Finite Horizontal Conductor

Self-inductance and capacitance of a finite horizontal conductor, exp. experimental result caL-fia calculated result of finite line impedance, cal.-inf. calculated result of Carson s infinite line impedance, (a) Inductance, (b) Capacitance. 

As x/h decreases, the accuracy of the finite conductor formula increases. It should be noted that the inductance per unit length decreases as the length decreases. The reason for this is that the inductance of an infinitely long conductor includes the mutual inductance between the reference part of a conductor and the remaining part with infinite length as explained in Sechon I.7.2.2. 

Mutual inductance between different-length horizontal conductors, (a) Inductance, (b) Capacitance. 

Because Carson s formula cannot deal with the different-length conductors, three approaches to determine an effective length x are investigated (a) x = shorter length X2, (b) arithrnetic mean distance and 

Surge Impedance of an Overhead Conductor with Length x = 4 m 

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The admittance of a finite-length horizontal conductor is evaluated by the potential coefficient of a perfecdy conducting earth [1] ... 

Let us consider the vertical multiconductor system illustrated in Figure 1.61. In the same manner as the finite-length horizontal conductor, the following impedance formula is obtained ... 

This section explains impedance and admittance formulas of nonuniform lines, such as finite-length horizontal and vertical conductors based on a plane wave assumption. The formulas are applied to analyze a transient on a nonuniform line by an existing circuit theory-based simulation tool such as the EMTP [9,11]. The impedance formula is derived based on Neumann s inductance formula by applying the idea of complex penetration depth explained earlier. The admittance is obtained from the impedance assuming the wave propagation velocity is the same as the light velocity in free space in the same manner as an existing admittance formula, which is almost always used in steady-state and transient analyses on an overhead line. 

Rogers, E. J. and J. F. White. 1989. Mutual coupling between finite length of parallel or angled horizontal earth return conductors. IEEE Trans. Power Deliv. 4(1) 103-113. 

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