Dynamic Models

Synchronous Machines

A synchronous machine is specified with its excitation controller (EXC) and torque controller (TOR):

SYNC_MACH Name BUS_NAME FP FQ P Q Snom Pnom H D ibratio
  XT/RL Xl Xd X'd X"d Xq X'q X"q m n Ra T'do T"do T'qo T"qo

EXC EXC_TYPE parameters_passed_to_EXC

TOR TOR_TYPE parameters_passed_to_TOR ;

For the complete mathematical model, per unit system, and detailed parameter descriptions, see the Synchronous Machine Model page.

Available Exciter Models

The following exciter types are available in the current version:

1storder, constant, kundur, generic1, generic2, ST1A, ST1A_lim, ST1A_PSS2B, ST1A_PSS3B, ST1A_PSS4B, ST1A_IEEEST, ST2A, AC1A, AC1A_RETRO, AC4A, AC8B, DC3A, IEEET5, EXPIC1, ENTSOE_simp, and many more with combinations of PSS and OEL models.

For detailed documentation of each model, see the Model Reference section.

Available Torque Controller Models

1storder, constant, DEGOV1, hydro_generic1, thermal_generic1, ENTSOE_simp

For detailed documentation of each model, see the Model Reference section.

Injectors

An injector is a component connected to a single AC bus:

INJEC INJ_TYPE NAME BUS_NAME FP FQ P Q parameters_passed_to_INJ ;

Available Injector Models

Model	Description
`load`	Generic load model
`PQ`	Constant PQ load
`restld`	Restorative load
`indmach1`, `indmach2`	Induction machine models
`IBG`	Inverter-based generator
`WT3WithChanges`, `WT4WithChanges`	Wind turbine models
`BESSWithChanges`	Battery energy storage system
`vfd_load`	Variable frequency drive load
`svc`	SVC model
`theveq`	Thévenin equivalent (infinite bus)

Thévenin Equivalent (Infinite Bus)

INJEC THEVEQ INJEC_NAME BUS_NAME FP FQ P Q MVA ;

A Thévenin equivalent imposes a constant-frequency voltage source and forces the synchronous reference frame.

Parameter	Description	Unit
`FP`, `FQ`	Fractions of bus injection (active, reactive)	—
`P`, `Q`	Initial powers (used if fractions are zero)	pu
`MVA`	Apparent power base used for per-unit values of the Thévenin equivalent	MVA

The FP, FQ, P, Q fields are power participation fractions and initial power values used during initialization. See Reference Frames & Initialization for detailed explanation.

Impedance Loads

IMPLOAD loadname BUS_NAME FP FQ P Q ;

Constant-impedance loads maintain the power factor at the initial voltage.

Parameter	Description	Unit
`FP`, `FQ`	Fractions of bus injection (active, reactive)	—
`P`, `Q`	Initial powers (used if fractions are zero)	pu

The FP, FQ, P, Q fields are power participation fractions and initial power values used during initialization. See Reference Frames & Initialization for detailed explanation.

Two-Port Components

Two-port components connect two buses:

Available Two-Port Models

Model	Description
`HVDC_LCC`	Line-commutated converter HVDC
`HVDC_VSC`	Voltage source converter HVDC
`HVDC_VSC_SC`	VSC-HVDC with short-circuit contribution
`DCL_WCL`	DC link model

For detailed documentation of each model, see the Model Reference section.

Discrete Controllers

DCTL CTRL_TYPE CTLNAME parameters ;

Available Discrete Controller Models

Model	Description
`ltc`, `ltc2`, `ltcinv`	Load tap changer controllers
`oltc2`	On-load tap changer
`uvls`	Under-voltage load shedding
`uvprot`	Under-voltage protection
`pst`	Phase-shifting transformer controller
`rt`	Real-time synchronizer
`mais`	Multi-area islanding scheme
`FRT`	Fault ride-through
`sim_minmaxvolt`	Voltage stopping criteria
`sim_minmaxspeed`	Speed stopping criteria
`voltage_variability`	Voltage variability monitor

Real-Time Synchronizer

DCTL RT CTLNAME ratio_to_rt ;

Setting ratio_to_rt = 1.0 slows the simulation to match real-time. Setting it to 2.0 means twice faster than real-time (if possible).

Stopping Criteria

Voltage-based:

DCTL SIM_MINMAXVOLT CTRL_Name VMAX(pu) VMIN(pu) DEADTIME(s) Stop_Simulation(T/F) ;

Speed-based:

DCTL SIM_MINMAXSPEED CTRL_Name MAX_SPEED(pu) MIN_SPEED(pu) DEADTIME(s) Stop_Simulation(T/F) ;

Next Steps

Disturbances — Define faults, trips, and parameter changes
Solver Settings — Configure the numerical solver
Model Reference — Browse available exciter, governor, and injector models