Load Characteristic Model: MOTORC

 

Model Equations and/or Block Diagrams

This model builds on the INDMOT1P model, but makes some modifications

1. Replaces the saturation input parameters and has user enter ASat and BSat directly

2. Simplifies the mechanical torque equation to a single parameter D.

3. Includes under-voltage, contractor, and thermal relays identical to the LD1PAC model

Parameters:

R_ds	stator d-axis resistance in per unit
R_qs	stator q-axis resistance in per unit
X_m	magnetizing reactance in per unit
X_c	capacitor reactance in per unit (will be negative)
X_ds^'	stator d-axis reactance in per unit
X_qs^'	stator q-axis reactance in per unit
X_r	rotor reactance in per unit
T_o^'	rotor time constant in seconds. Entered instead of R_r , R_r=X_r/(ω_b T_o^' )
H	inertia constant for the motor
D	Exponential term of the mechanical power equation: T_mech=T_nom (ω_r^(D-1) ); (Note: This term will always be 1 more than the Etrq term on a similar INDMOT1P model)
Asat	Parameter for Saturation equation
Bsat	Parameter for Saturation equation
n	ratio of stator auxiliary winding turns to stator main winding turns
ndelt	This parameter is not used by PowerWorld, but is carried around to support DYD files
wdelt	This parameter is not used by PowerWorld, but is carried around to support DYD files
V_c1off	Voltage in per unit at which load fraction begins decreasing
V_c2off	Voltage in per unit at which load fraction decreases to zero
V_c1on	Voltage in per unit at which load fraction begins increasing
V_c2on	Voltage in per unit at which load fraction increases
T_th	Compressor heating time constant in seconds
T_h1t	Compressor motors begin tripping
T_h2t	Compressor motors finish tripping
F_uvr	Fraction of compressor motors with undervoltage relays
V_tr1	First undervoltage pickup level, p.u.
T_tr1	First definite time for U/V trip, sec.
V_tr2	Second undervoltage pickup level, p.u.
T_tr2	Second definite time for U/V trip, sec.
T_v	Voltage measurement delay in seconds
MBase	If MBase > 0 then machine parameters are on MVABaseUsed=MBase; If MBase = 0 then machine parameters are on MVABaseUsed = abs(MWInit); If Mbase < 0 then machine parameters are on MVABaseUsed = abs(MWInit/MBase)