See Also
Simulator allows you to automatically generate critical clearing time contingencies. The actual calculation of the critical clearing time values is done as part of the transient stability contingency analysis during the transient stability run. In order to get the Critical Clearing Time, the multiple contingency mode has to be used. A Transient Limit Monitor has to be active or a Result Analyzer Time Window has to be defined. When a result analyzer time window is defined the options for Automatically analyze time windows and keep Signal Violations after running a transient stability simulation has to be checked and also the both Include in Calculation options has to be checked. The critical clearing time is calculated by changing the clearing time of the fault until there is a transient limit monitor violation or a result analyzer signal violation. To accomplish this, click the Critical Clearing Time Calculator... button along the bottom of the Transient Stability Dialog. This opens the Critical Clearing Time Calculator Dialog.
The object name is included in the contingency name.
Define Branch Filter
This is a filter to set the branches to which a fault is going to be added (solid three phase fault at 0 percent near). The Insert Branch Contingencies check is check of these contingencies are going to be added, unchecked to not add them.
Define Bus Filter
This is a filter to set the Bus to which a fault is going to be added (solid three phase fault at 0 percent near). The Insert Bus Contingencies check is check of these contingencies are going to be added, unchecked to not add them
Clear fault action to use
Set the action to clear the fault by either clearing the fault or opening both ends of the branch if a branch fault was created. The initial time of the fault clearing event is 1/4 cycle after the fault event.
Contingency run time (s)
Set the end time of the critical clearing time contingency.
Fault start time (s)
Set the start time of the critical clearing time contingency.
In order to work and calculate the critical clearing time the fields 'Critical Clearing Time Calculate', 'Critical Clearing Time Max Fault Duration' and 'Critical Clearing Time Result' should be added and set correctly in for each contingency in the Transient Contingency Elements table:
The 'Critical Clearing Time Calculate' field indicates that the critical clearing time should be calculated for the contingency element. This should be the fault clearing contingency element and there should be only one 'Critical Clearing Time Calculate' field per contingency. Right now, this isn't explicitly enforced, but we will only calculate the critical clearing time for the last 'Critical Clearing Time Calculate' element. To calculate the Critical Clearing Time per contingency you will need to set this field to YES in the Transient Contingency Elements Table.
The 'Critical Clearing Time Max Fault Duration' is used to stop the critical clearing time calculation if the fault duration exceeds the input value.
The 'Critical Clearing Time Result' field is used to hold the critical clearing time result instead of changing the time of the clearing event.
Note: These fields are available for any contingency element, so it is not necessary to use the critical clearing time dialog to create critical clearing time contingencies. You can set the flag on the fault clearing action to convert a standard contingency to a critical clearing time calculation.