Installation of motor at far distance
Installation of motor at far distance
(OP)
we wish to install a 3.3kV, 1250kW, Induction motor which will be started direct online.
The nearest 3.3kV source is at 600mtrs away, which is intern fed by 11/3.3kV, 10 MVA transformer 3.3kV Bus.
Please let us know is there any statutory requirement to limit the cable length or any other problem envisaged
for installation of the motor.
The nearest 3.3kV source is at 600mtrs away, which is intern fed by 11/3.3kV, 10 MVA transformer 3.3kV Bus.
Please let us know is there any statutory requirement to limit the cable length or any other problem envisaged
for installation of the motor.





RE: Installation of motor at far distance
600m is not an unreasonably long distance, but you must ensure that the volt-drop through the cable at LRC is calculated to ensure that the motor able to produce sufficient starting torque. Use worst-case bus voltage for this calculation. I personally don't think you will find any problem with the motor you describe, unless you have a really awkward load.
The statutory requirements is really dependent on your own country's regulations. Is the 11kV system yours, or the utility's? You should consider any limitations from the utility regarding voltage fluctuation at the PCC, but with a 10MVA transformer you must be on a fairly robust 11kV system.
RE: Installation of motor at far distance
thanks
RE: Installation of motor at far distance
Reference:
IEEE Std 141-1993 (Red Book) Section: 3.9.1 Motor Starting Voltage Sags