About the immunity of the equipment used to monitor the units of power transformers

The paper deals with problems related to electromagnetic compatibility occurring at an equipment used to monitor and diagnosis units for electric power transformation. Applying numerical methods during the process for data acquisition and processing results into an accurate monitoring, but new aspects had to be considered. They are related to immunity to electromagnetic disturbances. The above mentioned equipment is presented, paying a special attention to the places where problems related to electromagnetic susceptibility can occur: the supplying source, input/output interferences, electronics incorporated in the equipment, data communication systems. The operating modalities of the equipment under test are presented along with the criteria to be accomplished by the equipment. The accomplished immunity tests (performed according to the standards in force) are described and analyzed. They address the electrostatic discharges, the immunity to radiated radio-frequency electromagnetic field, the surge immunity and respectively the power frequency magnetic field immunity after the applying of anti-perturbative measures.