ABB REX521GHHPSH07G Protection and Control Relay

Overview

The REX521GHHPSH07G is a compact protection and control relay from the ABB REX500 family, engineered for dependable supervision and control of electrical systems in industrial and utility environments. As part of the long-established REX521 series, it integrates protection, measurement, logic control, and communication functions into a single robust unit, suitable for continuous operation in electrically demanding installations.

Developed by ABB, this relay reflects proven Nordic design practices with a strong focus on operational reliability, deterministic behavior, and long service life.

Technical Specifications

The REX521GHHPSH07G is designed as a multifunction protection relay rather than a general-purpose PLC. Specifications below reflect typical REX521 platform characteristics and correct common misinterpretations found in non-technical descriptions.

• Product Series: ABB REX521 (REX500 family)

• Device Type: Protection and Control Relay

• Order Code: REX521GHHPSH07G

• Country of Manufacture: Finland

• Power Supply: 24 V DC (industrial auxiliary supply)

• Processing Platform: Dedicated real-time protection processor (DSP-based architecture)

• Protection Functions: Overcurrent, earth fault, supervision and logic-based protection (configuration-dependent)

• Control Functions: Binary control, interlocking logic, event handling

• Inputs: Analog current/voltage inputs, digital status inputs

• Outputs: Relay outputs for trip, alarm, and control signaling

• Communication Interfaces:

• ABB SPA bus

• IEC 60870-5-103 (optional configuration)

• Serial service interface for parameterization and diagnostics

• Configuration Method: PC-based engineering tools via service port

• Environmental Protection: Industrial enclosure for control cabinet installation (not field IP-rated)

• Operating Temperature Range: –20 °C to +60 °C

• Mounting: Panel or rack mounting within protected enclosures

• Weight: 5 kg

Key Functional Characteristics

The REX521GHHPSH07G emphasizes deterministic protection behavior rather than high-level computing performance. Its design focuses on stable signal acquisition, fast protection response, and predictable control logic execution. The relay supports flexible parameterization, enabling adaptation to different network topologies and protection philosophies without hardware modification.

Typical Applications

This relay is commonly deployed in medium-voltage and auxiliary power systems where integrated protection and control are required, including:

• Industrial power distribution panels

• Generator and motor protection schemes

• Substation auxiliary systems

• Process industry electrical protection cabinets

FAQ

Is the REX521GHHPSH07G a PLC or a safety controller?
No. The REX521 is a dedicated protection and control relay. While it includes logic and control capabilities, it is not intended to replace PLCs or certified safety controllers.

Does this model support modern Ethernet-based protocols?
The REX521 platform primarily supports serial and ABB-specific communication protocols. Ethernet-based fieldbus support is not native to this generation.

Can it be used as a direct replacement for newer ABB protection relays?
Functionally similar roles may exist, but newer relay families differ in hardware architecture, communication options, and configuration tools. Application-level compatibility should be evaluated case by case.