Dear Ray, When I do an OPF with variable voltages I get different results while for the runmarket I get the same results. runmarket is done underlying an OPF. What is the reason?
Best Wishes Silvio Miceli On Sun, Mar 25, 2012 at 03:28, Silvio Miceli <[email protected]>wrote: > Dear Prof. Zimmerman, > > Thank you very much. > > Best Wishes > > Silvio Miceli > > > > On Sat, Mar 24, 2012 at 01:44, Ray Zimmerman <[email protected]> wrote: > >> As I mentioned before, in MATPOWER's OPF the voltages *are* optimization >> variables. In other words, they are *output* values that depend on all of >> the input parameters. If you want to treat the voltages at generator buses >> as inputs (that you can set randomly according to some distribution), then >> you will need to set the VMIN and VMAX values at that corresponding bus to >> the desired value before calling the OPF. >> >> Something like this, where randomvoltage() is a function that returns a >> voltage for each generator bus drawn from some specified distribution and >> ig is the vector of indexes of generator buses ... >> >> mpc = loadcase('mybasecase'); >> for k = 1:10000 >> V = randomvoltage(); % generate a random draw of voltages >> mpc.bus(ig, VMIN) = V; >> mpc.bus(ig, VMAX) = V; >> r = runopf(mpc); >> % save whatever outputs you want to collect >> end >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> >> On Mar 23, 2012, at 7:13 PM, Silvio Miceli wrote: >> >> Dear Johnny >> >> I want to do a probabilistic OPF by using Monte Carlo. So, I have to load >> a distribution of voltage at the buses. I think MATPOWER is not able to >> load variables as optimization variable. If you have an idea please let me >> know. >> >> Best Wishes >> >> Silvio Miceli >> >> >> On Fri, Mar 23, 2012 at 23:39, Johnny <[email protected]> wrote: >> >>> Silvio Miceli <[email protected]> writes: >>> >>> > Dear Shiyang, >>> > >>> > I also want to do it by Monte Carlo, but not loads. I want to have a >>> > distribution of voltage as input. When I load loadcase it gives error. >>> My mean >>> > is this: >>> > I want load variable voltage values in bus matrix. Is it possible? >>> > >>> >>> Silvio, >>> >>> I believe the best way to achieve this is to generate the normal >>> distibution in a script which calls the OPF solver and collect the >>> results to display as a distribution. So, in the Monte Carlo, you use >>> stochastic input on a Black Box model and collect stochastic >>> output. This normally takes some time, but what do you look for really? >>> >>> >>> >>> > Best Wishes >>> > >>> > Silvio Miceli >>> > >>> > On Fri, Mar 23, 2012 at 23:19, 李诗旸 <[email protected]> wrote: >>> > >>> > HI Silvio Miceli, >>> > >>> > I think Mr. Zimmerman’s suggestion is the way like Monte Carlo >>> Method. >>> > Normally, you may have the distributions of some parameters >>> (inputs) such >>> > as loads and active generations, then you could use that way to >>> get the >>> > distributions of the optimized voltages (output) numerically. >>> > >>> > >>> > >>> > Sincerely >>> > >>> > Shiyang Li >>> > >>> > >>> > >>> > 发件人: [email protected] [mailto: >>> > [email protected]] 代表 Silvio Miceli >>> > 发送时间: 2012年3月24日 4:31 >>> > 收件人: MATPOWER discussion forum; Ray Zimmerman >>> > 主题: Re: probabilistic voltage >>> > >>> > >>> > >>> > I want to a have a distribution of voltage at buses that it is an >>> > optimization variable in MATPOWER? These distributions are the >>> inputs for >>> > the OPF. >>> > >>> > Best Wishes >>> > >>> > >>> > >>> > Silvio Miceli >>> > >>> > On Fri, Mar 23, 2012 at 21:25, Ray Zimmerman <[email protected]> >>> wrote: >>> > >>> > I'm afraid I don't know what *you* mean. The voltages are >>> *outputs* of >>> > MATPOWER's OPF. So what are the input parameters that you would >>> like to be >>> > stochastic? Voltage limits? >>> > >>> > >>> > >>> > -- >>> > >>> > Ray Zimmerman >>> > >>> > Senior Research Associate >>> > >>> > 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>> > >>> > phone: (607) 255-9645 >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > On Mar 23, 2012, at 2:40 PM, Silvio Miceli wrote: >>> > >>> > My problem is this I cannot do loadcase. How can I do many, many >>> > deterministic optimization? If I introduce voltage as x and do it >>> with a >>> > FOR? >>> > >>> > >>> > >>> > Could you please explain better? I didn't understand. I am sorry. >>> > >>> > Best Wishes >>> > >>> > >>> > >>> > Silvio Miceli >>> > >>> > On Fri, Mar 23, 2012 at 19:22, Ray Zimmerman <[email protected]> >>> wrote: >>> > >>> > MATPOWER does not implement any stochastic optimization. All of >>> it's >>> > variables and parameters are assumed to be deterministic. However, >>> one >>> > approach to handling probabilistic parameters is to simply do >>> many, many >>> > deterministic optimizations, where each one involves, for each >>> > probabilistic parameter, drawing a value from the corresponding >>> > distribution. Such an approach could use MATPOWER's OPF as a >>> subroutine to >>> > solve the deterministic sub-problem. >>> > >>> > >>> > >>> > -- >>> > >>> > Ray Zimmerman >>> > >>> > Senior Research Associate >>> > >>> > 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>> > >>> > phone: (607) 255-9645 >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > On Mar 23, 2012, at 12:42 PM, Silvio Miceli wrote: >>> > >>> > Dear Dr. Zimmerman, >>> > >>> > >>> > >>> > I want to have probabilistic voltage or reactive power in an OPF. >>> In other >>> > words, I want to do OPF with probabilistic variables,e.g. voltage >>> should be >>> > a normal distribution of voltage. How can insert this kind of >>> variables to >>> > case file of MATPOWER? Is there this possibility in MATPOWER? >>> > >>> > >>> > >>> > Best Wishes >>> > >>> > >>> > >>> > Silvio Miceli >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> >>> -- >>> Johnny >>> >>> >>> >> >> >
