A new distribution automation technique without the need for communication link

The paper presents a new technique for distribution automation based on an accelerated protection theory. A specially designed directional under voltage relay is arranged to trip for faults on the line section from the source direction of the system. The relays on the source side of the line section detect the system balanced operation condition and accelerated operation isolates the fault from both ends of the line section. Extensive simulation studies with respect to a typical open ring main system show that the proposed technique is able to remove a faulted line section quickly and accurately from both ends and, therefore, enables the power supply to be quickly restored to the healthy line sections.