ABB 1MRK0023505-AA | Substation Protection and Control Module

Product Introduction

The ABB 1MRK0023505-AA is an ABB component associated with the Relion protection and control product family. Relion equipment is used in substations and industrial power systems for functions such as electrical fault detection, equipment protection, control, measurement, disturbance recording, and communication with higher-level substation automation systems.

There is a significant problem with the technical information published by secondary sellers for this exact material number. One listing describes 1MRK0023505-AA as a transformer differential protection relay, while another calls it a feeder protection relay, and yet another gives it a generic Relion spare/accessory classification. These descriptions are inconsistent enough that I would not assign a specific REL670, REF615, 87T, 51/51N, IEC 61850, I/O count, or power-supply specification to this material number without the complete ABB ordering code or the equipment nameplate.

This distinction is important because ABB Relion devices use detailed configuration codes to define protection functions, I/O, communications, auxiliary power, CT/VT inputs, and hardware options. The material number by itself may identify a hardware/spare component rather than a complete application-specific relay.

Technical Specifications

Important: I would not use the frequently published specifications of “8 relay outputs,” “250 VAC/5 A,” “IEC 61850,” or “48–250 VDC” as confirmed specifications for 1MRK0023505-AA. Those values appear in a secondary listing that also incorrectly places the part in an AC 800M/Advant I/O context.

1MRK0023505-AA

Main Features and Engineering Considerations

The main value of 1MRK0023505-AA is its association with ABB’s Relion protection and control architecture. Relion devices are designed for applications where protection logic, measurement, control, event recording, and station-level communications need to operate as part of a coordinated substation system.

For procurement, however, this particular part number requires more care than a standard ABB S800 I/O module. The search results show several contradictory classifications. One source describes it as a transformer differential protection relay, another as a feeder protection relay, while distributor catalogs list it more generically as a Relion spare.

That means the correct engineering procedure is to match the complete ordering designation, not simply the material number.

For an installed protection system, verify the:

• Exact Relion relay type
• Complete ordering code
• Hardware revision
• Auxiliary supply
• CT/VT input configuration
• Binary input/output configuration
• Communication modules
• IEC 61850 configuration, if applicable
• Protection setting file
• Firmware version
• Station-specific configuration

Application Scenarios

Depending on the complete Relion configuration, equipment associated with this material number may be encountered in:

• High- and medium-voltage substations
• Transformer protection systems
• Feeder protection systems
• Generator and power-plant switchyards
• Industrial electrical distribution
• Substation automation systems
• Protection-system refurbishment projects
• ABB Relion maintenance programs

The exact application should be determined from the installed relay type rather than inferred from 1MRK0023505-AA alone.

Engineer’s Guide: Field Pitfalls

⚠️ Do not assume this is a complete REL670 relay.

One online source claims it is a transformer differential relay in the REL670 family, but the available evidence does not establish that classification conclusively.

⚠️ Do not assume it is a REF615 feeder relay either.

Another source uses “feeder protection relay” terminology. The conflicting classifications indicate that the material number needs to be matched against the actual ABB ordering information.

⚠️ Do not copy generic electrical specifications.

The published values for voltage, current capacity, I/O count, operating temperature, and communication interfaces are not sufficiently reliable for this exact part.

⚠️ Protection-system compatibility is critical.

A physically similar ABB protection component may have completely different CT/VT circuits, binary I/O, communications, protection functions, or firmware requirements.

⚠️ Test settings as well as hardware.

For a protection-system replacement, a power-on test is not enough. The relay should be checked against the approved protection setting file and subjected to appropriate secondary-injection and functional testing before being returned to service.

Frequently Asked Questions

What is ABB 1MRK0023505-AA?
It is an ABB material number associated with Relion protection and control equipment. Available secondary sources do not agree on the exact device classification.

Is 1MRK0023505-AA a REL670?
Some secondary sources describe it as a REL670 transformer differential protection relay, but this should be verified against the complete ABB ordering code before treating that classification as definitive.

Is it a feeder protection relay?
Some listings use that description, but again, the evidence is inconsistent.

What should I provide to identify it precisely?

The most useful information would be:

1. Complete ABB nameplate photograph
2. Relay type designation, if printed
3. Full ordering code
4. Hardware revision
5. Serial number
6. Installed system/application
7. Front-panel photograph

For this part, I would not publish a detailed protection-function or I/O specification until the complete ABB type designation is confirmed. The available sources are too contradictory to safely infer those parameters from 1MRK0023505-AA alone.