See Also
After performing an automated contingency analysis, the results of the analysis can be saved to an auxiliary file. Once the results have been saved to a file, they can then be compared to different results in another file or to results existing in memory in the Contingency Analysis tool. To compare two sets of contingencies, do the following:
- Process each set of contingencies and save the results for at least one set in an auxiliary file.
- To save a contingency list, right-click on the list of contingencies and choose Save As > Auxiliary File.
- In the Save Contingency File Dialog, choose a name for the file, and then click Save.
- You will then be prompted to choose options for saving the contingency list to an auxiliary file. By default, the contingency definitions themselves are saved, along with the contingency options. The optional information you may choose to save are the Limit Monitoring Settings, General Power Flow Solution Options, List Display Settings, and Contingency Results. When saving the contingency results with the file, you may also choose to include inactive violations.
Inactive violations are considered violations on elements for a DIFFERENT limit than what is currently being monitored. For example, a branch may have an A limit rating of 50 MVA, and a B limit rating of 100 MVA. Consider if the B limits are being used to report violations during a contingency. A value of 75 MVA flow on the branch would not be reported in the contingency analysis as a violation, considering the B limit of 100 MVA is being used. However, Simulator internally will flag the element as a potential violation if the limit set used is switched to the A rating set. Simulator considers these types of situations as inactive violations. These are kept track of to allow the user to easily switch the rating set used for reporting violations from one set to another and see the results immediately, without having to re-run the entire contingency set to determine the violations for the new rating set. Choosing to include the inactive violations when saving an auxiliary file maintains this flexibility when the contingency definitions and results are read into a case from an auxiliary file. You can also choose for the identifiers used in the file to be either the bus numbers or the bus name and nominal kV voltage.
Note: For comparing two lists of contingency results, you MUST save the contingency results with each of the two auxiliary files being compared. - Click OK to save the contingencies and the results to the auxiliary file specified.
- Once you have two different lists of contingency results (at least one of the lists must be saved in an auxiliary file), right-click on the contingency list and choose Compare Two Lists of Contingency Results or choose Other > Compare Two Lists of Contingency Results. This will bring up a dialog on which you have to specify the Contingency Lists you are interested in comparing. You must specify the Controlling Contingency List and the Comparison Contingency List. The definitions of these two lists are found below.
- Click on the Browse buttons to specify the two Contingency Lists you would like to compare. You can also choose to use the presently open Contingency List as either the Controlling Contingency List or the Comparison Contingency List.
Controlling Contingency List:
The list that controls what is displayed on the dialog. Only contingencies that are defined in this list will be displayed on the form. Only violations that occur for contingencies in this list will appear in the Violations List for each contingency.
Comparison Contingency List:
This is the list to which the Controlling Contingencies will be compared. Comparisons will occur for those contingencies in the lists that have the same CONTINGENCY NAME. Note that contingencies in the Comparison list whose CONTINGENCY NAME does not match one of those in the Controlling list will not be displayed. Also, violations which occur in a specific Comparison contingency that do not occur in the respective Controlling contingency will not be displayed.
Example:
A user has a power system case and a list of contingencies. The user runs contingency analysis on this system for this list of contingencies. The results are saved in a file called comparison.aux. The user now changes the system state, possibly adding in a 500 MW transaction between two areas. The contingency analysis is run on this new state of the system for the list of contingencies. The results are saved in a file called controlling.aux. You should define the contingency results you are more interested in viewing as the Controlling List because this list determines what is shown on the dialog. In this case, we are more interested in seeing the violations caused when the transaction is in place, so that list is defined as the Controlling List.
The comparison of the two sets of contingencies is now done by right-clicking and choosing Compare Two Contingency List Results. The file controlling.aux is set as the Controlling List and comparison.aux as the Comparison List.
- After clicking OK on the dialog, the contingency lists will be read from the specified files or from the presently open list. After Simulator has completed reading these files, a prompt will appear which asks, "Would you like to set the dialog with default columns for comparing contingency lists?". It is recommended that you choose YES so that the case information displays on the Contingency Dialog will automatically be set to show fields that will help you compare the two lists of contingencies. For information on the default fields used when comparing contingencies see Comparing Contingencies List Displays.