Tales from the Frontline: Keys to Successful Self-Healing Distribution Projects

Self-healing is a critical aspect of the smart grid offering significant opportunity for reliability improvement. The average duration of outages on a system (SAIDI) can be cut in half with a self-healing network on a simple open-loop circuit with one sectionalizing point assuming the customers are evenly distributed and the fault rate is uniform. The goal of a self-healing network is to automatically restore the un-faulted sections of a feeder within the time defined as an “interruption” which is less than 5 minutes, as defined by IEEE 1366. The term “self-healing” may be misleading because thefault itself is not automatically repaired. Instead, the term “self-healing” really means the system automatically reconfigures around a fault to restore as many customers as possible without human intervention. This is done while line crews are dispatched to the faulted section to fix it.