Dear Muhammd, The coefficients of the cost function should be positive (see Figure 6-5 in the Matpower manual), and as dispatchable load is modelled as negative generation your cost value will be negative (i.e. a benefit). The OPF aims to minimize costs (or maximise negative costs) the model will now correctly aim to increase load as much as is economically feasible.

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In short, what you have now is correct! Kind regards, Samuel -----Original Message----- From: bounce-120786918-76238...@list.cornell.edu [mailto:bounce-120786918-76238...@list.cornell.edu] On Behalf Of Muhammd Ali Mohseni Sent: 14. september 2016 17:19 To: MATPOWER discussion forum <matpowe...@list.cornell.edu> Subject: Re: benefit function of dispatchable load Dear Samuel, I don't have any other problem. It is interesting when I change the benefit function coefficient to positive like this: mpc.gencost = [ ..... 2 0 0 3 0.5*0.015 13.0 0; ....] there isn't any warning and DC Opf converge!!! now results is true???!!! hence the power associated with dispatchable Loads is negative but first part of cost function is positive(0.5*0.015*P^2>0)!!!!!! Is the final value of Opf correct??? With respect, Ali On 9/14/16, Samuel Perkin <samu...@landsnet.is> wrote: > Dear Muhammd, > > Your error message is not really an error, but is just a warning > statement that you shouldn't need to react to. It simply means that > the optimisation algorithm doesn't require an initial guess of the > solution, and therefore any initial guess is ignored. This warning > message isn't related to dispatchable loads. Did you get any other error > messages? > > Your input for dispatachable load looks fine to me, except I think > Qmax (column 4) should probably be 0 to prevent your loads from acting > as 'reactive generators'. > > Kind regards, > > Samuel > > -----Original Message----- > From: bounce-120786253-76238...@list.cornell.edu > [mailto:bounce-120786253-76238...@list.cornell.edu] On Behalf Of > Muhammd Ali Mohseni > Sent: 14. september 2016 14:56 > To: matpower-l@cornell.edu > Subject: benefit function of dispatchable load > > Dear all > According to the Matpower manual (6.4.2 Dispatchable Loads) approach > to dispatchable loads is to model them as negative real power > injections with associated negative costs. but when I run dcopf I got this > error!!! > > " MATPOWER Version 6.0b1, 01-Jun-2016 -- DC Optimal Power Flow The > interior-point-convex algorithm does not accept an initial point. > Ignoring X0." > > I set negative output, ranging from 0 to -1000 like this mpc.gen = [ ..... > 1 0 0 100 -100 1.05 100 1 0 -1000 > 0 0 0 0 0 0 0 0 0 0 > 0; > ....] > also I assume that bid function of load like this : aP+ b and benefit > function of load : 0.5aP^2+bP > > mpc.gencost = [ > ..... > 2 0 0 3 -0.5*0.015 13.0 0; > ....] > >