METHOD OF PROTECTING FROM RECEIVING SIDE TWO PARALLEL LINES WITH ONE-SIDED SUPPLY Russian patent published in 2020 - IPC H02H7/22 

FIELD: electricity.

SUBSTANCE: use in power engineering for protection of parallel lines against short circuits. Method for protection from receiving side of two parallel lines with one-sided supply, in which instantaneous values of currents i₁ at first and i₂ on second line are measured in positive or negative half-wave of current at current rise, i₁ is compared to positive or negative half-wave with preset value of current i_ec, and when current i₁ reaches current value i_ec, while measuring instantaneous value of current i₁, beginning to count time t₁ to the moment, when to next positive or negative half-wave at current increase, value of current i₁ reaches specified value of current i_ec, measured time t₁ is compared to first and second preset time values t_ec1 and t_ec2, and if value t₁ is greater than a given time t_ec1, but less than a given time t_ec2, then the time count is repeated until the time value t₁ is greater than or equal to the preset time t_ec1 or the time value t₁ becomes less than or equal to the preset time t_ec2, then if one of these inequalities is satisfied, then disconnecting the first line, removing it for repair and after repair is included in operation, in the same way, with time reference t_1, time t₂ is counted when current i₂ reaches the second line with a given current value i_ec until the moment, when in next positive or negative half-wave at current rise value of current i₂ reaches i_ec, measured time t₂ is compared with first and second preset time values t_ec1 and t_ec2, and if value t₂ is more than preset time t_ec1, but less than a given time t_ec2, the time count is repeated until the time value t₂ is greater than or equal to a given time t_ec1 or the time value t₂ becomes less than or equal to a given time t_ec2, then if one of these inequalities is satisfied, then switching off second line, brought out for repair and, after repair, is put into operation, simultaneously with switching on deactivated second or first line in operation, when first or second line is in on position, starting to count time t₃ from moment, when current i₁ or i₂ reaches preset value of current i_ec in positive or negative half-wave of current till moment, when current i₂ or i₁ becomes equal to value of preset current i_ec, comparing t₃ with third preset time t_ec3, and if time t₃ is greater than or equal to value of preset time t_ec3, both lines are switched off, then through time t₄ includes first or second line, then after preset time t₅ after switching on its position is fixed, and if it is in on position, then second or first line is brought out for repair, if it is in disconnected position, then the second or the first line is switched on, and the first or the second line is brought out for repair.

EFFECT: detecting and reducing the time of disconnection of the damaged line when one of the lines is switched on for short-circuit during operation of the other line.

1 cl, 1 dwg