Load Flow Study

[mikeengurs]

I'm planning to add motor loads to an MCC fed from a 4160v swicthgear. For that, I'd like to to run a load flow and short circuit analysis to see if existing system can handle it. Both existing swicthgear and MCC have existing motor loads on them. My question is, if the plant gives me short circuit and other information at my tie point, can I use the MCC bus as my swing bus in SKM, and just model the added load, or I need to model everything up to the start-up transformer?

 

[juleselec]

At the very least, I would definitely recommend modelling the step-down transformer to your 4.16kV MCC. Then if you know the fault level and X/R ratio upstream, it should be acceptable to model the upstream network as a voltage source with a short circuit impedance. If you wanted to be more conservative, you could model the upstream network as an infinite bus.