Custom Monitors

See Also

 

Custom Monitors can be defined, modified, and viewed from the Contingency Analysis dialog under the Contingency Options tab under the Limit Monitoring page. Custom Monitors are also available in the Model Explorer in the Contingency Analysis folder under Custom Monitors.

Custom Monitors can be used to monitor specific objects and fields in addition to the devices that are monitored using the Limit Monitoring Settings. Custom monitors do not represent violations, but rather, specific object fields that are of interest during the contingency analysis. Results for custom monitors will appear in the Contingency Violations Display and Contingency Results tab on the View Results By Element page. Custom monitors will only be stored when in ac power flow mode and NOT using one of the linear contingency methods. When in dc power flow mode or using one of the linear methods, the impact of contingencies are determined from linear sensitivity calculations and contingencies are not actually implemented. The system state is always in the base case state meaning that contingency values cannot be recorded when monitoring custom monitors.

Added in version 19, build on Dec. 23, 2016 In addition to monitoring objects, custom monitors can also be used to trip objects or abort the entire contingency simulation. This functionality is also only available when in ac power flow mode and not using one of the linear contingency methods. This functionality can be used for modeling cascading outages.

The Custom Monitors table is a type of case information display and thus shares many of the properties and controls common to all other case information displays. Existing custom monitors can be edited directly in the table or by choosing Show Dialog either from the local menu obtained by right-clicking or choosing this option from the Case Information Toolbar. To create a new Custom Monitor, choose Insert from the local menu or Case Information Toolbar.

The dialog for creating and modifying a custom monitor has the following options:

 

Custom Monitor Name

Name of the custom monitor. Each custom monitor must have a unique name. A default name will be created based on existing custom monitors. Click the Rename button to open a dialog that will allow you to change the name.

Enabled

Check this box for the specified object(s) and field to be monitored during a contingency analysis run. When this box is not checked, no results will appear for the custom monitor following a contingency analysis run.

Categories

A 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.

Choose Object

All Objects of Element Type

Select this option to monitor all objects of the selected Element Type.

Specific Object

Select this option to monitor only a specific object of the selected Element Type. When this option is selected, the dialog will be modified with a chooser box that will allow selection of a specific object.

Element Type

Type of element to be monitored. One must be selected. Available elements types include: Area, Branch, Bus, DC Transmission Line, Generator, Injection Group, Interface, Limit Set, Load, Model Expression, Multi-Terminal DC Record, Nomogram, Owner, Substation, Super Area, Switched Shunt, Transformer, and Zone.

Choose a Field

Select the field to be monitored for the selected Element Type. A field must be selected.

Choose a Pre Filter

Name of an advanced filter or device filter. This is an optional field that can be left blank. If this is specified, an object must meet this filter in the contingency reference state in order for it to be monitored in the contingency analysis run. This filter can be used in conjunction with the option for monitoring All Objects of Element Type to select a specific set of objects rather than all objects of the selected Element Type.

Click the Add/Modify button to specify this filter.

Choose a Post Filter

Name of an advanced filter or device filter. This is an optional field that can be left blank. If this is specified, an object must meet this filter in the post-contingency state in order for it to be monitored in the contingency analysis run.

Click the Add/Modify button to specify this filter.

 

Options Specific to Contingency Results

The following options are useful if the goal is to use the custom monitors to report some sort of "violation." The options will allow comparison of the reference state value to the post-contingency state and allows elimination of the custom monitor object based on that comparison. This is something that cannot as easily be accomplished through the Post Filter as there is no direct access to the post-contingency values through the object being monitored.

Never report violations if the increase in field value <=

This value must be entered as a positive number. If the difference between the post-contingency and the reference monitored state value (Post-contingency - Reference) is greater than this threshold, the object result will be reported.

Never report violations if the decrease in field value <=

This value must be entered as a positive number. If the difference between the reference state and the post-contingency monitored value (Reference - Post-contingency) is greater than this threshold, the object result will be reported.

Meaning of Change Values

There are two possible interpretations of the change between the reference state and post-contingency monitored values:

Change from Initial Value

This will do a direct comparison of the difference between the post-contingency and reference monitored values, i.e. check Post-contingency minus reference state value against the specified threshold when checking for the increase or Reference state minus post-contingency value when checking for the decrease.

% Change from Initial Value

This will compare the percentage of the change, (Post-contingency - Reference)/(Reference), against the specified threshold when checking for the increase. (Reference - Post-contingency)/(Reference) will be used when checking for the decrease.

 

Device Tripping Added in version 19, build on Dec. 23, 2016

In addition to monitoring values, custom monitors can be used to trip an object or completely abort the contingency simulation if a condition is met. This functionality can be used for modeling cascading outages.

Custom monitors for tripping and aborting are evaluated in the POSTCHECK portion of the contingency process as shown with this description of the processing order of contingencies.

The following options are available when using these features:

Start Tripping Filter

Name of an advanced filter or device filter. This filter is applied to objects that meet the chosen Element Type or Specific Object and objects that meet the Pre Filter to determine if there are any objects that meet this filter. This filter is applied in the post-contingency state.

If the Action to Take is Trip (Open) Device and no tripping actions have already occurred for this custom monitor, this filter must be met before any objects are tripped. After at least one object is tripped for this custom monitor, the Post Filter is used for all subsequent checks to determine if any additional objects should trip.

If the Action to Take is Abort Simulation, this filter must be met for the entire simulation to be aborted.

Action to Take

Log Violation Only

This will record the monitored value as a violation with the contingency results. No additional actions will be taken.

Trip (Open) Device

This will open the object if it meets the appropriate filters. If no objects have been tripped for this custom monitor, the Start Tripping Filter must be met. If at least one object has tripped for this custom monitor, the Post Filter must be met.

Abort Simulation

This will abort the entire contingency simulation if the Start Tripping Filter has been met.

Use a Time Delay of

This is the amount of time to wait in seconds before the tripping or abort action is actually applied. This time is compared against the time delay of other contingency events that might occur at the same point in the contingency process. Only the events with the smallest time delay will actually be applied. If the custom monitor trip or abort action has a longer time delay than other contingency actions, it will not be applied.

A description of how time delays are treated during the contingency process can be found with the Treatment of Time Delay of Contingency Elements and Model Filter Condition Time Delays topic.