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REB500 - Distributed busbar protection

The IEC 61850 enabled REB500 IED is designed to support different protection philosophies. You can create a distributed protection solution by assigning bay units into dedicated bay cubicles. In this distributed solution, the bay protection is assigned to separate bay units. Alternatively, you can integrate all necessary functionality into one or several centralized cubicles. 


REB500 is using proven concepts and algorithms continuously used and improved for over 15 years. The unique signal prolongation principle enables continuous measurement and ensures correct operation of the busbar protection, even when the current transformers are heavily saturated during external faults. This principle ensures the correct operation of the busbar protection instead of blocking the protection function and leaving the busbar unprotected.


REB500 detects all bus and feeder faults for any type of system earthing, whether it is an isolated system or a solidly, low impedance or compensated earthed system. It operates selectively for all faults in the protected zone and maintains complete stability for faults outside the protected zone. 

The integrated overall check zone feature is completely independent of the isolator position indications. This feature enables REB500 to remain stable in case the busbar replica is not valid.

Relion – Complete confidence

Low impedance distributed busbar protection REB500 IEDs belong to the Relion protection and control product family. The Relion product family offers a wide range of products for the protection, control, measurement, and supervision of power systems. Hitachi Energy ensures interoperable and future-proof solutions for any application area and supports the core values of the IEC 61850 standard. With Hitachi Energy's leading-edge technology, global application knowledge, and experienced support network, you can be completely confident that your system performs reliably – in any situation.


Get to know more

REB500 is using state of the art technology and delivers enhanced protection and communication performance. Proven Relion series enable differential protection performance below one power cycle.

REB500 is flexible to protect various busbar configurations under all circumstances. By integrating a versatile selection of protection functions, REB500 IEDs safeguard the complete bay and optimize switchyard protection, delivering adaptable, scalable functionality to changing needs throughout the entire life cycle of the installation.

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