ABB REX521 Feeder Protection Relay

Overview

The REX 521 is a versatile protection relay designed to safeguard medium voltage networks, including feeders and motors. It offers a range of functions for protection, control, measuring, and supervision. The relay is ideal for incoming and outgoing feeders, motor feeders, and substation protection. Additionally, it serves as backup protection for power transformers and high-voltage line protection relays. This relay supports both conventional current and voltage transformers, as well as versions that can accommodate current and voltage sensors for added flexibility.

Technical Specifications

• Protection Functions:

  • Overcurrent protection (OC)
  • Earth fault protection (EF)
  • Over/under voltage protection (UV/OV)
  • Directional overcurrent protection (DO)
  • Thermal protection for motors
  • Back-up protection for power transformers and line protection relays

• Inputs:

  • Energizing inputs for conventional current and voltage transformers
  • Optional version with inputs for current and voltage sensors

• Relay Types:

  • Protection for large and medium-sized three-phase a.c. motors
  • Feeder protection for incoming and outgoing feeders
  • Suitable for solidly earthed, resistively earthed, and resonant earthed systems

• Communication and Connectivity:

  • Integrated communication interfaces for system integration
  • Standard configurations for easy network compatibility

• Operating Voltage:

  • Nominal voltage: 24V DC, 48V DC, or 110V DC

• Environment:

  • Temperature range: -40°C to +70°C
  • Humidity: 5% to 95% (non-condensing)

• Mounting:

  • Compact design for easy installation in medium voltage control panels

• Certifications:

  • Compliance with international standards for electrical protection systems (IEC 60255, IEC 61850)

• Display and Indicators:

  • LED indicators for status and fault conditions
  • Optional LCD display for detailed information

• Dimensions:

  • Width: 160 mm
  • Height: 250 mm
  • Depth: 120 mm