Description
IEEET3 model was developed based on the Type 3 excitation system specified in the IEEE committee report "Computer representation of excitation systems" [1][2]. The IEEET3 takes the generator terminal current as well as the potential as the excitation source [1].
Mask and Parameters
AVR parameters
Expanding the "IEEET3 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 | - | -- |
Tf | Excitation control system stabilizer time constant 1 | s | Tf1>=0.001 |
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 | -- | -- |
Kp | Potential circuit gain coefficient proportional to voltage | -- | -- |
Ki | Potential circuit gain coefficient proportional to current | -- | -- |
Vbmax | Maximum field voltage | pu | -- |
Initial value tab
Name | Description | Unit | Hard coded parameters |
Efd0 | Exciter output voltage initial value | pu | -- |
| Ifd0 | Initial field current | pu | -- |
The parameters Ifd0 and 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”:
- If a thermal machine or a hydraulic machine is used, Ifd0 shall be set as “=SM1.IfdInit” multiplied by the synchronous machine parameter Xad = Xd – Xl, and Efd0 shall be set as “=SM1.EfdInit”;
- If a pu standard or pu fundamental machine is used, Ifd0 shall be set as “=SM1.IF_Init” and Efd0 shall be set as "=SM1.EFD_Init".
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 If the Load Compensator block is not used upstream from the exciter block, then Vc1 is equal to Vt (main alternator terminal voltage) | pu |
Vref | Voltage regulator reference voltage | pu |
Vs | Is defined as the output voltage of a Power System Stabilizer (PSS) [1]. | pu |
Ifd** | Synchronous machine field current** | pu |
Id | Active component of generator terminal current or component from load compensator | pu |
Iq | Reactive component of generator terminal current or component from load compensator | pu |
Vd | Active component of generator terminal voltage or component from load compensator | pu |
Vq | Reactive component of generator terminal voltage or component from load compensator | pu |
Vuel* | Under-excitation limiter output* | pu |
Voel* | Over-excitation limiter output* | pu |
*Vuel and Voel is normally an input 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.
**If a Synch. Machine (Hydraulic or Thermal) from the Network Machines and Generators library is used, the machine observable Ifd must be multiplied by the synchronous machine parameter Xad = Xd – Xl prior to its input to the exciter. This multiplication is not needed if a Synchronous Machine (pu Standard) or (pu Fundamental) is used.
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.