WIDE-AREA CURRENT DIFFERENTIAL BACKUP PROTECTION EMPLOYING BROAD-BANDCOMMUNICATIONS AND TIME TRANSFER SYSTEMS

As power systems grow larger, it is becoming difficult to achieve reac h and time coordination in backup protection when using distance relay s. 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 propo sed to utilize ATM transmission networks and time synchronous systems which make the construction and operation of the proposed wide-area pr otection system easy and flexible.