See Also
Options for specifying the Transient Models that can be included in steady-state contingency analysis can be accessed from the Modeling group of the Contingency Analysis dialog Options page.
Using these options first requires that you have transient stability models defined for the types that are supported. See the Transient Stability Overview topic for links to information on modeling or view the Transient Stability Block Diagrams topic.
Stability Model Type
The following stability models are supported for use in steady-state contingency analysis:
- MSR1 : Switched Shunt Model
- MSC1 : Switched Shunt Model
- TIOCRSRF Line Relay Model
- TIOCRS : Line Relay Model
- LOCTI : Line Relay Model
- TIOCR1 : Line Relay Model
- LHVRT : Generator Relay Model Added in Version 18, build on March 16, 2015
Treatment During Contingency
For each model type there are several options on how to treat this model type during a contingency run. This will affect all models of this type. (To disable a particular model independently of these options, set the Device Status field to Inactive.) The following options are available:
- Ignore - This is the default setting. Nothing will happen with this model type during contingency analysis.
- Trip/Act - If the conditions of a model are met, actual actions will be taken (such as tripping a line for overcurrent). Models that act will appear in the What Occurred results. Some models have a Monitor flag that indicates if they should simply be monitored or if they should act. If this flag is set to monitor only, an individual model will not act regardless of this contingency setting.
- Monitor Only - If the conditions of a model are met, special contingency limit violations are reported. These will show up as Category Transient in the violations.
Maximum Time Delay (seconds)
This determines which models will be ignored during the analysis. A model's pick-up time, or the amount of time under which some condition must be met before the model acts, must be less than or equal to this value. It is not uncommon for users to define large values for these times with the intent of disabling a model. This option is available for those situations, although Simulator has a Status field with transient models to simply disable a model without changing other parameters.
Transient stability models are handled as part of the POSTCHECK solution steps in the contingency processing order. All models whose Treatment During Contingency is set to Trip/Act are evaluated to see if their conditions are met. All transient models and power flow actions whose conditions are met are ordered based on their time delays. All models and actions that will act first, i.e. have the same lowest time delays down to a microsecond, will have their actions implemented. Models and actions that have a zero time delay will act immediately. For inverse-time overcurrent relays, the time delay value is obtained based on the actual current. The power flow is solved after all necessary models have been implemented.