What is transposition of a transmission line?

The balancing effect on account of irregular spacing of conductors can be avoided by changing the position of the conductors at regular distances. this is called transposition of conductors. In case of 3- phase transmission lines, the inductance and capacitance of each phase will be different if the three conductors are spaced differently (each phase to the other two phases, and each phase to ground). the apparent resistance of the conductors is also affected on account of transfer of power between the phases which occur due to mutual coupling. so all the three parameters of the transmission lines are affected by irregular spacing of the conductors.