Protection system for medium-voltage potential transformers

摘要

The subject of the invention is a protecting system for medium-voltage potential transformers, finding application in the attenuation of ferroresonant states occurring in at least one of three potential transformers in a three-phase medium-voltage network. The system according to the invention features an element with a threshold voltage and current characteristic ( 1 ) and a thermal fuse ( 2 ), which are connected in series between an attenuating resistor (R 1 ) and the output of the auxiliary secondary winding of one of the single-phase transformers.