Tuesday, 2 August 2016

Advantage and Disadvantages -Transposition of Transmission Lines

Transposition of Conductors refers to the exchanging of position of conductors of a three phase system along the transmission distance in such a manner that each conductor occupies the original position of every other conductor over an equal distance as shown in figure below.

Advantages of Transposing Transmission Line:

  • When conductors are not transposed at regular intervals, the inductance and capacitance of the conductors will not be equal.
  • When conductors such as telephone lines are run in parallel to transmission lines, there is a possibility of high voltages induced in the telephone lines. This can result in acoustic shock or noise. Transposition greatly reduces this undesired phenomenon.
  • In practice, however, conductors are not transposed in the transmission lines. The transposition is done in the switching stations and the substations.

Disadvantages of Transposing Transmission Line:

There is literally no drawback associated with transposition but care must be taken while marking the position of R, Y and B phase at Tower correctly. In correct marking may lead to mismatch in Phase Sequence at the Switching Station and what expected in the Transmission Line.

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