Generator#
( Circuit Element, PC Element )
EPRI’s OpenDSS Documentation for this component: https://opendss.epri.com/Generator.html
# 
Name 
Type 
Default 
Units 
Description 

1 

integer 
3 
Number of Phases, this Generator. Power is evenly divided among phases. 

2 

string 
Bus to which the Generator is connected. May include specific node specification. 

3 

real 
12.47 
kV 
Nominal rated (1.0 per unit) voltage, kV, for Generator. For 2 and 3phase Generators, specify phasephase kV. Otherwise, for phases=1 or phases>3, specify actual kV across each branch of the Generator. If wye (star), specify phaseneutral kV. If delta or phasephase connected, specify phasephase kV. 
4 

real 
Total base kW for the Generator. A positive value denotes power coming OUT of the element, 

5 

real 
Generator power factor. Enter negative for leading powerfactor (when kW and kvar have opposite signs.) 

6 

real 
Specify the base kvar. Alternative to specifying the power factor. Side effect: the power factor value is altered to agree based on present value of kW. 

7 

integer 
1 
Integer code for the model to use for generation variation with voltage. Valid values are: 

8 

real 
0.9 
Minimum per unit voltage for which the Model is assumed to apply. Below this value, the load model reverts to a constant impedance model. For model 7, the current is limited to the value computed for constant power at Vminpu. 

9 

real 
1.1 
Maximum per unit voltage for which the Model is assumed to apply. Above this value, the load model reverts to a constant impedance model. 

10 

string 
Dispatch shape to use for yearly simulations. Must be previously defined as a Loadshape object. If this is not specified, a constant value is assumed (no variation). If the generator is assumed to be ON continuously, specify Status=FIXED, or designate a curve that is 1.0 per unit at all times. Set to NONE to reset to no loadshape. Nominally for 8760 simulations. If there are fewer points in the designated shape than the number of points in the solution, the curve is repeated. 

11 

string 
Dispatch shape to use for daily simulations. Must be previously defined as a Loadshape object of 24 hrs, typically. If generator is assumed to be ON continuously, specify Status=FIXED, or designate a Loadshape object that is 1.0 per unit for all hours. Set to NONE to reset to no loadshape. 

12 

string 
Load shape to use for duty cycle dispatch simulations such as for wind generation. Must be previously defined as a Loadshape object. Typically would have time intervals less than 1 hr – perhaps, in seconds. Set Status=Fixed to ignore Loadshape designation. Set to NONE to reset to no loadshape. Designate the number of points to solve using the Set Number=xxxx command. If there are fewer points in the actual shape, the shape is assumed to repeat. 

13 

string 
Default 
Dispatch mode. In default mode, the generator is either always on or follows dispatch curve as specified. Otherwise, the gen comes on when either the global default load level (Loadshape “default”) or the price level exceeds the dispatch value. 

14 

real 
0.0 
Dispatch value. 

15 

string 
Wye 
Generator connection. Default is wye. 

16 

string 
Variable 
If Fixed, then dispatch multipliers do not apply. The generator is alway at full power when it is ON. Default is Variable (follows curves). 

17 

integer 
1 
An arbitrary integer number representing the class of Generator so that Generator values may be segregated by class. 

18 

real 
1.0 
Per Unit voltage set point for Model = 3 (typical power flow model). 

19 

real 
Maximum kvar limit for Model = 3. Defaults to twice the specified load kvar. Always reset this if you change PF or kvar properties. 

20 

real 
Minimum kvar limit for Model = 3. Enter a negative number if generator can absorb vars. Defaults to negative of Maxkvar. Always reset this if you change PF or kvar properties. 

21 

real 
0.1 
Deceleration factor for PV generator model (Model=3). Default is 0.1. If the circuit converges easily, you may want to use a higher number such as 1.0. Use a lower number if solution diverges. Use Debugtrace=yes to create a file that will trace the convergence of a generator model. 

22 

boolean 
False 
Forces generator ON despite requirements of other dispatch modes. Stays ON until this property is set to NO, or an internal algorithm cancels the forced ON state. 

23 

real 
kVA rating of electrical machine. Defaults to 1.2 × kW if not specified. Applied to machine or inverter definition for Dynamics mode solutions. 

24 

real 
MVA rating of electrical machine. Alternative to using kVA=. 

25 

real 
1.0 
Per unit synchronous reactance of machine. Presently used only for Thevenin impedance for power flow calcs of user models (model=6). Typically use a value 0.4 to 1.0. Default is 1.0 

26 

real 
0.28 
Per unit transient reactance of the machine. Used for Dynamics mode and Fault studies. Default is 0.27.For user models, this value is used for the Thevenin/Norton impedance for Dynamics Mode. 

27 

real 
0.2 
Per unit subtransient reactance of the machine. Used for Harmonics. Default is 0.20. 

28 

real 
1.0 
Per unit mass constant of the machine. MWsec/MVA. Default is 1.0. 

29 

real 
1.0 
Damping constant. Usual range is 0 to 4. Default is 1.0. Adjust to get damping 

30 

string 
Name of DLL containing userwritten model, which computes the terminal currents for Dynamics studies, overriding the default model. Set to “none” to negate previous setting. 

31 

string 
String (in quotes or parentheses) that gets passed to userwritten model for defining the data required for that model. 

32 

string 
Name of userwritten DLL containing a Shaft model, which models the prime mover and determines the power on the shaft for Dynamics studies. Models additional mass elements other than the singlemass model in the DSS default model. Set to “none” to negate previous setting. 

33 

string 
String (in quotes or parentheses) that gets passed to userwritten shaft dynamic model for defining the data for that model. 

34 

real 
0.0 
hour 
Starting time offset [hours] into the duty cycle shape for this generator, defaults to 0 
35 

boolean 
False 
Turn this on to capture the progress of the generator model for each iteration. Creates a separate file for each generator named “GEN_name.csv”. 

36 

boolean 
False 
For Model=7, force balanced current only for 3phase generators. Force zero and negativesequence to zero. 

37 

real 
20.0 
X/R ratio for Xdp property for FaultStudy and Dynamic modes. 

38 

boolean 
False 
Activates the use of fuel for the operation of the generator. When the fuel level reaches the reserve level, the generator stops until it gets refueled. By default, the generator is connected to a continuous fuel supply, Use this mode to mimic dependency on fuel level for different generation technologies. 

39 

real 
0.0 
The nominal level of fuel for the generator (kWh). It only applies if UseFuel = True 

40 

real 
It is a number between 0 and 100 representing the current amount of fuel available in percentage of FuelkWh. It only applies if UseFuel = True 

41 

real 
It is a number between 0 and 100 representing the reserve level in percentage of FuelkWh. It only applies if UseFuel = True 

42 

boolean 
False 
Setting a true value manually refuels the generator when needed. It only applies if UseFuel = True 

43 

string 
The name of the dynamic equation (DynamicExp) that will be used for defining the dynamic behavior of the generator. if not defined, the generator dynamics will follow the builtin dynamic equation. 

44 

array of strings 
The name of the variables within the Dynamic equation that will be used to govern the generator dynamics.This generator model requires 2 outputs from the dynamic equation: 

45 

string 
defaultgen 
Name of harmonic voltage or current spectrum for this generator. Voltage behind Xd” for machine  default. Current injection for inverter. 

46 

real 
Hz 
Base Frequency for ratings. 

47 

boolean 
True 
Indicates whether this element is enabled. 

48 

string 
Make like another object, e.g.: 
Enumerations#
Generator: Dispatch Mode#
Value 




Generator: Model#
Value 
Description 


Constant PQ 

Constant Z 

Constant PV 

Constant P, fixed Q 

Constant P, fixed X 

User model 

Approximate inverter model 
Generator: Status#
Value 



Sample links#
These are the top 20 sample files with occurrences of this DSS object.
# of occurrences 
Link 

5 

5 

2 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 
Links are provided to the dssextensions/electricdsssrc repository since there are some edits and fixes. Otherwise, these files should be available on the official OpenDSS SVN or in the OpenDSS application folder if your have a local installation.