QV Curves Options: Contingencies

 

These options are found on the Contingencies sub-tab located on the Options page of the QV Curves dialog.

 

 

Process each of the currently defined contingencies

Check this box to have contingencies included in the QV analysis.

QV curves can be calculated for the specified buses for both base and contingency conditions. To analyze a set of contingencies, these must be defined using the separate Contingency Analysis Dialog. Any contingency whose Skip field is set to NO will then be included in the QV analysis.

Another option that is relevant to the QV analysis that must be set for a contingency on the contingency analysis dialog is the QV Autoplot field. This field must be set to YES in order to have a QV curve plotted automatically for a contingency scenario. More information about the option to plot curves automatically is found on the Output sub-tab. There is no requirement to have a plot made automatically during the run; this can always be done after the analysis is complete.

Note: The Robust Solution Process option that can be utilized with the contingency analysis when a contingency solution failure occurs is not applied when a contingency is implemented during the QV analysis. All other options defined with contingency analysis such as contingency-specific solution options and make-up power specifications are used when applying a contingency during the QV analysis.

Skip base case

Check this box to prevent the computation of QV curves for base case conditions.

Attempt to make unsolvable contingencies solvable with synchronous condenser

Some contingencies may not solve when implemented. If this box is checked, an attempt will be made to make an unsolvable contingency solvable by providing additional var injection/absorption through use of a fictitious generator (synchronous condenser). As each selected bus is processed, the fake generator (synchronous condenser) that is normally added to trace the QV curve at a bus, will first be used to determine if Mvar injection/absorption can be adjusted such that a solvable point is found. This process can be quite time consuming. The process first tries to find a solvable point by increasing the studied setpoint voltage and tracing up the curve up to the maximum voltage. It is more likely that a solvable point will be found tracing up the curve due to the increased Mvar injection required to meet the setpoint voltage. If a solvable point is found, this solvable point with the fake generator injection/absorption in place will then be the starting point for the QV curve tracing.

The Q0 results field found on the Listing sub-tab of the Results tab indicates the injection of the fake generator at the base case or initial contingency solution point. This field being non-zero is indicative of an unsolvable contingency with the value of the field being the Mvar injection required to solve the contingency.

Finding a solvable point can be time consuming if there are a number of contingencies that do not solve and a large number of buses are selected for analysis. Uncheck this box if long solution times become an issue.

It is possible that the base case does not solve. If this option is checked and not skipping the base case, there will be a prompt when running from the GUI asking if the base case should be made solvable. If running from script there is a parameter with the script command indicating if the base case should be made solvable. If the base case should be made solvable, an attempt will be made by using each selected bus as described in the process to make contingency scenarios solvable.