ABB REX 521 Motor Protection Relay

Description

The ABB REX 521 Motor Protection Relay is a multi-functional device designed for medium-voltage power grids, suitable for both feeder and motor protection applications. It delivers basic protection for busbars and feeders in public substations and industrial power distribution systems, and serves as backup protection for power transformers and high-voltage line protection relays. It also safeguards large and medium-sized three-phase AC motors, with use cases including incoming and outgoing feeders, motor feeders, and substation protection.

Equipped with integrated control, measurement, and monitoring functions, the relay supports breaker control, and offers enhanced features for efficient grid protection, expanded measurement capabilities, monitoring, and connectivity. It is optimized for single-busbar solutions, and via preconfigured standard settings, can be deployed in various network types including radial isolated neutral, resonant grounded, solid grounded, and resistance grounded systems for input and output feeders.

Key technical specifications include: 10-35V DC operating voltage, 25MHz output frequency, 16MB program capacity, 500MB data capacity, SIL 2/Ple Cat 4 safety functions, 2 SPNO output contacts, and a response time of ≤20ms. It has two input hardware versions: one for traditional current and voltage transformers, and another for current and voltage sensors. Environmental ratings cover a working temperature range of -25 degrees Celsius to 60 degrees Celsius, storage temperature range of -40 degrees Celsius to 80 degrees Celsius, 5 to 95% non-condensing humidity, IP67 protection rating, and resistance to 5.7g peak vibration (10 to 500Hz) and 30g half-peak shock (11ms). It features standard DIN rail mounting and weighs approximately 5kg.