OEL3C

IEEE OEL3C 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 input and output

The input signal is either the generator field current (for static excitation systems) or the exciter field current (for rotating exciters), in \(pu\).

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

Model parameters

Parameter	Description	Unit	Value
\(ITfPu\)	OEL timed field current limiter pick up level	\(pu\)	\(3.7\)
\(K1\)	Exponent for OEL error calculation	\(-\)	\(1\)
\(KOel\)	OEL gain	\(pu\)	\(1\)
\(KpOel\)	OEL proportional gain	\(pu\)	\(1\)
\(KScale\)	OEL input signal scaling factor	\(pu\)	\(-\)
\(tF\)	OEL field current measurement time constant	\(s\)	\(0.02\)
\(tOel\)	OEL integral time constant	\(s\)	\(24\)
\(VOel1MaxPu\)	OEL integrator maximum output	\(pu\) (base \(UNom\))	\(0.66\)
\(VOel1MinPu\)	OEL integrator minimum output	\(pu\) (base \(UNom\))	\(-1\)
\(VOel2MaxPu\)	OEL maximum output	\(pu\) (base \(UNom\))	\(0\)
\(VOel2MinPu\)	OEL minimum output	\(pu\) (base \(UNom\))	\(-1\)

Model diagram

Figure 1: OEL3C 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