METHOD TO PROTECT POWER TRANSMISSION LINES AND DEVICE FOR ITS REALISATION Russian patent published in 2013 - IPC H02H3/32 

FIELD: electricity.

SUBSTANCE: in the method to protect power transmission lines, which consists in generation of signals proportional to currents in direct and return wires of a power transmission line, generation of a signal proportional to a difference of the specified signals, comparison of this signal with a threshold one, generation of a working signal for disconnection of a power transmission line as this signal exceeds the threshold one, additionally signals proportional to currents in direct and return wires are produced from outputs of elements of thermal protection of electromagnetic circuit breakers. The device of power transmission line protection comprises a subtraction circuit (1), the output of which is connected with the input of the threshold device (2), the first (3) and second (4) electromagnetic circuit breakers, the inputs of which are connected accordingly with phase and zero input wires of the power transmission line, outputs with output wires of the power transmission line, elements of thermal protection of electromagnet circuit breakers are connected accordingly with the first and second inputs of the subtracting circuit (1), the output of the threshold device (2) is connected with the input of thyristor (5) control, the input and output of which are connected accordingly with outputs of the first (3) and second (4) electromagnetic circuit breakers.

EFFECT: development of a system of protection of electric lines.

2 cl, 1 dwg