METHOD FOR MANAGING EFFICIENT EARTHING OF POWER TRANSFORMER NEUTRAL LINE REGIME Russian patent published in 2018 - IPC H02H9/08 

FIELD: power engineering.

SUBSTANCE: invention relates to the field of electric power industry and can be used to protect against the influence of geo-induced currents in the periods of geomagnetic activity of power transformers of electric stations and substations operating in electric networks with a rated voltage of 110 kV and above. Method for controlling the earthing of the neutral of a power transformer through a parallel-connected current-limiting resistor and a thyristor key is that it provides a continuous conductivity of the thyristor key by the supply of control pulses, fix the appearance of a constant component of the neutral current and, in case of exceeding the permissible value, block the supply of control pulses, and resume the supply of control pulses only after the constant component of the neutral current has ceased. To achieve the technical result, the appearance of the sixth harmonic of the neutral current is detected and the control impulses are blocked when the sixth harmonic exceeds the permissible value.

EFFECT: reduction of reactive power losses in a power transformer during periods of geomagnetic disturbances and simplification of practical implementation.

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