On Jun 14, 2012, at 6:44 AM, iman wrote:
> Dear Shri,
> Thank you for your reply.Yes I managed to do that by multiplying all the
> loads by 3 and running PF (Power Flow).
> The thing is that if you multiply all the loads by 3 you will get the
> gerenartion at the slack bus equal to 454.7 MW.
> If loads are multiplied by 3.5 then power gerenartion at the bus 1 will be
> 615 MW .
> My questions are :
> 1-Isn't any limit for slack(swing) bus that it goes up by increasing the
> load?
The slack bus is supposed to provide/absorb active and reactive power
to/from transmission to provide losses since these are unknown till the final
solution of the power flow. Hence, slack bus is assumed to have the highest
possible capacity.
[1] http://en.wikipedia.org/wiki/Slack_bus
> 2-If theresn't any limit why increasing loads cannot make up for voltage drop
> at some buses?
Note that voltage drop is a function of the current flowing through the line
and the line impedance, i.e. \del{V}= I*X. If the load increases the currents
on the lines increase resulting in increased voltage drop.
Shri
> Regards
> Iman
>
> On Wed, Jun 13, 2012 at 8:43 PM, Shri <[email protected]> wrote:
>
> On Jun 13, 2012, at 10:41 AM, iman wrote:
>
> > Dear all,
> >
> > Has anyone managed to see voltage drop in MATPOWER(for example below 0.9
> > pu)?
> Yes, absolutely.
> If you scale the loads high enough you should see a drop in the voltages
> below the threshold you want. (unless you are (a) running a power flow and
> scaling the swing bus load only ;) or (b) running an OPF with Vmin = 0.9 pu )
>
> > The fact is in real bus systems when you increase loads, you experience
> > voltage drop at some points but with matpower you can't see that.In real
> > life substation's output (transformer MVA) and lines are limited but in
> > MATPOWER the more you raise loads, the more power comes from substation!
> > Has anyone have an idea?
> > --
> >
> > Iman
> >
>
>
>
>
>
>
> --
> Best regards
> Iman
>
