Generator and VSD motor load 2

[bigamp]

A plant is to have a single high capacity power supply from the grid and this is to run in parallel (normally) with an on-site generator (part of a co-gen plant). The generator is slated to be a 12.5MVA 11kV machine, size determined by waste heat requirements. The electrical load is to be about 8MW, of which approx 4MW will be a single VSD motor. The VSD will most probably be a 12-pulse type. Power to the VSD input transformer will be at 11kV, the VSD and motor will be 3.3kV. The generator will be required to be able to operate in island mode. What thoughts re the generator on its own being able to cope such a relatively large (4MW) VSD. When we issue specifications for the generator, I will certainly identify load types etc. We may need to consider harmonic filtering and it may be an idea to use a 24-pulse VSD. I would like some thoughts please before I approach generator vendors for info. The 4MW VSD sounds a little big for a 12.5MVA machine, are there any rules of thumb.

Regards,

bigamp

 

[electricuwe]

To htidke:

AFE stands for Active Front End, describing a cicuit containing power semiconductors with switch-of-capabilties (e.g. IGBT, GTO, IGCT) in the rectifier.