SCRX

SCRX model

This article is incomplete, some sections must be written.

Context

This voltage regulator model appears under the name ExcSCRX in the Common Information Model for Dynamics - Standard Models (2012) [1] and in the IEC 61970-302:2024 version [2].

Model use, assumptions, validity domain and limitations

To be completed

Model inputs and output

The input variables are :

Variable	Description	Units
\(I_r P_u\)	rotor current	\({pu}\) (base \(S_{Nom}\), user-selected base voltage)
\(U_s P_u\)	measured stator voltage	\({pu}\) (base \(U N_{om}\))
\(U_{s} R_{ef} P_u\)	reference stator voltage	\({pu}\) (base \(U N_{om}\))
\(U O_{el} P_u\) (optional)	output voltage of overexcitation limiter	\({pu}\) (base \(U N_{om}\))
\(U P_{ss} P_u\) (optional)	output voltage of power system stabilizer	\({pu}\) (base \(U N_{om}\))
\(U U_{el} P_u\) (optional)	output voltage of underexcitation limiter	\({pu}\) (base \(U N_{om}\))

The output signal is \(E_{fd} P_u\), the excitation voltage in \({pu}\) (user-selected base voltage).

Model parameters

Parameter	Description	Units
\({CSwitch}\)	If true, exciter is solid-fed, if false, exciter is bus-fed	\(-\)
\({IrThresholdOn}\)	If true, rotor current threshold applies	\(-\)
\(K\)	Voltage regulator gain	\({pu}\)
\({RcToRfd}\)	Ratio of field discharge resistance to field winding resistance	\(-\)
\(t_A\)	Transient gain reduction lead time constant	\({s}\)
\(t_B\)	Transient gain reduction lag time constant	\({s}\)
\(t_E\)	Voltage regulator time constant	\({s}\)
\(V_{r} Max P_u\)	Maximum output voltage of voltage regulator	\({pu}\) (user-selected base voltage)
\(V_{r} Min P_u\)	Minimum output voltage of voltage regulator	\({pu}\) (user-selected base voltage)

Model diagram

Figure 1: SCRX block 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	24/05/2024

References

1.

Commission IE (2012) Common information model (CIM) standard models 2012. https://doi.org/10.3403/30160442

2.

Commission IE (2024) Energy management system application program interface (EMS-API) part 302: Common information model (CIM) dynamics. IEC 61970-302