Communication Networks and Systems for Power Utility Automation – Cisco Blogs

Interoperability among network components and end devices—such as Intelligent Electronic Devices (IEDs) and Remote Terminal Units (RTUs)—is incredibly important in utility systems. Technology vendors that help develop and then incorporate networking standards into their solutions foster rapid adoption, reduce technology risk, and power innovations. Cisco customers in energy utilities and Transmission System Operators (TSO) are requiring compliance with the International Electrotechnical Commission’s (IEC) 61850 standard. In fact, compliance is becoming mandatory in RFPs because it is foundational for building Substation Automation Systems (SAS).

IEC 61850 is a standard series which comprises specifications and technical reports for power utility automation including protocols, data models, and configuration aspects for use cases in substation automation, distribution automation, and between these entities including control centers. The cyber security standards of IEC 62351 are designed to protect IEC 61850 systems and protocols as well as other automation and control protocols based on cryptographic and architectural definitions.

Time-Sensitive Networking in Power Utility Automation Networks

In February 2021, IEC TR 61850-90-13: Deterministic Networking Technologies was published. Under the leadership of Cisco, the Technical Report provides project management, editor, and contributor resources. Moreover, Cisco led the liaison with IEEE 802.1 Time-Sensitive Networking (TSN) Task Group in order to be aligned with the work in the Joint Working Group IEEE/IEC 60802 which creates TSN-profiles for Industrial Automation.

IEC TR 61850-90-13 covers the use of deterministic networking technologies such as Time-Sensitive Networking (TSN) to meet the strict requirements in substation automation, protection, and control. At the same time, the standard works towards the objective of a converged (multi-service) network. The latter goal is related to the need to consolidate networks to achieve higher efficiency but with no impact to critical automation and protection of traffic on the network. Furthermore, it demonstrates how TSN can help to meet non-functional requirements to improve network security, usability, and migration strategies.

In a dedicated clause, an initial approach to architecting a TSN-profile for IEC 61850 networks is undertaken by classifying protocols used in substation automation networks. As a whole, the standard provides guidance on how to use TSN and other technologies to support Power Utility Automation and Control Systems based on IEC 61850, while making such installations future-proof. TSN will be especially useful to foster the adoption of the Process Bus, a substation network entity that connects IEDs with the Process Interface Units (PIU) such as Merging Units (MU) and other equipment which requires bounded latency, high availability, and robust network security. This will be an important step to a fully-digitized electrical substation.

The Cisco IE4000 substation switching family is IEC 61850-3 compliant and certified. It provides the communication platform for IEC 61850 Substation Automation Systems (SAS), consisting of networks, equipment, and applications. It provides the network infrastructure for the 61850 Interop (IOP) events.

Cisco’s Role in the Development of Synchrophasor Network Architecture

IEC TR 61850-10-13 is not Cisco’s first engagement in the scope of IEC Technical Committee 57. For more than 10 years, Cisco has been providing thought leadership on network and security contributions. One of the most influential Cisco standards engagements was the development of IEC TR 61850-90-5, a network architecture and the related standards that support the rollout of synchrophasor networks to provide visibility into the power grid at scale. A synchrophasor is a monitoring device that can measure the instantaneous voltage, current, and frequency at specific locations on the grid. This gives operators a near-real-time picture of what is happening on the grid, enabling them to take proactive measures to prevent power outages.

The development of IEC TR 61850-90-5 describes the use of IEC 61850 to transmit synchrophasor information according to IEEE C37.118. This Technical Report essentially puts Generic Object-Oriented Substation Event (GOOSE) and Sampled-Value (SV) messages on top of IP Multicast, making the entire synchrophasor network much more scalable. In addition, security is defined in 90-5 based on Group Domain of Interpretation (GDOI) to achieve scalable cryptographic protection and key management based on a group key system.

Cisco’s Participation and Contributions to IEC 61850

In 2012, Cisco joined an initiative to provide an Open Source Stack of IEC 61850-90-5. In addition to this effort, Cisco provided resources and contributions to the following activities in the scope of IEC 61850 and IEC 62351.

• Contributions to IPv6 Task Force creating Migration Guidelines for all TC57 domains which led to the publication of IEC TR 62357-200: Guidelines for Migration to Internet Protocol 6 (IPv6)
• Contributions and editors work on IEC TR 61850-90-12: WAN Engineering Guidelines, Editions 1 and 2
• Contributions to IEC 61850-8-1 Ed2: Specific Communication Service Mappings (SCSM) – Mappings to MMS and to ISO/IEC 8802-3, especially regarding the IPv6 extensions and the new Routable GOOSE and Routable SMV Profile, derived from the work in IEC 61850-90-5
• Technology support and contributions to IEC 61850-8-2: Specific Communication Service Mappings (SCSM) – Mapping to Extensible Massaging Presence Protocol (XMPP), a stack definition for power automation use cases in Distribution Automation as well as for Distributed Energy Resources and Micro Grids
• Contributions and editors work on IEC 62351-9: Cyber Security Key Management for Power System Equipment, Editions 1 and 2
• Contributions and editors work on IEC 62351-10: Security Architecture Guidelines for TC57 Systems

In addition to the standardization work, Cisco has been attended in the IEC 61850 InterOp testing events organized by UCA to support the idea of interoperability between vendors’ IEDs and communication equipment. Looking forward, Cisco is committed to contributing to ongoing and new initiatives in the scope of IEC 61850 and IEC 62351 to extend and refine the capabilities of secure and scalable communication for power utility automation.

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