Selection Critaria for 11KV Cables and 11KV Bus-Duct

There is no hard and fast rule for cables and bus ducts. The criteria of selection is the current carrying capacity of the cables and whether 2 or 3 runs per phase can be terminated on the terminals of the motor/ generator. For a 15MW motor, assuming pf of 0.9, the current per phase will be about 875A. For cable selection, consiering 25% overload, the cable capacity should be about 1100A. I'll suggest 3 runs per phase each of 400A capacity. Please go thru' the catalogues of 11kV XLPE cables and see whether such current carrying cables are available. Alternatively, bus duct (segregated) can be used depending on the location of the motors and panels. But then the cost economics will be the deciding factor

suggest to please contact the motor manufacturer to get a good advice in this kind of installations. Prepare a good details of the motor terminals, take note of all the clearances and how to provide the necessary supports and flexible copper connections (cable or bus ducts).

Best regards,

rudy_fernando5r

Dear sir,

The selection between bus duct and cables is goverened by;

1 Economics

2 Layout [ for bus duct have only one or two bends ]

3 Termination space.

Electrically there are no advantages of one over the other.

S. V. Iyer