Distributed busbar protection IED - REB500

Fast, scalable, and secure: REB500 protects the heart of your substation with proven differential protection and a future-ready architecture.

REB500 belongs to the family of Relion protection and control products designed for the protection, control, measurement, and supervision of power systems. It delivers consistent performance across all switchyard configurations: from 2 to 60 bays and up to 32 differential zones.

Proven in service for over 15 years, REB500 combines fast, low-impedance differential protection with a hardened, standards-based security architecture, so the busbar stays protected and the system stays secure throughout its life cycle.

• Proven busbar protection: Low-impedance differential protection with sub-cycle performance. The signal-prolongation principle maintains continuous, correct measurement even when current transformers saturate during external faults, and the isolator-independent check zone keeps the busbar secured even when the busbar replica is invalid.
• Scalable architecture: A single REB500 system protects from 2 to 60 bays and up to 32 differential zones, scaling with the installation throughout its life cycle.
• Cyber security by design: IEC 61850 MMS and event logging run over TLS (Secure MMS and Secure Syslog per RFC 5425). A dedicated certificate can be assigned per communication service, and offline Certificate Signing Requests are supported for sites without a connected PKI. The cryptographic stack is built on OpenSSL 3, with user lockout, HMI500 session timeout, and a forced change of the default password.
• Secure network integration: Multiple IP VLANs on the Central Unit SCS interface segment engineering, monitoring, and SCADA traffic within the station network. Time synchronization supports up to three SNTP servers.
• Centralized user management:  Native Microsoft Active Directory integration provides role-based access aligned with the wider Relion portfolio, with a local fallback user that keeps the system operable when Active Directory is unavailable.
• IEC 61850 interoperability: Supports IEC 61850-8-1 Edition 1 or Edition 2 with Parallel Redundancy Protocol (IEC 62439-3); GOOSE initiates the integrated breaker-failure protection.
• Easy to operate: A single toolchain, PCM600, HMI500, and WebHMI, configures, operates, and maintains a complete installation from any IED in the system.
• Architecture: up to 60 bays and 32 zones; redundant power supply on Central Unit and Bay Units; Bay Units with or without LHMI.
• Communication and standards: IEC 61850-8-1 Ed. 1/2 with PRP (IEC 62439-3); IEC 60870-5-103; Secure MMS and Secure Syslog over TLS; multiple IP VLANs; up to three SNTP servers; whitelisted process-bus switches.
• Cyber security and user management: per-service certificates; offline CSR; OpenSSL 3; user lockout, session timeout, and forced default-password change; Active Directory with local fallback; User Access Management and Activity Logging; SNMP V2c/V3.
• Engineering: configuration with PCM600, HMI500, and WebHMI.