Description
Product Overview
The ABB REX521GHHPSH51G is a numerical feeder protection and control relay belonging to ABB’s REX 521 protection platform. It is designed for protection, control, measurement, and supervision in medium-voltage electrical networks, with typical applications including incoming and outgoing feeders, substation protection, and selected medium-voltage motor applications. The REX 521 uses a multiprocessor architecture with digital signal processing to provide fast protection response, accurate measurement, local HMI operation, and configurable control functions.
The REX521GHHPSH51G is a configuration-specific version of the REX 521 family. ABB’s ordering structure indicates that the model code identifies the hardware type, auxiliary-power arrangement, rear communication interface, optical interface, standard configuration, and configuration revision, so the complete code should be retained when selecting a replacement. The ABB REX521GHHPSH51G is therefore particularly valuable in established medium-voltage switchgear where reliable feeder protection, breaker control, measurement, event supervision, and substation communication are required.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | REX521GHHPSH51G |
| Manufacturer | ABB |
| Product Family | REX 521 |
| Product Type | Numerical Feeder Protection & Control Relay |
| Hardware Version | High / G-series configuration |
| Main Application | Medium-Voltage Feeder Protection |
| Typical Functions | Overcurrent, short-circuit, earth-fault and configurable protection functions |
| Measurement Inputs | Conventional CT/VT inputs |
| Rated Frequency | 50 / 60 Hz |
| Current Input Options | 0.2 A / 1 A / 5 A |
| Voltage Input | 100 / 110 / 115 / 120 V, configurable |
| Communication | SPA / IEC / other options according to configuration |
| Optical Interface | Glass-fiber option indicated by “G” configuration code |
| HMI | Front-panel LCD and local controls |
| Auxiliary Supply | High-voltage PS_87H family; exact rating depends on configuration |
| Installation | Medium-voltage switchgear / substation panel |
| Operating Temperature | Configuration-dependent; verify installed revision |
| Protection & Diagnostics | Self-supervision, event indication and configurable alarms |
ABB documentation specifies 50/60 Hz operation, conventional CT inputs with 0.2/1/5 A options, and configurable voltage inputs of 100/110/115/120 V for the REX 521 platform. The order-code structure also confirms that “G” identifies a glass-fiber rear communication option, while “H” identifies the high-voltage power-supply family.
Main Features and Advantages
Multifunctional feeder protection
The REX521GHHPSH51G integrates several protection, measurement, control, and supervision functions into one numerical device. It can be applied to incoming and outgoing feeders in different medium-voltage neutral configurations, including isolated, resonant-earthed, solidly earthed, and resistance-earthed systems.
High-performance digital processing
The REX 521 platform uses a multiprocessor architecture and digital signal processing to improve protection response and measurement performance. This is especially useful where fast short-circuit and earth-fault detection is required to limit equipment damage and reduce unnecessary interruption of healthy feeders.
REX521GHHPSH51G
Flexible protection configuration
The relay supports standard application configurations and configurable protection logic, allowing the same platform to be adapted to different switchgear arrangements. The REX 521 documentation specifically provides standard configurations for different hardware versions and feeder applications.
Integrated local HMI
A front-panel LCD and user interface provide local access to measurements, indications, alarms, and relay settings. This reduces dependence on a separate engineering workstation for routine field inspection and troubleshooting.
Fiber-optic communication capability
The REX521GHHPSH51G ordering code includes the glass-fiber communication designation, providing an electrically isolated communication path that is useful in electrically noisy substation environments. The REX 521 platform supports ABB substation-automation communication architectures, including IEC 60870-5-103 and SPA-related communication.
Suitable for legacy ABB switchgear
For existing REX 521 installations, maintaining the exact hardware and configuration code is important because different order-code combinations can have different I/O, power-supply, communication, and application characteristics. This makes the REX521GHHPSH51G a practical maintenance spare for established ABB medium-voltage protection systems.
Application Fields
The ABB REX521GHHPSH51G is primarily used in medium-voltage substations and distribution switchgear. It can protect incoming and outgoing feeders against short circuits, overcurrent conditions, earth faults, and other abnormal electrical operating conditions. Its measurement and control capabilities also allow it to participate in circuit-breaker control and feeder-status monitoring.
In power-generation plants, the relay can be deployed in medium-voltage auxiliary distribution systems, generator auxiliaries, plant switchboards, and outgoing feeder bays. It provides a dedicated protection layer while measurements and events can be incorporated into the plant’s SCADA or substation automation architecture.
For oil & gas, chemical, petrochemical, mining, metallurgy, and large manufacturing facilities, the REX521GHHPSH51G is suitable for protecting medium-voltage feeders supplying motors, transformers, process equipment, and production-area distribution panels. The platform is also documented for protection of medium- and large-size three-phase AC motors, expanding its usefulness beyond conventional feeder applications.
The relay is especially valuable where different neutral-grounding arrangements are encountered. Isolated-neutral, resonant-grounded, solidly grounded, and resistance-grounded systems can require different earth-fault protection philosophies, and the REX 521 platform provides configurable functions for these applications.
Related Products
- REX521BBHGLB01C – Another REX 521 configuration; suitable for comparison when replacing an existing REX 521, but hardware, communication, and configuration codes must be matched carefully.
- REX521GHHGSH05G – Related high-version REX 521 configuration with different standard application and hardware coding.
- REX 521 B01 – Basic standard configuration intended for applicable feeder protection arrangements.
- REX 521 B02 – Alternative Basic hardware configuration within the REX 521 family.
- REX 521 M01 – Medium hardware configuration offering a different I/O and application arrangement.
- REX 521 M02 – Related Medium hardware configuration for expanded feeder/substation applications.
- REX 521 H01 – High hardware configuration for applications requiring the corresponding REX 521 high-level I/O architecture.
- REF541 – ABB feeder protection and control relay from the same general generation, suitable for medium-voltage feeder applications.
- REF543 – Expanded ABB feeder protection and control platform for more demanding medium-voltage applications.
- REF615 – Later ABB Relion feeder protection platform providing a more modern numerical protection and substation-automation solution.
