Contingency Analysis Dialog: Contingencies Tab

 

The Contingencies tab of the Contingency Analysis dialog provides tools for managing and simulating lists of contingencies. The top portion of the page lists the contingency records that have been defined for the case. This table is called the Contingency Records Display. The contingency records display is a type of case information display and thus shares many of the properties and controls common to all other case information displays.

 

General Functionality

You can sort the display’s contents by any field just by clicking on the field’s heading. The default fields shown in the contingency records display are described at the bottom of this page.

As you scroll through the records in the contingency records display, you will notice that the contents of the tables that occupy the middle third of the contingency analysis dialog change. These tables are the Contingency Definition Display, the Contingency Violations Display, and the What Occurred Display. These displays show the violations, the specific actions, and what actions were applied if the contingency was implemented for the contingency that is selected in the contingency records display at the top of the dialog. You may optionally hide the Contingency Definition Display by clicking on the X to the upper right of this display. To show the display again, click on the O to reopen it. You may change the relative width of the Contingency Definition and Violations/What Occured displays by moving your mouse over the line between the displays until your cursor changes. Then left click and drag to modify these widths.

When you first load a new contingency list into memory, the current status indicator along the bottom of the display will indicate the contingencies have been Initialized. During a contingency analysis run, the current status indicator may take on the values Running, Paused, Aborted, or Finished.

The contingency tab of the contingency analysis dialog offers several ways to run the contingency analysis. To start a run, you may click the Start Run button. Alternatively, you may choose Run Contingency Analysis from the local menu of the contingency records display. Once a contingency analysis run has started, you may pause it at any time by clicking the Pause Run button, after which you may resume the run by clicking Continue. In addition to running the full set of contingencies, you may also choose to run just a single contingency. See Running the Contingency Analysis for more details.

Several other actions related to contingency analysis are also available from the Contingencies Tab. These are accessed by clicking on the Other Actions > button. They are described on the Other Contingency Actions page.

You may close the Contingency Analysis Dialog at any time either by clicking Close or by selecting Close from the local menu of the Contingency Records Display or the Contingency Violations Display.

 

Local Menu Options

By right-clicking on the display, you gain access to its local menu, which offers several choices:

• Insert allows you to insert a new contingency record
• Insert Special gives the following options:
  • Quick Insert of Single Element Contingency will allow you to quickly specify a single element contingency via the Contingency Element Dialog
  • Auto Insert Contingencies will open the Auto Insert Contingencies dialog
  • Merge Contingency Block Elements will eliminate contingency blocks by adding the elements that are in contingency blocks to the contingency elements, Global Actions, or Remedial Actions that are using the blocks. We encourage you to discontinue use of Contingency Blocks.
  • Convert Global Actions into Remedial Action will convert legacy Global Actions into a more versatile Remedial Action. A single Remedial Action will be created. We encourage you to use Remedial Actions instead of Global Actions.
  • Merge Pairs of Selected Contingencies will generate every possible pair of contingencies based on the selected contingencies. For instance, if you select 4 contingencies (A, B, C, D), then click Merge Pairs of Selected Contingencies, 6 new contingencies will be generated: A+B, A+C, A+D, B+C, B+D, and C+D.
  • Clone Contingencies will make a copy of each selected contingency.
  • Join Active Contingencies creates new contingencies that are the join of the current contingency list and a list read in from an auxiliary file or the present list itself. Contingencies with their Skip property set to YES will not be included in the join. A dialog will allow selection of the list to join with the present list. The dialog will also allow you to insert a solve power flow action between the joined actions and delete the original existing contingencies upon completion of the join.
  • Create Stuck Breaker Contingencies... creates new contingencies from contingencies that have explicit breaker outages defined. New contingencies will be created by treating each breaker as stuck in turn. The new contingencies will be comprised of all existing elements, minus the stuck breaker outage, plus open actions for breakers that are identified to isolate the stuck breakers. Only branches with Branch Device Type of Breaker will be considered in determining the stuck breakers. Selecting this option will open a dialog with options as described in the Create Stuck Breaker Contingencies topic.
  • Create Expanded Breaker Contingencies converts any "Open with Breakers" or "Close with Breakers" contingency actions into OPEN or CLOSE actions on explicit breakers. This will permanently modify the contingency definitions.
  • Merge Contingencies that Result in Identical Breaker Actions will modify existing contingencies. If a contingency is defined with OPENCB or CLOSECB actions and results in the same set of actions as another contingency, the contingencies will be merged into a single contingency. One contingency will be retained and the other deleted. The one that is retained contains the highest priority element with the priority determined by: (1) line with largest X, (2) generator with largest MaxMW, (3) load with largest Nominal MW, and (4) switch shunt with largest nominal Mvar.
  • Convert into Primary Contingencies converts regular/secondary contingencies to Primary contingencies that are used with CTG Combo Analysis. After selecting this option a dialog will open that contains the following options for the conversion. Once the options are set, click the OK button to do the conversion or Cancel to abandon the conversion. Not all actions that are supported for regular/secondary contingencies are supported for Primary contingencies. Examine any messages in the log after the conversion to determine if actions were not converted.
    • Only Selected
    • The contingencies that have been selected by using the mouse will be converted.
    • Currently Displayed
    • All contingencies that are currently in the display will be converted. If an advanced filter or area/zone/owner filter is being used, only the contingencies that are displayed because they meet the filter will be converted.
    • Keep the original contingency
    • The original regular/secondary contingency will be retained and a new Primary contingency will also be created.
    • Delete the original contingency
    • The original regular/secondary contingency will be deleted and a new Primary contingency will be created.
    • Prefix
    • The Primary contingency will be named using the name of the regular/secondary contingency modified including this prefix.
    • Suffix
    • The Primary contingency will be named using the name of the regular/secondary contingency modified including this suffix.
• Delete allows you to delete a particular contingency
• Show Dialog displays the Contingency Definition Dialog corresponding to a particular contingency
• Contingency Records gives the following options:
  • Open Dependency Explorer will open the Dependency Explorer with the selected contingency as the Top object
  • Solve Selected Contingency (see Contingency Case References - Reference State Solution Options)
  • Solve and Set as Reference (see Contingency Case References - Reference State Solution Options)
  • Apply Selected Contingency will apply the actions in the contingency definition, but does not solve the contingency or calculate violations.
  • What Occurred will display the details of the actions that were applied and skipped during the contingency (see Contingency Results: What Occurred)
  • Run Contingency Analysis (see Running the Contingency Analysis)
  • Filter Results Using Limit Monitoring Settings (see Other Contingency Actions)
  • Compare Contingency Definitions will compare the current contingency list against a contingency list stored in a user-specified auxiliary file. The results of comparison are saved in a user-specified CSV (Comma-Separated Value) file. To determine if contingencies are the same, only their actions are compared. Model Criteria is not included.
  • Compare Two Lists of Contingency Results (see Comparing Contingency Analysis Results)
  • Verify Contingencies for Iterated Linear Actions will evaluate the contingency list and save a summary of fields that are handled and not handled properly if using the iterated linear method. The user is prompted to specify a text file in which to save the summary. (see Contingency Iterated Linear Analysis)
• Many other options (e.g., printing, finding, and sorting) which are characteristic of case information displays.
• Save As gives several options characteristic of case information displays as well as options unique to the contingency records display:
  • Auxiliary File, Auxiliary File (only selected records), and Auxiliary File (only selected records/columns) will only save contingency definitions. Any supporting data such as contingency blocks, global actions, model criteria, etc. will not be saved. To make sure that this supporting data is saved, use one of the (all contingency related info) options described below.
  • Auxiliary File with Options and Auxiliary File with Options (Last Used) will save contingency definitions using options that specify the objects to save and formats to use according to the Saving Auxiliary Files with Options dialog. The (Last Used) option allows quickly saving using the options that were last specified without having to change options in the dialog.
  • Auxiliary File (all contingency related info) first opens a file dialog for specification of the auxiliary file. Clicking Save from the file dialog opens a Contingency Settings dialog for specification of related settings to save in the same auxiliary file, including Contingency Options, Limit Monitoring Settings, General Power Flow Solution Options, List Display Settings (Case Information Customization), Contingency Results, and whether or not to save unlinked elements. Definitions of all contingencies are also saved. This has the same functionality as clicking the Save button in the bottom panel.
  • Auxiliary File (all contingency related/only selected records) has the same functionality as Auxiliary File (all contingency related info), except contingency definition(s) are only saved for the selected contingency record(s). You may also specify related settings to save.

Field Descriptions

By default, the contingency records display presents the following fields:

Label

The name of the contingency.

Category

Comma-separated list of user specified category names. Categories determine which Custom Monitors are applied to each contingency. See the Contingency Category topic for more information.

Skip

Indicates whether Simulator should skip the corresponding contingency in performing the contingency analysis. If the value of the Skip field is YES for a contingency, then that contingency will not be implemented when performing the contingency analysis. This is a toggleable field, which means that you can toggle its value by double-clicking the field.

Processed

Indicates whether the contingency has been analyzed yet as part of the current contingency run. Possible entries are YES and NO.

Solved

The possible entries for this field are as follows. Based on the entry fields for the contingency record will be highlighted if the contingency has been processed:

NO - Contingency has not been processed (Processed = NO) or contingency has been processed (Processed = YES) but the power flow is unable to converge within tolerance. Highlighting color is light red.

YES - Contingency has been processed (Processed = YES) and the power flow is able to converge within tolerance. Highlighting color is the normal fill color.

ABORTED - Contingency that has been aborted due to an Abort contingency action being implemented. Highlighting color is light orange.

RESERVE LIMITS - Indicates that there was not enough MW reserves in the make-up power specification to cover the MW changes caused by the contingency. This can only result if enforcing generator MW limits for the make-up power option selected. This will only be reported for full ac contingency analysis. Violations will still be recorded if there are any, but you must be aware that a portion of the make-up power has been covered by the system slack bus instead of the specified make-up power option. To see how much deficit there is in the reserves, the Make Up Power Deficit field can be added to the contingency records display. Highlighting color is light yellow.

PARTIAL -Added in Version 20 Indicates that there are multiple islands in the solution and some islands solved while other islands did not solve. If using the option to Report Violations for Islands, the islands that were unsolved will be reported as violations. Highlighting color is light yellow.

Include Remedial Actions Added in Version 20

Indicates if all Remedial Actions and Global Actions should be included with this contingency. Possible entries are YES and NO.

Screen Allow Added in Version 20

Indicates if the contingency screening process should be run for this contingency. Possible entries are YES and NO. If this is set to NO and the screening process is being used, the screening process will not be run for this contingency and the full ac contingency analysis will always be run for this contingency.

Post-CTG AUX

The auxiliary file specified here will be loaded at the start of this contingency, which can be used to alter the reference state for this contingency. If an auxiliary file is specified here, the contingency options Post-Contingency Auxiliary File will not be loaded for this contingency. 

Double-click a cell to edit the specified post-contingency auxiliary file. A specified post-contingency auxiliary file may be removed using the Contingency Definition Dialog.

Only data stored with the contingency reference state will be "reset" when the reference state is restored. Therefore, only data stored with the reference state should be loaded via a post-contingency auxiliary file. Click here for details on the specific information stored with the reference state.

Islanded Load

Displays the sum of the amount of load that was islanded from the rest of the system due to the contingency. This will only include load that is islanded due to changes in topology. It does not include load where the status of the load is opened as part of the contingency.

Islanded Gen

Displays the sum of the amount of generation that was islanded from the rest of the system due to the contingency. This will only include generation that is islanded due to changes in topology. It does not include generation where the status of generator is opened as part of the contingency.

Global Actions

Number of Global Actions applied during a contingency.

Transient Actions

Number of Transient Actions applied during a contingency.

Remedial Actions

Number of Remedial Actions applied during a contingency.

Custom Monitor Violations

Number of Custom Monitors that are listed with the Violation results. The Violations value does not include the number of Custom Monitors in the Violations.

Violations

This field has several entries based on the value of the Solved field. If Solved is the following, the explanation determines what the Violations field contains:

NO - The string Unsolvable will be displayed

YES - An integer number identifying the number of violations caused by this contingency. This number represents the total number of violations (branch thermal violations + bus violations + interface violations) that were caused by the contingency. Depending on how you have configured the reporting of Base Case violations, this number may include all, some, or none of the violations that were present in the Base Case model.

Custom Monitors are listed with the Violations results, but they are not included in the total number of violations caused by this contingency. Separate fields exist that provide the number of violations of specific types, i.e. Branch Violations, Bus Violations, Interface Violations, and Custom Monitor Violations.

ABORTED - The string Aborted will be displayed

RESERVE LIMITS - The string All make-up power at limits will be displayed

PARTIAL - The string Partial will be displayed Added in Version 20

Max Branch %

Indicates the percentage overload of the worst-case branch violation. If there are no branch violations, this field will be blank.

Min Volt

Indicates the lowest bus voltage resulting from the contingency. If there are no low voltage violations, this field will be blank.

Max Volt

Indicates the highest bus voltage resulting from the contingency. If there are no high voltage violations, this field will be blank.

Max Interface %

Indicates the percentage overload of the worst-case interface violation. If there are no interface violations, this field will be blank.

Max Bus Pair Angle Added in Version 20

Indicates the maximum angle difference for all bus pair violations resulting from the contingency. If there are no bus pair violations, this field will be blank.

Memo

User specified text entered for a particular contingency.