Load Characteristic Model: WSCC

 

Model Equations and/or Block Diagrams

Model supported by PSLF

Parameters:

p1 Constant impedance fraction in p.u.
q1 Constant impedance fraction in p.u.
p2 Constant current fraction in p.u.
q2 Constant current fraction in p.u.
p3 Constant power fraction in p.u.
q3 Constant power fraction in p.u.
p4 Frequency dependent power fraction in p.u.
q4 Frequency dependent power fraction in p.u.
lpd Real power frequency index in p.u.
lqd Reactive power frequency index in p.u.

If p4 OR q4 are non-zero then

P=P_o [p_1 V^2+p_2 V+p_3+p_4 (1+lpd(freqpu-1))]

Q=Q_o [q_1 V^2+q_2 V+q_3+q_4 (1+lpq(freqpu-1))]

else

P=P_o [p_1 V^2+p_2 V+p_3 ][1+lpd(freqpu-1)]

Q=Q_o [q_1 V^2+q_2 V+q_3 ][1+lpq(freqpu-1)]

V= per unit voltage magnitude at the terminal bus

freqpu = per unit bus frequency at the terminal bus

P_o and Q_o are calculated during initialization to match the initial conditions