Computer Control of the Large Power System during Faults for Inherently Adaptive Selective Protection

In this paper a new overall approach is presented to the selective network protection problem in the framework of computer control of the power system in normal and emergency conditions. The result is an inherently adaptive selective protection based on the concept of minimal nested protection units. This system uses no explicite individual relays but it is a systemwide interacting computer control. Adherence to classical concept such as distance relays has became an impediment on developing selective protection which actually exploits the potential of digital computer technology. These classics were ingenious developments in an age when microprocessors were built of steel, copper and an aluminum disk. Much more effective selective protection should be possible in todays technological context. This paper tries to point the way.