UEL1

Authors: Erwan Guichard (DPS for RTE)

Reviewers: Lampros Papangelis (CRESYM)

IEEE UEL1 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
itPu Complex stator current pu (base SnRef, UNom)
utPu Complex stator voltage pu (base UNom)
VfPu Excitation system stabilizer signal pu

The output signal is UUelPu, the underexcitation limiter voltage in pu (base UNom).

Model parameters

Parameter Description Unit Value
Kuc UEL center setting pu 1.38
Kuf UEL excitation system stabilizer gain pu 3.3
Kui UEL integral gain pu 0
Kul UEL proportional gain pu 100
Kur UEL radius setting pu 1.95
tU1 UEL first lead time constant s 0
tU2 UEL first lag time constant s 0.05
tU3 UEL second lead time constant s 0
tU4 UEL second lag time constant s 0
VUcMaxPu UEL maximum voltage magnitude pu (base UNom) 5.8
VUiMaxPu UEL maximum output pu (base UNom) 18
VUiMinPu UEL minimum output pu (base UNom) 18
VUrMaxPu UEL maximum radius pu (base UNom) 5.8

Model diagram

UEL1

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

  1. 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
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