A protection plan for distribution feeders

MANY UTILITIES are increasing distribution system primary circuit voltages as a means of supplying continually growing loads in urban areas. However, the fundamental advantage of higher-voltage feeder design, the ability to serve more load in larger areas, prevents the substation circuit breaker and its associated relays from providing adequate protection for the entire feeder. Automatic line-sectionalizing devices must be provided to restrict outages to a portion of a feeder area, thereby limiting the customers without service and reducing the area that must be patrolled to locate the fault.