Description

The Siemens 7UT61 is a SIPROTEC 4 transformer differential protection relay providing high-speed percentage biased differential protection for two-winding power transformers. It incorporates 2nd and 5th harmonic restraint to prevent operation during magnetising inrush and core saturation while maintaining sensitivity to genuine internal faults. The 7UT61 is used for primary protection of 33 kV to 400 kV transformers in transmission grid substations.