runcpf problem

[Amal Elramly]

Dear,
runcpf function does not work for 33 radial distribution system
Error Message below:
MATPOWER Version 5.0, 17-Dec-2014 -- AC Continuation Power FlowError using  - 
Matrix dimensions must agree.Error in runcpf (line 213)Sxfr = Sbust - Sbusb; 
could you help me 
Best Regards,
Amal Hassan

Re: Effect of loads in IEEE 39 bus system

[Abhyankar, Shrirang G.]

Arun,
  Please help us to understand the meaning of "stuck" by providing relevant 
details of (a) equations you are trying to implement (b) what have you 
attempted till now c) code snippets (d) errors/warnings.

Shri
From: arun s nair mailto:arunsnair...@gmail.com>>
Reply-To: MATPOWER discussion forum 
mailto:matpowe...@list.cornell.edu>>
Date: Sat, 21 Feb 2015 18:10:11 -0700
To: MATPOWER discussion forum 
mailto:matpowe...@list.cornell.edu>>
Subject: Effect of loads in IEEE 39 bus system

Hi All,

I am trying to implement the different load models((like ZIP load model, 
composite load model, exponential load model etc ) in matpower to analyse it's 
effect on the load  buses in an IEEE 39 bus system (using cpf ). But now I am 
stuck as to how to implement it in matpower.

Can anyone please give me some guidelines as to how I should proceed so to get 
it implemented. Your help will be greatly appreciated, its for my graduate 
research.

Thanking you and With Regards,

Arun Nair

Re: Convergence Issue for Distribution Network Power Flow Analysis

[Abhyankar, Shrirang G.]

http://www.pserc.cornell.edu//matpower/#pfconvergence

From: #ZHANG TIAN# mailto:tzhang...@e.ntu.edu.sg>>
Reply-To: MATPOWER discussion forum 
mailto:matpowe...@list.cornell.edu>>
Date: Mon, 23 Feb 2015 07:39:09 +
To: "MATPOWER-L@cornell.edu" 
mailto:MATPOWER-L@cornell.edu>>
Subject: Convergence Issue for Distribution Network Power Flow Analysis

Dear All,

I am using Matpower for a distribution network power flow analysis.

The data I used are taken from a real network, and the network is working fine 
using PowerWorld simulator. Basically, it is a radial network with 14 buses. 
Bus 1 is the connection point to the main grid, which I modelled it as a slack 
bus (type 3).

However, when converting the model into a Matpower case, I can only get a 
failure notification “Did NOT converge (0.01 seconds)”.

Does anyone have any idea about what might be the problem? Or what are the 
options for me to debug?

I attached my case data in this email for your reference.

Thank you all very much.

Best regards,
Tian


*
function mpc = caseSG
%CASE SGPower flow data for a distribution network.

%% MATPOWER Case Format : Version 2
mpc.version = '2';

%%-  Power Flow Data  -%%
%% system MVA base
mpc.baseMVA = 1;

%% bus data
%   bus_i   typePd  Qd  Gs  Bs  areaVm  Va  baseKV  zoneVmaxVmin
mpc.bus = [
1   3   0   0   0   0   1   1   0   22  1   1.1 0.9;
2   1   0   0   0   0   1   1   0   22  1   1.1 0.9;
3   1   0   0   0   0   1   1   0   22  1   1.1 0.9;
4   1   0   0   0   0   1   1   0   0.4 1   1.1 0.9;
5   1   0   0   0   0   1   1   0   0.4 1   1.1 0.9;
6   1   0.23 0.07 0 0   1   1   0   0.4 1   1.1 0.9;
7   1   0.2 0.06 0  0   1   1   0   0.4 1   1.1 0.9;
8   1   0.2 0.03 0  0   1   1   0   0.4 1   1.1 0.9;
9   1   0.13 0.06 0 0   1   1   0   0.4 1   1.1 0.9;
10  1   0.3 0.07 0  0   1   1   0   0.4 1   1.1 0.9;
11  1   0.2 0.05 0  0   1   1   0   0.4 1   1.1 0.9;
12  1   0.2 0.05 0  0   1   1   0   0.4 1   1.1 0.9;
13  1   0.17 0.05 0 0   1   1   0   0.4 1   1.1 0.9;
14  1   0.08 0.03 0 0   1   1   0   0.4 1   1.1 0.9;
];

%% generator data
%   bus Pg  Qg  QmaxQminVg  mBase   status  PmaxPminPc1 Pc2 
Qc1min  Qc1max  Qc2min  Qc2max  ramp_agcramp_10 ramp_30 ramp_q  apf
mpc.gen = [
1   0   0   5   -5  1   1 1   10  0   0   0   0   0   0   0   0   0   0   0 
  0;
];

%% branch data
%   fbus tbus r  x  b rateA rateB rateC ratio angle status  angmin  
angmax
mpc.branch = [
1   2   0.000489 0.000640   5   5   5   0   0   1   -360360;
1   3   0.000489 0.000640   5   5   5   0   0   1   -360360;
2   4   0.0941.34   0   5   5   5   55  0   1   -360360;
3   5   0.0941.34   0   5   5   5   55  0   1   -360360;
4   6   5.876034 3.193497   0   1   1   1   0   0   1   -360360;
4   7   5.208303 2.8306 0   1   1   1   0   0   1   -360360;
4   8   6.343446 3.447525   0   1   1   1   0   0   1   -360360;
4   9   8.179707 4.445493   0   1   1   1   0   0   1   -360360;
4   10  7.678908 4.173320   1   1   1   0   0   1   -360360;
5   11  6.677312 3.628974   0   1   1   1   0   0   1   -360360;
5   12  6.343446 3.447525   0   1   1   1   0   0   1   -360360;
5   13  3.639135 1.977791   0   1   1   1   0   0   1   -360360;
5   14  5.876034 3.193497   0   1   1   1   0   0   1   -360360;
];

%%-  OPF Data  -%%
%% generator cost data
%   1   startup shutdownn   x1  y1  ... xn  yn
%   2   startup shutdownn   c(n-1)  ... c0
mpc.gencost = [
2   0   0   2   1   0;
];

Re: runcpf problem

[Abhyankar, Shrirang G.]

Please check if your base case and target case have the same number of buses.

Shri

From: Amal Elramly mailto:amal_...@yahoo.com>>
Reply-To: MATPOWER discussion forum 
mailto:matpowe...@list.cornell.edu>>
Date: Mon, 23 Feb 2015 12:58:12 +
To: MATPOWER Discussion Forum 
mailto:matpowe...@list.cornell.edu>>
Subject: runcpf problem

Dear,

runcpf function does not work for 33 radial distribution system

Error Message below:

MATPOWER Version 5.0, 17-Dec-2014 -- AC Continuation Power Flow
Error using  -
Matrix dimensions must agree.
Error in runcpf (line 213)
Sxfr = Sbust - Sbusb;

could you help me

Best Regards,

Amal Hassan

Re: Convergence Issue for Distribution Network Power Flow Analysis

[Carlos E Murillo-Sanchez]

  
  
Hi;
  
  You have used the TAP column of the branch table to indicate two
  transformers with a 55:1 ratio, and then you used the LV
  impedances, I think, still in PU with a base voltage of 22KV; they
  are pretty large.  The TAP column should be used to specify small
  variations about 1.0 for true tap-changing transformers.  All
  branch impedances should be specified using a single pu system.  
  I believe that the following is what you are actually trying to
  run:
  
  define_constants;
  mpc = loadcase('caseSG');
  mpc.branch(3:end, BR_R:BR_X) = mpc.branch(3:end, BR_R:BR_X) /
  55^2;
  mpc.branch(3:4, TAP) = 0;
  runpf(mpc);
  
  #ZHANG TIAN# wrote:


  
  
  
  
Dear All,
 
I am using Matpower for a
distribution network power flow analysis.

 
The data I used are taken
from a real network, and the network is working fine using
PowerWorld simulator. Basically, it is a radial network with
14 buses. Bus 1 is the connection point to the main grid,
which I modelled it as a slack bus (type 3).
 
However, when converting the
model into a Matpower case, I can only get a failure
notification “Did NOT converge (0.01 seconds)”.
 
Does anyone have any idea
about what might be the problem? Or what are the options for
me to debug?
 
I attached my case data in
this email for your reference.
 
Thank you all very much.
 
Best regards,
Tian

 

  


  

Re: negative price

[Ray Zimmerman]

Prices are marginal quantities, so the don’t tell you anything about the 
“amount” of “shortage”, but rather the sensitivity of the overall system 
objective to load/generation at the given bus. When you have prices that are 
far above or below the range of generator costs, it means that a small change 
in injection at that bus can cause a significant shift in generation between 
expensive and inexpensive generators.

Ray


> On Feb 20, 2015, at 6:13 PM, mohd  wrote:
> 
> Dear all,
> 
> I have run my own test case as a DCOPF. I got results that show negative 
> price in several buses and some other buses have large positive numbers in 
> the order of $10,000 or so. I have checked the supply curve for generators 
> and the most expensive generator has an incremental cost of around $104 
> (flat). I understand that a negative price indicates excess generation in 
> that specific area and what i want to understand if the numbers indicate 
> anything. For example, i have one bus having -$81 and the other is -$15. Does 
> that mean the first one has more excess generation compared to the later. 
> Also, if i have a really huge number like in one bus, i have $3000 while the 
> other $10,000. Does that mean the $10,000 bus has more shortage of generation 
> compared to the other one. I appreciate any comments or suggestions about the 
> interpretation of the results as well as how to improve my model further. 
> Thanks and have a great weekend.
> 
> Kindly,
> Mans

Re: Errors on distribution network OPF

[Ray Zimmerman]

Hi Hui,

In your case, you’re probably isolating whole islands as opposed to single 
buses, so you’ll probably want to set all of the buses in any groups except the 
one with the supply bus to NONE.

Ray



> On Feb 22, 2015, at 12:20 PM, Hui Guo  
> wrote:
> 
> Hi, Ray,
> 
> thanks for your help.
> Following your instruction, I can apply find_islands function.
> The group cell from result is correct. However, ​the isolated cell is empty. 
> Do you know why that cell is empty? and how to let it show me the isolated 
> buses?
> I can write a line to extract isolated buses from group cell, but I think 
> this function could extract isolated buses and form a cell named isolated 
> cell automatically.
> 
> Best Regards,
> Hui
> 发件人: bounce-118842948-72742...@list.cornell.edu 
>  
>  > 代表 Ray Zimmerman 
> mailto:r...@cornell.edu>>
> 发送时间: 2015年2月20日 19:12
> 收件人: MATPOWER discussion forum
> 主题: Re: Errors on distribution network OPF
>  
> Yes, NONE means isolated. See idx_bus() 
>  to 
> see where those constants are defined. So …
> 
> define_constants;
> [g, i] = find_islands(mpc);
> mpc.bus(i, BUS_TYPE) = NONE;
> 
> — Ray
> 
> 
>> On Feb 20, 2015, at 11:53 AM, Hui Guo > > wrote:
>> 
>> Dear Ray,
>> 
>> Sorry for bother. I'd like to know how to do this action: set the value of 
>> their BUS_TYPE column to NONE​. because I've only got four types of bus.
>> the NONE means Isolated?
>> 
>> Best Regards,
>> Hui
>> 
>> 
>> 发件人: bounce-118841626-72742...@list.cornell.edu 
>>  
>> > > 代表 Ray Zimmerman 
>> mailto:r...@cornell.edu>>
>> 发送时间: 2015年2月20日 14:18
>> 收件人: MATPOWER discussion forum
>> 主题: Re: Errors on distribution network OPF
>>  
>> Setting branch capacity to 0 is not the same as taking the branch out of 
>> service. First of all, setting RATE_A to zero in the branch matrix actually 
>> means that the branch does not have a limit. And second, even setting it to 
>> some small non-zero value simply means that it is electrically connected, 
>> but the operator must dispatch generation such that there is no flow on the 
>> line, which is impossible in a radial distribution system with downstream 
>> load.
>> 
>> What you want to do is change the branch status to zero, then use 
>> find_islands() 
>> 
>>  to get a list of all of the buses you have blacked out and set the value of 
>> their BUS_TYPE column to NONE.
>> 
>>Ray
>> 
>>> On Feb 20, 2015, at 8:15 AM, Hui Guo >> > wrote:
>>> 
>>> Dear Ray,
>>> 
>>> Thanks for your response. 
>>> Now, the OPF can run without errors on a healthy network.
>>> However, I've got another problem on Matpower.
>>> the network I applied is distribution network which is radial structure.
>>> Thus, when I set one branch statue to 0 which means branch fail then 
>>> running OPF, the downstream buses and branch data is weird.
>>> Based on my experience, the voltage of downstream bus and the power flow on 
>>> the branch should be 0 due to no power supply.
>>> In order to fix this. I turn on branch statue to 1 and change the branch 
>>> capacity to 0, which suppose to have the same effect with branch fail 
>>> condition.
>>> However, it didn't show me the proper results.
>>> the result look like no branch fail and all customer got supply.
>>> Do you know, what happened on power flow?
>>> 
>>> Best Regards,
>>> Hui
>>> 
>>> 发件人: bounce-118839050-72742...@list.cornell.edu 
>>>  
>>> >> > 代表 Ray Zimmerman 
>>> mailto:r...@cornell.edu>>
>>> 发送时间: 2015年2月19日 19:45
>>> 收件人: MATPOWER discussion forum
>>> 主题: Re: Errors on distribution network OPF
>>>  
>>> The warning you mentioned from the DC OPF is not an error, just an 
>>> informational warning (from Matlab's linprog() I think). You do not need to 
>>> do anything about it.
>>> 
>>> The fact that the AC problem exhibits numerical difficulties and does not 
>>> converge could be an indication that the AC problem is infeasible. You 
>>> might try relaxing line limits and reactive power limits to see if that 
>>> helps.
>>> 
>>> The shadow prices that result from a failed run are meaningless. 
>>> 
>>> Ray
>>> 
>>> 
 On Feb 19, 2015, at 1:56 PM, Hui Guo >>> > wrote:
 
 Thank you very much Ray, based on your instruction, the opf can run 
 further and I've check the network structure and branches constraints.
 However, there is still something wrong with opf. 
 I'll list it below, 
 
 First, we I running dcopf.
 th

RE: Convergence Issue for Distribution Network Power Flow Analysis

[#ZHANG TIAN#]

Hello!

Yes, by changing the LV impedances I can get the correct results. This is worth 
noting that the data in the "Model Explorer" in PowerWorld Simulator is in per 
unit based on the whole system, rather than its real value.

Many thanks.

Tian

From: bounce-118850794-72551...@list.cornell.edu 
[mailto:bounce-118850794-72551...@list.cornell.edu] On Behalf Of Carlos E 
Murillo-Sanchez
Sent: Monday, February 23, 2015 22:56
To: MATPOWER discussion forum
Subject: Re: Convergence Issue for Distribution Network Power Flow Analysis

Hi;

You have used the TAP column of the branch table to indicate two transformers 
with a 55:1 ratio, and then you used the LV impedances, I think, still in PU 
with a base voltage of 22KV; they are pretty large.  The TAP column should be 
used to specify small variations about 1.0 for true tap-changing transformers.  
All branch impedances should be specified using a single pu system.   I believe 
that the following is what you are actually trying to run:

define_constants;
mpc = loadcase('caseSG');
mpc.branch(3:end, BR_R:BR_X) = mpc.branch(3:end, BR_R:BR_X) / 55^2;
mpc.branch(3:4, TAP) = 0;
runpf(mpc);

#ZHANG TIAN# wrote:
Dear All,

I am using Matpower for a distribution network power flow analysis.

The data I used are taken from a real network, and the network is working fine 
using PowerWorld simulator. Basically, it is a radial network with 14 buses. 
Bus 1 is the connection point to the main grid, which I modelled it as a slack 
bus (type 3).

However, when converting the model into a Matpower case, I can only get a 
failure notification "Did NOT converge (0.01 seconds)".

Does anyone have any idea about what might be the problem? Or what are the 
options for me to debug?

I attached my case data in this email for your reference.

Thank you all very much.

Best regards,
Tian