See Also
As a simple example of using the OPF, consider the seven bus, three area system contained in the file B7OPF.pwb (included with the PowerWorld Simulator). For this case all three areas are initially on Economic Dispatch (ED) AGC control and hence by default would not be included in the OPF solution. Also, the initial interchange between the areas is equal to zero and the generators are modeled using cubic cost functions.
To initially solve the case using the standard power flow, select Solve Power Flow in the Power Flow Tools ribbon group on the Tools ribbon tab. The case should look like the following figure:
B7OPF Case Solved using Economic Dispatch
Now we'll modify the case to set the three areas for OPF control. To do this, select Optimal Power Flow > Results > Areas in the Model Explorer to display the OPF Area Records display. Toggle the AGC status for each of the three areas to change it to "OPF". Now select Primal LP in the OPF ribbon group on the Add Ons ribbon tab to solve the case using the LP OPF. The results should look similar to the figure below. The one-line shows the hourly cost for each area and the total case hourly cost, equal to $ 16,888 / hr.
B7OPF Case Solved using LP OPF
Note that the results are very similar but not identical to the economic dispatch case. We would expect the cases to be similar since for cases with no congestion the OPF solution should be (ideally) equal to the economic dispatch solution. The difference between the two is because in the LP OPF the generator cost functions are converted from a cubic model to a piece-wise linear model using a user specified number of segments, which is 5 segments by default. This value can be viewed/modified from the Control Options page of the OPF Options and Results display.
Change the Total Points Per Cost Curve field to 100 and resolve. The results are shown in the figure below, which now are almost identical to the economic dispatch results. The disadvantage in using a large number of cost segments is that it degrades the performance of the LP OPF slightly on larger cases.
B7OPF Case Solved using LP OPF with 100 Cost Segments for Generators