Load Characteristic Model: LD1PAC_CMP

 

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 < Tth < 0.5*Mult*TimeStep then Tth = 0
    ElseIf 0.5*Mult*TimeStep < Tth < Mult*TimeStep then Tth = Mult*TimeStep
  • If 0.0 < Tf < 0.5*Mult*TimeStep then Tf = 0.0
    ElseIf 0.5*Mult*TimeStep < Tf < Mult*TimeStep then Tf = Mult*TimeStep

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

Model Equations and/or Block Diagrams

-Model is the same as LD1PAC, except parameters on the right below are

-Hard-coded as shown.

Parameters:

Lfm Loading Factor
TV Voltage input time in sec.
CompPF Compressor Power Factor
Vstall Compressor Stalling Voltage in p.u.
Rstall Compressor Stall resistance in p.u.
Xstall Compressor Stall impedance in p.u.
Tstall Compressor Stall delay time in sec.
Frst Restarting motor fraction
Vrst Restart motor voltage in p.u.
Trst Restarting time delay in sec.
Vc1off Voltage 1 contactor disconnect load in p.u.
Vc2off Voltage 2 contactor disconnect load in p.u.
Vc1on Voltage 1 contactor re-connect load in p.u.
Vc2on Voltage 2 contactor re-connect load in p.u.
Tth Compressor heating time constant in sec.
Th1t Compressor motors begin tripping
Th2t Compressor motors finished tripping
fuvr Fraction of compressor motors with undervoltage relays
uvtr1 to uvtr2 Undervoltage pickup level in p.u.
ttr1 to ttr2 Undervoltage definite time in sec.
Tf 0.05
LFadj 0
KP1 to KP2 Kp1 = 0; Kp2 = 12
NP1 to NP2 Np1 = 1; Np2 = 3.2
KQ1 to KQ2 Kq1 = 6; Kq2 = 11
NQ1 to NQ2 Nq1 = 2; Nq2 = 2.5
Vbrk 0.86
CmpKpf 1
CmpKqf -3.3.
MBase Treated as -abs(Lfm)