MAXIMUM DEMAND CONTROL: A SURVEY AND COMPARATIVE EVALUATION OF DIFFERENT METHODS
FCT - Universidade de Coimbra
Departamento de Engenharia ElectrotΘcnica
Laboratório de Gestão de Energia
Maximum demand (MD) control is a well established tool by means of which electricity end-users avoid the penalties of MD charges, in use under a great number of tariff schemes. This type of control is based on some means of measuring the power demand and automatically shedding and restoring loads in order that a pre-specified level of power is not surpassed. It may be supported on large energy management systems or on dedicated controllers with specific firmware. In either case, there are several algorithms that may be used to implement MD control. A few fundamental classes of algorithms may be identified, and a great number of modified versions are currently implemented, with different degrees of flexibility and effectiveness of control. The paper assesses some of the fundamental classes referred and also some modified algorithms. A software simulation package (SIMCA - E2) has been used to perform the tests, using some typical as well as some extreme load situations, seeking to assure comparability between the different tested algorithms. The main criteria used for evaluation have been: effectiveness of MD control, unavailability of loads and frequency of shedding actions. The results are discussed both in a self- -contained analysis for each class of algorithms and in a cross- -comparative fashion.
Load control algorithms