The Economics of Direct-Current Railway Distribution With Particular Reference to the Automatic Substation

Abstract

The comparatively recent development of the full automatic substation and also the automatic substation combined with remote control, has served to re-open the entire subject of the economics of distribution. But quite aside from the questions that the automatic substation has presented, the great fluctuations in the prices of materials and, of labor have made necessary renewed study of this subject. In other words, the proper design of a distribution system should represent a balance between all of the different items of cost that go to make up the total cost of power. Any change in the relative cost of materials as against labor or of a certain class of materials as against another class of materials tends to upset such a balance. Now that we begin to emerge from the unsettled conditions of the past few years during which the old relationships have been substantially changed, it is necessary to ask the question whether or not the rules by which distribution systems have been planned in the past still apply. More specifically, it is the purpose of this paper to determine, first, the relations that govern the size of feeders and the correct feeder layouts for any given arrangement of substations, and second, the principles underlying the correct location, size, and type of substations, assuming the fullest development of automatic and semi-automatic control. There is involved also the important question of stray currents.