Overview
EN 61850-9-2:2011/A1:2020 (amendment A1) is the CLC-adopted update to IEC 61850‑9‑2 that defines the Specific Communication Service Mapping (SCSM) for Sampled Values (SV) over Ethernet (ISO/IEC/IEEE 8802-3). The amendment clarifies layer‑2 SV mapping, multicast handling, protocol stacks (A‑Profile / T‑Profile), and configuration details needed for interoperability of merging units, protection and control devices in IEC 61850 substations.
Keywords: EN 61850-9-2, IEC 61850-9-2, sampled values, SCSM, ISO/IEC/IEEE 8802-3, Ethernet, substation automation.
Key topics and requirements
- Layer‑2 SV transmission: The document focuses on non-routable (layer‑2) Sampled Values; routable SV mechanisms are covered in IEC 61850‑8‑1.
- Multicast preferred; unicast deprecated: Multicast SV messages are the recommended model; unicast SV is considered deprecated.
- Protocol profiles:
- A‑Profile (application mapping) and T‑Profile (transport/network/link specifics) are specified; parts of the client/server profile are referenced to IEC 61850‑8‑1.
- Security reference to IEC 62351‑6 (optional handling for subscribers).
- Time and redundancy:
- References to precision time synchronization (IEC 61588 / PTP) and the PTP profile for utilities (IEC/IEEE 61850‑9‑3).
- High-availability redundancy protocols (PRP/HSR, IEC 62439‑3) for resilient networks.
- Ethernet framing and VLAN/QoS:
- IEEE 802.1Q tag must be present on egress frames from SV publishers.
- Default values: VID = 0 and priority = 4 for Sampled Values (configurable).
- Receivers must accept any VID/priority and handle frames without 802.1Q.
- MMS mapping for MSVCB: MMS attributes for the Multicast Sampled Value Control Block (e.g., MsvCBName, MsvCBRef, SvEna, MsvID, DatSet, SmpRate, ConfRev) define how SV configuration and control are exchanged.
Practical applications
- Distribution of real‑time sampled current and voltage data from merging units to protection relays and bay controllers.
- Enabling vendor‑interoperable protection and measurement systems in IEC 61850 substations.
- Designing Ethernet networks for deterministic SV traffic using VLAN/QoS and redundancy (PRP/HSR).
- Implementing synchronized sampling with PTP for accurate phasor and protection algorithms.
Who uses this standard
- Substation automation engineers and system integrators
- Protection & control device manufacturers and merging unit vendors
- Network architects for utility Ethernet infrastructures
- Test labs and certification bodies validating IEC 61850 interoperability
Related standards
This amendment ensures robust, interoperable, and time‑sensitive sampled value exchange over Ethernet, supporting modern substation automation, protection and measurement systems.
