Remote power supply system for equipment on a transmission line

A remote power supply system for powering remote equipment located at a point along a transmission line, said transmission line being equipped with a remote power supply loop which passes through said point and which loops through a source of electrical energy, the system including at said point:

• a first control switch;
• a looping impedance connected in series with the first controlled switch, means connecting said series connection of switch and impedance in shunt across the remote supply loop, thereby dividing the remote supply loop into two partial loops, one of which includes the source of energy;
• two local power supply circuits within the remote supply loop, one on either side of the looping impedance, a first one of said local power supply circuits being within the partial loop that includes the source of energy and serving to supply power to the equipment in normal operation, the other, second local power supply circuit being within the other partial loop;
• and
• a control circuit for said first controlled switch, the control circuit including means sensitive to the state of operation of each of the local power supply circuits and including means for closing the first controlled switch when the first local power supply circuit is not in operation and for opening the first controlled switch when both local power circuits are operating simultaneously.