I’m afraid I don’t know without seeing the actual code.
Ray
> On Nov 30, 2015, at 3:22 PM, lydia edwin <[email protected]> wrote:
>
> Thank you very much sir for your reply. I have made the corrections suggested
> by you. Reg. query 3, I have calculated Va as the product of Zbus and
> injected currents. But I find that this Va is different from the power flow
> output Vc (in which Pa and Qa are the inputs)
>
> What could be the possible reason? Thanks
>
>
> On Mon, Nov 30, 2015 at 6:33 PM, Ray Zimmerman <[email protected]
> <mailto:[email protected]>> wrote:
> 1. Setting values of bus loads and voltages in code after loading from a case
> file is fine.
> 2. See caseformat()
> <http://www.pserc.cornell.edu//matpower/docs/ref/matpower5.1/caseformat.html>
> or Table B-1 in the User’s Manual
> <http://www.pserc.cornell.edu/matpower/docs/MATPOWER-manual-5.1.pdf>. You
> will see that the PD and QD columns in the bus matrix are in MW and MVAr, not
> in p.u. So you will have to convert them by multiplying by mpc.baseMVA.
> 3. Your Va is a voltage angle in radians, Vc is the complex voltage.
>
> As a MATPOWER “best practices”, I also suggest that you use the named
> constants rather than numerical column indices when referencing columns of
> the data matrices. See define_constants()
> <http://www.pserc.cornell.edu//matpower/docs/ref/matpower5.1/define_constants.html>
> and the next to last paragraph in section 2.3.2 of the User’s Manual
> <http://www.pserc.cornell.edu/matpower/docs/MATPOWER-manual-5.1.pdf> for more
> details.
>
> Ray
>
>
>
>
>> On Nov 26, 2015, at 5:35 AM, lydia edwin <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Hello sir
>>
>> I am a beginner in MATPOWER. I wanted to solve a power flow problem using
>> the IEEE_30 bus system. I have Va, Pa, Qa in pu quantities. I used Pa and
>> Qa as inputs and wanted to solve the AC power flow and check if I get Va. I
>> used the following code:
>>
>> mpc=loadcase(case30);
>> mpc.bus(:,3)=Pa; % Input Pa in pu
>> mpc.bus(:,4)=Qa; % Input Qa in pu
>> mpc.bus(1,8)=1; % slack bus voltage
>> mpc.bus(1,9)=0; % slack bus angle
>> results=runpf(mpc); % stored the results
>> Vm1=results.bus(:,8); % output voltage magnitude
>> Va1=results.bus(:,9)*pi/180; %output voltage angles
>> % convert the voltage from polar to cartesian
>> for j=1:length(Vm1)
>> [Vr1(j),Vr2(j)]=pol2cart(Va1(j), Vm1(j));
>> Vc(j)=Vr1(j)+ 1i*Vr2(j);
>> end
>>
>> Queries:
>> 1. Is the way I have coded right? Or should I create a separate case format?
>> 2. Can I input Pa and Qa in pu values?
>> 3. The output Vc that I get is not same as Va.
>>
>> Please help. Thanks
>> Lydia Edwin
>
>
