Economic study of secondary distribution

IN working toward the efficient and economical design of the central station system as a whole no link in the chain connecting the consumer with the coal pile may be overlooked. The ultimate purpose of all study in this direction is to enable energy to be delivered to the customer at the least possible cost per unit, while at the same time good service is maintained. To this purpose considerable attention has been paid to generating plant, transmission lines and substations, but on the final link before reaching the customer — the distribution lines — the tendency has been to apply “rule of thumb” methods and “experience” only to the layouts. When it is considered that even in a well designed system the investment in distribution lines will often be from one-fifth to one-fourth of the total investment on the system and that the energy losses on these lines will be equal to or somewhat more than one-half of the total loss between the generator and the customer, it may be expected that a study of the economical design of distribution lines will be found of great profit. Such has been found to be the case, and the results of the study of secondary distribution described in this paper have been already applied to good advantage in the layout of such lines.