Branch Model: TIOCRS
AutoCorrection Properties
Following checks and corrections are applied during Validation and AutoCorrection.
- CurveType: Error is created if curve type is not 1 (for IEEE), 2 (for IEC), or 3 (for IAC).
Mult represents the user-specified value Minimum time constant size as multiple of time step option on the Validation page of the Transient Stability Dialog
TimeStep represents the integration time step being used as described on TimeStep
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 TimeToClose function. 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 |
| CurveType | Curve Type. Determines the function used to describe Relay Time Inverse Curve. Options are 1 = IEEE C37.113 standard; 2 = IEC 255-4 and British BS142; 3 = IAC GE Type |
| ThresholdCurrent | Threshold current, Amps |
| BreakerTime | Circuit Breaker Time in Seconds |
| Tdm | Time Dial Multiplier. All times specified will be treated as this multiple larger |
| ResetTime | Zero Current Reset time in seconds. Let M = (I/Ithres). Then Time To Reset = Tdm*{ResetTime/(1-M^2)} |
| p | Curve Exponent Parameter. See more information with paramters A, B, C, D, E |
| A | Curve Coefficient A. Usage depends on Curve Type. Let M = (I/Ithres). Then IEEE curves use Tdm*{B + A/(M^p - 1)}; IEC curves use Tdm*{A/(M^p - 1)} |
| B | Curve Coefficient B. Usage depends on Curve Type. Let M = (I/Ithres). Then IEEE curves use Tdm*{B + A/(M^p - 1)}; IEC curves use Tdm*{A/(M^p - 1)} |
| C | Curve Coefficient C. Usage depends on Curve Type. Let M = (I/Ithres). Then IEEE curves use Tdm*{B + A/(M^p - 1)}; IEC curves use Tdm*{A/(M^p - 1)}; IAC curves use Tdm*{A + B/(M-C) + D/[(M-C)^2] + E/[(M-C)^3]} |
| D | Curve Coefficient D. Usage depends on Curve Type. Let M = (I/Ithres). Then IEEE curves use Tdm*{B + A/(M^p - 1)}; IEC curves use Tdm*{A/(M^p - 1)}; IAC curves use Tdm*{A + B/(M-C) + D/[(M-C)^2] + E/[(M-C)^3]} |
| E | Curve Coefficient E. Usage depends on Curve Type. Let M = (I/Ithres). Then IEEE curves use Tdm*{B + A/(M^p - 1)}; IEC curves use Tdm*{A/(M^p - 1)}; IAC curves use Tdm*{A + B/(M-C) + D/[(M-C)^2] + E/[(M-C)^3]} |
| t3trip | 0 means trip monitor winding; 1 means trip whole 3 winding Xfmr |
| 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 |