Contingency Element Dialog

See Also

 

The Contingency Element Dialog provides information on the individual elements that comprise a contingency definition. You may use this dialog to modify an existing contingency’s definition or to add elements to new or existing contingencies.

This dialog is also used when defining Remedial Action Elements and Global Actions. The options that appear will be different depending on what type of object is being defined with the dialog and the dialog caption will change to reflect the type of object being defined. Differences will be noted in the option descriptions.

There are several ways to open the Contingency Element Dialog:

• By pressing the Insert New Element button on the Contingency Definition Dialog.
• By right-clicking on a Contingency Definition Display and choosing Insert or Show Dialog.
• By right-clicking on the Contingency Tab of the Contingency Analysis Dialog and choosing Insert Special > Quick Insert of Single Element Contingency.

 

After making the desired changes, click OK to save changes and close the dialog or click Cancel to close the dialog without saving your changes.

 

 

 

The Contingency Element Dialog has the following options and controls:

Description

Identification of the element action that is defined by the dialog options. This is a drop-down control that allows the selection of any element that is defined for the currently selected contingency. This allows any element for the current contingency to be modified, inserted, or deleted without having to close the dialog. New contingency elements can be added by clicking the Insert button. Clicking the Save button will modify the selected element with any changes that have been made in the dialog. Clicking the Delete button will delete the selected element.

Element Type

Indicates the type of element involved in the contingency action. The Element Type will dictate what Action Types are available, and the selection of the Element Type, in conjunction with the Action Type, Amount, and in options settings, determines what actually happens during the contingency.

What actually happens during a contingency action based on the Element Type, Action Type, and in options is described in detail in the topics referenced below:

Branch

Generator

Load

Switched Shunt

Bus

Interface

Injection Group

Multi-Section Line

Series Capacitor

Phase Shifter

3-Winding Transformer

Line Shunt

DC Line

VSC DC Line (Added in version 20, build on January 11, 2018)

DC Converter

Area

Substation

Script

Abort

Solve Power Flow

Contingency Block

The individual actions of the Contingency Block are applied according to how they are defined. There are no Action Types available for a Contingency Block.

Choose the Element

Use this portion of the dialog to choose the element involved in this action. This behaves the same as the Advanced Find Dialogs used throughout the software.

Action Type

Defines the change specified by the contingency action. The Action Types available depend on the Element Type selected. Possible Action Types include: Open, Open Breakers, Close, Close Breakers, Move, Set To, Change By, Bypass, and Inservice. The behavior of each of these actions for the different elements is described with Element Type.

Amount

Enterable fields used to specify the quantity of change desired for the contingency element. The Amount fields are enabled when the appropriate Action Type is set depending on the Element Type selected. The top field is used to define a Constant, Field, or Model Expression depending on the entry selected in the bottom drop-down box. Use the Find button to display a dialog listing Fields or Model Expressions. This dialog behaves the same as the Advanced Find Dialogs used throughout Simulator.

The Amount of change that occurs is based on the value of the top field entry. The top entry field is a constant, field name, or model expression name. When this entry is a field name, the value of the change is based on the value of the selected element field when the contingency occurs. When this entry is a model expression, the value of the change is based on the value of the selected model expression when the contingency occurs. If the Evaluate in Reference State box is checked when specifying a Field or Model Expression, the value is based on the value of the respective entry in the contingency reference state (base case).

The Amount of change that occurs for the selected element is based on the value entered in the top field and the parameter set with the in options. The availability of the in options will change based on the Element Type selected and the Action Type selected. The availability of these options is described in detail with Element Type.

Make-up Power Sources

Power injection contingency actions result in power imbalances - typically picked up by the system slack - that may result in Power Flow Convergence Problems. Simulator provides the option of specifying Make-up Power Sources for generation, load, injection group, and switched shunt contingencies to both offset the resulting real power imbalance and provide a more realistic simulation. See Make-up Power Sources for more information.

Status

This field determines how an action is applied in the presence or absence of Model Criteria. See the Contingency Element Status topic for more details.

Persistent Added in Version 19

Normally after any contingency element, RemedialActionElement, etc. is applied during the contingency solution process it will not be applied again. Marking an action as Persistent changes this behavior. Any action that is marked as Persistent and also has the Status field set to SOLUTIONFAIL, POSTCHECK or TOPOLOGYCHECK will be applied in the appropriate section of the overall contingency process any time that its Criteria is met. An exception to this is that a SOLUTIONFAIL element will only remain persistent up until a solution is successfully achieved. Once a solution is achieved then the SOLUTIONFAIL elements that had been applied will no longer be evaluated. This is done to ensure the SOLUTIONFAIL loop is not entered repeatedly.

Criteria Check Once Added in version 22, build on August 11, 2022

This option will only be available when the dialog is being used to define Remedial Action Elements.

When this option is checked the Model Criteria will only be checked once during the process of applying a Remedial Action Element in response to contingency actions. This means that the Model Criteria will only be evaluated once for elements with TOPOLOGYCHECK, POSTCHECK, or SOLUTIONFAIL Status. If the criteria is not met, this action will not be implemented and the criteria will not be evaluated again. The Persistent field is ignored when this option is checked. The action will not be implemented and the criteria will not be evaluated again for a criteria that is met but the Time Delay is greater than the time delays of other actions whose criteria is also met. This option has no impact if the Model Criteria is not defined.

This option is intended to allow the modeling of a Remedial Action Element that should only be implemented due to contingency actions and not respond due to remedial actions.

Model Criteria

Simulator allows you to define Model Criteria, which can consist of both Model Conditions and Model Filters. These specify a criterion under which a contingency action would occur. For example, you could specify that a generation outage only occur if the pre-contingency flow on a line is higher than a specified amount. Normally, no Model Criteria will be specified, and this field will be blank. The Status field will determine when Model Criteria is evaluated.

Special options exist for Model Conditions and Filters during contingency analysis that affect how they are evaluated. See the Model Conditions and Model Filters topics for more information on this.

Arming Status Added in Version 20

This option will only be available when the dialog is being used to define Remedial Action Elements.

This field determines how an element is armed in the presence or absence of Arming Criteria. See the Contingency Element Status topic for more details.

Arming Criteria Added in Version 20

This option will only be available when the dialog is being used to define Remedial Action Elements.

If specified, Arming Criteria can be either a Model Condition or Model Filter. This specifies a criterion under which a remedial action element is armed. In order for a remedial action element to actually be applied it must first be armed. The Arming Criteria is always evaluated in the contingency reference state. The Arming Status field determines if the Arming Criteria needs to be evaluated or if the remedial action element is simply always armed or never armed.

In order for a remedial action element to actually be implemented, it must be armed based on its own criteria and the Remedial Action to which it belongs must also be armed. Remedial Actions have their own Arming Criteria and Arming Status that are described with the Remedial Action Definition dialog topic.

Special options exist for Model Conditions and Filters during contingency analysis that affect how they are evaluated. See the Model Conditions and Model Filters topics for more information on this.

Inclusion Filter

This option will only be available when the dialog is being used to define Global Actions or Remedial Action Elements.

The Inclusion Filter is an advanced filter or device filter that gets applied to each contingency. If the contingency meets the Inclusion Filter defined with a particular global action or remedial action element, that contingency will include that global action or remedial action element. Otherwise, a global action or remedial action element will be ignored for that contingency. To select an Inclusion Filter, click the Add/Modify button. This will open the advanced filter dialog that will allow selection of the filter. To include a global action or remedial action with all contingencies, leave the Inclusion Filter blank. The Inclusion Filter is evaluated in the reference case to determine if a contingency meets the filter.

Time Delay

The time to wait in seconds before an action is applied. Default value is 0. When other than 0, this serves as a relative ordering for the implementation of actions during steady state analysis. When a ContingencyElement’s Criteria refers to a ModelCondition, then this TimeDelay will be used directly. When a ContingencyElement’s Criteria refers to a ModelFilter, then the Time Delay used will be the summation of the ContingencyElement’s TimeDelay and the Calculated Time Delay of a Model Filter. For more information on how a ModelFilter’s Calculated Time Delay is determined see Treatment of Model Filter and Contingency Element Time Delays.

Actions with the smallest time delay (down to a microsecond) will be applied first during the TOPOLOGYCHECK and POSTCHECK solution steps. The time delay is ignored during the CHECK solution step. This is NOT an absolute time at which an action occurs, but serves as a relative ordering for the implementation of actions. Actions with the smallest time delay will be applied first during the TOPOLOGYCHECK and POSTCHECK solution steps. See the contingency processing order topic for more information on how the time delay is used in the solution steps.

Contingency Blocks and Post Power Flow Solutions Actions do not allow a Time Delay.

Comment

An optional user-specified comment string associated with the action. For example, for an action with Model Criteria specified, you could add a sentence explaining why the action is only performed under the specified criteria. While this comment is not used by Simulator in any way, it is saved with the contingency element when saving contingency records in contingency auxiliary data files or with the case PWB file.

Open Breakers for Contingencies

When using the Open Breakers contingency action, Simulator will automatically search the topology of the system to determine which breakers must be opened to isolate this device. For more information on this functionality see the topic Contingency Element: Open Breakers.

Close Breakers for Contingencies

When using the Close Breakers contingency action, breakers are identified individually for each element that is using this action and the element is not already energized. A list of breakers to be closed is created for each affected element regardless of whether closing the breakers will actually energize the element. The lists of breakers for each individual element are merged into a set of unique breakers. New temporary contingency actions are created for these breakers so that when the contingency action is actually implemented, the selected breakers are closed instead of the element itself changing status. Once the contingency has been implemented and solved, the temporary contingency actions are removed so that the user never sees the actions created for the breakers. During the actual contingency solution, the What Occurred list will be updated and can be examined in the results to determine what breakers were needed to energize the device, even though the actions created for the breakers are removed after the contingency has been examined.

The Close Breakers contingency action is only available for contingency records and remedial actions and is not available for contingency block definitions or for global contingency actions. Only branches of Branch Device Type of Breaker are used with contingency actions, and Disconnects are not used.

More information about how breakers are selected can be found in the Close Breakers Overview topic.