An intelligent approach for system separation to prevent a blackout

A system blackout is a hazardous fault to the security of operation of power systems. It causes heavy damage to the industry and social life. In this paper an on-line approach to determine the optimal separate point (s) is proposed. It includes the following parts: (1) To detect whether it is a transient stability disturbance. (2) If it is, a transient stability simulation is started to run until rotor angles between the leading generator and lagging one reaching 180 degrees. (3) Classify generators into leading group and lagging group by their angles at the instant of 180 degrees between the leading generator and lagging one. (4) Trip all lines between the leading group and lagging group, then the power system will be separated into two islands. (5) Adjust the separation points to make both islands nearly balanced (summation of active power in all lines flowing into and from either leading or lagging group should be minimum). IEEE 10 machine, 39 bus test system has been used as an example to test the validity of this approach.