RE: [emix] Groups - EMIX Product and Time (2).pdf uploaded

["Considine, Toby (Campus Services IT)" <Toby.Considine@unc.edu>]

From: Toby Considine [mailto:Toby.Considine@gmail.com] 
Sent: Wednesday, November 10, 2010 7:41 AM
To: emix@lists.oasis-open.org (bounced this morning because of document size)
Subject: FW: EMIX Product and Time

Excellent question, Ed.

The real question, underneath, has to do with ramps, and perhaps with my understanding of them (which is getting better, now).

I had a concept of a ramp interval, i.e., an interval during which power varied but all other aspects were constant. This required me to have an interval with a (Begin power / end power) as opposed to a “normal” interval which had a single power. As at that time, all quantities were in the interval, and this was external to the product (resources had not really come together then), I needed another way to handle it.

What I did at the time was sub-class the EMIX interval, itself an instance of a WS-Calendar Interval, into an interval that was either constant or ramp power. This sub-class, then, with a choice if ramp or constant, can exist anywhere a an EMIX interval does, which includes as any member of an EMIX Sequence. 

So, it is not really an additional interval, but a redefinition for use in Power.

The CIM handles this by having “steps” of constant power instead. It then deals with the predicted variance between actual power and stepped power by having a market rule requiring the resource to “make good” on the difference with spot purchases.

I was concerned that such tacit “everyone knows how this works” assumptions break down as we move into common definitions for generation resources, distributed resources, and distributed generation. A key goal is to make all the tacit assumptions explicit in the interfaces, a goal as strong as that of hiding unnecessary technical detail.

The use of ramp rates in Resources has perhaps reduced the need for such intervals, meaning perhaps we can fall back to the un-elaborated, un-redefined bare emix sequence. If not, as your question indicates, then the Power Sequence warrants a couple paragraphs, perhaps in Chapter 5, as it is an underpinning structure throughout the other Power-based interfaces.

As always, we need to support the present and the future, rather than perfect the past. A good quick discussion?

Sean? Donna? Bruce? Phil? Ruchi? Brian? Each of you has chimed in on aspects of this subject.

tc


"It is the theory that decides what can be observed."   - Albert Einstein

Toby Considine
Chair, OASIS oBIX Technical Committee
U.S. National Inst. of Standards and Tech. Smart Grid Architecture Committee
Facilities Technology Office
University of North Carolina
Chapel Hill, NC
  
Email: Toby.Considine@ unc.edu
Phone: (919)962-9073 
http://www.oasis-open.org 
blog: www.NewDaedalus.com


-----Original Message-----
From: toby.considine@unc.edu [mailto:toby.considine@unc.edu] 
Sent: Wednesday, November 10, 2010 2:48 PM
To: emix@lists.oasis-open.org
Subject: [emix] Groups - EMIX Product and Time (2).pdf uploaded

The document named EMIX Product and Time (2).pdf has been submitted by Toby Considine to the OASIS Energy Market Information Exchange (eMIX) TC document repository.

Document Description:
Ed Cazalet raised issues in the attached document by email last night. I am sharing his comments with the group. Attachment (until I made it into PDF) was too large to send throguh OASIS Mailer. Ed's comment below:

Toby, Bill:  Above is the emix shema and the power interval schema that applies to the constant power product. Question: why does powerinterval have a wscal:interval when emix also has a wscal:interval.  I know we are to apply the product description to the intervals but to me that involves creating an XML payload that assigns price, quantity and duration to wscal intervals or glueons which are in type-emix.  And can we rename emix:product as emix:schedule and rename  type-powerinterval as type-constant powerproduct and delete its reference to wscal:interval?

View Document Details:
http://www.oasis-open.org/committees/document.php?document_id=40200

Download Document:  
http://www.oasis-open.org/committees/download.php/40200/EMIX%20Product%20and%20Time%20%282%29.pdf


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