Overcoming substation timing-over-Ethernet challenges

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By Aaron Martin, Bonneville Power Administration (BPA), and Bob Noseworthy, University of New Hampshire InterOperability Laboratory (UNH-IOL)

For the power industry, correct time and timing is essential in enabling the communication and orchestration of technologies for accurate and optimal wide area monitoring, protection and control (WAMPAC). Today, advancements in smart grid technologies are providing new capabilities and increased flexibility for grid operators, but also raising new security concerns. A co-hosted workshop of the National Institute of Standards and Technology (NIST), the IEEE Standards Association (IEEE-SA) and the University of New Hampshire Interoperability Lab (UNH-IOL) gathered inputs from stakeholders to identify, analyze and provide guidance on technologies, standards and methodologies for addressing the practical timing challenges that are currently being experienced in wide area time synchronization. 

Topping the list of challenges faced by utilities and system integrators is integrity assurance, with the first steps being device conformance and interoperability testing, performance monitoring and timely detection of any potential anomalies. These issues point to a real need for robust conformance and interoperability test methods to provide a degree of assurance that reference time can be properly distributed and that devices can synchronize to a required degree of accuracy as defined by industry. What’s more, system end-to-end interoperability and performance testing also provide assurance that the time distribution across multiple devices from various manufacturers can meet industry specifications.

With the emerging use of Ethernet for intra-substation communications, in 2008 the IEEE introduced the C37.238-2008 time-distribution protocol (eliminating the need for the traditional IRIG-B dedicated-wiring time-distribution links); the latest revision is IEEE C37.238-2017. To mitigate these inter-vendor interop issues, a TSS (Test Suite Specification) has been generated from collaborative efforts of the IEEE Conformity Assessment Program (ICAP), NIST and UNH-IOL, who have established a pilot conformity test program based on the NIST TSS for IEEE C37.238, IEEE Standard Profile for Use of IEEE 1588 Precision Time Protocol in Power System Applications, with the goal of establishing a certification process for device manufacturers provisioning the power generation and distribution market space. Released in late 2017, IEEE C37.238 specifies an extended common profile for the use of IEEE 1588, IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems, in power system protection, control, automation and data communication applications utilizing Ethernet communications architectures. It is compliant with both the core Ethernet time-distribution standard, IEEE 1588-2008 (=IEC 61588:2009), and the base Power Profile standard, IEC/IEEE 61850-9-3:2016, with special attention given to ensuring consistent and reliable time distribution within substations, between substations and across wide geographic areas.

ICAP develops and implements programs that couple standards development activities with conformity assessment activities in order to accelerate market adoption, while reducing implementation costs.