Respected All,
For Calculating the power flow
1. The state variables are related to the measurements through the
following model:
* z=h(x)+e .......(1)*
here *x* is the matrix of state variables
and *e* is the normally distributed meter error (noise) with zero
mean in the measurements.
(This is calculated this part using matpower standard Newton Raphson's
Method)
2. For *state estimation* using the *DC power flow model*, Equation (1) can
be represented by a linear regression model following
* z=H(x)+e ........(2)*
where *H* is the Jacobin Matrix
and *z * is the matrix of real power injections in the node ( In DC
power flow we only consider active power injection in to bus)
*WLS Criteria: *
Now using the weighted least-square criteria for the calculation of
estimated following equation is used
* x_estimated= [ Inverse{ (Transpose(H)) . W. H) } .
Transpose (H).W] z .... (3)*
(a diagonal matrix with elements are reciprocal of variance)
**
*Now My Question:*
I want to know how to extract the* H *Matrix ?
As per my understanding H Matrix (*Using DC Power Flow Method*) is
different from the H Matrix ( *AC Power Flow*) and it is built as
following:
Step 1 : Build the Ybus matrix ( Need to know which function to be used ?
Can i use the function
[Ybus, Yf, Yt] = makeYbus(baseMVA, bus, branch)
Is the loop for calculation of diagonal and off-diagonal elements is
already included in this function
Step 2 : Build the B Matrix (B=imaginary (Ybus) )
Does this gives the correct B Matrix ?
*Step 3 : Build the H Matrix *
( I think it should also include the bus incident matrix . How can i
calculate/ extract the bus incidence matrix ?)
*Please correct me if i am wrong in my understanding and also guide me how
to extract H Matrix*
Step 4 : Compare DC State Estimation using WLS function results with the
runpf results in MATpower
Regards
Saeed Ahmed
On 21 July 2017 at 14:37, Saeed Ahmed <[email protected]> wrote:
> Thank you Sir .... I am really grateful...
>
> Now after a lot of reading and following your guidance i am understanding
> how to start working on matpower. Your cooperation is highly appreciated. I
> will keep on seeking guidance , please.
>
>
>
> Regards
> Saeed Ahmed
>
>
> On 20 July 2017 at 22:59, Ray Zimmerman <[email protected]> wrote:
>
>> For a case that has consecutive bus numbers (e.g. one that has been
>> converted to internal indexing via ext2int()
>> <http://www.pserc.cornell.edu/matpower/docs/ref/matpower6.0/ext2int.html>),
>> simply use makeSbus()
>> <http://www.pserc.cornell.edu/matpower/docs/ref/matpower6.0/makeSbus.html>.
>> It returns the complex bus injections in per-unit, so you’ll need to take
>> only the real part and multiply by baseMVA to get the MW values.
>>
>> E.g.
>>
>> mpc = rundcpf('case30', mpoption('out.all', 0));
>> Pbus = real(makeSbus(mpc.baseMVA, mpc.bus, mpc.gen)) * mpc.baseMVA
>>
>> — Ray
>>
>>
>>
>> On Jul 19, 2017, at 9:43 PM, Saeed Ahmed <[email protected]> wrote:
>>
>> Hi All,
>>
>> I need to calculate the the injected power(Pi) matrix at each bus . It is
>> equal to the generated power(Pg) - demand/load power. Now how to extract it
>> using matpower
>>
>>
>>
>>
>
