Abstract: A remote transmission device for the automation of an electrical power distribution system includes a pilot and slave mechanism of communication by on-line carrier currents using capacitive coupling of the lines of the power system as transmission support for the exchange of information and order to a plurality of breaking devices. Depending on the priority code of modems in the system, on the level of the received signal, and on the open or closed position of certain breaking devices, the transmission device breaks down automatically into several disunited subsystems, each containing a source substation to which a communication zone is assigned, whose boundaries in normal operating conditions are formed by open line switches. In emergency situations, the boundaries of the communication zones are modified by a coupling circuit which can be in a first by-pass state or in a second dual coupling state.