OEL4C

IEEE OEL4C model

Context

This overexcitation limiter model first appeared in the IEEE Std 421.5-2016 [1].

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 [1].

The model provides an overexcitation limiter signal for the purpose of summation : the overexcitation limiter signal is added to the stator voltage deviation from the reference, thus being taken into account in the calculation of the excitation voltage.

Model inputs and output

The input signals are :

Variable	Description	Unit
\(QGenPu\)	Reactive power generated by the synchronous machine	\(pu\) (base \(SnRef\))
\(QRefPu\)	Reference reactive power	\(pu\) (base \(SnRef\))

They both follow the generator convention.

The output signal is \(UOelPu\), the overexcitation limiter voltage in \(pu\) (base \(UNom\)).

Model parameters

Parameter	Description	Unit	Value
\(Ki\)	OEL integral gain	\(pu\)	\(1\)
\(Kp\)	OEL proportional gain	\(pu\)	\(1\)
\(tDelay\)	OEL integral time constant	\(s\)	\(20\)
\(VMinPu\)	OEL minimum output	\(pu\) (base \(UNom\))	\(-0.2\)

Model diagram

Figure 1: OEL4C 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

1.

Electrical TI of, Engineers E (2016) IEEE recommended practice for excitation system models for power system stability studies. IEEE Std 4215-2016