Abstract :
Originally designed for railway service in small units, the use of the non-attended automatic substations has gradually been extended to substations feeding d-c. networks and a-c. lighting and power distributions of increased capacity and importance. They are justified economically up to the point at which the fixed charges and operating costs on the additional equipment required over and above a manually-operated station, equal the costs of attendance. A description of an a-c. station having an ultimate capacity of 12,000 kw. follows, emphasis being laid upon the more interesting features of design.
