Ali,
Firstly, you have an error in the case file. The generator set point voltage
(gen(1,VG) is set to 2 pu which is incorrect. It should be around 1.0 pu.
Even after setting the generator set point voltage to 1 pu, the case does not
converge because the loading surpasses the steady state loading limit causing a
collapse of the bus voltages. You can see this by running the continuation
power flow in MATPOWER.
mpctarget = case30_1dep;
mpcbase = mpctarget;
mpcbase.bus(:,[3;4]) = 0.0; %% Set Pd and Qd at all buses to 0.0
[RESULTS, SUCCESS] =
runcpf(mpcbase,mpctarget,mpoption('cpf.plot.level',1,'cpf.plot.bus',19)); % Run
a continuation power from base case (Pd/Qd = 0.0) to target (Pd/Qd = given
values in case30_1dep).
The figure below plots lambda (the load scaling factor in this example) versus
bus 19 voltage magnitude. Lambda= 0.0 denotes to the base case having no real
and reactive power demand at the buses, while lambda = 1.0 denotes the target
demand. As you can see the curve turns around at lambda=0.6 indicating the
steady state loading limit has been reached. In other words, this system can
only serve 60% of the given target load. Anything above 60% would cause a
voltage collapse.
[cid:61039831-DD0F-45E4-A312-41FDD0ABA4A9]
You can do similar analysis with your second case and see that lambda goes
beyond 1.0 indicating that the extra generation on the downstream bus improves
the voltage stability of the system.
Shri
-----Original Message-----
From: ALI ZAZOU Abdelkrim
<[email protected]<mailto:[email protected]>>
Reply-To: MATPOWER discussion forum
<[email protected]<mailto:[email protected]>>
Date: Wed, 17 Sep 2014 17:36:00 +0200
To: <[email protected]<mailto:[email protected]>>
Subject: Convergence and generator
Hi,
I'm trying to run a simple PF with the newton method, i attached my case
files with this message.
And i also attached 2 pictures of the network cases.
I'm working with the case30.m that i modify, i just wanted to use the
line specifications.
The network now have just 16 bus, 17 branch and 1 Generator(also slack
bus), and the network is radial.
1st problem: The powerflow for this network ("case30_1dep.m") doesn't
converge and i can't understand why, how can it be explain?
But it run normally if i add a generator ("case30_1dep_ok.m") that i
take from the original "case30.m".
So i thought that maybe the slack bus genreation limit is reached but
even with modyfing the slack bus specification in the "case30_1dep.m",
it's still doesn't convergent.
2nd question: What kind of physical specification (V, P and Q limits
for example) can affect the convergence.
Thank you in advance for the time you will take to read my questions
Best regards
Abdelkrim Ali Zazou
.
The problem is that this loadflow don't converge and i can't understand
whey,
can you give me some explaination about this issue.
The problem
