METHOD OF PARALLEL LINES PROTECTION Russian patent published in 2017 - IPC H02H7/22 G01R31/08 

FIELD: electricity.

SUBSTANCE: method of parallel lines protection is to measure the instantaneous currents i₁ and i₂ in the same phases of the first and second lines with increasing currents and comparing them with a given value of the current i_et. Then, the sequence of the instantaneous current achievement moments i₁ and i₂ in the same-name phases of the first and second lines is simultaneously recorded as the magnitude current buildup of current specified value, and the time t is measured between the moment when the instantaneous current i₁ in the phase of the first line reaches the value of the current specified value i_et, and the moment when the instantaneous value of the current i₂ in the same-name phase of the second line reaches the value of the preset current i_et, then the measured time t is compared with a predetermined time t_et1. If t≥t_et1, then a signal is sent to cut off the line the current of which has reached the value of the specified current value first. After the instantaneous value of the i_et current in the phase of the first line and the instantaneous value of the current in the phase of the second line reaches a specified value of the current i_et, in a time t_et2= t_op+t_pr+Δt, where t_op is the time required for line circuit breaker opening on the opposite side; t_pr is the duration of the protection established on the opposite side; Δt is the time of the reserve, taking into account the effect of errors, a signal is sent to turn off the line the current of which is greater or equal to the specified value of the i_et current.

EFFECT: increased security of parallel lines.

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