Transformer differential
protection relay


The various protective functions of the MRDT4 are specifically tailored to the protection of two winding transformers. The device offers in addition to the differential protection various communication and backup protection functions. Furthermore the MRDT4 can be used for generator differential protection.

Comprehensive protection package
• All protection features without extra charge
• Parameter setting and evaluation software
• Disturbance record analysis software

power quality
THD protection

Demand Management/peak values
• Peak values of current and power,average current and energy demand

Transformer PHASE DIFFERENTIAL protection
• Stabilized phase differential protection with transients and C.T. saturation detection
• Various selectable transformer groups
• Zero sequence removal
• Three point slope characteristic
• High set element (non-restraint)

Two Elements ground differential protection
• Three point slope characteristic
• High set element (non-restraint)

Temperature protection
• Buchholz (sudden pressure), ext.oil temperature, and aux. temperature protection via digital input
• Temperature measurement via external RTD-box (option)

• Disturbance recorder: 120 s non volatile
• Fault recorder: 20 faults
• Event recorder: 300 events
• Trend recorder: 4000 non volatile entries

Additional highlights
• Inrush Thermal replica
• Four elements external protection
• Plausibility checks
• Adaptive parameter sets
• Status display
• Masking of unused functions
• Breaker Manager and
• Breaker wear

PC Tools
• Setting and analyzing software
• Smart view for free
• Including page editor to design own pages

Commissioning support
• USB connection
• Customizable Display (Single-Line, ...)
• Customizable Inserts
• Copy and compare parameter sets
• Configuration files are convertible
• Forcing and disarming of output relays
• Fault simulator: current and voltage
• Graphical display of tripping characteristics
• 7 languages selectable within the relay

Communication options
• IEC61850
• Profibus DP
• Modbus RTU or Modbus TCP
• IEC60870-5-103
• DNP 3.0 (RTU, TCP, UDP)

• of up to six breakers (or isolators/grounding switches)
• Breaker wear

• Up to 80 logic equations for protection,
• control and monitoring

Time synchronisation
• SNTP, IRIG-B00X, Modbus, IEC60870-5-103