Under Excitation Limiter: UEL2C

 

Following checks and corrections are applied during Validation and AutoCorrection.

  • If Kfix <= 0.0001 then Kfix = 0.0001
  • If 0.0 < Tuv < 0.5*Mult*TimeStep then Tuv = 0, ElseIf 0.5*Mult*TimeStep < Tuv < Mult*TimeStep then Tuv = Mult*TimeStep
  • If 0.0 < Tup < 0.5*Mult*TimeStep then Tup = 0, ElseIf 0.5*Mult*TimeStep < Tup < Mult*TimeStep then Tup = Mult*TimeStep
  • If 0.0 < Tuq < 0.5*Mult*TimeStep then Tuq = 0, ElseIf 0.5*Mult*TimeStep < Tuq < Mult*TimeStep then Tuq = Mult*TimeStep
  • If 0.0 < TuL < 0.5*Mult*TimeStep then TuL = 0, ElseIf 0.5*Mult*TimeStep < TuL < Mult*TimeStep then TuL = Mult*TimeStep
  • If 0.0 < Tu2 < 0.5*Mult*TimeStep then Tu2 = 0, ElseIf 0.5*Mult*TimeStep < Tu2 < Mult*TimeStep then Tu2 = Mult*TimeStep
  • If 0.0 < Tu4 < 0.5*Mult*TimeStep then Tu4 = 0, ElseIf 0.5*Mult*TimeStep < Tu4 < Mult*TimeStep then Tu4 = Mult*TimeStep
  • If 0.0 < TQref < 0.5*Mult*TimeStep then TQref = 0, ElseIf 0.5*Mult*TimeStep < TQref < Mult*TimeStep then TQref = Mult*TimeStep
  • If 0.0 < Tadj < 0.5*Mult*TimeStep then Tadj = 0, ElseIf 0.5*Mult*TimeStep < Tadj < Mult*TimeStep then Tu4 = Mult*TimeStep
  • Kul and Kui: Kul can't be 0 if Kui = 0, if true then Kul changed to 40.

  • If VUImax < VUImin then swap the values. If VUImax < 0 then VUImax change sign to positive. If VUImin > 0 then change sign to negative.

  • If VUELmax1 < VUELmin1 then swap the values. If VUELmax1 < 0 then VUELmax1 change sign to positive. If VUELmin1 > 0 then change sign to negative.
  • If VUELmax2 < VUELmin2 then swap the values. If VUELmax2 < 0 then VUELmax2 change sign to positive. If VUELmin2 > 0 then change sign to negative.

Mult represents the user-specified value Minimum time constant size as multiple of time step option on the Validation page of the Transient Stability Dialog

TimeStep represents the integration time step being used as described on TimeStep

Following treatment is handled during the transient numerical simulation

  • If VUEL > VUELmax1 , then VUELmax1 = VUEL limits or if VUEL < VUELmin1 , then VUELmin1 = VUEL
  • If LeadLagU1U2 > VUELmax2, then VUELmax2 = LeadLagU1U2 limits or if LeadLagU1U2 < VUELmin2 , then VUELmin2 = LeadLagU1U2
  • If PIIntegrator > VUImax, then VUImax = PIIntegrator limits or if PIIntegrator < VUImin, then VUImin = PIIntegrator

Model Equations and/or Block Diagrams

Parameters:

Tup UEL real power filter time constant (s)
Tuq UEL reactive power filter time constant (s)
Tuv UEL voltage filter time constant (s)
Vbias UEL voltage bias (pu)
K1 Voltage exponent for real power input to UEL table
K2 Voltage exponent for reactive power output to UEL table
Kuf UEL excitation system stabilizer gain (pu)
TQref UEL reactive power reference time constant (s)
Kfix UEL fixed gain reduction factor (pu)
Tadj UEL adjustable gain reduction time constant (s)
SW1 UEL logic switch for adjustable gain reduction (1 = Position A, 2 = Position B)
Kui UEL integral gain (pu/s)
Kul UEL proportional gain (pu)
Vuimax Vuimax: UEL PI control maximum output (pu)
Vuimin Vuimin: UEL PI control minimum output (pu)
Tu1 UEL numerator lead time constant in first block (s)
Tu2 UEL denominator lag time constant in first block (s)
Tu3 UEL numerator lead time constant in second block (s)
Tu4 UEL denominator lag time constant in second block (s)
VUELmax1 VUELmax1: UEL maximum output 1 (pu)
VUELmin1 VUELmin1: UEL minimum output 1 (pu)
VUELmax2 VUELmax2: UEL maximum output 2 (pu)
VUELmin2 VUELmin2: UEL minimum output 2 (pu)
Kfb UEL FB Gain
TuL UEL FB time constant (s)
Xq The Q-axis synchronous reactance of the generator (pu)
P0 UEL lookup table real power (first point)
Q0 UEL lookup table reactive power (first point)
P1 UEL lookup table real power (second point)
Q1 UEL lookup table reactive power (second point)
P2 UEL lookup table real power (third point)
Q2 UEL lookup table reactive power (third point)
P3 UEL lookup table real power (fourth point)
Q3 UEL lookup table reactive power (fourth point)
P4 UEL lookup table real power (fifth point)
Q4 UEL lookup table reactive power (fifth point)
P5 UEL lookup table real power (sixth point)
Q5 UEL lookup table reactive power (sixth point)
P6 UEL lookup table real power (seventh point)
Q6 UEL lookup table reactive power (seventh point)
P7 UEL lookup table real power (eigth point)
Q7 UEL lookup table reactive power (eigth point)
P8 UEL lookup table real power (ninth point)
Q8 UEL lookup table reactive power (ninth point)
P9 UEL lookup table real power (tenth point)
Q9 UEL lookup table reactive power (tenth point)