METHOD TO PROTECT FURNACE TRANSFORMER WITH PHASES ARRANGED AT LOWER VOLTAGE SIDE SUCH AS GROUP OF SEPARATE CONDUCTORS Russian patent published in 2011 - IPC H02H7/04 

FIELD: electricity.

SUBSTANCE: in method to protect a furnace transformer with phases arranged at the lower voltage side in the form of a group of separate conductors, when the current is measured in each phase at the higher voltage of the transformer and voltage between phases, speeds of current growth and voltage reduction are calculated, and if their values or ratios between them exceed the specified limits, the transformer breaker is disconnected. Additionally sums of magnetic flows are measured, developed by currents of the specified quantity of phase conductors, differences are identified between these sums, and if at least one of differences exceeds the first reference value, a signal is sent about the damage, and if it exceeds the second reference value, then the transformer breaker is disconnected.

EFFECT: detection of individual conductors fixation weakening and faults between them.

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