FIELD: electrical engineering. SUBSTANCE: gear for centralized directional protection against fault to ground in network with neutral grounded through high-resistance resistor is designed for protection of aerial power lines in corresponding systems. Known gear for centralized directional protection against fault to ground incorporating first instrument voltage transformer of zero sequence which input is connected to first section of collecting buses of feeding substation and which output is connected to input of first filter 1 of commercial frequency to which output first input of first logic AND gate 4, actuators 30 in number equal to number n of protected lines are connected through phase shift unit 2 and first comparator 3 is additionally inserted with second instrument voltage transformer of zero sequence, three current transformers into each circuit of protected line two current transformers in circuits of high- resistance grounding resistors, n pickups of current of zero sequence, n+1 filters 9, 19 of commercial frequency, 3n+3 comparators 20, 23, 29, 8, 11, 13, 2n+1 logic AND gates 12, 21, 25, 2n converters 22, 28 of rectangular pulses to sawtooth voltage, n pulse stretchers 24, n+2 operational plates 31, 43, 46, four threshold elements 5, 14, 41, 44, two matching elements 6, 15 second phase shift unit 10, adder 7, 2n+2 signalling elements 16, 17, 32, 33, two time delay elements 42, 45, tester 40 of serviceability of gear and n diodes with corresponding couplings. Proposed gear uses information both from group of lines connected to one section of collecting buses of substation and of second section of collecting buses. EFFECT: higher selectivity and sensitivity of proposed gear as compared with prototype. 10 dwg
