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unit 7
Unit7 Assignment 1
#1
transmission lines are specialized cables and other media designed to carry alternating current and electromagnetic waves of high frequency (radio frequency or higher), high enough that its wave nature must be taken into account.
#3
Solid dielectric cable has become the national standard for underground electric transmission lines less than
200 kV. There is less maintenance with the solid cable, but impending insulation failures are much more difficult to monitor and detect.
#7
Near end crossing , a measure of the level of signal coupling within the cable with the high next (dB) value being desirable. Attenuation is the amount loss in the signal strength as it propagate down the Wire.
#12

An electrical transmission line can be modelled as a two-port network (also called a quadrupole network), In the simplest case, the network is assumed to be linear (i.e. the complex voltage across either port is proportional to the complex current flowing into it when there are no reflections), and the two ports are assumed to be interchangeable.
#15

#20.

#21
Three major losses in transmission lines:
Copper losses: One type of copper loss is I2R LOSS. In rf lines the resistance of the conductors is never equal to zero. Whenever current flows through one of these conductors, some energy is dissipated in the form of heat. This heat loss is a POWER LOSS. With copper braid, which has a resistance higher than solid tubing, this power loss is higher. Another type of copper loss is due to SKIN EFFECT. When dc flows through a conductor, the movement of electrons through the conductor's cross section is uniform
Dielectric losses: DIELECTRIC LOSSES result from the heating effect on the dielectric material between the conductors. Power from the source is used in heating the dielectric. The heat produced is dissipated into the surrounding medium. When there is no potential difference between two conductors, the atoms in the dielectric

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