FIELD: electrical engineering; electric power industry.
SUBSTANCE: invention relates to AC power supply lines. Contact system feeders remote protection device, containing primary current and voltage converters, connected through the corresponding current and voltage band-pass filters to the actuating angular characteristic generator and the input resistance calculation unit, at that, the output of the primary current converter is also connected through the series-connected unit for calculating the constant harmonic current component and the threshold element of the constant harmonic current component to the input of the AND logic element, other inputs of which are connected to the output of the angular characteristic generator and through the threshold element of the input resistance to the output of the resistance calculation unit, and the output of which is connected through the series-connected logic element of the time delay generator and the output element to the circuit breaker drive of the protected feeder of the contact system, characterized by that it additionally includes a unit for calculating the constant harmonic current component and a threshold element of the constant harmonic current component.
EFFECT: increased sensitivity of protection of feeders of contact network to short circuits in conditions of residual load and improved detuning from normal operation mode, which makes it possible to unambiguously determine short circuit with its subsequent disconnection, thereby preventing development of accident with damages of connected equipment, as well as preventing false operation of protection in normal operating mode of line at increased current loads; due to the presence in the disclosed device of elements for the identification of normal and emergency modes by the content of the constant harmonic current component, additionally, it becomes possible to implement protection against short circuits in three-phase distribution networks.
1 cl, 1 dwg
