Photothyristor control of neutral grounding mode of power transformers for limitations of geomagnetically induced currents

The article recommended the method of protection of power transformer from the influence of geomagnetically induced currents, by launching the resistive grounding mode at the period of geomagnetic disturbances and reversion to the solid-grounded mode on completing of geomagnetic disturbances. The article shows that for the identification of single-side saturation of the magnetic system of power transformer at the periods of geomagnetic disturbances could be used registration of simultaneous appearance of 6th harmonic and DC component of the magnetizing current in the neutral of power transformer.