Inductance of Three Phase Double Circuit with Symmetrical Spacing

 Consider the three phase double circuit with the conductor placed at the vertices of a regular hexagon which is shown in the Fig. 1.

Fig. 1

      
Conductor x, y, z are forming one circuit whereas conductors x' , y' and z' are forming another circuit.

       Let us find out flux linkage of conductor x due to currents in other phases.

       since the            I_x + I_y + I_z = 0

.^..                              I_y + I_z  = - I_x 

       As the conductor are in parallel,

       Inductance of each conductor = 2L_x