HighPROTEC MRU4 voltage and frequency protection relay
HighPROTEC MRU4 is a digital voltage and frequency protection relay for medium voltage networks, generation facilities and ships. Six voltage stages, six frequency stages and asymmetry monitoring are packed into a compact housing for the relay compartments of GIS.
- Voltage
- 6 stages U<, U> with programmable time-dependent characteristic
- Asymmetry
- 6 stages (positive and negative sequence)
- Frequency
- 6 stages f<, f>, df/dt (ROCOF), combinations, vector jump
- Zero sequence
- 2 stages UE>
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
MRU4 from the HighPROTEC line monitors voltage and frequency and trips the equipment on dangerous deviations. Typical cases are a voltage dip during a short circuit in the network, or a rise when load is shed or the generator voltage regulator fails. The housing is compact, so the relay is installed in the low voltage relay compartments of compact gas-insulated medium voltage switchgear. The functions are adapted to VDE-AR-N 4110:2023-09, the relay has Lloyd’s Register marine approval and built-in test sockets.
Voltage protection has six undervoltage and overvoltage stages, and a time-dependent trip characteristic can be programmed for undervoltage. Another six stages monitor asymmetry by undervoltage and overvoltage of the positive sequence and overvoltage of the negative sequence. For zero sequence voltage there are two UE> stages. The fourth voltage input is flexible: it is used for two UE> stages or as the UX input for synchronism check, including through a transformer.
The frequency package consists of six stages. Each can be set as f< or f>, as rate-of-change-of-frequency protection df/dt (ROCOF), as a combination of f< and df/dt or f> and df/dt, as a combination with frequency increase DF/DT, or as voltage vector jump protection ΔΦ. There are also moving average voltage monitoring to VDE-AR 4105 and fault ride through FRT (LVRT) with adjustable profiles and coordination with auto-reclosing. Supervision functions cover voltage transformers, the trip circuit and breaker failure protection based on breaker position signals.
The relay runs on a dual-core processor. Communication is via Modbus, Profibus, DNP3.0, IEC 61850, IEC 60870-5-103 and IEC 60870-5-104, data points can be assigned individually, time is synchronized via SNTP and IRIG-B, and cybersecurity functions are provided. Non-volatile recorders store waveforms for 120 s, 20 faults, 300 events and a trend of 4000 records. Under the all-inclusive concept the full set of functions, the Smart view software and waveform analysis are supplied at no extra charge.
MRU4 is used for decoupling protection of generation facilities, busbar and incomer voltage protection, in under-frequency load shedding automation, and for voltage monitoring on ships and in industrial networks.
Technical specifications
| Voltage | 6 stages U<, U> with programmable time-dependent characteristic |
|---|---|
| Asymmetry | 6 stages (positive and negative sequence) |
| Frequency | 6 stages f<, f>, df/dt (ROCOF), combinations, vector jump |
| Zero sequence | 2 stages UE> |
| 4th voltage input | UE> or UX (synchronism) |
| Additional | moving average monitoring (VDE-AR 4105), FRT/LVRT, synchronism through a transformer |
| Supervision | VT, trip circuit, breaker failure protection by position |
| Marine approval | Lloyd’s Register |
Request a price and lead time
HighPROTEC MRU4 voltage and frequency protection relay. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8537 10 98 00 |
|---|---|
| HS, 6 digits | 8537 10 |
| CN (EU) | 8537 10 98 |
| HTSUS (USA) | 8537 10 91 70 |
| China customs tariff | 8537 10 90 90 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Does MRU4 meet the VDE-AR-N 4110 requirements?
Yes, the relay functions are adapted to VDE-AR-N 4110:2023-09. There is also moving average voltage monitoring to VDE-AR 4105 and the FRT (LVRT) function.
How many frequency protection stages does MRU4 have?
Six stages, each set as f<, f>, df/dt, a combination with df/dt, or vector jump protection. This is enough for under-frequency load shedding automation and generation decoupling protection.
Can MRU4 be used on ships?
Yes, the relay has Lloyd’s Register marine approval and is used for voltage monitoring in ship networks.
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