Synchronous Machine

 Machine Name

Text

Just an identifier.  A name should be entered here to avoid compilation warnings

No. of Q-axis Damper Windings

Choice

Select the appropriate number of q-axis windings. Normally, One is used to represent a salient-pole machine and Two for a round-rotor machine.

Data Entry Format

Choice

Select Generator or Equiv cct.  See Data Entry Formats for more details

Multimass Interface

Choice

Select Enable or Disable.  See Interfacing to the Multi-Mass Torsional Shaft for more details

Armature Resistance As

Choice

Select Time Constant or Resistance.  See Data Entry Formats for more details

 Saturation

Choice

Select Enabled or Disabled.  The D-axis saturation is disabled by default.  When enabled, a saturation characteristic is applied as given by data points in the Saturation Curve section of the component properties.  See Saturation Curve for more details

Type of Settings for Initial Condition

Choice

Select None, Powers or Currents.  See Start-up and Initialization for more details

Machine Scaling Factor?

Choice

Select Yes or No.  See Coherent Machines for more details

Graphics Display

Choice

Select 3-Phase View or Single Line View

External Neutral Connection

Choice

Select Enable or Disable.  

NOTE: Care must be taken when the machine is scaled to model several machines. If the external connections are used, the connected elements should be scaled appropriately. See Coherent Machines for more details.

 D-axis Transfer Admit Data Available?

Choice

Select Yes or No

Force Currents = 0 at t = 0?

Choice

Select Yes or No

Control Source P out?

Choice

Select Yes or No

Control Machine P out?

Choice

Select Yes or No

Modify Mechanical Dynamics?

Choice

Select Yes or No

Accelerated Flux Build-Up at Start?

Choice

Select Yes or No

 Supply Terminal Conditions to Exciter

Choice

Select None, Terminal Voltage, Terminal Current or Both Voltage and Current.  Some exciters need only the voltage and some need both voltage and real/reactive parts of the currents.  This option will create an output scalar, a 2-element vector or a 3-element vector (depending on the option chosen) to be passed to the exciter.  The exciter will use this information to initialize its internal variables so that an initialized output is provided to the machine, when the machine is switched from a 'source' to a 'machine'.  See Start-up and Initialization for more details

Smoothing Time Constant

REAL

Variable

This input is enabled only if an option other than None is chosen under Supply Terminal Conditions to Exciter. This input is used in smoothing the signal sent to the exciter [s]

Output Exciter Initialization Data?

Choice

Select Yes or No.  If Yes, the required field voltage is used to initialize the exciter, so that the machine can be switched from source mode to machine mode smoothly.  See Start-up and Initialization for more details

Output Governor Initialization Data?

Choice

Select Yes or No.  If Yes, the required mechanical torque is used to initialize the turbine and/or governor, so that the machine can be switched from 'locked-rotor' to 'free running' mode smoothly.  See Start-up and Initialization for more details

Output Speed

Choice

Select per-unit or radians per second, depending on that needed by the Governor/Turbine models interfaced

Source [0] -> Machine [1] Transition

INTEGER

Variable

This input accepts an integer 0 or 1.  While 0, the machine is modeled as a simple 3-phase voltage source.  When 1, the machine runs in 'constant speed' mode.   See Start-up and Initialization for more details

Lock-rotor [0] <-> Normal Mode [1] Transition

INTEGER

Variable

This input accepts an integer 0 or 1.  While 0, the machine will run in 'constant speed' mode.  When 1, the machine will run as a full-blown machine.  See Start-up and Initialization for more details

Rating Specified As

Choice

Select Current or MVA to specify the rating.

Voltage Specified As

Choice

Select Line to Neutral or Line to Line to specify the voltage.

Rated RMS Line Current

REAL

Constant

Enter the machine rated line current [kA].

 Rated RMS Line-to-Line Voltage

REAL

Constant

Enter the machine rated line-to-line voltage [kV].

Rated MVA

REAL

Constant

Enter the machine rated MVA [MVA].

Base Angular Frequency

REAL

Constant

Enter the base angular frequency to which the machine is initialized at time t = 0.0.  If the rotor is locked during initialization, the machine will run at this constant speed [rad/s].

Inertia Constant

REAL

Constant

This input represents the stored energy in the rotor at rated speed per machine rating and is typically between 2.0 and 6.0 [MWs/MVA]

Mechanical Friction and Windage

REAL

Constant

Enter the mechanical damping constant.  This input is typically between 0.0 and 0.05 (0.0 meaning no frictional losses).  See Mechanical Friction and Windage for more details [pu]

Neutral Series Resistance

REAL

Constant

The real component of fundamental frequency impedance, which is connected between the machine neutral and ground [pu]. This parameter is enabled only if External Neutral Connection is disabled.

Neutral Series Reactance

REAL

Constant

The reactive component of fundamental frequency impedance, which is connected between the machine neutral and ground [pu]. This parameter is enabled only if External Neutral Connection is disabled.

Iron Loss Resistance

REAL

Constant

This value is provided as a shunt resistance at the machine terminals and should be between 66.7 and 300 [pu]

Number of Coherent Machines

REAL

Variable

Enter the number of machines acting coherently. See Coherent Machines for more details.

Armature Resistance

REAL

Constant

Resistance per phase of a stator winding [pu]

Stator Leakage Reactance

REAL

Constant

Leakage reactance of a phase winding [pu]

D-Axis Unsaturated Magnet. React.

REAL

Constant

Enter the d-axis unsaturated magnetizing reactance (Xd) [pu]

Field Resistance

REAL

Constant

Resistance of the field winding [pu]

Field Leakage Reactance

REAL

Constant

Leakage reactance of the field winding [pu]

D-Axis Damper Resistance

REAL

Constant

Resistance assigned to the winding placed on the d-axis to model the effects of damper bars [pu]

D-Axis Damper Leakage Reactance

REAL

Constant

Leakage reactance assigned to the winding placed on the d-axis to model the effects of damper bars [pu]

D: Field-Damp Mutual Leakage Reactance

REAL

Constant

Mutual reactance between the field winding and the d-axis damper windings, due to flux that does not cross the air gap [pu]

Q-Axis Magnetizing Reactance

REAL

Constant

Enter the q-axis magnetizing reactance (Xq) [pu]

Q-Axis Damper No.#  Resistance

REAL

Constant

Resistance assigned to the windings placed on the q-axis to model the effects of damper bars [pu]

Q-Axis Damper No.#  Leakage React.

REAL

Constant

Leakage reactance assigned to the windings placed on the q-axis to model the effects of damper bars [pu]

Q: Damp-Damp Mutual Leak. React.

REAL

Constant

Mutual reactance between two q-axis damper windings, due to flux that does not cross the air gap.[pu]

 Armature Resistance [Ra]

REAL

Constant

Enter the armature resistance.  This is only enabled if the Armature Resistance As input is set to Resistance [pu]

Armature Time Constant [Ta]

REAL

Constant

Enter the armature time constant.  This is only enabled if the Armature Resistance As input is set to Time Constant [s]

Potier Reactance [Xp]

REAL

Constant

This is related to the stator leakage reactance by the equation XL = XP x Air Gap Factor.  Stator Leakage Reactance must be less than the Direct-Axis Reactance, Transient Reactance and Sub-Transient Reactance

Unsaturated Reactance

REAL

Constant

Xd, Xq [pu]

Unsaturated Transient Reactance

REAL

Constant

Xd', Xq' [pu]

Unsat. Transient Time  (Open)

REAL

Constant

Tdo', Tqo' [s]

Unsat. Sub-Trans. Reactance

REAL

Constant

Xd", Xq" [pu]

Unsat. Sub-Trans. Time (Open)

REAL

Constant

Tdo", Tqo" [s]

D: Real Transfer Admit (Armat-Field)

REAL

Constant

Enter the d-axis real transfer admittance for the armature field.  For more information, see the Configuration - Advanced input parameter window [pu]

D: Imag Transfer Admit (Armat-Field)

REAL

Constant

Enter the d-axis imaginary transfer admittance for the armature field.  For more information, see the Configuration - Advanced input parameter window [pu]

Air Gap Factor

REAL

Constant

This factor is used in the calculation of stator leakage reactance, based on the Potier Reactance: XL = XP x Air Gap Factor

Number of Data Points Available

Choice

Point # - Current

REAL

Output

Enter the I data point for the mutual magnetizing inductance saturation curve.  See Saturation Curve for more details [pu]

Point # - PU Voltage

REAL

Output

Enter the V data point for the mutual magnetizing inductance saturation curve.  See Saturation Curve for more details [pu]

Terminal Voltage Magnitude at Time = 0-

REAL

Constant

Terminal voltage magnitude at start-up [pu].

Terminal Voltage Phase at Time = 0-

REAL

Constant

Terminal voltage phase angle at start-up.  Care must be taken if the machine is connected through a Y-D transformer, with the bus side on Y and the machine on D.  If the bus phase angle is being determined from a conventional load flow program, Y-D transformations are not taken into account. Therefore, 30° must be subtracted from this angle if obtained from load flow calculations [rad]

 Terminal Real  Power at Time = 0- ; Out +

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Powers [MW]

Terminal Reactive Power at Time = 0- ; Out +

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Powers [MVAr]

Initial Rotor Angle ref: Stator

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Currents [rad]

D-axis Armature Current; In +

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Currents [pu]

Q-axis Armature Current; In +

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Currents [pu]

Initial Field Current

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Currents [pu]

Initial Machine Speed

REAL

Constant

This parameter is available only if the Type of Settings for Initial Condition input parameter is set to Currents [pu]

 Time to Ramp Source Limit to Rated

REAL

Constant

This parameter is used to provide a 'soft start', when starting from time = 0.0 as a source, so that network transients are minimized [s].

System Fault Level (Excluding Machine)

REAL

Constant

This parameter is available only if the Control Source P out? or the Control Machine P out? input parameter is enabled [pu]

Time Constant for Power Correction

REAL

Constant

This parameter is available only if the Control Source P out? or the Control Machine P out? input parameter is enabled [pu]

Real power (pu)

REAL

Output

Real power output of the machine. (+) - power flowing out [pu]

Reactive power (pu)

REAL

Output

Reactive power output of the machine. (+) - power flowing out [pu]

Neutral voltage (kV)

REAL

Output

Voltage at the machine neutral (star) point [kV]

Neutral current to ground (kA)

REAL

Output

Machine neutral current [kA]

Load angle (rad) (Lang)

REAL

Output

This is the phase difference between the internal voltage and the terminal voltage and is responsible for pushing the power in/out of machine.  This angle should not be confused with Internal Phase A Angle with Respect to sin(wt) as described below [rad]

Rotor Mechanical Angle (rad)

REAL

Output

This is a saw tooth wave from 0 to 2p radians.  The value indicates the position of the rotor [rad]

Internal Phase A Angle with Respect to sin(wt) (Wang) (rad)

REAL

Output

This is calculated as Wang = Phase angle of Terminal Voltage + Lang + Integral of (wpu - 1.0) x d(t).

Steady Electric Torque (rad)

REAL

Output

Smoothed output of the electrical torque of the machine [rad]

Real/Reactive Power pu Output is Based on Base MVA of

Choice

Select either Single Machine or Total Number of Machines.

Source (0) machine (1) Transition

REAL

Variable

Give a variable name.  This will change its assigned value from 0 to 1 when the machine is switched from a 'source' to a 'machine'.  Use this variable in the exciter model to initialize it

Constant speed (0) normal (1) Transition

REAL

Variable

Give a variable name.  This will change its assigned value from 0 to 1 when the machine is switched from a 'constant speed operation' to a 'normal machine'.  Use this variable in any governor/turbine models to initialize them

Monitor Internal Storage NEXC +

INTEGER

Constant

If you wish to monitor any of the internal variables listed in the table below, enter the corresponding NEXC storage array pointer number here.

Name for # Monitored Output

Text

Enter a name to the define the variable created by the corresponding Monitor Internal Storage NEXC + input parameter.

NEXC #

Description

1

is 1.0 if operation as a voltage source is still active, otherwise it is 0.0

2

angle in radians used for the A phase of the voltage source sin wave generator

23

VD, d-axis armature voltage

24

VFPU, field voltage (not normalized)

25

VQ, q-axis armature voltage

26

RA, stator resistance

27

XA, stator leakage reactance

28

RI, iron loss resistance provided as a shunt resistance at the machine terminals

31

XMD0, d-axis unsaturated magnetizing reactance

32

RFD, resistance of the field winding

33

XFD, leakage reactance of the field winding

34

RKD, resistance of the d-axis damper winding

35

XKD, leakage reactance of the d-axis damper winding

41

XMQ, q-axis magnetizing reactance

42

RFQ, resistance of the first damper winding on the q-axis

43

XFQ, leakage reactance of the first damper winding on the q-axis

44

RKQ, resistance of the second damper winding on the q-axis

45

XKQ, leakage reactance of the second damper winding on the q-axis

177

NFLGAD, is 1.0 if the voltage source power controller has been active at any time previous in the simulation, otherwise it is 0.0. When NFLGAD is 1.0, the input argument VSAADJ is ignored.

301

CD2, d-axis armature current

302

CFD2, field current

303

CKD2, current in the d-axis damper winding

304

CQ2, q-axis armature current

305

CFQ2, current in the first q-axis damper winding

306

CKQ2, current in the second q-axis damper winding