Development and Testing of an Electro-Mechanical Relay to Detect Fallen Distribution Conductors

If undetected by phase or ground overcurrent relaying methods, fallen distribution conductors or high impedance faults may be a fire hazard and a threat to public safety. Four promising relay schemes to detect these faults are evaluated using both digital and analog techniques and one scheme was chosen for prototype construction. In the light of economic and performance data, a prototype Ratio Ground Relay has been constructed for installation and testing on six Pennsylvania Power and Light distribution feeders.