Adaptive non-communication protection for power lines BO scheme. II. The instant operation approach

This paper presents the instant operation scheme of the adaptive non-communication protection technique for power lines. In the technique, protection relays make tripping or reclosure decisions adapting to system and fault conditions without the need for communication links. The non-communication is achieved by the detection of whether or not the system is in a balanced operation, in order to identify the breaker operation at the remote end of the protected section. In the scheme, the distance relay will trip instantly when a fault is detected outside its zone 1, but within its zone 2 reach. Subsequently, it detects whether the fault is on the protected section or not, and recloses when a fault is cleared from the protected line section. Simulation studies with responses to various system and fault condition have shown that the technique is able to give fast and correct response without the need for a communication link.