UEL2C
Reviewers: Lampros Papangelis (CRESYM)
IEEE UEL2C model
Context
This underexcitation limiter model first appeared in the IEEE Std 421.5-2016 (of Electrical & Engineers, 2016).
Model use, assumptions, validity domain and limitations
This model is associated to one of the voltage regulators (types AC, DC, ST) defined by the IEEE Std 421.5-2016 (of Electrical & Engineers, 2016).
The model provides an underexcitation limiter signal for the purpose of takeover : the underexcitation limiter signal acts as a lower limit on the voltage regulator main signal which then becomes the excitation voltage.
Model inputs and output
The input signals are :
Variable | Description | Unit |
---|---|---|
PGenPu | Active power generated by the synchronous machine | pu (base SnRef) |
QGenPu | Reactive power generated by the synchronous machine | pu (base SnRef) |
utPu | Complex stator voltage | pu (base UNom) |
VFbPu | Reference voltage from ST7C | pu (base UNom) |
VfPu | Excitation system stabilizer signal | pu |
Both PGenPu and QGenPu follow the generator convention.
The output signal is UUelPu, the underexcitation limiter voltage in pu (base UNom).
Model parameters
Parameter | Description | Unit | Value |
---|---|---|---|
K1 | Voltage exponent for active power input to UEL table | - | 2 |
K2 | Voltage exponent for reactive power output of UEL table | - | 2 |
KFb | UEL gain of reference voltage from ST7C | pu | - |
KFix | UEL fixed gain reduction factor | pu | 1 |
Kuf | UEL excitation system stabilizer gain | pu | 0 |
Kui | UEL integral gain | pu | 0.5 |
Kul | UEL proportional gain | pu | 0.8 |
Sw1 | UEL logic switch for adjustable gain reduction | - | true |
tAdj | UEL adjustable gain reduction time constant | s | 3 |
tQRef | UEL reactive power reference time constant | s | 0 |
tU1 | UEL first lead time constant | s | 0 |
tU2 | UEL first lag time constant | s | 0 |
tU3 | UEL second lead time constant | s | 0 |
tU4 | UEL second lag time constant | s | 0 |
tUl | UEL time constant of filter for reference voltage from ST7C | s | 0 |
tUP | UEL active power filter time constant | s | 5 |
tUQ | UEL reactive power filter time constant | s | 0 |
tUV | UEL voltage filter time constant | s | 5 |
VBiasPu | UEL voltage bias | pu (base UNom) | 1 |
VUel1MaxPu | UEL maximum output | pu (base UNom) | 0.25 |
VUel1MinPu | UEL minimum output | pu (base UNom) | 0 |
VUel2MaxPu | UEL maximum output | pu (base UNom) | 99 |
VUel2MinPu | UEL minimum output | pu (base UNom) | -99 |
VUiMaxPu | UEL PI control maximum output | pu (base UNom) | 0.25 |
VUiMinPu | UEL PI control minimum output | pu (base UNom) | 0 |
XqPu | UEL characteristic reactance | pu (base SnRef, UNom) | - |
The UEL lookup table is defined by 5 pairs (active power, reactive power) in pu, typically with the following values :
P | Q |
---|---|
0 | -0.31 |
0.3 | -0.31 |
0.6 | -0.28 |
0.9 | -0.21 |
1.02 | 0 |
Model diagram
Open source implementations
This model has been successfully implemented in :
Software | URL | Language | Open-Source License | Last consulted date | Comments |
---|---|---|---|---|---|
Dynawo | Link | Modelica | MPL v2.0 | 09/10/2024 |
References
- of Electrical, T. I., & Engineers, E. (2016). IEEE recommended practice for excitation system models for power system stability studies . IEEE Std 421.5-2016. https://home.engineering.iastate.edu/ jdm/ee554/IEEEstd421.5-2016RecPracExSysModsPwrSysStabStudies.pdf