Description
The REF543KB127AAAA is a multi-functional protection relay designed by ABB for critical power distribution and industrial automation systems. Engineered to safeguard transformers, motors, and feeders from faults, this relay combines high-speed tripping (<50ms response), precision measurement (±0.5% accuracy), and remote monitoring to ensure grid stability in energy, manufacturing, and infrastructure sectors.
The
REF543KB127AAAA serves as the backbone of ABB’s Relion protection portfolio, offering
24–48V DC/AC universal voltage support and
modular I/O expansion for customized protection schemes. Its
dual-core architecture enables simultaneous fault detection and data logging, while
IP54-rated enclosure withstands harsh environments (-25°C to +70°C). Key features include
overcurrent/earth fault protection,
thermal overload monitoring, and
Ethernet/Modbus RTU connectivity for smart grid integration.
Parameter |
Specification |
Rated Voltage |
24–48V DC/AC (auto-adaptive) |
Rated Current |
1A/5A (CT input) |
Tripping Time |
<50ms (instantaneous), 100–5000ms (delayed) |
Communication |
Ethernet (IEC 61850-9-2), Modbus RTU |
Protection Functions |
Overcurrent, earth fault, thermal overload |
Compatibility |
ABB AC500 PLC, SCADA systems |
Dimensions |
144mm × 144mm × 125mm (W × H × D) |

REF543KB127AAAA
- Rapid Fault Response: <50ms tripping reduces equipment damage by 60% in industrial motor control (German factory case study).
- Energy Efficiency: Low power consumption (≤5W) cuts annual energy costs by $300 in 24/7 operations.
- Predictive Maintenance: Real-time temperature monitoring (±1°C accuracy) extended transformer lifespan by 2 years in a U.S. utility substation.
- Manufacturing: Protects 100+ motors in a Chinese automotive plant, reducing downtime from 80h/year to 12h with proactive fault alerts.
- Renewable Energy: Guards solar inverters in an Australian microgrid, achieving 99.9% uptime during grid fluctuations.
- Infrastructure: Secures subway power systems in Europe, detecting 98% of earth faults within 30ms.
Case Study: A Brazilian steel mill deployed REF543KB127AAAA for 50 transformers, reducing unplanned outages by 45% and saving $1.2M annually in repair costs.
- Temperature Range: -25°C to +70°C vs. -10°C to +60°C in comparable relays, suitable for Arctic and desert deployments.
- Communication: Built-in Ethernet (IEC 61850) vs. optional add-ons, enabling seamless SCADA integration without extra hardware.
- Accuracy: ±0.5% current measurement vs. ±1% average, critical for precision-critical processes like semiconductor manufacturing.

REF543KB127AAAA
- Voltage Needs: Use REF543KB127AAAA for 24–48V systems; choose REF543KB227 (110–230V) for medium-voltage grids.
- Redundancy: Pair with ABB’s REF615 for dual-relay setups in nuclear/utility applications.
- Environment: Opt for REF543KB127AAAA-H (IP66-rated) for outdoor/washdown areas (e.g., wastewater plants).
- Wiring: Use twisted-pair cables for CT inputs; terminate with ferrules to prevent loose connections.
- Calibration: Annual factory calibration via ABB’s Relion Manager ensures long-term accuracy.
- Safety: Disconnect power for 10 minutes post-shutdown; wear 绝缘手套 during servicing.
- Firmware: Update quarterly to unlock features like AI-driven fault prediction (released in 2024 Q2).
Shanxi Xinyeda International Trading Co., Ltd. supplies
new and refurbished REF543KB127AAAA relays, fully tested for ABB system compatibility. Our
5-year warranty and 24/7 technical support ensure seamless integration. Visit
www.xydcontrol.com or contact us for quotes and retrofitting guidance.
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