Exciter Model: REEC_B and REECB1

 

Following checks and corrections are applied during Validation and AutoCorrection.

  • If 0.0 < Tv < 0.5*Mult*TimeStep then Tv = 0, ElseIf 0.5*Mult*TimeStep < Tv < Mult*TimeStep then Tv = Mult*TimeStep
  • If 0.0 < Tp < 0.5*Mult*TimeStep then Tp = 0, ElseIf 0.5*Mult*TimeStep < Tp < Mult*TimeStep then Tp = Mult*TimeStep
  • If 0.0 < Tiq < 0.5*Mult*TimeStep then Tiq = 0, ElseIf 0.5*Mult*TimeStep < Tiq < Mult*TimeStep then Tiq = Mult*TimeStep
  • If 0.0 < Tpord < 0.5*Mult*TimeStep then Tpord = 0, ElseIf 0.5*Mult*TimeStep < Tpord < Mult*TimeStep then Tpord = Mult*TimeStep
  • Kpp and Kip can't be both zero. Must be corrected by user.
  • If Vmax < Vmin then swap the values
  • If Qmax < Qmin then swap the values
  • If Pmax < Pmin then swap the values
  • If RPmax < RPmin then swap the values
  • If Iqh < Iql then swap the values

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 Q limits > Qmax , then Qmax = Q limits or if Q limits < Qmin , then Qmin = Q limits
  • If PIq limits > Vmax , then Vmax = PIq limits or if PIq limits < Vmin, then Vmin = PIq limits
  • If Pord > Pmax , then Pmax = Pord or if Pord < Pmin, then Pmin = Pord

Model Equations and/or Block Diagrams

Parameters:

PfFlag Power factor flag (1 – power factor control, 0 – Q control, which can be commanded by an external signal)
VFlag Voltage control flag (1 – Q control, 0 – voltage control)
QFlag Reactive power control flag ( 1 – voltage/Q control, 0 – constant pf or Q control)
Pqflag P/Q priority selection on current limit flag. 0 = Q priority; 1 = P priority
Vdip The voltage below which the reactive current injection (Iqinj) logic is activated (i.e. voltage_dip = 1)
Vup The voltage above which the reactive current injection (Iqinj) logic is activated (i.e. voltage_dip = 1)
Trv Filter time constant for voltage measurement
dbd1 Deadband in voltage error when voltage dip logic is activated (for overvoltage – thus overvoltage response can be disabled by setting this to a large number e.g. 999)
dbd2 Deadband in voltage error when voltage dip logic is activated (for undervoltage)
kqv Gain for reactive current injection during voltage dip (and overvoltage) conditions
Iqh1 Maximum limit of reactive current injection (Iqinj)
Iql1 Minimum limit of reactive current injection (Iqinj)
Vref0 The reference voltage from which the voltage error is calculated. This is set by the user. If the user does not specify a value it is initialized by the model to equal to the initial terminal voltage.
Tp Filter time constant for electrical power measurement
Qmax Reactive power limit maximum
Qmin Reactive power limit minimum
Vmax Voltage control maximum
Vmin Voltage control minimum
Kqp Proportional gain on Q control
Kqi Integral gain on Q control
Kvp Proportional gain on V control
Kvi Integral gain on V control
Tiq Time constant on lag delay
dPmax Positive Ramp rate on power reference
dPmin Negative Ramp rate on power reference
Pmax Maximum power reference
Pmin Minimum power reference
Tpord Filter time constant on Pord
Imax Maximum allowable total converter current limit
MVABase MVABase

Current Limit Logic Psuedo Code

The following pseudo-code describes how the values for Ipmax, Ipmin, Iqmax, and Iqmin are updated.

  local_V = StateVtfilter // Vt State 1

  Iqmax = Imax

  Ipmax = Imax

  if PQFlag = 0 then begin // Q priority [default]

    Iqmin = -Iqmax

    local_I = Sqr(Imax) - Sqr(Iqcmd)

    if local_I < 0 then local_I = 0

    else local_I = sqrt( local_I )

    if local_I < Ipmax Then Ipmax = local_I

    Ipmin = 0

  end

  else Begin// P priority

    Ipmin = 0

    local_I = Sqr(Imax) - Sqr(Ipcmd)

    if local_I < 0 then local_I = 0

    else local_I = sqrt( local_I )

    if local_I < Iqmax Then Iqmax = local_I

    Iqmin = -Iqmax

  end