On an overhead transmission line, transpositions are the intentional rotation of the position of the phase conductors with respect to each other. For example, say the original phase position on one structure is A-B-C. At the next structure the positions would be transposed to B-C-A.
The primary purpose of transpositions on long transmission lines is reduction of electrostatic and electromagnetic unbalance between phases that can result in unequal phase voltages. That limits induced current, reduces power losses and, depending upon their location, can reduce electromagnetic coupling of power line currents in adjacent telecommunications lines.
Transpositions are also used for overhead telephone lines and overhead shield wires for similar purposes.
On long EHV transmission lines, transpositions are usually made every 10 or 11 miles or so and are made at tangent structures or, more commonly, at jumpered deadends.
Transmission
Re: Transmission
