Welcome. If you've been with us up til now, you will doubtless recall that YHA (your humble author) is on a quest to provide you, the ISGO (interested smart grid observer) with an overview of Special NIST Document 1108, the NIST Framework and Roadmap for Smart Grid Interoperability Standards. This week we intend to focus in on an important Chapt, that being No. 3, The Conceptual Reference Model. If you are a first-time offender, it might be helpful to refer back to last week's blog to get an overview of the whole document. Or you can go to the one before that and read them in series, if you are having trouble sleeping or something.
But before we start on Chapt 3, a correction from last week's epistle. An alert reader (1 of the 3) noted my reference to Mary Poppins, whom (I said) would not be happy because she wanted us to 'start at the very beginning' which we weren't going to. Anyways, that was the right actress, Julie Andrews, but the wrong movie. As anyone who knows anything knows, that song 'Do-Re-Mi' was actually from the film 'The Sound of Music', and Ms Andrews was playing Maria, not Mary Poppins. I stand corrected. In fact, this makes me YEHA, your Even humbler author. BTW, one of the other 2 readers noted that the blog interactive comment feature does not seem to be working. Fear not. Our crack IT staff is resolving this thorny issue even as we blog.
So, on to Chapt 3 – the Conceptual Reference Model. Given the material, this week's discussion has to start with a disclaimer. I suppose that anything YHA tries to explain to anyone should start with a disclaimer. Leaving that aside, it doesn't take genius to grasp that a Reference Model probably involves some graphical depiction, which is not so easy to re-render in a blog. Thus, this disclaimer: get a copy of this Chapt and read it. Just as a reminder, the site is www.nist.gov/smartgrid. This Chapt contains 3 figures, 2 of which are excellent. OK, the other one is pretty good, but a little complicated. Any ISGO such as yourself would do well to review and understand these, along with the accompanying text. Here's what you'll be looking for.
The objective of Chapt 3 is to help us understand the high-level pieces, parts, and people that make up the Smart Grid, and the interactions amongst them. Recognizing that the Smart Grid is a 'system of systems' and a 'network of networks', that is not such an easy thing to do, but Chapt 3 succeeds quite nicely. Any participant could use the conceptual model presented to help analyze and plan for their own smart grid implementation, and perhaps as important, understand how their particular smart grid fits into the overall Smart Grid. Maybe I should've explained my use of capitalization before now. Whenever I am referring to the concept, or to the electrical system that will connect a whole country, continent, or world, I will generally use 'Smart Grid', in caps. When I am talking about a specific implementation, such as at a utility or a regional level, I will usually write 'smart grid', in lower case. Unless I forget. Or don't feel like it. Just kidding. Same thing for the acronyms, SG and sg. OK, you probably would've gotten that on your own.
But back to the topic at hand. The comprehensive material in Chapt 3 starts with a definition of 7 domains in the Smart Grid (see Table 3-1, p 32):
- Customers
- Markets
- Service Providers
- Operations
- Bulk Generation
- Transmission
- Distribution
High-level definitions are given, with more detail provided in the Appendix. Within each domain, actors (or participants) are also categorized. These are groups of people or systems who are operating in a particular domain to do a similar thing, like residential, commercial, and industrial actors in the Customer domain. Some actors are not people at all, but systems, like a SCADA system that controls electrical equipment in the Operations and Distribution domains. And some actors work in more than one domain, or interact with other actors across domains. So, it can get kind of complicated, and that's why the Conceptual Reference Model is important.
By breaking the Smart Grid up in this way, a foundation is laid for depicting and understanding the interactions that will be required in the SG. The excellent, simple graphic in Fig 3-1 at the bottom of page 33 does exactly that. A more detailed diagram (Fig 2) is provided 2 pages hence, which gives a number of the commonly-found systems in each domain. This graphic isn't as easy to follow, but it is worth taking the time to study it. When you, the ISGO, get to the point that you'll have to start mapping out your own model of your own sg, this diagram will help to give you some organizing principles. Think of it as a starting point.
Chapt 3 then goes on to spend a fair bit of time talking about information networks. Since many of us in the power business are not communications experts, this segment is particularly helpful. It not only presents the concepts of the communications infrastructure that will be needed for the Smart Grid, but also addresses some important issues and clears up some vexing questions. For example, we all know that IP stands for Internet Protocol, and that IP-based communications will play an important role in the SG. But how many of us know what MPLS stands for? It makes me think of Minneapolis, where they have a beautiful new baseball stadium that replaced that raggedy – well, that's a bit off topic. Actually, MPLS stands for Multi Protocol Label Switching, one of a number of technologies that will be required in SG communications. And of course, no discussion of communications in today's world would be complete without acknowledging cyber security as an important concern. Chapt 3 just touches on that, since there is an entire Chapt on that topic.
In its final sections, Chapt 3 describes the Use Case Methodology employed in the standards framework and roadmap, and then goes on to take special notice of the interface to the Customer domain in the Smart Grid. It turns out that, in no small part because of the interest in smart metering, this part of the Reference Model merits some extra attention. This section spends some time on the idea that there is a difference between the Energy Services Interface (ESI) and the Meter. The ESI is the connection between the Premise Network or Home Area Network, including all the energy-consuming smart devices in the home or commercial building, and the Smart Grid. The Meter in this definition is the measurement tool that can also record and communicate to the SG. Now, it is intuitively obvious to even the most casual observer that some people believe that the Meter would make an ideal ESI. Like people who sell smart meters and AMI systems, for example. On the other hand, people who sell HAN technology, or who provide demand response systems thru separate (non-meter) devices, would like us very much to accept the idea that the gateway to the premise need not be the meter.
You may have your own thoughts on the matter. Section 3.5 does a nice job of clarifying the high-level requirements for this part of SG interaction, and giving the reader some good information to ponder. Revisit Figure 3-2 with the ESI and Meter carefully in mind. Read and ponder away. YHA believes that you'll find the Conceptual Referemce Model well worth the investment.
And please make plans to be with us next week when we review the movie 'Iron Man 2'. Kidding again. We'll be digging into Chapt 4 of the Roadmap, touching on the highlights of Standards identified so far. Riveting, actually. Please join us.
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