Principles for Implementation of Digital Power Direction Control in Microprocessor Current Protections

In the existing microprocessor-based directional current protection lines from phase-to-phase short circuits, digital power direction elements are used, which, as a rule, switched on at full currents and voltage according to so-called 90-degree pattern. With this switching scheme, “dead” zone appears only in case of three-phase circuits close installation site, which make up small fraction all possible types such damage. Nevertheless, its presence is significant drawback organs. The principles organ execution based operations with orthogonal components input voltages have been considered. result functioning body reduced development an information sign equal to: one – direct power; minus when it opposite direction. To eliminate zone, work organized using “memory”. order obtain required duration “memory”, frequency compensation implemented. study effectiveness decisions made, well behavior control normal emergency modes, has carried out by method computational experiment. MATLAB-Simulink-SimPowerSystems dynamic simulation system, models electrical system developed. results research shown that joint use proposed for implementation ensures increase technical perfection eliminates while maintaining stable operation arbitrarily long period time.