Description
ABB REX615G_A Relion Protection and Control Relay
Product Overview
The ABB REX615G_A belongs to the ABB Relion REX615 family of all-in-one protection and control relays. REX615 is designed for medium-voltage power generation and distribution applications where a single IED may combine protection, measurement, breaker control, supervision, automation and substation communication functions. ABB describes REX615 as the successor platform for the earlier Relion 615 and 620 series, with modular hardware and software that can be configured for different protection applications.
Unlike a fixed-function feeder relay, the REX615 architecture is intentionally configurable. ABB provides application packages covering feeder protection, transformer protection, motor and generator protection, line differential protection, busbar protection, capacitor-bank protection, voltage protection, interconnection protection, grid automation, load shedding, Petersen-coil control, auto-synchronization and arc-flash protection. The actual functions available in an individual relay depend on the application packages selected for that unit.
The G_A designation should therefore be treated carefully. ABB’s public Relays-Online configurator recognizes REX615G_A as a REX615 composition code, but the public page does not provide enough information to decode every character into an exact CT/VT arrangement, binary I/O count, communication option, power-supply variant or application package. That information should come from the complete ordering code, nameplate, PCM600 project, or ABB configuration record rather than being inferred from the short identifier.
For retrofit work, this distinction is important. REX615 is mechanically related to the 615/620 relay platform, and ABB states that uses the same basic mechanical dimensions, wiring connections and mounting kits as the corresponding 615/620 form factors. That does not mean every configuration is electrically or functionally interchangeable with every REF615, RET615, REM615 or other 615/620 relay. The installed protection scheme remains the controlling reference.
Product Introduction
Protection replacement is rarely just a matter of matching the enclosure. With REX615G_A, the application package, I/O configuration, communication architecture and stored protection settings can determine whether a physically compatible relay is actually usable.
For a legacy replacement or DCS/substation upgrade, recover the complete ordering code and PCM600 project before changing hardware. ABB explicitly treats application configuration as a function-block-based engineering task rather than a fixed default configuration.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | REX615G_A |
| Manufacturer | ABB |
| Product Family | Relion |
| Product Type | Numerical protection and control IED |
| Application | Power generation and distribution |
| Architecture | Modular and scalable hardware/software |
| Protection Functions | Application-package dependent |
| Control Functions | Bay control and configurable automation functions |
| Measurement | Basic electrical measurements included in base functionality |
| Recording | Basic recorders included; advanced functions depend on configuration |
| Communication | IEC 61850 and other protocol options depending on configuration |
| Engineering Platform | ABB PCM600 |
| Connectivity Package | Connectivity Package |
| Application Configuration | IEC 61131-3 Function Block Diagram based |
| Local Interface | family HMI/display arrangement |
| Mechanical Platform | 615/620-related standard or wide casing architecture |
| Hardware Configuration | Must be verified from complete ordering code |
| CT/VT Configuration | Must be verified from exact hardware code |
| Auxiliary Supply | Must be verified from exact hardware code |
| Binary I/O | Configuration dependent |
| Ethernet Ports | Configuration dependent |
| Firmware | Version must be verified from relay/PCM600 |
| Hot Replacement | Follow ABB-approved relay replacement procedure; do not assume energized withdrawal is permissible |
| Default Application | None; application must be configured for the installation |
ABB explicitly states that has no default application configuration and that protection functionality is added through selected application packages.
ABB REX615G_A
Major Features / Practical Advantages
All-in-One Protection Platform
is designed to combine several functions that might otherwise require separate protection and control devices. ABB lists feeder, transformer, machine, generator, line differential, busbar, capacitor-bank, voltage, interconnection and arc-flash applications among the product scope.
This is useful in compact medium-voltage switchgear where panel space, wiring and engineering effort are significant considerations. It also changes the procurement risk: the relay’s physical model is only one part of the specification.
Modular Application Packages
The protection architecture is based on selectable application packages. ABB states that base functionality includes measurement, supervision, control and basic recording, while protection functions are added through application packages. Multiple packages can be combined within one relay.
That makes the platform adaptable, but it also means a replacement unit should not be ordered simply as “another .” The protection engineer needs to reproduce the actual application.
IEC 61850 Substation Integration
ABB positions within its IEC 61850-compliant Relion protection portfolio. The relay can participate in modern digital-substation communication architectures, with the exact communication functions dependent on the installed hardware and software configuration.
For engineering teams, this can include much more than basic status reporting. Protection signals, control commands and logical communications can become part of the station automation architecture. Any replacement therefore needs its communication configuration checked alongside the protection settings.
IEC 61131-3 Function-Block Application Logic
application configuration is based on IEC 61131-3 Function Block Diagrams. ABB’s engineering documentation describes dedicated function blocks for protection, control, monitoring and communication functions, with many mapped as logical nodes under IEC 61850.
This is particularly relevant when troubleshooting a replacement relay. A relay may pass basic hardware tests while still behaving incorrectly because the application logic, signal routing or logical-node mapping does not match the original installation.
Integrated Arc-Flash Protection Options
ABB lists integrated arc-flash protection within the product scope. The actual arc-protection implementation depends on the selected application package and hardware arrangement.
Where arc protection is part of the switchgear safety scheme, the engineer should verify the optical sensors, trip paths, logic, breaker interface and associated settings rather than treating the relay replacement as a simple device swap.
Compatibility With Earlier 615/620 Mechanical Platforms
ABB states that is mechanically identical to the corresponding 615 and 620 platforms, with the same hardware dimensions, wiring connections and mounting kits for the relevant form factors.
That is useful for retrofit projects because mechanical replacement can be straightforward. Electrical and functional compatibility still needs separate verification. A relay that fits the existing cutout may have a different protection application, I/O arrangement or communication configuration.
Current Engineering Toolchain
ABB provides a dedicated Connectivity Package and configuration templates, while PCM600 remains the engineering environment for Relion protection and control products. ABB’s current documentation portal lists connectivity packages, configuration templates, technical manuals and application manuals.
For maintenance teams, keeping the correct PCM600 project and connectivity-package version is as important as keeping the relay itself.
Related Products
- REF615 — Feeder protection and control relay in the earlier Relion 615 family; is positioned by ABB as the next step for the 615/620 platform.
- RET615 — Transformer protection and control relay; suited to transformer-specific protection applications.
- REM615 — Motor protection and control relay for medium-voltage motors.
- RED615 — Line differential protection and control relay for feeder/line applications.
- REU615 — Voltage protection and control relay for voltage-related applications.
- REV615 — Capacitor and filter-bank protection and control relay.
- REL670 — Higher-end Relion platform used for more advanced line and transmission protection applications.
- REX610 — Related ABB Relion protection relay for distribution applications with a different hardware/application approach.
- REX640 — Higher-capability Relion protection and control platform with broader modular application scope.
- SSC600 — Centralized protection and control platform that can consolidate multiple protection functions at the substation level.
FAQ
What is ABB REX615G_A?
REX615G_A is an ordering/configuration identifier for an ABB Relion protection and control relay. is an all-in-one IED for power generation and distribution applications.
Is REX615G_A a feeder relay?
Not necessarily. supports feeder protection, but the platform is not restricted to feeder applications. ABB lists transformer, machine, generator, line differential, busbar, capacitor-bank, voltage, interconnection and other applications. The actual function set depends on the selected application packages.
Does REX615G_A have a fixed protection configuration?
No. is designed around configurable application packages. ABB states that the relay has no default application configuration, and the actual application is created using configurable function blocks.
Can I use REX615G_A as a direct replacement for REF615?
Not automatically. The mechanical platform may be compatible, but CT/VT inputs, binary I/O, protection functions, communication interfaces, firmware, application logic and settings must all be compared. ABB describes as the next step for the 615/620 families, not as a universal hardware-equivalent replacement for every earlier relay.
Does support IEC 61850?
Yes. is part of ABB’s IEC 61850-compliant Relion protection portfolio. The exact IEC 61850 features and communication hardware should still be checked against the installed configuration.
Does REX615G_A support firmware v3.1?
A specific v3.1 firmware assignment for REX615G_A cannot be established from the short ordering identifier alone. ABB currently publishes multiple firmware and connectivity-package generations. The installed firmware should be read from the relay or confirmed through the relevant project rather than assumed.
Can I hot-swap REX615G_A?
Do not assume unrestricted hot swapping. ABB uses a plug-in relay design intended to facilitate maintenance and replacement, but the actual withdrawal/replacement procedure must follow the relay and switchgear manufacturer’s approved isolation and test procedure. ABB specifically describes the Relion design as plug-in for maintenance and replacement.
What should I back up before replacing the relay?
At minimum, preserve the project, application configuration, protection settings, communication settings, IEC 61850 configuration, disturbance records where required, and the complete original ordering code. For an operating substation, also document the breaker-control and interlocking logic before removing the existing IED.
Is the “G_A” suffix enough to identify the exact hardware?
No. ABB’s public configurator identifies REX615G_A as a composition code, but the public listing does not expose enough information to safely decode every hardware and application option from those two characters alone.
Procurement Note
ABB REX615G_A should be procured as a configured protection IED, not simply as a generic relay. The complete ordering code and installed configuration are critical.
Before approving a replacement, obtain the relay nameplate and verify:
- Complete ABB ordering code, not just
REX615G_A. - Hardware casing type and module arrangement.
- CT and VT input ratings.
- Binary input/output allocation.
- Auxiliary power supply range.
- Ethernet and serial communication hardware.
- IEC 61850 configuration and station communication requirements.
- Installed firmware version.
- project and Connectivity Package version.
- Protection application packages and custom function-block logic.
- Existing protection settings and active setting groups.
- Arc-flash, breaker-failure, interlocking and trip logic where applicable.
The most important point is simple: is configurable, so the model family does not define the complete protection function set. ABB’s own documentation confirms that application packages determine the actual protection functionality and that there is no default application configuration.
For a live protection-system replacement, compare the complete configuration before energizing the relay. A physically compatible with the wrong application package or IEC 61850 logic can fit perfectly and still be functionally wrong.
