FIELD: measurement.
SUBSTANCE: invention relates to electric measuring equipment and can be used in electric installations, at electric stations and substations, electric networks and communication networks to determine insulation state and to predict insulation life. Result is achieved due to installation of a delay unit into the system. This unit provides unobstructed transmission of signals of reverse and zero sequence currents in system operating mode. When the line is switched on for voltage, this unit for a certain period of time breaks the connection between the outputs of the reverse and zero sequence current sensors and microcontroller inputs. Time interval to which communication is interrupted shall ensure sufficient attenuation of shots of charging currents and false actuation of the system under the influence of these currents. It comprises zero-sequence current transformers; zero-sequence current sensors; zero-sequence voltage transformer; zero-sequence voltage sensor; microcontroller; power supply unit; interface converter; personal computer; current transformers; negative sequence currents filter; delay unit.
EFFECT: technical result consists in improvement of reliability and ensuring selectivity of the system.
1 cl, 3 dwg
