An analysis of the load on a modern electricity-supply system

The paper contains an analysis of the load on the system of the Northmet Power Co. during a pre-war year. The block of annual load is split up into a basic, or all-the-year round, portion, and a seasonal portion, the latter representing all the consumption due to spaceheating, and about half that due to lighting. The basic portion is sub-divided into its principal components, and, as regards the seasonal portion, an attempt is made to separate lighting load and spaceheating load, both as to demand and annual consumption. For this purpose ¿seasonal demand curves¿ are developed, in which the load at a certain time of day is plotted for a series of days, and compared with the simultaneous conditions of outdoor temperature and illumination. The annual load factors of modern lighting and spaceheating loads are found to be normally of equal order of magnitude; in a year with a ¿cold snap¿ the load factor of the latter may even be considerably lower than that of the former. Characteristic collective and component load curves are given; and also graphs dealing particularly with the space-heating load. The paper concludes with recommendations for further research.