See Also
The Transient Limit Monitors page is found on the Transient Stability Analysis dialog.
As a transient stability run is processed, any violations of the Transient Limit Monitors will be stored as a monitor violation and can be seen in the Monitor Violations table. An example is shown in the following case information display. Note that there is an option in the Records Menu for this object to Make a New Plot. Choosing to make a new plot will automatically create a new plot definition on the Plot Designer portion of the dialog.
The key fields for the Monitor Violations will be the Limit Monitor Name, Transient Contingency Name, and the identity of the violated device. In addition to these keys, up to four additional points will be reported. Each of these four points will be represented by a value and a time of value representing the y-x point of the trace for that point. This gives up to 8 additional values. The four points are depicted in the following figure.
A description of the four points are as follows.
- Point A represents the initial time at which the trace has violated the Limit Value. When processing the transient stability run, a monitor violation will not be generated at the point but the trace will start to be tracked. Also note that as soon as the trace no longer violates the limit value, point A will essentially be reset.
- Once a Point A has been encountered and the trace is being tracked, a value/time pair for Point B will be maintained as part of the result to indicate when the most extreme violation of the limit value occurs. Note that point B may occur before or after point C depending on the shape of the trace.
- Point C represents the time at which the trace completely violates the limit monitoring. At this point the limit value has been violated for the appropriate limit duration. Once this violation occurs then a Transient Limit Monitor Violation object will be generated for the results. Points A and B will be stored at this point as well, although point B may be modified if the trace continues to get worse. If the limit duration is zero, then point C and point A are the same point.
- After the violation occurs, the tracking of the trace will continue to see if at a later time during the simulation the value no longer violates the Limit Value. If this occurs then a Point D will also be stored with the monitor violation object. This provides information about how long the value was ultimately violated so that you know if you almost met the standard. For instance if you have a limit duration of 0.3333 seconds (20 cycles) you might want to know the difference between a violation that lasted 0.34 seconds and one that lasted 1.2 seconds.