Description

IEEET2 model was developed based on the Type 2 excitation system specified in the IEEE committee report "Computer representation of excitation systems" [1][2].The IEEET2 takes the source used for the excitation system stabilizing feedback as proportional to the control element output.

Mask and Parameters

AVR parameters

Expanding the "IEEET2 diagram" displays the block diagram in the parameters window.

Name	Description	Unit	Parameter range
Tr	Regulator input filter time constant	s	--
Ka	Voltage regulator gain	-	--
Ta	Regulator time constant	s	--
Kf	Excitation control system stabilizer gain	-	--
Tf1	Excitation control system stabilizer time constant 1	s	Tf1>=0.001
Tf2	Excitation control system stabilizer time constant 2	s	--
VRmax	Maximum voltage regulator output	pu	--
VRmin	Minimum voltage regulator output	pu	--

Exciter Parameters

Expanding the "Exciter diagram" displays the block diagram in the parameters window.

Name	Description	Unit	Parameter Range
Te	Exciter time constant	s	Te >= 0.04
Ke	Exciter constant related to self-excited field	-	--
Se1, Se2	Exciter saturation factor at the corresponding Vex	pu	--
Efd1, Efd2	Exciter voltage for the exciter saturation function	pu	--

Initial value tab

Name	Description	Unit	Variable = {Possible Values}
Efd0	Exciter output voltage initial value	pu	--

The parameters Efd0 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. For instance, if the name of the synchronous machine on which the excitation system is connected is “SM1”, then Efd0 shall be set as “=SM1.EfdInit” if a thermal machine or a hydraulic machine is used, and as "=SM1.EFD_Init" if a pu standard or pu fundamental machine is used.

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
Vc1	Signal proportional to compensated terminal voltage (refer to the load compensator block documentation) If the load compensator block is not used upstream from the exciter block, then Vc1 is equal to Vt	pu
Vref	Voltage regulator reference voltage	pu
Vs	Combined PSS and possibly discontinuous control output after any limits or switching, as summed with terminal voltage and reference signals. For example, Voel and Vuel should be added to the signal before connecting to this input.	pu

Outputs

Name	Description	Unit
Efd	Exciter output voltage	pu

References

1. C. Report, "Computer representation of excitation systems," IEEE Transactions on Power Apparatus and Systems, pp. 1460-1464, June 1968

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