1. General Information

• Model: REF542plus

• Type: Multifunction protection relay, feeder terminal, switchbay controller

• Manufacturer: ABB

• Application: Medium‑voltage switchgear (MV), feeders, transformers, motors, busbars, industrial distribution systems

• Architecture: Separated HMI + base unit (flexible mounting)

2. Electrical Ratings

Supply Voltage

• DC: 24 / 48 / 110 / 220 V DC (−20% … +20%)

• AC: 110 / 230 V AC (−15% … +10%), 50/60 Hz

• Power Consumption: ≤ 15 W (base unit + HMI)

CT/VT Inputs

• Rated Current In: 0.2 A / 1 A / 5 A

• Rated Voltage Un: 100–125 V AC

• Rated Frequency: 50 Hz / 60 Hz

• Overload Capability: 250 × In (thermal)

3. Protection Functions (ANSI)

• 50/51: Instantaneous & time‑delay overcurrent (IDMT: Normal/Very/Extreme/Long‑time inverse)

• 50N/51N: Earth fault protection

• 67: Directional overcurrent (forward/backward)

• 27/59: Undervoltage / Overvoltage

• 81: Frequency protection (40.00–75.00 Hz, df/dt: 0.01–1.00 Hz/s)

• 21: Distance protection (line)

• 87: Differential protection (transformer/feeder)

• 46: Negative sequence (unbalance)

• 49: Thermal overload (motor/transformer)

• 37: Underpower / Reverse power

• 50BF: Breaker failure

4. Measurement Accuracy

• Current: Class 0.5S (0.1–4 × In)

• Voltage: Class 0.5 (0.2–1.5 × Un)

• Power/Energy: Class 1.0

• Frequency: ±0.01 Hz

• Calculated Values: Max/mean current, interrupted current sum, operating time, switching cycles

5. I/O Interfaces

Analog Inputs

• 8 × analog channels (CT/VT, 4–20 mA optional)

Binary Inputs

• 16 × opto‑isolated DI (24–250 V DC/AC)

Binary Outputs

• 8 × DO (relay or transistor; 250 V AC / 5 A resistive)

Communication

• Ethernet: 2 × RJ45, 10/100 Mbps; IEC 61850, Modbus TCP, embedded web server

• Fieldbus: PROFIBUS DP, CANopen, LON (optional)

• Serial: RS‑232/485 (service)

• Time Sync: IRIG‑B (optical input)

6. HMI & Data Logging

• Display: Multilingual backlit LCD, single‑line diagram, fault messages

• Controls: Local/remote selector, breaker control buttons, LED status indicators

• Event Log: 30 events, time‑stamped, non‑volatile memoryeero

• Fault Recorder: 8 analog + 32 binary channels, 1.2 kHz sampling, 1–5 s recordingeero

• Fault Locator: Calculates fault distance (km) via impedanceeero

7. Mechanical & Environmental

• Dimensions (W × H × D):

  • Base unit: 255 × 145 × 60 mm

  • HMI: 210 × 150 × 40 mm

• Weight: Base unit ~1.2 kg; HMI ~0.5 kg

• Operating Temp: −25°C to +70°C

• Storage Temp: −40°C to +85°C

• Humidity: 5%–95% RH, non‑condensing

• Protection: IP20 (base), IP54 (HMI front)

• Vibration: 2 g (IEC 60255)

8. Key Features

• All‑in‑one: Protection, control, measurement, monitoring, diagnostics, communication

• Flexible Licensing: Enable only needed protection functionseero

• Redundancy: Dual Ethernet, redundant power supply

• Cybersecurity: IEC 62443 compliant, user authentication

• Certifications: CE, UL, CSA, RoHS, ATEX (optional)

9. Applications

• Medium‑voltage distribution switchgear

• Primary/secondary substations

• Industrial plants (mining, metals, pulp & paper, oil & gas)

• Renewable energy (wind/solar farm grid connection)

• Motor control centers (MCC), transformer protection