Wide-area current differential backup protection employing broadband communications and time transfer systems

As power systems grow larger, it is becoming difficult to achieve reach and time coordination in backup protection when using distance relays. To cope with those problems, current differential backup protection for a busbar and transmission circuits connected to that busbar on an inter-station or wide-area basis is proposed. The proposed system can operate better than conventional systems with respect to operate time, section selectivity, and so on. A system configuration is also proposed to utilize ATM transmission networks and time synchronous systems which make the construction and operation of the proposed wide-area protection system easy and flexible.