Excitation Limiters

Note:

The limiters that have uel_ prefixes are from the PSSE compatible library in PowerFactory 2022 and prior versions. Comparatively, the limiters that have uel_PSSE_ prefixes are from the PSSE compatible library in PowerFactory 2023 and more recent versions.

The version of the ElmDsl components can be determined using the following pattern:

Version	Type Prefixes
PowerFactory 2022 and prior versions	Overexcitation limiters: oel_
PowerFactory 2022 and prior versions	Underexcitation limiters: uel_
PowerFactory 2023 and more recent versions	Overexcitation limiters: oel_PSSE_
PowerFactory 2023 and more recent versions	Underexcitation limiters: uel_PSSE_

These PowerFactory components are mapped to UEL2 limiter exciter of the Native Library.

Parameter	Description	Acceptable Values
`k1` _{(Ver. 23 and after)}	Voltage exponent for real power input to UEL table [pu]	Any value
`k2` _{(Ver. 23 and after)}	Voltage exponent for reactive power output of UEL table [pu]
`k` _{(Ver. 22 and before)}	k-exponent (=0,=1 or =2) [0/1/2]
`Tuv`	Voltage filter time constant [s]
`Tup`	Real power filter time constant [s]
`Tuq`	UEL reactive power filter time constant [s]
`Kuf`	Excitation system stabilizer gain [pu]
`Kfb`	Gain [pu]
`Tul`	UEL time constant [s]
`Kul`	Proportional gain [pu]
`Kui`	Integral gain [pu]
`Tu2`	UEL denominator (lag) time constant (first block) [s]
`Tu1`	UEL numerator (lead) time constant (first block) [s]
`Tu4`	UEL denominator (lag) time constant (second block) [s]
`Tu3`	UEL denominator (lead) time constant (second block) [s]
`VUImin`	UEL PI control minimum output [pu]
`VULmin`	UEL PI control maximum output [pu]
`VUImax`	UEL minimum output [pu]
`VULmax`	UEL maximum output [pu]
`p [0-10]`	UEL lookup table real power [pu]
`q [0-10]`	UEL lookup table reactive power [pu]

These PowerFactory components are mapped to MAXEX2 limiter exciter of the Native Library.

Parameter	Description	Acceptable Values
`Kmx`	OEL Gain [pu]	Any value
`L/M`	0 for EFD limiting, 1 for IFD limiting [0/1]
`TIME1`	Over Excitation Relay - Time First Value of Curve [s]
`XFDdes`	Minimum Excitation to Enable OEL [p.u.]
`XFDres/XFDrated`	XFD Rated [p.u.]
`XFD1`	Over Excitation Relay - Voltage/Current First Value of Curve [p.u.]
`XFD2`	Over Excitation Relay - Voltage/Current Second Value of Curve [p.u.]
`TIME2`	Over Excitation Relay - Time Second Value of Curve [s]
`XFD3`	Over Excitation Relay - Voltage/Current Three Value of Curve [p.u.]
`TIME3`	Over Excitation Relay - Time Three Value of Curve [s]
`Vlow`	Maximum OEL signal [p.u.]