METHOD FOR PHASE-COMPARISON PROTECTION OF POWER TRANSMISSION LINE Russian patent published in 2004 - IPC

FIELD: power engineering; protection of power transmission lines.

SUBSTANCE: proposed method that makes it possible to maintain serviceable condition of protective gear in case of trouble detected in secondary power circuits for operation on lines whose length L ranges within L_max ≤ L < 2L_max, where 2L_max is maximal length determined for each class of power transmission lines according to protective gear selectivity, involves following procedures: setting of protective gear off-operation threshold and complete high-frequency signal keying threshold on each end of power transmission line; correction of capacitive currents incorporated in protective gear starting currents and high-frequency keying current; check-up of secondary-voltage circuits, and disabling of capacitive current correction on end of power transmission line where trouble is detected in secondary-voltage circuits. For line whose length L ≤ 2L_max complete high-frequency signal keying threshold and/or protective gear off-operation threshold is enhanced when disabling correction of capacitive currents.

EFFECT: enhanced reliability of protective gear.

3 cl, 1 dwg