Look under the hood: IEC 61850 for DER interconnections
Engineers should consider IEC 61850, which is being considered as a communications protocol.
Today let’s consider a standard called IEC 61850, which is being promoted as a protocol for communications between distributed energy resources such as wind power, solar photovoltaics, and an electric utility.
IEC 61850 has actually been around for some time, beginning with a project called UCA2 at the Electric Power Research Institute (EPRI). Although it hasn't had widespread use in North America, it has been adopted enthusiastically in international markets, particularly in Europe.
After nearly 15 years, however, European utilities are finding that due to vendor-specific implementations the standard’s facility for cost-effective interoperability is not being achieved. Implementations of IEC 61850 are more costly than anticipated and pose greater technical risks to success.
In response, the European Network of Transmission System Operators for Electricity (ENTSOE) has issued a paper calling for IEC 61850 stakeholders (including IEC’s Working Group 10 and TC57) to address the issues it has identified.
The statement calls on IEC working groups and affected stakeholders, including secondary systems suppliers, conformance testing companies and third-party tool developers to resolve the issues because IEC 61850 “is of potentially large benefit to electricity transmission system operators (TSOs) as it addresses across different vendors many crucial aspects of TSO communications, with the promise of seamless interoperability of different vendors’ subsystems within the overall TSO system management architecture.”
What’s the relevance to the consulting engineer in North America? Precisely this: IEC 61850 has been actively promoted as a solution for the interconnection of distributed energy resources (DERs), such as wind and solar, which are priorities for North American utilities. And it’s not yet performing as expected. So the consulting and specifying engineer could be hearing from vendors of these systems that IEC 61850 is the solution for interconnection of those DERs.
The fact is, the implementation of IEC 61850 could have a vender-specific flavor to it, which would not produce the interoperability that the control system engineer or the consulting specifying engineer may be led to believe is there. Thus I’d advise the consulting specifying engineer to look carefully into this, and ask the right questions about a utility's ability to interconnect to it.
I can imagine a scenario where an engineer is working with an industrial customer that is installing wind turbines with the intention of feeding excess generation back onto the grid. The engineer asks the wind control system vendor, “In your control system, what options do we have for interconnecting back to the electric utility?” The vendor might cite IEC 61850, adding, persuasively: “Tastes like chocolate, cures cancer, and costs a nickel.” So what’s not to love?
With this blog, I’d simply like to alert the engineer that experience has shown IEC 61850 needs work to achieve the cost-effectiveness interoperability for which it was designed. That calls for rigorous due diligence in identifying where the weaknesses are in this standard and evaluating alternatives.
Fortunately, help is on the way. The IEEE Power & Energy Society’s Substation Committee’s automation sub-committee (via Working Group C15) has embarked in the past 90 days on a review of IEC 61850. I’d expect that effort to address these issues in a manner that should give engineers in greater understanding of the issues and greater confidence in possible solutions.
Sam Sciacca is an active senior member in the IEEE and the International Electrotechnical Commission (IEC) in the area of utility automation. He has more than 25 years of experience in the domestic and international electrical utility industries. Sciacca serves as the chair of two IEEE working groups that focus on cyber security for electric utilities: the Substations Working Group C1 (P1686) and the Power System Relay Committee Working Group H13 (PC37.240). Sciacca also is president of SCS Consulting.