Abstract: In a utility power distribution system having at least one primary electric power source and at least one secondary electric power source, each of said primary and secondary sources being connected to the distribution system through respective controllable circuit breakers, the improvement comprising communication signal generating apparatus arranged for introducing a communication signal into the power distribution system from the connection of the primary power source, communication signal receiving apparatus arranged for receiving the communication signal via the power distribution system at the secondary power source, and apparatus responsive to the interruption of receipt of the communication signal at the receiving apparatus for operating the circuit breakers at the secondary power source for disconnecting the secondary power source from the power distribution system.

Abstract: In a utility power distribution system having at least one primary electric power source and at least one secondary electric power source, each of said primary and secondary sources being connected to the distribution system through respective controllable circuit breakers, the improvement comprising communication signal generating apparatus arranged for introducing a communication signal into the power distribution system from the connection of the primary power source, communication signal receiving apparatus arranged for receiving the communication signal via the power distribution system at the secondary power source, and apparatus responsive to the interruption of receipt of the communication signal at the receiving apparatus for operating the circuit breakers at the secondary power source for disconnecting the secondary power source from the power distribution system.

Abstract: A broken conductor guard system for a single neutral power distribution system in which at least one high voltage power conductor is suspended between power poles with a neutral conductor being similarly suspended between the poles vertically below the high voltage conductor includes a broken conductor guard comprising an elongated rod with hook-shaped ends clamped with a clamping mechanism to a single neutral conductor in a horizontal plane and transverse to the neutral conductor. Apparatus is coupled to the clamping mechanism for preventing rotation of the broken conductor guard about the neutral conductor so as to maintain the guard in the horizontal plane.

Abstract: A broken conductor guard for use in an electrical power transmission system including at least one high potential power conductor positioned vertically above two neutral conductors. The broken conductor guard comprises a conductive rod electrically connected transverse to the neutral conductors. The rod extends a predetermined distance on each side of the two neutral conductors in a substantially horizontal plane such that a broken high-potential conductor will fall on the rod and be short-circuited to the neutral conductors.