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Four-wire Unbalanced Feeder

Author: Edmund A. Laport

All Wires in Parallel at the Corners of a Square. The application of this type of line (Fig. 4.3) is the same as for types I and II, and it can be used where lower characteristic impedances are desired.


When h » a,


Sample values for a four-wire feeder of this type are:

p (inches) h (inches) a (inches) Z0 (ohms)
0.100 120 10 254

In types I, II, and III, all of the return current is in the ground. Attenuation tends to be large unless the soil conductivity is reduced by using ground wires parallel to the line and distributed in such a manner as to correspond approximately with the cross-sectional current distribution in the ground.

Fig. 4.3
Fig. 4.4

Last Update: 2011-03-19