That's correct ... it was a trivial fix.
Ray
On Apr 30, 2007, at 12:25 PM, Jun Wu wrote:
Do you mean that the bug can be fixed by replacing the original file with
this version of pfsoln.m? How fast you work!
2007/4/30, Ray Zimmerman <[email protected]>:
>
> Yes. I did see your mail. I am attaching a version of pfsoln.m to be
> used with MATPOWER 3.1b2 that includes a fix.
>
>
>
> --
> Ray Zimmerman
> Senior Research Associate
> 428-B Phillips Hall, Cornell University, Ithaca, NY 14853
> phone: (607) 255-9645
>
>
> On Apr 30, 2007, at 11:05 AM, Jun Wu wrote:
>
> Dear Ray Zimmerman,
>
> Did you see the letter I sent to your mailbox? Maybe it's a supplement
> for this problem.
> ======================================================
> After exhaustive tests for parameters setting of Matpower, I found a
> problem, maybe a bug. Qmax and Qmin can not be set both as zero, otherwise
> the reactive power is unbalanced if the 3.0.0 or 3.1b2 is used.
> For an example, the default case14.m. If not both of Qmax and Qmin are
> zero, then the PF result shows that the Q of bus1 is -16.55 and Q of the
> system is balanced. But if both Qmax and Qmin are zero, Q of bus1 is 0 while
> Q of the system is unbalanced.
> On the other hand, I found this problem doesn't exit for 3.0b3. Whatever
> Qmax and Qmin are set, the PF result always shows that the Q of bus1 is -
> 16.55 and Q of the system is balanced. So I think maybe it is a bug.
> Please explain it, thanks a lot!
> =======================================================
> Hope the latest version comes soon, :)
>
> --------------
> Yours sincerely,
>
> Wu Jun
> Unit: State Key Lab. of Power Systems,
> Dep. of Electrical Engineering,
> Tsinghua University, P.R. China.
> 2007-04-29
>
>
> 2007/4/30, Ray Zimmerman <[email protected]>:
> >
> > Hi Jun Wu,
> >
> >
> > Thanks for pointing this out. You have, indeed, found a bug that was
> > introduced in 3.0b4 and is present it all subsequent versions. It will
> > be fixed for the next release.
> >
> >
> > Specifically, if any generator has QMIN equal to QMAX, the power flow
> > solution will have Qg incorrectly set to zero for that generator. This does
> > not affect the OPF.
> >
> >
> > In response to your question regarding Vg, it should be the desired
> > voltage set-point for that generator, and in the absence of better
> > information, 1 p.u. is a reasonable default.
> >
> >
> > Ray
> >
> >
> >
> > On Apr 27, 2007, at 11:07 PM, Jun Wu wrote:
> >
> > By your instruction, the problem is smoothed. Thank you very much!
> > But I found an interesting thing, the PF result of 3.0b3 is slightly
> > different from that of 3.0.0 or 3.1b2. The attachment is my test
> > system and results of different versions. The only difference is the Q of
> > bus 1. I set the Qmax and Qmin of bus 1 to zero so that I think the Q
> > calculated should also be zero. But it is not zero by using 3.0b3while it
is zero by using
> > 3.0.0 or 3.1b2.
> > By the way, I want to ask another question. If the initial values of
> > Vg should be 1 or other?
> >
> >
> > 2007/4/27, Ray Zimmerman <[email protected]>:
> > >
> > > When upgrading you should completely remove all files from the
> > > previous version from your Matlab path. Then add all of the files from
your
> > > new version to your Matlab path.
> > >
> > >
> > > If 'isload' is not defined it means you do not have the new version
> > > installed correctly ... isload.m is one of the files in the new
> > > version and should be in your path.
> > > --
> > > Ray Zimmerman
> > > Senior Research Associate
> > > 428-B Phillips Hall, Cornell University, Ithaca, NY 14853
> > > phone: (607) 255-9645
> > >
> > >
> > > On Apr 27, 2007, at 1:27 AM, Jun Wu wrote:
> > >
> > > Dear Ray Zimmerman,
> > >
> > > Is the higher version compatible with the lower version well? I
> > > found some problems. I used 3.0b3 before, which is lack of the new
> > > feature you've referred. So I copy all files of 3.1b2 to replace
> > > them. But the same program can not work with the error--Undefined function
> > > or method 'isload' for input arguments of type 'double'. I don't know how
> > > update it simply
> > >
> > > Yours sincerely,
> > > Wu Jun
> > > Unit: State Key Lab. of Power Systems,
> > > Dep. of Electrical Engineering,
> > > Tsinghua University, P.R. China.
> > > Email: [email protected]
> > > 2007-04-27
> > >
> > >
> > >
> > > 2007/4/27, Ray Zimmerman <[email protected]>:
> > > >
> > > > On Apr 26, 2007, at 11:02 AM, Jun Wu wrote:
> > > >
> > > > Thanks for your attention and suggestion. I think reading the
> > > > manual more will help me. But I never saw it before. Is this the latest
> > > > feature for version 3.1b2? Does 3.0b3 has this setting?
> > > >
> > > >
> > > >
> > > > This feature was added in 3.0b4 and was included in the final
> > > > 3.0.0 release (3.0b4 was a beta version). It is also included in
> > > > the beta releases for 3.1.
> > > >
> > > > By the way, what do below settings mean?
> > > >
> > > > 38 - OUT_ALL_LIM, -1 control constraint info output
> > > > [ -1 - individual flags control what constraint info
> > > > prints]
> > > > [ 0 - no constraint info (overrides individual
> > > > flags) ]
> > > > [ 1 - binding constraint info (overrides individual
> > > > flags)]
> > > > [ 2 - all constraint info (overrides individual
> > > > flags) ]
> > > > 39 - OUT_V_LIM, 1 control output of voltage
> > > > limit info
> > > > [ 0 - don't
> > > > print ]
> > > > [ 1 - print binding constraints
> > > > only ]
> > > > [ 2 - print all
> > > > constraints ]
> > > > [ (same options for OUT_LINE_LIM, OUT_PG_LIM,
> > > > OUT_QG_LIM) ]
> > > > 40 - OUT_LINE_LIM, 1 control output of line limit
> > > > info
> > > > 41 - OUT_PG_LIM, 1 control output of gen P limit
> > > > info
> > > > 42 - OUT_QG_LIM, 1 control output of gen Q limit
> > > > info
> > > >
> > > >
> > > >
> > > > These options control the constraint sections of the output for
> > > > the OPF solver only.
> > > >
> > > >
> > > > Ray
> > > >
> > > > 2007/4/26, Ray Zimmerman <[email protected]>:
> > > > >
> > > > > By default, the power flow solver does not take into account the
> > > > > voltage or reactive power limits. However [1] ...
> > > > >
> > > > > For the AC power flow solvers, if the ENFORCE_Q_LIMS option is
> > > > > set to true (default is false), then if any generator reactive power
limit
> > > > > is violated after running the AC power flow, the corresponding bus is
con-
> > > > > verted to a PQ bus, with the reactive output set to the limit, and
the case
> > > > > is re-run. The voltage magnitude at the bus will deviate from the
specified
> > > > > value in order to satisfy the reactive power limit. If the generator
at the
> > > > > reference bus is reaches a reactive power limit and the bus is
converted to
> > > > > a PQ bus, the first re- maining PV bus will be used as the slack bus
for the
> > > > > next iteration. This may result in the real power out- put at this
generator
> > > > > being slightly off from the specified values.
> > > > >
> > > > >
> > > > > [1] Taken from p. 10 of the User's Manual
(http://www.pserc.cornell.edu/matpower/manual.pdf
> > > > > ).
> > > > >
> > > > > --
> > > > > Ray Zimmerman
> > > > > Senior Research Associate
> > > > > 428-B Phillips Hall, Cornell University, Ithaca, NY 14853
> > > > > phone: (607) 255-9645
> > > > >
> > > > >
> > > > > On Apr 26, 2007, at 5:23 AM, Wu Jun wrote:
> > > > >
> > > > > Hi all,
> > > > >
> > > > >
> > > > > From the case30.m in Matpower, Vmax and Vmin for buses are
> > > > > listed, also the Qmax and Qmin for generators. I want to know how
they work
> > > > > during the process of calculating the power flow. If one of them are
> > > > > violated, how does Matpower treat it? Does Matpower keep the original
> > > > > outputs or change the calculation condition automatically then put
out a
> > > > > result without breaking any limit?
> > > > >
> > > > >
> > > > > --------------
> > > > > Yours sincerely,
> > > > > Wu Jun
> > > > > Unit: State Key Lab. of Power Systems,
> > > > > Dep. of Electrical Engineering,
> > > > > Tsinghua University, P.R. China.
> > > > > Email: [email protected]
> > > > > 2007-04-26
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > <PF of 3.0b3.txt>
> > <PF2 of 3.0.0 and 3.1b2.txt>
> > <testcase30.m>
> >
> >
> >
> >
>
>
>
>
>
>
