PROTECTIVE DEVICE FOR NETWORK POWER TRANSMISSION

PROBLEM TO BE SOLVED: To provide a protective device for network power transmission that surely protects power transmission lines while minimizing a power failure range when an accident occurs in power transmission lines connected in a loop shape. SOLUTION: A protective device protects a power transmission system configured in a loop shape by interconnecting a plurality of power stations 11, 12, 13, and 14 by power transmission lines 41, 42, 43, and 44. Each of the power stations constituting the loop-shaped power transmission system, is provided with calculation stations 21, 21a, a plurality of terminal stations 22, 22a, 23, 23a, and 24, 24a and two sets of protective systems 60, 60a allowing data transfer among these stations. As cutoff conditions to both-end circuit breakers in the fault section at a power transmission line accident, elements for detecting an overcurrent state caused by the power transmission line accident as well as cutoff commands from both protective systems are added as AND conditions. Consequently, it minimizes a power failure section while preventing the unnecessary cutoff of a healthy section. COPYRIGHT: (C)2009,JPO&INPIT