Carrier Current Supervisory System for Distribution Circuits

A new method is described for supervising sectionalizing devices on distribution systems by utilizing a centrally transmitted, unmodulated carrier. This carrier is remotely modulated by equipment located on the load side of the monitored sectionalizing device, and the modulated carrier is received at a conveniently located receiver. A novel indicator gives instantaneous warning of operation of sectionalizing devices or equipment failure. Simplicity and low cost make its use on distribution systems feasible for monitoring of large numbers of sectionalizing devices.