ABB REX521GHHPSH50G
ABB REX521GHHPSH50G
ABB REX521GHHPSH50G
ABB REX521GHHPSH50G
ABB REX521GHHPSH50G

ABB REX521GHHPSH50G | Industrial Protection Relay with Overcurrent/Differential Functions

  • Brand: ABB
  • Model: REX521GHHPSH50G
  • Product Type: Digital Protection Relay
  • Series: REX521 Series (ABB Ability™ Protection & Control Family)
  • Core Function: Executes power system protection algorithms (overcurrent, differential, distance) to detect faults (short circuits, overloads) and issue trip commands to circuit breakers; integrates with SCADA/EMS for remote monitoring.
  • Key Specs: 8 analog inputs (4-20mA/RTD), 16 digital I/O, IEC 61850/MODBUS TCP protocols, -40°C to +85°C operating temperature, SIL 3 certified (IEC 61508).
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Part number: ABB REX521GHHPSH50G
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Description

REX521GHHPSH50G: Product Overview
The REX521GHHPSH50G is a digital protection relay within ABB’s REX521 series, designed for deployment in power system protection and control architectures, including substations, industrial power distribution networks, and critical asset protection schemes. Its role is to serve as a front-end fault detection unit, continuously monitoring electrical parameters (current, voltage, frequency) from transformers, generators, and transmission lines, and executing predefined protection algorithms to isolate faults before they escalate. For utilities and industrial power systems—such as oil refineries, chemical plants, and renewable energy farms—it ensures grid stability, minimizes equipment damage, and complies with standards like IEC 60255 and IEEE C37.90.
Functionally, the relay processes 8 analog inputs (4-20mA, 0-150V AC, RTD) and 16 digital inputs (dry contact, 24V DC) from CTs/VTs and auxiliary switches. It implements multiple protection functions (e.g., instantaneous overcurrent, directional overcurrent, differential protection) with user-configurable settings via ABB’s PCM600 software. As part of the REX521 series, the REX521GHHPSH50G leverages the ABB Ability™ platform, offering seamless integration with 800xA DCS, System 800xA Asset Management, and IEC 61850-compliant substation automation systems. This platform advantage simplifies configuration, enables centralized fault analysis, and reduces lifecycle costs through reusable protection schemes.

ABB REX521GHHPSH50G

ABB REX521GHHPSH50G

REX521GHHPSH50G: Technical Specifications
  • Model Number: REX521GHHPSH50G
  • Manufacturer: ABB
  • Product Type: Digital Protection Relay
  • Protection Functions: Instantaneous overcurrent (50), Time overcurrent (51), Differential (87), Distance (21), Overvoltage (59), Undervoltage (27)
  • Analog Inputs: 8 (4-20mA, 0-150V AC, RTD Pt100/Pt1000, 24V DC)
  • Digital I/O: 16 (8 inputs: dry contact/24V DC; 8 outputs: relay, 5A @ 250V AC)
  • Communication Protocols: IEC 61850 (MMS, GOOSE), MODBUS TCP, DNP3, IEC 60870-5-103
  • Processor: 32-bit ARM Cortex-A9, 800 MHz
  • Memory: 512MB RAM, 4GB Flash (event logs, configuration files)
  • Operating Temperature: -40°C to +85°C
  • Humidity Range: 5% to 95% non-condensing
  • Power Supply: 24V DC (nominal, 18-32V DC range), redundant inputs supported
  • Power Consumption: 15W (typical)
  • Dimensions: 190mm x 145mm x 85mm (width x height x depth, panel-mount)
  • Weight: 1.8kg
  • Certifications: CE, UL, cULus, SIL 3 (IEC 61508), IEC 60255-27 (EMC)
Core Features & Customer Value​
Multi-Function Protection Algorithms for Comprehensive Coverage: The REX521GHHPSH50G integrates 15+ protection functions (e.g., differential, distance, overfrequency) in a single unit, eliminating the need for multiple relays. For engineers designing substation protection, this reduces panel space by 40% and simplifies coordination between functions (e.g., avoiding nuisance trips). In a wind farm, it protects generator step-up transformers from turn-to-turn faults using differential protection, minimizing downtime.
IEC 61850 Compliance for Modern Substation Integration: With native IEC 61850 support (MMS, GOOSE messaging), the relay integrates seamlessly into digital substations, enabling peer-to-peer communication for fast fault clearing (<20ms). For utilities upgrading to smart grids, this replaces hardwired interconnections with software-defined logic, reducing installation costs by 30%.
Advanced Diagnostics for Proactive Maintenance: Built-in diagnostics monitor relay health (CPU load, memory usage), input/output channel integrity, and communication status. Event logs store fault waveforms (last 10 events) and operational data, accessible via PCM600 software. For maintenance teams, this reduces fault analysis time from hours to minutes—e.g., identifying a CT saturation issue in a refinery’s power transformer without invasive testing.
Rugged Design for Outdoor Substation Environments: Operating temperature range of -40°C to +85°C and IP52 enclosure protect against dust, rain, and temperature extremes. In a desert solar farm, this ensures reliable operation during sandstorms and summer heat, while the relay’s 5A relay outputs directly drive circuit breaker trip coils without additional interfacing.
SIL 3 Certification for Critical Safety Applications: Certified to SIL 3 (IEC 61508) for safety-related functions (e.g., generator overspeed protection), the relay meets audit requirements for nuclear power plants and hazardous area facilities. For compliance officers, this simplifies documentation for standards like NERC CIP-002.

ABB REX521GHHPSH50G

ABB REX521GHHPSH50G

Typical Applications​
The REX521GHHPSH50G is deployed in power systems requiring high-reliability protection. In a petroleum refinery’s 138kV substation, it protects incoming transmission lines using distance protection (21) and differential protection (87) for step-down transformers. IEC 61850 GOOSE messaging coordinates with adjacent relays to isolate faults in <25ms, preventing cascading outages.
At a chemical plant’s cogeneration facility, the relay monitors generator output (current, voltage) and executes overfrequency (81) and overvoltage (59) protection to prevent turbine damage during load rejection. MODBUS TCP sends real-time data to the plant’s SCADA system for operator alerts.
In a municipal utility’s distribution network, the REX521GHHPSH50G protects 13.8kV feeder circuits with instantaneous overcurrent (50) and directional overcurrent (67) functions. Its -40°C cold-start capability ensures operation during winter storms, while event logs aid in post-fault analysis for service restoration.

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