HighTECH Line – MRR1
MULTIFUNCTIONAL GENERATOR ROTOR PROTECTION RELAY
The generator rotor protection relay MRR1 com-bines rotor earth fault protection, excitation over- and undercurrent protection as well as rotating diode failure protection.
Thus providing a powerful protection regarding the rotor of synchronous generators, covering the following ANSI codes:
37 DC undercurrent relay
40 Field relay
58 Rectification failure relay
64 Ground detector relay
76 DC over current relay
The MRR1 is recommended for synchronous generators and motors above 1 MVA rating.
The rotor earth fault element detects high- and low resistance earth faults of the rotor winding. It is equipped with two stages, one for alarm, one for trip.</P.
The excitation current protection element super-vises the DC excitation current of brushless excitor machines. The protective functions are: Undercurrent, over current and ripple detection for diode failure protection.
- Detection of high impedance earth faults with a test frequency of 0.5 Hz
- Short circuit and overvoltage proof measuring input for the earth fault protection
- Excitor current measurement galvanically isolated via Hall-transducer, measuring range 0 to 20 A
- Display of insulation resistance
- Display of the excitation current
- Excitation current over- and undercurrent protection with independent settings for current and delay time
- Detection of diode failures by supervision of the ripple component of the excitation current
- Two stage supervision of the rotor insulation resistance with independent settings for resistance and time delay
- Two trip relays, one for excitation under- and over current, one for diode failure detection
- Digital inputs for blocking and for remote reset
- Programmable function of the blocking input
- Programmable assignment of protective functions to output relays
- Remote interfacing via RS485
- Rotor Earth Fault Detection:
Detects insulation failures in the rotor’s DC field winding, preventing severe generator damage. - Two-Stage Protection:
Provides separate alarm (warning) and trip (shutdown) stages, enabling early intervention before a critical fault occurs. - High & Low Impedance Fault Detection:
Capable of identifying both major (low-impedance) and minor (high-impedance) earth faults for comprehensive protection. - Application in Synchronous Machines:
Designed for use in synchronous generators and motors, where rotor earth faults pose operational risks.
- Device Type: Multifunctional Generator Rotor Protection Relay
- Manufacturer: SEG Electronics (Woodward)
- Application:
Designed for synchronous generators and motors above 1 MVA. - Supported ANSI Protection Functions:
- 37 – DC Undercurrent
- 40 – Field Relay
- 58 – Rectification Failure
- 64 – Ground Detector
- 76 – DC Overcurrent
- Auxiliary Power Supply:
Wide-range AC/DC auxiliary inputs available (24V, 48V, 110V, 220V options). - Communication:
RS485 interface, with optional Modbus RTU for SCADA/automation integration. - Output Relays:
- Total 5 output relays
- Relays 1–4: Fully programmable
- Relay 5: Dedicated for self-supervision
- Excitation Current Measurement:
- Galvanically isolated input via Hall-effect transducer
- Measuring range: 0 to 20 A DC
- Rotor Earth Fault Detection:
Detects high-impedance rotor earth faults using a low-frequency AC test voltage (0.5 Hz or 1 Hz).
