Grebeniuk A. Devices and principles for protection of wire breakages in distribution and traction supply mains

The thesis is devoted to development of principles for air supply mains reliability improvement. The devices of preceding cutoff in open pit's safety facilities and electric supply efficiency context are developed. Typical ground shorts are considered, probable standard protection system fault under wire breakage or air mains electric power consumer short is proven. Methods for calculation of short circuit currents and zero sequence currents and voltages under specific ground shorts in isolated neutral mains and mains with compensators or resistors in neutrals are developed. Meteorological factors influence on open pits' air distribution mains and traction mains is considered. Aluminium wires' corrosion and its mechanical strength in distribution networks with 6(10) - 35 kV rated voltage is considered. Methods and principles of preceding cutoff for air distribution mains are developed for case of wire breakage. Methods provide wire's cutoff before its touchdown of the ground or grounded electric equipment. Thus electric safety improves and further emergency extension, equipment faults and economical losses are prevented.