Supervisory systems for electric power apparatus

A general survey and description of the various types of supervisory systems for control and indication of remotely located electrical apparatus is given in the paper, the author first of all comparing the better known remote-control system with the supervisory system in general practise today. Description is given of the selector, distributor, audible, code-visual, synchronous-relay-visual and the carrier-current systems, the principles and features of each being discussed. The subject of telemetering is also included, together with an expression of the author´s ideas of future possibilities for each of the systems above enumerated.