Contingency Screening Elements
| Units: | - |
| Mode: | Input Only |
| Multi-band: | False |
| Default Value: | 0 |
| Validation Rule: | In (0,1,2) |
| Key Property: | No |
| Description: | Determines which lines/transformers would be screened for post-contingency flow under this contingency |
Contingency Screening Elements determines which Lines/Transformers would be screened for post-contingency flow under this contingency.
- None (value = 0)
- None of the Lines/Transformers would be examined for post-contingency flow under the contingency.
- Monitored Memberships (value = 1)
- Monitored Lines/Transformers defined under the contingency would be examined for post-contingency flow.
- Network Selections (value = 2)
- Lines/Transformers defined with Screening Mode would be examined for post-contingency flow under the contingency.
- The ST Phase must be enabled, with the Transmission Detail set to Nodal.
- There has to be at least one screen contingency in the model. A screen contingency is a contingency with Screening Elements set to Monitored Membership or Network Selections.
- Binding Contingencies under diagnostic object must be enabled.
- 1. "PreContingencyLoadingPctThreshold" under "Transmission" class.
- 2. "PostContingencyLoadingPctThreshold" under "Transmission" class.
- 3. "LoadingChangeWithContingencyPctThreshold" under "Transmission" class.
- 4. "TopContingencyMonitoredCount" under "Transmission" class. For a screened Line/Transformer under a screen contingency, if its pre/post-contingency flow is violating any of the first 3 thresholds defined by the user, then this contingecy-monitored pair is a candicate to be reported. Most of the time, we found enforcing only a small subset of these contingency-monitored pairs is already sufficient to guarantee that all the remaining ones are automatically satisfied. So TopContingencyMonitoredCount is designed for such purposes. All contingency-monitored pairs identified in the ST phase would be ranked by their aggregated loading changes due to contingency over the run horizon from high to low. TopContingencyMonitoredCount determins the top number of pairs to be reported if more pairs are identified than what users want to report.
For contingency screening logic to work:
After ST phase simulation completes, PLEXOS will generate a report file with all the contingency-monitored pairs that has a flow violation. This report file can be found in the solution folder, with file name ends with "Screen Contingency Selection Report.txt". Users can make use of this report and import records in this file back to PLEXOS manually and iterate the process to find all contingency-monitored pairs that need to be monitored in the run for a SCUC solution.
To start the contingency screening process, users need to specify Screening Elements for contingencies wanted to be screened and Screening Mode for Lines/Transformers. Then, users can start to run the first simulation and obtain the screen contingency selection report. Here is an example showing how to use the records displayed in screen contingency selection report for the next iteration of simulation. In the example dataset, ContLine_E_TE2 is a screen contingency, and North_South_230 a screened line with flow violation.
The report file shows the contingency-monitored pairs with flow violations that comes out of the contingency screening logic. This part of records can be added to contingency membership table for the next round of simulation.
Users can iterate this process until they are statisfied with the collection of contingency-monitored pairs they found or when there is no new contingency-monitored pairs generated.
The following undocumented parameters are used to determine if a contingency-monitored pair has a flow violation. Please refer to the Hidden Parameters for default values and more details on those hidden parameters.
Please note that adding contingency-monitored pairs to the next iteration through contingency membership table does not guarentee the monitored memberships' post-contingency flow limits would be enforce in the next iteration. Users need to make sure Enforce Limit on Lines/Transformers or SCUC Constraint Voltage Threshold are specified for the expected behavior. Users can also control the From kV level of reported contingency-monitored pairs by putting Lines/Transformers below certain kV with Screening Mode = None.