FAQ

IEC 61850-90-4 switch selection and integration essentials

IEC 61850-90-4 highlights the central role of Ethernet switches in substation automation. The points below summarise the checks required during selection and design to help engineering teams keep protection and control traffic real-time, available, and verifiable.


Five key considerations for switch selection

  • Multicast capability
    • Must support multicast transport for GOOSE and SV (Sampled Values).
    • Provide IGMP Snooping or an equivalent mechanism to manage multicast groups and prevent flooding; use VLAN/QoS for isolation and prioritisation.
  • High throughput and low latency
    • Handle high-frequency, high-volume traffic (especially SV) without drops.
    • Keep latency within the limits of protection/control applications (typically within hundreds of microseconds) with sufficient buffering for line-rate forwarding.
  • Time synchronisation support
    • Must support IEEE 1588 PTP, preferably the Power Profile (IEC/IEEE 61850-9-3).
    • Boundary Clock (BC) or Transparent Clock (TC) improves accuracy and stability across the network.
  • Redundancy mechanisms
    • Support PRP (Parallel Redundancy Protocol) or HSR (High-availability Seamless Redundancy) for seamless redundancy.
    • Ensure traffic continues without interruption if a single device or link fails; use a RedBox where needed.
  • Industrial-grade reliability
    • Select industrial-rated specifications for temperature, humidity, and EMI/EMC conditions on site.
    • Support long-term stable operation with higher MTBF and robust power/surge protection design.

Integration and design highlights

  • Topology design
    • Adopt a layered architecture (core, distribution, access) for manageability and scalability.
    • Choose star, ring, or dual-network layouts based on application needs, balancing fault tolerance and O&M.
  • Traffic analysis and budgeting
    • Estimate throughput and buffering by GOOSE / SV / MMS message types and rates.
    • Validate switch and backbone performance under the worst-case traffic scenario, including loss rates.
  • SCL configuration and consistency
    • Use SCL (System Configuration Language) to describe topology and device parameters.
    • Maintain consistent communications between switches and IEDs (Intelligent Electronic Devices) with traceable versions.
  • Testing and validation
    • Run lab simulation and stress tests; measure redundancy switchover time, PTP accuracy, and packet loss.
    • Finalise during FAT / SAT and archive the test reports.

Suggested features matrix

ItemNotes
Network topologySupport star, ring, and dual networks; assess pros/cons and plan fault tolerance and redundancy.
Time synchronisationIEEE 1588v2 PTP (Power Profile); TC/BC depending on model.
GOOSE / SV transportLine-rate multicast and low latency; plan VLAN/QoS and IGMP Snooping.
Seamless redundancyPRP / HSR; use RedBox where required; can mix with RSTP / ERPS / α-Ring (non-seamless).
SCL configuration supportManage device and network parameters via SCL for consistent settings and version control.
Bridge / clock modelsSupport topology and clock object models to streamline system integration and engineering.
Design and testingDesign review, FAT / SAT; provide PICS / PIXIT / MICS and test reports when required.

Evaluate the above recommendations against actual project requirements and site conditions.

Need the complete feature list? → Recommended features
Want the reasoning? → Design rationale
How far should you go? → Trade-off principles
Related products: IEC 61850-3 / IEEE 1613 switches