Load Response Coefficients Monitoring System : Theory and Field Experience

The active and reactive powers, at a high voltage bus level, have generally been modelled either as functions of the time of the day or as load response functions of voltage and frequency changes (at a given time). The study of the dependence of these load response coefficients on time and weather has not been possible until now, since the determination of these coefficients required test perturbations. A mobile mini-computer based load response coefficient monitoring system has been conceived and tested, based on an estimation procedure requiring no test perturbations. Results, including the load response coefficients at about 6-minute intervals, from the operation of the system, at two Hydro-Quebec 120 kV substations, are also presented.