I think you may have missed my point ... since some of the "flow" is lost in the line itself, the apparent power entering the line at i and the power leaving the line at j will be different. So you have two numbers. Which one do you want to use to represent *the* "flow"? the flow at i? the flow at j? the min? the max? the average?
How you choose to define "flow" in this case, I suppose, is a function of how you intend to use it. -- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On May 26, 2011, at 1:22 PM, Idris Musa wrote: > Dear Dr Ray, > Thank you very much. Yes I was referring to radial network. > By 'the total MVA flow' I am referring to MVA flow between any 2 nodes(say, i > & j). > I am trying to compute what will be the MVA flow through the branch given the > branches values of PF, QF and PT, QT injections from the power flow results. > > Idris > >> -----Original Message----- >> From: [email protected] [mailto:bounce-32610422- >> [email protected]] On Behalf Of Ray Zimmerman >> Sent: 26 May 2011 17:32 >> To: MATPOWER discussion forum >> Subject: Re: total MVA flow in a branch >> >> I think you have to define "the total MVA flow in a branch". In the >> standard branch model used in MATPOWER, there are losses in the branch, >> so the flow at one end and the flow at the other are not equal, so there >> isn't a single value of MVA flow that is *the* flow. The OPF flow limits >> are based on the max of the two. Or you might want to use the average, >> but certainly not the sum. >> >> I'm not sure what you mean by the "first branch" and the "source", >> unless you are referring to a radial system with a single generator. In >> that case, the P and Q flows at the end of the line connected to the >> source should match the generation at the source (assuming there are no >> shunt elements and loads at that bus). >> >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> On May 26, 2011, at 6:04 AM, Idris Musa wrote: >> >>> Dear all, >>> How do I compute the total MVA flow in a branch? >>> if >>> >>> MVA_flow_from = sqrt(results.branch(:, PF).^2 + results.branch(:, >> QF).^2); >>> >>> and >>> >>> MVA_flow_to = sqrt(results.branch(:, PT).^2 + results.branch(:, >> QT).^2); >>> >>> Can I add the 2 results above directly to give me the total flow in a >> branch? If Yes then I expect that sum of the MVA flow in the first >> branch when I run power flow should reflect the total generation from >> the source. Else how do I go about it. >>> I would glad if someone could put me through. >>> Many thanks >>> Idris >>> >>> >>> >> >> > > >
