Single-Phase Power Service from Central Stations

The purpose of the paper is to outline several methods by which single-phase power may be supplied from a polyphase system and to discuss their advantages and disadvantages. The unbalance in voltage when single-phase power is supplied direct from a polyphase circuit is explained. The law of distribution of load in the polyphase system is deduced, and the limitations of this method of supplying single-phase power are discussed. Single-phase generation is one solution of the problem, motor or steam drive may be used depending on the size of unit required. An outline of the theory of the single-phase generator is given from different points of view. The essential requirements for phase balancing are deduced from which an outline of the theory of phase balancing is developed. Attention is called to the requirements of the control apparatus. The behavior of the balancer under short circuit is given consideration. The merits of single-phase generation and phase balancing in the case of a single-phase load from one phase are discussed, with the conclusion that there is little difference in cost between the two schemes and there is much to be said in favor of single-phase generation for such a case.