Woodward MRU4-2A0AAA Voltage frequency protection relay

Product Description

MRU4-2A0AAA is a voltage & frequency protection relay of Woodward HighPROTEC family, built with dual-core processor technology. It is dedicated to voltage and frequency monitoring & protection for medium voltage systems. The device integrates complete protection logics including overvoltage, undervoltage, overfrequency, underfrequency, voltage unbalance and loss-of-voltage protection. It is equipped with disturbance recorder, SER sequence of event recording and built-in fault simulator for commissioning. Supported by SmartView configuration software for parameter setting and fault waveform analysis. Compact door-mount design fits the low-voltage compartment inside SF6 medium voltage switchgear, complying with grid interconnection codes. Widely used for voltage/frequency protection of generator sets and medium voltage distribution networks, for new panel supply and legacy protection relay spare part replacement.

Technical Parameters

1. Model: MRU4-2A0AAA (HighPROTEC Voltage & Frequency Protection Relay)
2. Voltage Input: 4 voltage inputs, measuring range 0~800V, with PT fuse failure supervision
3. Digital I/O: 8 programmable digital inputs, 7 relay output contacts
4. Power Supply: Wide range power supply, 24~270VDC / 48~230VAC (-20%/+10%)
5. Core Protection Functions: Overvoltage 59, Undervoltage 27, Overfrequency 81O, Underfrequency 81U, voltage unbalance, loss-of-voltage protection, synchrocheck, LVRT low voltage ride-through
6. Recording Functions: SER event log, DDR disturbance recorder, fault waveform storage
7. Communication: No built-in communication interface (Code A = no communication)
8. Mounting: Panel door flush mounting
9. Front Panel Protection Class: IP54; internal cabinet IP20
10. Operating Temperature: -20℃ ~ +60℃; Storage Temperature: -40℃ ~ +85℃
11. Certifications: CE, compliant with VDE-AR-N-4110 grid interconnection standard

Application Scope

• Voltage & frequency protection at grid connection point of synchronous generators, gas turbine and hydro turbine units
• Voltage monitoring & protection for medium voltage switchgear and SF6 ring main units
• Island / grid-connected protection for captive power plants and diesel generator sets
• Grid interconnection protection for new energy power plants (solar, wind)
• Protection retrofit of industrial medium voltage distribution systems, spare parts replacement for legacy voltage relays

HighPROTEC Series Protection Relay Models

1. MRU4-2A0AAA: Voltage & frequency protection relay (this model, no communication)
2. MRU4-2B0AAA: Version with RS485 Modbus RTU / IEC60870-5-103
3. MRU4-2C0AAA: Version with Ethernet Modbus TCP
4. MRA4: Directional feeder protection relay (current + voltage protection)
5. MRI4: Motor protection relay
6. MCA4: Line differential / feeder protection device