NETWORK NODE FOR A POWER NETWORK, VARIABLE TRANSFORMER FOR A NETWORK NODE, AND METHOD FOR OPERATING A NETWORK NODE

摘要

The invention relates to a network node (10) for a power network (19), in particular a transformer substation or distribution substation, comprising: a variable transformer (11), which has a primary side and a secondary side; an input line (12), which is connected to the primary side; an output line (13), which is connected to the secondary side; a safety switch (14), which sits in the input line (12) or the output line (13); a sensor (15), which senses an electrical characteristic value in the input line (12) and/or the output line (13) and can produce a measurement signal; a control device (16), which is coupled to the variable transformer (11), the safety switch (14), and the sensor (15) and which is designed in such a way that the control device can control the variable transformer (11) in dependence on the measurement signal in such a way that the variable transformer has a predetermined voltage ratio; and that the control unit can control the safety switch (14) in dependence on the measurement signal in such a way that the safety switch opens; wherein the opening of the safety switch (14) caused by the control occurs as soon as the variable transformer (11) has the predetermined voltage ratio.