Switched Shunt Model: MSC1

Treatment of Model in Power Flow Contingency Analysis

When a transient stability model is used in the power flow contingency analysis using the special option for the power flow contingency solution, then the model determines how to report violation for the Monitor Only option as well as specifying a TimeDelay and Trip/Act action. The following table describes this and uses the following text conventions.

Greenext are parameters of a stability model.
Blue text are a parameter of the contingency options.
Other bold text are “local variables” used in this description.

Model Evaluation	Description	Specific Implementation for this model
Monitor Only	Determine a Boolean result to indicate whether the stability model is “violated” and ready to do something?	Find the highest low voltage value (Vmin1 or Vmin2) specified which has a time-delay associated with it which is less than the TSModelMaxDelay specified as part of dynamic model input data (call this UseLowVolt). For the value found for UseLowVolt, take the corresponding Voltage Trip Time and call this UseLowVoltTime (Tin1 or Tin2). Find the lowest high voltage value (Vmax1 or Vmax2) specified which has a time-delay associated with it which is less than the TSModelMaxDelay specified as part of dynamic model input data (call this UseHighVolt). For the value found for UseHighVolt, take the corresponding Voltage Trip Time and call this UseHighVoltTime (Tout1 or Tout2). Evaluate whether “Present Voltage PU > UseHighVolt” or “Present Voltage PU < UseLowVolt”
TimeDelay used in Trip/Act	Time in seconds that the model needs to remain “violated” before it will actually apply an action.	If Violated because of exceeding UseHighVolt, then TimeDelay is UseHighVoltTime If Violated because of exceeding UseLowVolt, then TimeDelay is UseLowVoltTime
Trip/Act Action	If violated for the particular time, then this procedure must be written to actually implement the action.	If above UseHighVolt, then move the switched shunt down one step in Mvar injection If below UseLowVolt, then move the switched shunt up one step in Mvar injection

Model Equations and/or Block Diagrams

Parameters:

Tin1	Time 1 for Switching in (sec.)
Vmin1	Voltage lower limit 1 (p.u.)
Tout1	Time 1 for Switching out (sec.)
Vmax1	Voltage upper limit 1 (p.u.)
Tin2	Time 2 for Switching in (sec.)
Vmin2	Voltage lower limit 2 (p.u.)
Tout2	Time 2 for Switching out (sec.)
Vmax2	Voltage upper limit 2 (p.u.)
Tlck	Lock out time (sec.)