A long overhead lossless power transmission line is terminated with its characteristic impedance. While the line is in operation

A long overhead lossless power transmission line is terminated with its characteristic impedance. While the line is in operation

Right Answer is:

There is no reflected wave on the line

SOLUTION

The two important electrical properties of a symmetrical network are:

  1. Characteristic impedance (Zo)
  2. Propagation constant.

Characteristic Impedance (Zo)

  1. Characteristic impedance is a fine and useful concept of the transmission line.
  2. When no part of the power sent down an infinite line returns no reflection, there is no loss of power.
  3. When a line that is terminated at its characteristic impedance, behaves as an infinite line, it will also have no reflection.
  4. A long overhead lossless power transmission line is terminated with its characteristic impedance. It indicates that the reflection coefficient is zero.

The reflection coefficient is,

${\rm{\Gamma }} = \frac{{{Z_0} – {Z_L}}}{{{Z_0} + {Z_L}}}$

Where

ZL is the line impedance
Z0 is the load impedance.

Therefore, there is no reflected wave on the line.

  • When a line is terminated in its characteristic impedance, it is said to be correctly terminated or termed as a non-resonant line.
  • The characteristic impedance of a uniform transmission line is defined as the steady-state vector ratio of the voltage to the current at the input of an infinite line.
  • Alternately it is defined as the impedance looking into an infinite length of the line.
  • Its unit is Ohms. It is also known as surge impedance.
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