METHOD TO CONNECT THREE-PHASE TRANSMISSION LINE Russian patent published in 2014 - IPC H02H3/06 

FIELD: electricity.

SUBSTANCE: first phase is connected, voltage is measured on the second and third phases, it is checked how the first reference value exceeds each of the measured voltages, and if the check results are positive, they connect the second phase, measure voltage on the third phase, inspect how the second reference voltage value exceeds the voltage measured in the third phase, and if the result of the check is positive, they connect the third phase, and in case of negative check result in the first reference value exceeding voltages measured in the second and third phases, and the second reference value exceeding the voltage measured in the third phase, subsequent phases are not connected, and the ones connected previously are disconnected. When a signal is received on availability of an earth fault in the first phase during its connection, it is disconnected, and subsequent phases are not connected, after connection of the second and third phases they compare modules |U₁₂₍₁₃₎| of vector difference of voltages in the first and second phases |U₁₂| and the first and third phases |U₁₃| with low reference value 0.1|U pn|, where |U pn| - nominal phase voltage, and if the condition |U₁₂₍₁₃₎|<0.1 IU pn| is met, they fix the closure of accordingly the first and second and the first and third phases to each other, afterwards they disconnect the first and second and the third phases, accordingly.

EFFECT: expanded area of application and higher safety.