Abstract :
A technique to quantitatively determine the limits to zones of simultaneous tripping, considering the effects of various power system parameters´ uncertainties, is presented. The relay reach is modelled as a function of these parameters, and mathematical programming is used to determine its optimum value, satisfying the specified set of system constraints. Simulation results are presented for different types of faults on a three-terminal line considering factors such as transmission line parameter uncertainties, metering errors, and variations in load requirements, source impedances and the charging currents
