I don't know what your algorithm does but I think you can do the same, 
determine optimal generation and load, using MATPOWER's optimal power flow 
(runopf). runopf supports all the constraints that you've listed.



Shri

________________________________

From: [email protected] 
[[email protected]] on behalf of Electric 
[[email protected]]
Sent: Thursday, April 09, 2015 3:18 PM
To: MATPOWER discussion forum
Subject: How to verify the feasibility of your solution without running Power 
flow?

    I am using an algorithm that changes the amount of demand and generation at 
each bus (Pd,Pg) to mitigate over load of lines and enhance the security. The 
output of my algorithm (Pd,Pg) must be checked to insure that they are 
feasible. So, it is obvious that by assigning this new calculated values 
instead of old Pg and Pd (generation and demand ) at each bus and running a 
simple power flow (pf), I can find out if the calculated results are feasible.
    However, this is an optimization problem. Therefore,  feasibility of the 
suggested values of Pd and Pg by fmincon must be verified at each 
iteration(1000 times). Basically, it can be accomplished by running a power 
flow in constraint function of fmincon and checking lines loading and voltage 
range.
    But, doing so is very time consuming and takes more than an hours to 
calculate the feasible Pg and Pd. So I was wonder if there is another faster 
way to check the feasibility of the calculated Pd,Pg without running power flow.
I think, if the solution (calculated Pd,Pg) satisfies these constraints,the 
answer is then feasible and there is no need to run power flow.
But I have some problems in considering the constraints 5,8,9,10.

1) Pgmin(j) <Pg(j) <Pgmax(j)     % j indicates buses with generator
2) Qgmin(j) <Qg(j) <Qgmax(j)    % j indicates buses with generator
3) Pdmin(k) <Pd(k) <Pdmax(k)  % k indicates buses with demand
4) Qd(k)=Pd(k)*tan(phi(k))         % ph(k) is load P.F at bus K
Nodal active balance:
5) Pg(n) -Pd(n)=|V(i)| sum( |Y(h,n)| .V(h)*Cos(del(n)-del(h)-teta(n,h)))
where Pg(n) is nodal generation which is calculated as:
6) Pg(n)=sum (Pg(j)) at bus n
7) Pd(n)=sum (Pd(k)) at bus n
teta(n,h) is the angle of Y(n,h), del(n) and del(h) are bust angle of n and h.
Nodal reactive balance:
8) Qg(n) -Qd(n)=|V(i)| sum( |Y(h,n)| .V(h)*Sin(del(n)-del(h)-teta(n,h)))

9) Vmin(n)<V(n)<Vmax(n)  % voltage range at all buses.
10) S(i,j)<Smax(i,j).  transmitted apparent power  from i,j must be less than 
capacity of line.

Thanks in advance


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