Description

DEGOV1 is the Woodward diesel generator governor model developed in line with the governor-turbine architecture given in the references [1-3]. The governor model consists of an electric actuator, a fuel injection actuator and the diesel engine.

Mask and Parameters

AVR parameters

Expanding the "DEVGOV1 Block diagram" displays the block diagram in the parameters window.

Name	Description	Unit
T1	Electric Control Box time constants	s
T2		s
T3		s
T4	Actuator time constants and gain	s
T5		s
T6		s
K		pu
TD	Engine time delay	s
R	Droop	pu
TE	Power droop Time constant	s
Pm0	Initial mechanical power output	pu
Tmax	Maximum limit	pu
Tmin	Minimum limit	pu
Selector	0= Feedback signal is take from output of actuator 1= Feedback signal is take from output of electrical port	Boolean

Initial value tab

Name	Description	Unit
Pm0	Initial power output	pu

The initial power output can be set manually, by entering a numerical value. It can also be set automatically based on load flow calculations, by entering a referenced synchronous machine variable. Machine variables can be found in the machine netlist.

For instance, if the name of the synchronous machine on which the governor/turbine is connected is “SM1”, then Pm0 shall be set as =SM1.Peo/SM1.BaseMVA, if a thermal machine or a hydraulic machine is used, and as "=SM1.lfP/1e6/SM1.sBase" if a pu standard or a pu fundamental machine is used, where Peo and IfP are the initial power outputs of the machines, respectively.

The HYPERSIM simulation option “Set Initial Conditions” must be checked for the automatic initialization to work properly.

Inputs and Outputs and Additional Signals Available for Monitoring

Inputs

Name	Description	Unit
wref	Reference speed of the Governor	pu
w	Machine actual speed	pu
VAR	External reference (Pref, etc)	pu
Pe	Electrical power input	pu

*Vuel and Voel are normally inputs to this excitation system but the user has the option to use a fixed constant value directly in the mask by choosing internal in the mask option.
**The observable field current Ifd from the synchronous machine in HYPERSIM needs to be multiplied in its current version by the machine’s Xad = Xd – Xl prior to its input to the exciter if a thermal machine or a hydraulic machine is used. This multiplication is not required if a pu standard or pu fundamental machine is used.

Outputs

Name	Description	Unit
Pm	Mechanical power output	pu

Limitations

The variable TD for transport delay has a maximum buffer size of 20,000 input points. For example at 5us, the maximum TD allowed is 100ms.

TD = 20000 * 5us = 100 ms

References

1. P. Kundur, Power System Stability and Control, New York:McGraw-Hill, 1994.

2. NEPLAN AG. Turbine-Governor Models, Standard Dynamic Turbine-Governor Systems in NEPLAN Power System Analysis Tool; NEPLAN: CH-8700 Küsnacht (ZH), Switzerland, 2013; p. 91.

3. PSS®E 34.2.0 Model Library. NY, USA: Siemens Industry, Inc., 2017.