GE Reason MU320E – IEC61850 Process Interface Unit


The GE MU320E is the Process Interface Unit (PIU) with analog and binary interfaces for full switchyard modelling, control and digitalization over IEC 61850 standards & protocols such as Sampled Value (SV) and GOOSE.
  • Compact form factor supports field installation options into circuit breakers cabinets, marshalling kiosks and metal-clad switchgear.
  • 6 slots for I/O cards allows multiple applications. As a merging unit, Remote I/O device or PIU. Right size and point count for all types of applications.
  • Card slots for 2 CT/VT analog boards supports application on breaker-and-a-half lines, dual distribution feeders, combination protection and metering installations.
  • Optional metering accuracy CT/VT analog board for revenue metering and power quality applications.
  • 2 SV streams possible (one per CT/VT analog board). Each stream can be protection (80 s/c) or power quality (256 s/c) SV streams.
  • Full integration into the digital substation through 2 Ethernet ports, support for Parallel Redundancy Protocol (PRP) high availability networks and IEEE 1588 Precision Time Protocol.
  • Full IEC 61850 Edition 2, including support for test mode and simulation. Multiple logical devices to integrate multiple circuit breakers and disconnectors in one MU320E.
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The MU320E enables benefits of digital substation, as the I/O interfaces with every bay level IED, especially protective relays and the bay control units. Limiting the field wiring to only the MU320E also reduces project complexity by reducing cabling and physical connections. Bay IEDs can use data from redundant MU320E units, increasing system availability and can be quickly replaced as no field wiring is involved.

The MU320E has the additional benefit of improving CT performance and cost through a lower connected burden and a reduction in the number of CT cores required for an application.


  • Process Interface Unit for full bay digitalization.
  • Standalone Merging Unit for conventional instrument transformers.
  • Remote I/O (RIO) device for interfacing to primary equipment such as circuit breakers and disconnectors.
  • Bay unit for GE B30X distributed bus bar protection system.
  • Revenue accuracy and power quality metering applications.
  • Breaker-and-a-half line terminals using a single PIU device.
  • Two feeders in a single PIU device.


By integrating binary inputs, outputs and analogue connections into one box, the MU320E offers a cost-effective solution for a multitude of bay configurations. Up to two buses and two lines may be monitored per box with a flexible configuration of up to 96 binary inputs or 48 binary outputs.

Future Proof and Interoperable

The MU320E complies with the IEC 61850-9-2 Light Edition (LE) implementation guideline, which guarantees its interoperability.  This was tested and approved by the global testing and certification company TUV SUD according to the Implementation Guideline for Digital Interfaces to Instrument Transformers.  Furthermore, measurements of each CT/VT set may be broadcasted in protection and measurement profiles, allowing multiple protection, automation and control applications. Covering the gap between conventional and digital substations serves to future-proof substation technologies.

Test Modes

IEC 61850 edition 2 provides standard mechanisms for testing purposes, reducing commissioning complexity and allowing new bay installations without affecting substation operation.
MU320E is fully compatible to IEC 61850 ed. 2 allowing users to independently configure mode and behavior of each logical devicesallowing then to operate as: On, Test, Blocked, Test/Blocked and Off.

A safer substation

Transmitting the instrument transformers´ measurements digitally through optical fibers eliminates the risk of inadvertent mishandling of the current and voltage circuits and makes the relay room a safer work environment, eliminating hazards and reducing the risk of personnel injury.

Reduce the engineering effort and cost

The use of Process Bus with the MU320E drastically reduces the need for trenches, ducts, glands, cable trays and copper hardwiring, as the information is exchanged among IEDs using fiber optic cables and ethernet switches.
Fewer cables to manage also means reduced engineering complexity as extensive wiring schematics are replaced by standardized version-controlled configuration files. Future reconfigurations are automatically documented by the IED configuration tool.

Switchyard modelling and digitization

The Process Interface Unit MU320E stands as the device responsible to be the physical to digital interface for primary equipment, including the possibility to represent them through the IEC 61850-7-4 data model, in a way that the MU320E becomes the extension of the CT/VT, circuit breakers and disconnectors through the logical nodes TCTR, TVTR, XCBR and XSWI.
Through simple user interface IEC 61113-3 based logic it is possible to connect MU320E physical and digital inputs to its data model and digital outputs, allowing true Switchyard digitization

Improved Reliability

Power systems applications are mission critical systems, where the industry standard is to offer inherent redundancy in the schemes applied. The Reason MU320E provides unsurpassed reliability, as a flexible, redundant solution. The Ethernet connections support the IEC standard Parallel Redundancy Protocol (PRP), where a redundant star-connected topology allows zero-time – or bumpless – recovery. The shallow case design makes it easy to deploy MU320E in main and backup, or dual main applications, each connected to different cores of the line CTs and individual protection.
MU320 is the first of its class to manage both PRP redundancy and IEEE 1588 PTP operating together in the substation architecture. Profit from a single redundant network for higher reliability in communication and synchronization simultaneously.

Download the GE Reason MU320E brochure here:

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