Voltage and Frequency Protection

    Voltage and Frequency Protection

    The MRU4 is a protection relay which uses the latest Dual-Core-Processor Technology to provide precise and reliable protective functions and is very easy to operate.

    The MRU4 is designed to protect electrical equipment from dangerous voltage fluctuations. For example protection against under voltages caused by mains shortcircuits, or overvoltages due to load shedding or failure of a generator voltage controller. Its compact design makes the MRU4 ideal for installation within the LV terminal compartments of compact SF6-insulated MV systems.

    The intuitive operating concept with plausibility checks and extensive commissioning functions such as the built-in fault simulator allows a safe and time-optimized maintenance and commissioning. The parameter setting and evaluation software Smart view can be used consistently across the entire family of devices.

    ANSI: 27, 59, 59N, 81U/O, 60FL, 47, 86, 74TC , 81R, 78, ROCOF, 25

    Device MRU4
    Line HighPROTEC
    Binary inputs 8
    Control and detection of switchgears Yes
    Control and supervision of a circuit breaker (remote or local) 1
    Output relays 5
    Voltage transformer inputs 4
    Watchdog relay 1
    Circuit breaker failure protection [50BF] Yes
    Fault Ride Through (FRT) Yes
    Frequency gradient [81] Yes
    Frequency protection [81O/U] Yes
    IEC 60870-5-103 Optional
    IRIG-B00X Yes
    Modbus (TCP) Optional
    Modbus RTU Protocol Optional
    Output relay matrix Yes
    Parameter sets 4
    Phase balance [47] Yes
    Profibus DP Optional
    Programmable Logic Yes
    Reset / Blocking Yes
    Residual voltage [59N] Yes
    Synchrocheck [25] Yes
    Time Synchronization via SNTP Yes
    Time Date Yes
    Trip- and auxiliary relays [86] Yes
    Trip circuit resp. control circuit supervision [74TC] Yes
    Vector surge / mains decoupling [78] Yes
    Voltage protection [27/59] Yes
    Voltage transformer supervision [60FL] Yes
    IEC 61850 Optional
    Intertripping Yes
    Time Synchronization via Modbus Yes
    Time Synchronization via IEC 60870-5-103 Yes
    THD (Todal Harmonic Distortion) Protection Yes
    Disturbance recorder Yes
    Event recorder Yes
    Fault recorder (none volatile) Yes
    Trend recorder Yes
    ANSI: IEC:
    25; Synchro.
    27; U<
    47; (U1<, U2>, U0>)
    59; U>
    59N; UE>
    60FL; Yes
    74TC; Yes
    78; ΔΘ
    81R; ROCOF
    86; Yes
    81UFLS; -


    All shown details without any guarantees!  We reserve the right of changes without prior notice.
    *Only the basic device structure is shown.  Differences in detail are possible.