Unity

[marada93]

Say you have an AC generator connected to the grid with a PF controller set to produce 10 MVAr out.

If you then set the PF controller to produce unity, do you realize an increase in unit efficiency. Reduced fuel consumption perhaps?

Any documentation out there to prove it one way or another?

 

[imok2]

Marada, Maybe this can help:

http://www.rudrashakti.com/enquiry.htm

 

[dpc]

If you change generator output from a reactive power output of 10 MVar to 0, without changing the real power output, the generator current is reduced. This reduces the copper losses in the generator. This increases the overall efficiency. The efficiency increase is very small in relation to other factors.

 

[jbartos]

Suggestion: The fuel consumption will increase with the increase generator MW output since the prime mover has to deliver the higher MW~HP on the shaft.
Reference:
M.G. Say "Alternating Current Machines," John Wiley & Sons, Inc., 1978

 

[jbartos]

Suggestion: Visit

http://www.ces.clemson.edu/powsys2002/ppt/TA2/1

http://www.lehmanengineering.com/quiz/quiz3sol.html

etc. for more info

 

[tarong]

dps's reply is 100% correct

 

[marada93]

Thanks for the feedback and some of the documentation provided. My thinking is, if your reactive load isn't dispatched, why provide it? It would make more sense to run at unity (or so it seems to me) and reap the efficiency benefit however slight it might be.

Am I off base?

 

[alehman]

I think you are on the right track. You need to evaluate your rate structure with your utility company. If there is a power factor penalty it may be beneficial to export enough VAR's to offset your loads (if any).