Overview
IEC 61850-9-2:2004 defines the Specific Communication Service Mapping (SCSM) for the transmission of sampled values (SV) over Ethernet (ISO/IEC 8802-3) as part of the IEC 61850 family for substation automation. It maps the abstract sampled-value model in IEC 61850-7-2 onto a mixed protocol stack that uses direct access to an ISO/IEC 8802-3 link for real‑time sample transport, together with selected services from IEC 61850-8-1. This part is a core standard for digital process-bus architectures and is of high relevance to the Smart Grid.
Key topics and technical requirements
- Communication stack specification: Defines how the abstract SV model is implemented on an Ethernet (ISO/IEC 8802-3) link and how it coexists with IEC 61850-8-1 services.
- Mapping of data models: Maps IEC 61850-7-2 data attributes, classes and services (including multicast and unicast sampled value control blocks) onto real protocol elements.
- SV frame and encoding rules: Includes guidance on frame formats and ASN.1 encoding (see informative annexes) for sampled value transport.
- Multicast and unicast SV services: Specifies both multicast SV transmission and optional unicast arrangements for sampled values, and their control‑block mappings.
- Process bus architectures: Describes alternative process-bus layouts and how merging units, electronic current/voltage transformers (ECT/EVT) and IEDs connect to the Ethernet process bus.
- Integration with MMS and SCL: Identifies which IEC 61850-8-1 (MMS) services are needed to access and manage SV control blocks and how SCL (Substation Configuration Language) entries describe SV configuration.
- Conformance and interoperability: Provides conformance statements and PICS guidance to support interoperability among vendors.
Applications and who uses it
- Utilities and substation automation teams implementing digital process buses and Smart Grid projects.
- Manufacturers of merging units, digital ECT/EVT, protection relays, bay controllers and meters that produce or consume sampled values.
- System integrators and design engineers specifying Ethernet-based SV transport and ensuring interoperability.
- Test laboratories and certification bodies validating IEC 61850 SV conformance and performance.
Related standards
IEC 61850-9-2 is essential when designing low-latency, interoperable Ethernet-based sampled-value transport in substations and process-bus deployments for modern Smart Grid systems.
