Two things.
1. You have specified 2 reference buses. I think bus 2 should be type
1 (PQ bus).
2. The load at bus 2 is way too large. Try backing it off to about
250 (or 235 if you use the Qd = 28 MVAr as shown in the figure) and
you'll see that the load flow converges, but the voltage at that bus
is on the order of 0.7 p.u. If you increase the load much beyond that
the voltage collapses and the Newton power flow does not converge.
The transformer ratio can be entered in column 9 of the branch
matrix. The transformer model used is described in section 3.2 in the
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 Jun 15, 2007, at 4:48 AM, Fortunato Villella wrote:
Dear all,
I just joined the mailing list.
I'm trying to get a powerflow solution to initialize a transient
stability analysis for the system described in the attached .gif file.
I wrote down the parameters as defined in caseformat.m and I tried
to solve the powerflow.
The solution do not converge.
I have no idea of how to treat the transformers parameters. What
should I do ? Where should I lump the parameters, how to define the
transformer ratio (if needed) the bus 1 and 3 are at 13kV, if I
specify this it does not work anyway)?
Here you will find the function file with the parameters.
Thank you for your help, I hope I do not bother you too much.
With regards
Fortunato
*********START OF THE TwoGeneratorsPFSimpl.m**********
function [baseMVA, bus, gen, branch, areas, gencost] =
TwoGeneratorsPFSimp
%TwoGeneratorsPFSimpl Power flow data for 5 bus, 2 generator case.
%%--Datas of the example...
%Transformers
Rt1=0.006;
Xt1=0.08;
Rt2=0.003;
Xt2=0.04;
%Line 24
R24=0.036;
X24=0.4;
B24=0.43;
%Line 52
R52=0.018;
X52=0.2;
B52=0.22;
%Line 45
R45=0.009;
X45=0.1;
B45=0.11;
%%----- Power Flow Data -----%%
%% system MVA base
baseMVA = 100;
%% bus data
% bus_i type Pd Qd Gs Bs area Vm Va
baseKV zone Vmax Vmin
bus = [
1 2 0 0 0 0 1 1 0 345 1 1.1
0.9;
2 3 500 10 0 0 1 1 0 345 1
1.1 0.9;
3 3 0 0 0 0 1 1 0 345 1 1.1
0.9;
4 1 100 50 0 0 1 1 0 345 1
1.1 0.9;
5 1 100 80 0 0 1 1 0 345 1 1.1
0.9;
]
%% generator data
% bus Pg Qg Qmax Qmin Vg mBase
status Pmax Pmin
gen = [
1 200 130 500 -500 1 100 1 400 0;
3 500 10 500 -500 1 100 1 800 0;
% 3 85 0 300 -300 1 100 1 270 10;
]
%% branch data
% fbus tbus r x b rateA rateB rateC
ratio angle status
branch = [
1 5 Rt1 Xt1 0 1000 1000 1000 0
0 1;
5 4 R45 X45 B45 1000 1000 1000 0
0 1;
4 3 Rt2 Xt2 0 1000 1000 1000 0
0 1;
5 2 R52 X52 B52 1000 1000 1000 0
0 1;
4 2 R24 X24 B24 1000 1000 1000 0
0 1;
]
return;
***********END OF THE FILE TwoGeneratorsPFSimpl.m************
<TwoMachinesExample.gif>
<fortunato.villella.vcf>
