a vacuum. The article also analyses the technical means with which this effect can be conveyed to very long cables.
文摘Model of an atom by analogy with the transmission line is derived using Maxwell’s equations and Lorentz’ theory of electrons. To be realistic such a model requires that the product of the structural coefficient of Lecher’s transmission lines σ and atomic number Z is constant. It was calculated that this electromechanical constant is 8.27756, and we call it structural constant. This constant builds the fine-structure constant 1/α = 137.036, and with permeability μ, permittivity ε and elementary charge e builds Plank’s constant h. This suggests the electromagnetic character of Planck’s constant. The relations of energy, frequency, wavelength and momentum of electromagnetic wave in an atom are also derived. Finally, an equation, similar to Schrodinger’s equation, was derived, with a clear meaning of the wave function, which represents the electric or magnetic field strength of the observed electromagnetic wave.
文摘多源数据是一种综合多个信息源的复杂数据类型,其主要特点是不同的信息源从不同的角度刻画了样本以及样本之间的关系(具体到配电网领域,不同量测系统针对同一节点所得到的数据是不同的,甚至存在较大差异)。提出了一种适用于配电网线损计算的多源数据综合利用方法,为便于数据融合,对多源量测数据进行转换;为保证量测时间断面一致性,选择同步相量测量单元(phasor measurement unit,PMU)某一量测时刻作为基准,对数据采集与监视控制(supervisory control and data acquistion,SCADA)系统数据进行时间配准与数据填充操作,对智能电表数据采用“量测值+预测值”方式进行时标对齐;对时序数据进行滤波,获得较为准确的配电网数据;基于登普斯特-沙夫特(dempster-shafter,D-S)证据理论法实现多源数据融合。以某10 kV配电网为算例分析计算了配电网线损,结果表明,所提方法可较好地完成多源数据的综合利用,提高配电网线损计算的准确性。
