Branch Model: TIOCR1

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?	Evaluates whether “Present Current on Branch >ThresholdCurrent”.
TimeDelay used in Trip/Act	Time in seconds that the model needs to remain “violated” before it will actually apply an action when the Trip/Act option is chosen	TimeDelay is calculated by taking the Present Current on Branch and run this through the Lookup Table specified in the dynamic model parameters along with the Time Dial Multiplier. Essentially we use a time assuming that the current remains at this level forever.
Trip/Act Action	If violated for the particular time, then this procedure must be written to actually implement the action.	Model will open appropriate branches as would be done in transient stability

Model Equations and/or Block Diagrams

Parameters:

RelaySlot	Relay Slot [1 or 2]
Monitor	Monitor=0, and trip=1
ThresholdCurrent	Threshold current, pu
ResetTime	Zero Current Reset time in seconds. Let M = (I/Ithres). Then Time To Reset = Tdm*{ResetTime/(1-M^2)}
M1	Multiple Current Threshold for Pickup Point 1
Tm1	Time to Close in Seconds for Pickup Point 1
M2	Multiple Current Threshold for Pickup Point 2
Tm2	Time to Close in Seconds for Pickup Point 2
M3	Multiple Current Threshold for Pickup Point 3
Tm3	Time to Close in Seconds for Pickup Point 3
M4	Multiple Current Threshold for Pickup Point 4
Tm4	Time to Close in Seconds for Pickup Point 4
M5	Multiple Current Threshold for Pickup Point 5
Tm5	Time to Close in Seconds for Pickup Point 5
BreakerTime	Circuit Breaker Time in Seconds
LoadShedPerc	Fraction of Transfer Trip Load to shed
direct	0 means no directional element; 1 means directional element AND Direction will be based upon current leaving the FROM end of the branch; 2 means directional element AND Direction will be based upon current leaving the TO end of the branch