Contents
Industrial and agricultural loads are implemented using a parametric load model, calculating the real and imaginary current, power, and resistance load components based on the time and existing weather data.
Parametric Loads
Parametric loads can be defined using the pqload object, which is derived from powerflow::load. A pqload object has varying contributions to constant impedance, current, and power depending on prevailing time and weather conditions, such as sunlight, temperature, humidity, wind speed, and rainfall. Each load component (Z, I, P) is nominally computed based on the prevailing weather and adjusted based on the time.
The weather load is computed from a linear transformation as a function of weather as follows:
where
 , , are the constant impedance, current and power components of the load, with and indicated the real and reactive parts and and are the magnitude and angle, respectively;
 is the outdoor temperature at the time in °F;
 is the relative humidity at the time in %;
 is the solar gains at the time in Btu/h;
 is the wind speed at the time in mph;
 is the rainfall at the time in inch/h;
Properties
The pqload object publishes the following variables, in addition to those published by powerflow::load.
Property  Type  Unit  Default  Description 

schedule  char1024    * * * * *:1.0;  The load schedule (default is always 1.0) 
weather  object    NULL  The climate object to use for this load. If NULL, the temperature coefficients will be ignored. 
Zp_T  double  ohm/degF  0  Resistance response to temperature 
Zp_H  double  ohm/%  0  Resistance response to humidity 
Zp_S  double  ohm.h/Btu  0  Resistance response to solar gains 
Zp_W  double  ohm/mph  0  Resistance response to wind 
Zp_R  double  ohm.h/in  0  Resistance response to rainfall 
Zp  double  ohm  ∞  Invariant resistance 
Zq_T  double  F/degF  0  Capacitance response to temperature 
Zq_H  double  F/%  0  Capacitance response to humidity 
Zq_S  double  F.h/Btu  0  Capacitance response to solar gains 
Zq_W  double  F/mph  0  Capacitance response to wind 
Zq_R  double  F.h/in  0  Capacitance response to rainfall 
Zq  double  F  0  Invariant capacitance 
Im_T  double  A/degF  0  Current magnitude response to temperature 
Im_H  double  A/%  0  Current magnitude response to humidity 
Im_S  double  A.h/Btu  0  Current magnitude response to solar gains 
Im_W  double  A/mph  0  Current magnitude response to wind 
Im_R  double  A.h/in  0  Current magnitude response to rainfall 
Im  double  A  0  Invariant current magnitude 
Ia_T  double  deg/degF  0  Current angle response to temperature 
Ia_H  double  deg/%  0  Current angle response to humidity 
Ia_S  double  deg.h/Btu  0  Current angle response to solar gains 
Ia_W  double  deg/mph  0  Current angle response to wind 
Ia_R  double  deg.h/in  0  Current angle response to rainfall 
Ia  double  deg  0  Invariant current angle 
Pp_T  double  W/degF  0  Real power response to temperature 
Pp_H  double  W/%  0  Real power response to humidity 
Pp_S  double  W.h/Btu  0  Real power response to solar gains 
Pp_W  double  W/mph  0  Real power response to wind 
Pp_R  double  W.h/in  0  Real power response to rainfall 
Pp  double  W  0  Invariant real power 
Pq_T  double  VAr/degF  0  Reactive power response to temperature 
Pq_H  double  VAr/%  0  Reactive power response to humidity 
Pq_S  double  VAr.h/Btu  0  Reactive power response to solar gains 
Pq_W  double  VAr/mph  0  Reactive power response to wind 
Pq_R  double  VAr.h/in  0  Reactive power response to rainfall 
Pq  double  VAr  0  Invariant Reactive power 
input_temp  double  degF    Observed temperature. Read only. 
input_humid  double  %    Observed humidity. Read only. 
input_solar  double  Btu/h    Observed solar gains. Read only. 
input_wind  double  mph    Observed wind speed. Read only. 
input_rain  double  in/h    Observed rainfall. Read only. 
output_admit_p  double  Ohm    Observed resistance. Read only. 
output_admit_q  double  Ohm    Observed capacitance. Read only. 
output_current_m  double  A    Observed current magnitude. Read only. 
output_current_a  double  degrees    Observed current angle. Read only. 
output_power_p  double  W    Observed real power. Read only. 
output_power_q  double  VAr    Observed reactive power. Read only. 
output_admittence  complex  Ohm    Observed impedance. Read only. 
output_current  complex  A    Observed complex current. Read only. 
output_power  complex  W    Observed complex power. Read only. 
The schedule is defined based the POSIX standard for crontab. The general syntax is
moh hod dom moy dow[ lpu][; ...]
where

moh
is the minute of hour; 
hod
is the hour of day; 
dom
is the day of month; 
moy
is the month of year; 
dow
is the day of week; 
lpu
is the load per unit (optional, 1.0 if omitted);
The block may be repeated as many times as needed to complete the schedule. Any unscheduled time interval is assumed to be 0.