load during CPF (was Re: Optimal power flow with DG connected)

[Ray Daniel Zimmerman]

The load at each step is a function of lambda, the continuation parameter, 
which is used to interpolate between the base case load (lambda = 0) and the 
target case load (lambda = 1). So you can use the following to find the load at 
the current value of lambda …

Pd_current = Pd_base * (1 - lambda) + Pd_target * lambda

… where Pd_base is taken from the PD column of mpc_base and Pd_target from the 
PD column of mpc_target.

The target and base cases and current value of lambda are available to CPF 
callback functions, if you really need it during the process. But the 
step-by-step history of lambda is also available after the CPF run is complete 
in results.cpf.lam.

Hope this helps,

Ray



On Oct 4, 2020, at 12:45 AM, 走下去 <1411608...@qq.com<mailto:1411608...@qq.com>> 
wrote:

Hi,everyone, I want to ask a question, which is that when I run the cpf 
function in MATPOWER, how can I get the Pload during the process?


-- 原始邮件 --
发件人: "MATPOWER discussion forum" 
mailto:mirishtha...@gmail.com>>;
发送时间: 2020年9月17日(星期四) 晚上9:29
收件人: "MATPOWER discussion 
forum"mailto:matpowe...@list.cornell.edu>>;
主题: Re: Optimal power flow with DG connected

Hi,
It's the file or casefile or M-file/MAT-file on which you are performing opf 
operations for analysis.
e.g. runopf(case9) here case9 is the file he asked for.
Thanks
Mirish

On Wed, Sep 16, 2020 at 6:43 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Which file do I need to send you?
please specify it.

Regards
Surbhi Aggarwal


On Tue, Sep 15, 2020 at 7:03 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
Looks like the Jacobian is singular. Feel free to send me the case (off-list) 
and I’ll have a look.

Ray


On Sep 14, 2020, at 11:35 PM, Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:

Even after doing everything, this error prompts out.
Please help me out with this issue.

Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)


Regards
Surbhi Aggarwal


On Mon, Sep 14, 2020 at 7:31 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
You would have to confirm the cause of the non-convergence before drawing any 
conclusions. You may find FAQ #5<https://matpower.org/doc/faq/#pfconvergence> 
helpful.

   Ray

On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:

Hello
If the system does not converge within 10 iterations, can we say that it is one 
of the most severely affected lines in contingency studies?
Or any other explanation for this non-convergence?
Regards
Surbhi Aggarwal


On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello
Thank you all for your help and I'll definitely look out for the solutions.
Thank you so much
Regards
Surbhi Aggarwal


On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
Hi Surbhi,

It looks like you were using the default Newton power flow. To increase the 
number of iterations, you can increase the pf.nr.max_it option. However, this 
is rarely necessary. If the Newton method is going to converge, it usually does 
so in less than the default 10 iterations. If it is not converging within 10 
iterations, it is likely that the problem has no solution or that you need a 
better starting point.

   Ray


On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

First of all why do you want to increase the number of steps/ iterations in the 
calculation? Is there any specific need? Actually the number of iterations 
depends on the power flow optimization tolerance. Maybe you can focus on the 
mpoption function and read it carefully. You can update something like here:
mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
I'm not 100 % sure about it but it may help you. Thanks.

Kind regards
Mirish

On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello Everyone,
I tried your suggestions and it somehow helped me.
Now my doubt is " If I want to increase my number of iterations, what steps I 
have to do"?
Please help me out
Regards
Surbhi Aggarwal


On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
I also suspect that the network becomes disconnected by removing certain lines. 
You can check the connectivity using 
case_info()<https://matpower.org/docs/ref/matpower7.0/lib/case_info.html> or 
find_islands()<https://matpower.org/docs/ref/matpower7.0/lib/find_islands.html>.
 If there are islands, then each island needs to have its own reference bus, 
and the local generation needs to be able to meet the local load in each island.

Ray


On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
mailto:mirish

?????? Optimal power flow with DG connected

[??????]

Hi,everyone, I want to ask a question, which is that when I run the cpf 
function in MATPOWER, how can I get the Pload during the process?




--  --
??: 
   "MATPOWER discussion forum"  
  

Re: Optimal power flow with DG connected

[Mirish Thakur]

Hi,
It's the file or casefile or M-file/MAT-file on which you are performing
opf operations for analysis.
e.g. runopf(case9) here *case9 *is the file he asked for.
Thanks
Mirish

On Wed, Sep 16, 2020 at 6:43 AM Surbhi Aggarwal 
wrote:

> Which file do I need to send you?
> please specify it.
>
> Regards
> Surbhi Aggarwal
>
>
> On Tue, Sep 15, 2020 at 7:03 PM Ray Daniel Zimmerman 
> wrote:
>
>> Looks like the Jacobian is singular. Feel free to send me the case
>> (off-list) and I’ll have a look.
>>
>> Ray
>>
>>
>> On Sep 14, 2020, at 11:35 PM, Surbhi Aggarwal 
>> wrote:
>>
>> Even after doing everything, this error prompts out.
>> Please help me out with this issue.
>>
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>>
>>
>> Regards
>> Surbhi Aggarwal
>>
>>
>> On Mon, Sep 14, 2020 at 7:31 PM Ray Daniel Zimmerman 
>> wrote:
>>
>>> You would have to confirm the cause of the non-convergence before
>>> drawing any conclusions. You may find FAQ #5
>>>  helpful.
>>>
>>>Ray
>>>
>>> On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal 
>>> wrote:
>>>
>>> Hello
>>> If the system does not converge within 10 iterations, can we say that it
>>> is one of the most severely affected lines in contingency studies?
>>> Or any other explanation for this non-convergence?
>>> Regards
>>> Surbhi Aggarwal
>>>
>>>
>>> On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal <
>>> surbhiaggarwa...@gmail.com> wrote:
>>>
 Hello
 Thank you all for your help and I'll definitely look out for the
 solutions.
 Thank you so much
 Regards
 Surbhi Aggarwal


 On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
 wrote:

> Hi Surbhi,
>
> It looks like you were using the default Newton power flow. To
> increase the number of iterations, you can increase the pf.nr.max_it
> option. However, this is rarely necessary. If the Newton method is going 
> to
> converge, it usually does so in less than the default 10 iterations. If it
> is not converging within 10 iterations, it is likely that the problem has
> no solution or that you need a better starting point.
>
>Ray
>
>
> On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
> wrote:
>
> Hi Surbhi,
>
> First of all why do you want to increase the number of steps/
> iterations in the calculation? Is there any specific need? Actually the
> number of iterations depends on the power flow optimization tolerance.
> Maybe you can focus on the mpoption function and read it carefully. You 
> can
> update something like here:
> mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
> I'm not 100 % sure about it but it may help you. Thanks.
>
> Kind regards
> Mirish
>
> On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal <
> surbhiaggarwa...@gmail.com> wrote:
>
>> Hello Everyone,
>> I tried your suggestions and it somehow helped me.
>> Now my doubt is " If I want to increase my number of iterations, what
>> steps I have to do"?
>> Please help me out
>> Regards
>> Surbhi Aggarwal
>>
>>
>> On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
>> wrote:
>>
>>> I also suspect that the network becomes disconnected by removing
>>> certain lines. You can check the connectivity using case_info()
>>>  or
>>> find_islands()
>>> .
>>> If there are islands, then each island needs to have its own reference 
>>> bus,
>>> and the local generation needs to be able to meet the local load in each
>>> island.
>>>
>>> Ray
>>>
>>>
>>> On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
>>> wrote:
>>>
>>> Hi Surbhi,
>>>
>>> Could you please check the continuity of the system before running
>>> opf? I mean to say if you run opf for (n-1) criteria the system should 
>>> be
>>> still well connected. There shouldn't be any island within the system
>>> itself. Perhaps you can test your model by removing any one parallel 
>>> line
>>> (which you can observe later for analysis) and run the model under (n-1)
>>> criteria. This could be the easiest way to test the model. Thank you.
>>>
>>> Kind regards
>>> Mirish
>>>
>>>
>>> On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <
>>> surbhiaggarwa...@gmail.com> wrote:
>>>
 Dear All,
 I am working on optimal power flow to find the contingency (N-1)
 situation of the system. For some of the line outage, certain output 
 pops
 out

 MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
 Warning: Matrix is singular to working precision.
 > In 

Re: Optimal power flow with DG connected

[Surbhi Aggarwal]

Which file do I need to send you?
please specify it.

Regards
Surbhi Aggarwal


On Tue, Sep 15, 2020 at 7:03 PM Ray Daniel Zimmerman 
wrote:

> Looks like the Jacobian is singular. Feel free to send me the case
> (off-list) and I’ll have a look.
>
> Ray
>
>
> On Sep 14, 2020, at 11:35 PM, Surbhi Aggarwal 
> wrote:
>
> Even after doing everything, this error prompts out.
> Please help me out with this issue.
>
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
>
>
> Regards
> Surbhi Aggarwal
>
>
> On Mon, Sep 14, 2020 at 7:31 PM Ray Daniel Zimmerman 
> wrote:
>
>> You would have to confirm the cause of the non-convergence before drawing
>> any conclusions. You may find FAQ #5
>>  helpful.
>>
>>Ray
>>
>> On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal 
>> wrote:
>>
>> Hello
>> If the system does not converge within 10 iterations, can we say that it
>> is one of the most severely affected lines in contingency studies?
>> Or any other explanation for this non-convergence?
>> Regards
>> Surbhi Aggarwal
>>
>>
>> On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal <
>> surbhiaggarwa...@gmail.com> wrote:
>>
>>> Hello
>>> Thank you all for your help and I'll definitely look out for the
>>> solutions.
>>> Thank you so much
>>> Regards
>>> Surbhi Aggarwal
>>>
>>>
>>> On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
>>> wrote:
>>>
 Hi Surbhi,

 It looks like you were using the default Newton power flow. To increase
 the number of iterations, you can increase the pf.nr.max_it option.
 However, this is rarely necessary. If the Newton method is going to
 converge, it usually does so in less than the default 10 iterations. If it
 is not converging within 10 iterations, it is likely that the problem has
 no solution or that you need a better starting point.

Ray


 On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
 wrote:

 Hi Surbhi,

 First of all why do you want to increase the number of steps/
 iterations in the calculation? Is there any specific need? Actually the
 number of iterations depends on the power flow optimization tolerance.
 Maybe you can focus on the mpoption function and read it carefully. You can
 update something like here:
 mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
 I'm not 100 % sure about it but it may help you. Thanks.

 Kind regards
 Mirish

 On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal <
 surbhiaggarwa...@gmail.com> wrote:

> Hello Everyone,
> I tried your suggestions and it somehow helped me.
> Now my doubt is " If I want to increase my number of iterations, what
> steps I have to do"?
> Please help me out
> Regards
> Surbhi Aggarwal
>
>
> On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
> wrote:
>
>> I also suspect that the network becomes disconnected by removing
>> certain lines. You can check the connectivity using case_info()
>>  or
>> find_islands()
>> .
>> If there are islands, then each island needs to have its own reference 
>> bus,
>> and the local generation needs to be able to meet the local load in each
>> island.
>>
>> Ray
>>
>>
>> On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
>> wrote:
>>
>> Hi Surbhi,
>>
>> Could you please check the continuity of the system before running
>> opf? I mean to say if you run opf for (n-1) criteria the system should be
>> still well connected. There shouldn't be any island within the system
>> itself. Perhaps you can test your model by removing any one parallel line
>> (which you can observe later for analysis) and run the model under (n-1)
>> criteria. This could be the easiest way to test the model. Thank you.
>>
>> Kind regards
>> Mirish
>>
>>
>> On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <
>> surbhiaggarwa...@gmail.com> wrote:
>>
>>> Dear All,
>>> I am working on optimal power flow to find the contingency (N-1)
>>> situation of the system. For some of the line outage, certain output 
>>> pops
>>> out
>>>
>>> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is sin

Re: Optimal power flow with DG connected

[Ray Daniel Zimmerman]

Looks like the Jacobian is singular. Feel free to send me the case (off-list) 
and I’ll have a look.

Ray


On Sep 14, 2020, at 11:35 PM, Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:

Even after doing everything, this error prompts out.
Please help me out with this issue.

Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)


Regards
Surbhi Aggarwal


On Mon, Sep 14, 2020 at 7:31 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
You would have to confirm the cause of the non-convergence before drawing any 
conclusions. You may find FAQ #5 
helpful.

   Ray

On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:

Hello
If the system does not converge within 10 iterations, can we say that it is one 
of the most severely affected lines in contingency studies?
Or any other explanation for this non-convergence?
Regards
Surbhi Aggarwal


On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello
Thank you all for your help and I'll definitely look out for the solutions.
Thank you so much
Regards
Surbhi Aggarwal


On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
Hi Surbhi,

It looks like you were using the default Newton power flow. To increase the 
number of iterations, you can increase the pf.nr.max_it option. However, this 
is rarely necessary. If the Newton method is going to converge, it usually does 
so in less than the default 10 iterations. If it is not converging within 10 
iterations, it is likely that the problem has no solution or that you need a 
better starting point.

   Ray


On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

First of all why do you want to increase the number of steps/ iterations in the 
calculation? Is there any specific need? Actually the number of iterations 
depends on the power flow optimization tolerance. Maybe you can focus on the 
mpoption function and read it carefully. You can update something like here:
mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
I'm not 100 % sure about it but it may help you. Thanks.

Kind regards
Mirish

On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello Everyone,
I tried your suggestions and it somehow helped me.
Now my doubt is " If I want to increase my number of iterations, what steps I 
have to do"?
Please help me out
Regards
Surbhi Aggarwal


On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
I also suspect that the network becomes disconnected by removing certain lines. 
You can check the connectivity using 
case_info() or 
find_islands().
 If there are islands, then each island needs to have its own reference bus, 
and the local generation needs to be able to meet the local load in each island.

Ray


On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

Could you please check the continuity of the system before running opf? I mean 
to say if you run opf for (n-1) criteria the system should be still well 
connected. There shouldn't be any island within the system itself. Perhaps you 
can test your model by removing any one parallel line (which you can observe 
later for analysis) and run the model under (n-1) criteria. This could be the 
easiest way to test the model. Thank you.

Kind regards
Mirish


On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Dear All,
I am working on optimal power flow to find the contingency (N-1) situation of 
the system. For some of the line outage, certain output pops out

MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singul

Re: Optimal power flow with DG connected

[Surbhi Aggarwal]

Even after doing everything, this error prompts out.
Please help me out with this issue.

Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)


Regards
Surbhi Aggarwal


On Mon, Sep 14, 2020 at 7:31 PM Ray Daniel Zimmerman 
wrote:

> You would have to confirm the cause of the non-convergence before drawing
> any conclusions. You may find FAQ #5
>  helpful.
>
>Ray
>
> On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal 
> wrote:
>
> Hello
> If the system does not converge within 10 iterations, can we say that it
> is one of the most severely affected lines in contingency studies?
> Or any other explanation for this non-convergence?
> Regards
> Surbhi Aggarwal
>
>
> On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal <
> surbhiaggarwa...@gmail.com> wrote:
>
>> Hello
>> Thank you all for your help and I'll definitely look out for the
>> solutions.
>> Thank you so much
>> Regards
>> Surbhi Aggarwal
>>
>>
>> On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
>> wrote:
>>
>>> Hi Surbhi,
>>>
>>> It looks like you were using the default Newton power flow. To increase
>>> the number of iterations, you can increase the pf.nr.max_it option.
>>> However, this is rarely necessary. If the Newton method is going to
>>> converge, it usually does so in less than the default 10 iterations. If it
>>> is not converging within 10 iterations, it is likely that the problem has
>>> no solution or that you need a better starting point.
>>>
>>>Ray
>>>
>>>
>>> On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
>>> wrote:
>>>
>>> Hi Surbhi,
>>>
>>> First of all why do you want to increase the number of steps/ iterations
>>> in the calculation? Is there any specific need? Actually the number of
>>> iterations depends on the power flow optimization tolerance. Maybe you can
>>> focus on the mpoption function and read it carefully. You can update
>>> something like here:
>>> mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
>>> I'm not 100 % sure about it but it may help you. Thanks.
>>>
>>> Kind regards
>>> Mirish
>>>
>>> On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal <
>>> surbhiaggarwa...@gmail.com> wrote:
>>>
 Hello Everyone,
 I tried your suggestions and it somehow helped me.
 Now my doubt is " If I want to increase my number of iterations, what
 steps I have to do"?
 Please help me out
 Regards
 Surbhi Aggarwal


 On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
 wrote:

> I also suspect that the network becomes disconnected by removing
> certain lines. You can check the connectivity using case_info()
>  or
> find_islands()
> . If
> there are islands, then each island needs to have its own reference bus,
> and the local generation needs to be able to meet the local load in each
> island.
>
> Ray
>
>
> On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
> wrote:
>
> Hi Surbhi,
>
> Could you please check the continuity of the system before running
> opf? I mean to say if you run opf for (n-1) criteria the system should be
> still well connected. There shouldn't be any island within the system
> itself. Perhaps you can test your model by removing any one parallel line
> (which you can observe later for analysis) and run the model under (n-1)
> criteria. This could be the easiest way to test the model. Thank you.
>
> Kind regards
> Mirish
>
>
> On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <
> surbhiaggarwa...@gmail.com> wrote:
>
>> Dear All,
>> I am working on optimal power flow to find the contingency (N-1)
>> situation of the system. For some of the line outage, certain output pops
>> out
>>
>> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> >

Re: Optimal power flow with DG connected

[Ray Daniel Zimmerman]

You would have to confirm the cause of the non-convergence before drawing any 
conclusions. You may find FAQ #5 
helpful.

   Ray

On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:

Hello
If the system does not converge within 10 iterations, can we say that it is one 
of the most severely affected lines in contingency studies?
Or any other explanation for this non-convergence?
Regards
Surbhi Aggarwal


On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello
Thank you all for your help and I'll definitely look out for the solutions.
Thank you so much
Regards
Surbhi Aggarwal


On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
Hi Surbhi,

It looks like you were using the default Newton power flow. To increase the 
number of iterations, you can increase the pf.nr.max_it option. However, this 
is rarely necessary. If the Newton method is going to converge, it usually does 
so in less than the default 10 iterations. If it is not converging within 10 
iterations, it is likely that the problem has no solution or that you need a 
better starting point.

   Ray


On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

First of all why do you want to increase the number of steps/ iterations in the 
calculation? Is there any specific need? Actually the number of iterations 
depends on the power flow optimization tolerance. Maybe you can focus on the 
mpoption function and read it carefully. You can update something like here:
mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
I'm not 100 % sure about it but it may help you. Thanks.

Kind regards
Mirish

On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello Everyone,
I tried your suggestions and it somehow helped me.
Now my doubt is " If I want to increase my number of iterations, what steps I 
have to do"?
Please help me out
Regards
Surbhi Aggarwal


On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
I also suspect that the network becomes disconnected by removing certain lines. 
You can check the connectivity using 
case_info() or 
find_islands().
 If there are islands, then each island needs to have its own reference bus, 
and the local generation needs to be able to meet the local load in each island.

Ray


On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

Could you please check the continuity of the system before running opf? I mean 
to say if you run opf for (n-1) criteria the system should be still well 
connected. There shouldn't be any island within the system itself. Perhaps you 
can test your model by removing any one parallel line (which you can observe 
later for analysis) and run the model under (n-1) criteria. This could be the 
easiest way to test the model. Thank you.

Kind regards
Mirish


On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Dear All,
I am working on optimal power flow to find the contingency (N-1) situation of 
the system. For some of the line outage, certain output pops out

MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)

Newton's method power flow (power balance, polar) did not converge in 10 
iterations.

>  Did NOT converge (7.38 seconds)  <

What to do to correct this error. It would be of great help.
Regards
Surbhi Aggarwal

Re: Optimal power flow with DG connected

[Surbhi Aggarwal]

Hello
If the system does not converge within 10 iterations, can we say that it is
one of the most severely affected lines in contingency studies?
Or any other explanation for this non-convergence?
Regards
Surbhi Aggarwal


On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal 
wrote:

> Hello
> Thank you all for your help and I'll definitely look out for the solutions.
> Thank you so much
> Regards
> Surbhi Aggarwal
>
>
> On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
> wrote:
>
>> Hi Surbhi,
>>
>> It looks like you were using the default Newton power flow. To increase
>> the number of iterations, you can increase the pf.nr.max_it option.
>> However, this is rarely necessary. If the Newton method is going to
>> converge, it usually does so in less than the default 10 iterations. If it
>> is not converging within 10 iterations, it is likely that the problem has
>> no solution or that you need a better starting point.
>>
>>Ray
>>
>>
>> On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
>> wrote:
>>
>> Hi Surbhi,
>>
>> First of all why do you want to increase the number of steps/ iterations
>> in the calculation? Is there any specific need? Actually the number of
>> iterations depends on the power flow optimization tolerance. Maybe you can
>> focus on the mpoption function and read it carefully. You can update
>> something like here:
>> mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
>> I'm not 100 % sure about it but it may help you. Thanks.
>>
>> Kind regards
>> Mirish
>>
>> On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal <
>> surbhiaggarwa...@gmail.com> wrote:
>>
>>> Hello Everyone,
>>> I tried your suggestions and it somehow helped me.
>>> Now my doubt is " If I want to increase my number of iterations, what
>>> steps I have to do"?
>>> Please help me out
>>> Regards
>>> Surbhi Aggarwal
>>>
>>>
>>> On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
>>> wrote:
>>>
 I also suspect that the network becomes disconnected by removing
 certain lines. You can check the connectivity using case_info()
  or
 find_islands()
 . If
 there are islands, then each island needs to have its own reference bus,
 and the local generation needs to be able to meet the local load in each
 island.

 Ray


 On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
 wrote:

 Hi Surbhi,

 Could you please check the continuity of the system before running opf?
 I mean to say if you run opf for (n-1) criteria the system should be still
 well connected. There shouldn't be any island within the system itself.
 Perhaps you can test your model by removing any one parallel line (which
 you can observe later for analysis) and run the model under (n-1) criteria.
 This could be the easiest way to test the model. Thank you.

 Kind regards
 Mirish


 On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <
 surbhiaggarwa...@gmail.com> wrote:

> Dear All,
> I am working on optimal power flow to find the contingency (N-1)
> situation of the system. For some of the line outage, certain output pops
> out
>
> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
>
> Newton's method power flow (power balance, polar) did not converge in
> 10 iterations.
>
> >  Did NOT converge (7.38 seconds)  <
>
> What to do to co

Re: Optimal power flow with DG connected

[Surbhi Aggarwal]

Hello
Thank you all for your help and I'll definitely look out for the solutions.
Thank you so much
Regards
Surbhi Aggarwal


On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman 
wrote:

> Hi Surbhi,
>
> It looks like you were using the default Newton power flow. To increase
> the number of iterations, you can increase the pf.nr.max_it option.
> However, this is rarely necessary. If the Newton method is going to
> converge, it usually does so in less than the default 10 iterations. If it
> is not converging within 10 iterations, it is likely that the problem has
> no solution or that you need a better starting point.
>
>Ray
>
>
> On Sep 11, 2020, at 5:48 AM, Mirish Thakur  wrote:
>
> Hi Surbhi,
>
> First of all why do you want to increase the number of steps/ iterations
> in the calculation? Is there any specific need? Actually the number of
> iterations depends on the power flow optimization tolerance. Maybe you can
> focus on the mpoption function and read it carefully. You can update
> something like here:
> mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
> I'm not 100 % sure about it but it may help you. Thanks.
>
> Kind regards
> Mirish
>
> On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal <
> surbhiaggarwa...@gmail.com> wrote:
>
>> Hello Everyone,
>> I tried your suggestions and it somehow helped me.
>> Now my doubt is " If I want to increase my number of iterations, what
>> steps I have to do"?
>> Please help me out
>> Regards
>> Surbhi Aggarwal
>>
>>
>> On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
>> wrote:
>>
>>> I also suspect that the network becomes disconnected by removing certain
>>> lines. You can check the connectivity using case_info()
>>>  or
>>> find_islands()
>>> . If
>>> there are islands, then each island needs to have its own reference bus,
>>> and the local generation needs to be able to meet the local load in each
>>> island.
>>>
>>> Ray
>>>
>>>
>>> On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
>>> wrote:
>>>
>>> Hi Surbhi,
>>>
>>> Could you please check the continuity of the system before running opf?
>>> I mean to say if you run opf for (n-1) criteria the system should be still
>>> well connected. There shouldn't be any island within the system itself.
>>> Perhaps you can test your model by removing any one parallel line (which
>>> you can observe later for analysis) and run the model under (n-1) criteria.
>>> This could be the easiest way to test the model. Thank you.
>>>
>>> Kind regards
>>> Mirish
>>>
>>>
>>> On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <
>>> surbhiaggarwa...@gmail.com> wrote:
>>>
 Dear All,
 I am working on optimal power flow to find the contingency (N-1)
 situation of the system. For some of the line outage, certain output pops
 out

 MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)
 Warning: Matrix is singular to working precision.
 > In mplinsolve (line 75)
   In newtonpf (line 110)
   In runpf (line 260)

 Newton's method power flow (power balance, polar) did not converge in
 10 iterations.

 >  Did NOT converge (7.38 seconds)  <

 What to do to correct this error. It would be of great help.
 Regards
 Surbhi Aggarwal

>>>
>>>
>

Re: Optimal power flow with DG connected

[Ray Daniel Zimmerman]

Hi Surbhi,

It looks like you were using the default Newton power flow. To increase the 
number of iterations, you can increase the pf.nr.max_it option. However, this 
is rarely necessary. If the Newton method is going to converge, it usually does 
so in less than the default 10 iterations. If it is not converging within 10 
iterations, it is likely that the problem has no solution or that you need a 
better starting point.

   Ray


On Sep 11, 2020, at 5:48 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

First of all why do you want to increase the number of steps/ iterations in the 
calculation? Is there any specific need? Actually the number of iterations 
depends on the power flow optimization tolerance. Maybe you can focus on the 
mpoption function and read it carefully. You can update something like here:
mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
I'm not 100 % sure about it but it may help you. Thanks.

Kind regards
Mirish

On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Hello Everyone,
I tried your suggestions and it somehow helped me.
Now my doubt is " If I want to increase my number of iterations, what steps I 
have to do"?
Please help me out
Regards
Surbhi Aggarwal


On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
mailto:r...@cornell.edu>> wrote:
I also suspect that the network becomes disconnected by removing certain lines. 
You can check the connectivity using 
case_info() or 
find_islands().
 If there are islands, then each island needs to have its own reference bus, 
and the local generation needs to be able to meet the local load in each island.

Ray


On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

Could you please check the continuity of the system before running opf? I mean 
to say if you run opf for (n-1) criteria the system should be still well 
connected. There shouldn't be any island within the system itself. Perhaps you 
can test your model by removing any one parallel line (which you can observe 
later for analysis) and run the model under (n-1) criteria. This could be the 
easiest way to test the model. Thank you.

Kind regards
Mirish


On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Dear All,
I am working on optimal power flow to find the contingency (N-1) situation of 
the system. For some of the line outage, certain output pops out

MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)

Newton's method power flow (power balance, polar) did not converge in 10 
iterations.

>  Did NOT converge (7.38 seconds)  <

What to do to correct this error. It would be of great help.
Regards
Surbhi Aggarwal

Re: Optimal power flow with DG connected

[Mirish Thakur]

Hi Surbhi,

First of all why do you want to increase the number of steps/ iterations in
the calculation? Is there any specific need? Actually the number of
iterations depends on the power flow optimization tolerance. Maybe you can
focus on the mpoption function and read it carefully. You can update
something like here:
mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4)
I'm not 100 % sure about it but it may help you. Thanks.

Kind regards
Mirish

On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal 
wrote:

> Hello Everyone,
> I tried your suggestions and it somehow helped me.
> Now my doubt is " If I want to increase my number of iterations, what
> steps I have to do"?
> Please help me out
> Regards
> Surbhi Aggarwal
>
>
> On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
> wrote:
>
>> I also suspect that the network becomes disconnected by removing certain
>> lines. You can check the connectivity using case_info()
>>  or
>> find_islands()
>> . If
>> there are islands, then each island needs to have its own reference bus,
>> and the local generation needs to be able to meet the local load in each
>> island.
>>
>> Ray
>>
>>
>> On Sep 9, 2020, at 4:57 AM, Mirish Thakur  wrote:
>>
>> Hi Surbhi,
>>
>> Could you please check the continuity of the system before running opf? I
>> mean to say if you run opf for (n-1) criteria the system should be still
>> well connected. There shouldn't be any island within the system itself.
>> Perhaps you can test your model by removing any one parallel line (which
>> you can observe later for analysis) and run the model under (n-1) criteria.
>> This could be the easiest way to test the model. Thank you.
>>
>> Kind regards
>> Mirish
>>
>>
>> On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <
>> surbhiaggarwa...@gmail.com> wrote:
>>
>>> Dear All,
>>> I am working on optimal power flow to find the contingency (N-1)
>>> situation of the system. For some of the line outage, certain output pops
>>> out
>>>
>>> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>> Warning: Matrix is singular to working precision.
>>> > In mplinsolve (line 75)
>>>   In newtonpf (line 110)
>>>   In runpf (line 260)
>>>
>>> Newton's method power flow (power balance, polar) did not converge in 10
>>> iterations.
>>>
>>> >  Did NOT converge (7.38 seconds)  <
>>>
>>> What to do to correct this error. It would be of great help.
>>> Regards
>>> Surbhi Aggarwal
>>>
>>
>>

Re: Optimal power flow with DG connected

[Surbhi Aggarwal]

Hello Everyone,
I tried your suggestions and it somehow helped me.
Now my doubt is " If I want to increase my number of iterations, what steps
I have to do"?
Please help me out
Regards
Surbhi Aggarwal


On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman 
wrote:

> I also suspect that the network becomes disconnected by removing certain
> lines. You can check the connectivity using case_info()
>  or
> find_islands()
> . If
> there are islands, then each island needs to have its own reference bus,
> and the local generation needs to be able to meet the local load in each
> island.
>
> Ray
>
>
> On Sep 9, 2020, at 4:57 AM, Mirish Thakur  wrote:
>
> Hi Surbhi,
>
> Could you please check the continuity of the system before running opf? I
> mean to say if you run opf for (n-1) criteria the system should be still
> well connected. There shouldn't be any island within the system itself.
> Perhaps you can test your model by removing any one parallel line (which
> you can observe later for analysis) and run the model under (n-1) criteria.
> This could be the easiest way to test the model. Thank you.
>
> Kind regards
> Mirish
>
>
> On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal 
> wrote:
>
>> Dear All,
>> I am working on optimal power flow to find the contingency (N-1)
>> situation of the system. For some of the line outage, certain output pops
>> out
>>
>> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>> Warning: Matrix is singular to working precision.
>> > In mplinsolve (line 75)
>>   In newtonpf (line 110)
>>   In runpf (line 260)
>>
>> Newton's method power flow (power balance, polar) did not converge in 10
>> iterations.
>>
>> >  Did NOT converge (7.38 seconds)  <
>>
>> What to do to correct this error. It would be of great help.
>> Regards
>> Surbhi Aggarwal
>>
>
>

Re: Optimal power flow with DG connected

[Ray Daniel Zimmerman]

I also suspect that the network becomes disconnected by removing certain lines. 
You can check the connectivity using 
case_info() or 
find_islands().
 If there are islands, then each island needs to have its own reference bus, 
and the local generation needs to be able to meet the local load in each island.

Ray


On Sep 9, 2020, at 4:57 AM, Mirish Thakur 
mailto:mirishtha...@gmail.com>> wrote:

Hi Surbhi,

Could you please check the continuity of the system before running opf? I mean 
to say if you run opf for (n-1) criteria the system should be still well 
connected. There shouldn't be any island within the system itself. Perhaps you 
can test your model by removing any one parallel line (which you can observe 
later for analysis) and run the model under (n-1) criteria. This could be the 
easiest way to test the model. Thank you.

Kind regards
Mirish


On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal 
mailto:surbhiaggarwa...@gmail.com>> wrote:
Dear All,
I am working on optimal power flow to find the contingency (N-1) situation of 
the system. For some of the line outage, certain output pops out

MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)

Newton's method power flow (power balance, polar) did not converge in 10 
iterations.

>  Did NOT converge (7.38 seconds)  <

What to do to correct this error. It would be of great help.
Regards
Surbhi Aggarwal

Re: Optimal power flow with DG connected

[Mirish Thakur]

Hi Surbhi,

Could you please check the continuity of the system before running opf? I
mean to say if you run opf for (n-1) criteria the system should be still
well connected. There shouldn't be any island within the system itself.
Perhaps you can test your model by removing any one parallel line (which
you can observe later for analysis) and run the model under (n-1) criteria.
This could be the easiest way to test the model. Thank you.

Kind regards
Mirish


On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal 
wrote:

> Dear All,
> I am working on optimal power flow to find the contingency (N-1) situation
> of the system. For some of the line outage, certain output pops out
>
> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
>
> Newton's method power flow (power balance, polar) did not converge in 10
> iterations.
>
> >  Did NOT converge (7.38 seconds)  <
>
> What to do to correct this error. It would be of great help.
> Regards
> Surbhi Aggarwal
>

Re: Optimal power flow with DG connected

[Md Ashfaqur Rahman]

Hi Surbhi,

The system is becoming unobservable, I guess.

Regards,
Md


On Wed, Sep 9, 2020, 2:12 AM Surbhi Aggarwal 
wrote:

> Dear All,
> I am working on optimal power flow to find the contingency (N-1) situation
> of the system. For some of the line outage, certain output pops out
>
> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
>
> Newton's method power flow (power balance, polar) did not converge in 10
> iterations.
>
> >  Did NOT converge (7.38 seconds)  <
>
> What to do to correct this error. It would be of great help.
> Regards
> Surbhi Aggarwal
>

Re: Optimal power flow with DG connected

[Jagadeesh Gunda]

Hi Surabhi,

It seems the problem is with your network, not with the power flow
algorithm.
*Technical interpretation:* For the generation and demand you are
targeting; your network is N-1 contingency incompliant.
*Mathematical interpretation:* Because of the above problem, power flow
Jacobian is becoming singular. As we know, Jacobian needs to be inverted in
every iteration. But inversion is failing because the matrix is singular.

You may correct the issue as below.

Solution-1: Increase the number of Newton Iterations and try again. But I
don’t think it will work.
Solution-2: Rather than disconnecting the line, change its impedance to
very large value. This should work, and it represents your outage
condition. You will see almost no flow on the line after power flow
converged.
Solution-3: Take a different network.
Solution-4: Fix your network first, and then analyze your scenario again.

Best Regards,
Dr  JGunda
Optimization Engineer
Power Systems & Electricity Markets
*GE Grid Solutions Denmark*
LinkedIn: https://www.linkedin.com/in/jgunda/
Google Scholar:
https://scholar.google.co.uk/citations?user=Zy1m33QJ&hl=en
ResearchGate: https://www.researchgate.net/profile/Jagadeesh_Gunda


On Wed, 9 Sep 2020 at 09:12, Surbhi Aggarwal 
wrote:

> Dear All,
> I am working on optimal power flow to find the contingency (N-1) situation
> of the system. For some of the line outage, certain output pops out
>
> MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
> Warning: Matrix is singular to working precision.
> > In mplinsolve (line 75)
>   In newtonpf (line 110)
>   In runpf (line 260)
>
> Newton's method power flow (power balance, polar) did not converge in 10
> iterations.
>
> >  Did NOT converge (7.38 seconds)  <
>
> What to do to correct this error. It would be of great help.
> Regards
> Surbhi Aggarwal
>

Re: Optimal power flow with DG connected

[sebaa haddi]

 Try with DC power flow 

Le mercredi 9 septembre 2020 à 08:11:45 UTC+1, Surbhi Aggarwal 
 a écrit :  
 
 Dear All,I am working on optimal power flow to find the contingency (N-1) 
situation of the system. For some of the line outage, certain output pops out
MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 
Warning: Matrix is singular to working precision. 
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260) 

Newton's method power flow (power balance, polar) did not converge in 10 
iterations.

>  Did NOT converge (7.38 seconds)  <
What to do to correct this error. It would be of great help.
RegardsSurbhi Aggarwal  

Optimal power flow with DG connected

[Surbhi Aggarwal]

Dear All,
I am working on optimal power flow to find the contingency (N-1) situation
of the system. For some of the line outage, certain output pops out

MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)
Warning: Matrix is singular to working precision.
> In mplinsolve (line 75)
  In newtonpf (line 110)
  In runpf (line 260)

Newton's method power flow (power balance, polar) did not converge in 10
iterations.

>  Did NOT converge (7.38 seconds)  <

What to do to correct this error. It would be of great help.
Regards
Surbhi Aggarwal