Description

This module is based on the IEEE Std 412.5 type DC2A excitation system model [1]. The excitation system uses a field controlled DC commutator to the terminal voltage.

Mask and Parameters

AVR Parameters

DC2A AVR parameters

Expanding the "DC2A diagram" displays the block diagram in the parameters window.

DC2A AVR Block diagram

Name	Description	Unit
Tr	Regulator input filter time constant	s
Tb	Voltage regulator time constant	s
Tc	Voltage regulator time constant	s
Ka	Voltage regulator gain	-
Ta	Regulator time constant	s
Kf	Excitation control system stabilizer gain	-
Tf	Excitation control system stabilizer time constant	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
Te	Exciter time constant	s
Ke	Exciter constant related to self-excited field	-
Se1, Se2	Exciter saturation factor at the corresponding Vex	pu
ZEfd1, Efd2	Exciter voltage for the exciter saturation function	pu

Initial Values Mask Parameters

Name	Description		Unit
Efd0	Exciter output voltage initial value		pu

The parameter 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 Signals Available for Monitoring

Inputs

Name	Description	Unit
Vc1	Signal proportional to compensated terminal voltage If a load compensator block is not used upstream from the exciter block, then Vc1 is equal to Vt (main alternator terminal voltage)	pu
Vref	Voltrage regulator reference voltage	pu
Vs	Is defined as the output voltage of a power system stabilizer (PSS)	pu
Vuel	Underexcitation limiter output	pu

Outputs

Name	Description	Unit
Efd	Exciter output voltage	pu

References

1. “IEEE Recommended Practice for Excitation System Models for Power System Models for Power System Stability Studies,” IEEE Standard 421.5-2005.