Hi Maliha,
When using dispatchable loads, the objective function value includes a large
“negative cost” to represent the value of serving the dispatchable load. If all
load is dispatchable, you could think of the objective function value as the
negative of the social welfare.
If you want to compare results between cases with and without dispatchable
load, you will want to explicitly compute the costs of the actual generators
(excluding those that represent dispatchable loads) for each case.
>> define_constants
>> r = runopf('case30', mpopt);
>> k = ~isload(r.gen);
>> sum(totcost(r1.gencost(k, :), r1.gen(k, PG)))
ans =
576.8922
>> r = runopf(load2disp('case30'), mpopt);
>> k = ~isload(r.gen);
>> sum(totcost(r1.gencost(k, :), r1.gen(k, PG)))
ans =
576.8922
I have no idea why you would get the error of "too many refrence buses making a
connected system…” when increasing the load in the Pd column.
Ray
On Oct 27, 2021, at 7:38 AM, MALIHA SHAH
<mshaheep19....@student.nust.edu.pk<mailto:mshaheep19....@student.nust.edu.pk>>
wrote:
Respected Ray
I performed simple runopf function to check the cost minimization of case 30 by
observing objective function in dollar per hour.
Similarly, when i increased the load in Pd column it gives error of "too many
refrence buses making a connected system..."
But when i run case 30 with dispatchable loads the opf results in negative
objective function. What does the negative objective function means. How can it
made positive?
The objective function is not only negative but is very different from base
case.
Base case had 576 $/hr and dispatchable loads case has 21940$/hr (the loads are
20% more then base case but let me know if this answer of obj fcn is feasible
under this situation,it can be around tgis figure or its impossible and I am
msking other mistakes ).
Thanking you in advance.
Maliha
