RE: Questions about Interval VEE rules
Sorry about the ambiguity on my part - I didn't mean to imply estimating the
interval with the outage - just not using it as an end point. This does get
complicated!
Keeping in mind that this method is only used for "gaps" 2 hours or less in
length....
An interval with an outage is not a complete interval - for example, a 15
minute interval with an outage does not contain 15 minutes worth of data. In
that sense it is not a good representation of normal usage, and I believe that
is why the group felt it should not be used as an end point for interpolation.
For example, if there was a 10 minute outage during the interval, the interval
would only have 5 minutes of usage - about 1/3 of its normal value. From the
raw data, you don't know if it was a 2 minute outage or a 10 minute outage.
There are (at least) two cases:
1. There are outages on both sides of the "gap". In this case, you might
assume power was out for the duration of the gap and the estimation would be 0
kWh - no power equals no usage. (Again, this is for 2 hours max) There is
always the case of intermittent outages, where power wasn't out for the
duration of the gap, but came on and off. I don't know which is more common -
maybe the UDCs have some feel for that.
2. There is an outage on one side of the gap, and a good interval on the other
side. The outage could have been entirely within one interval, and not affect
the gap at all. In this case, I would either propose Valerie's option D (use
good interval closest to outage interval) or E (use good interval at other end
for both points). Or the outage could extend into the gap - but I don't know
how you detect that from the raw data. Again, maybe the UDCs have some
experience on what is most typical that could help us choose a "standard"
approach that everyone always follows.
"Vanderlinde, H. John" <JVanderl@SDGE.com>
07/23/98 08:57 PM
To: Kathy Smith/Raleigh/USTRA/ABB, 'Valerie Nibler'
<valerie@energyinteractive.com>
" - (052)estradam(a)sce.com" <estradam@sce.com>
"Roome, Jane" <JRoome@SDGE.com>
" - (052)MSL6(a)pge.com" <MSL6@pge.com>
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"Sabin, Leslie" <LSabin@SDGE.com>
Subject: RE: Questions about Interval VEE rules
I agree with Valerie & Kathy regarding item 2; item 1 is not so clear. The
methodology used in examples D & C in Valerie's document are what I thought
would be used. I think there are 2 important issues here: 1) There is a
flaw, as Valerie pointed out, in using the methodology for examples C & D;
if the power outage is for an extended period of time the first point
(interval) might not be accurate. Unless we want to add language that
specifies: "use method C or D if the power outage is less than 2 hours in
length and method A if the power outage exceeds 2 hours in length" this
problem will exist. And 2) is the consistency issue concerning power outage
intervals. I agree with Valerie that intervals during power outages must be
considered as actual in order to be consistent with the rest of the
document.
I just wanted to mention that we are really splitting hairs here!
H. John VanderLinde
San Diego Gas & Electric
Analyst - Customer Service Policy Support
Phone: (619) 654-8380 Fax: (619) 654-8393
E-mail: jvanderl@sdge.com
> ----------
> From: Valerie Nibler[SMTP:valerie@energyinteractive.com]
> Sent: Thursday, July 23, 1998 10:22 AM
> To: kathy.smith@USTRA.mail.abb.com
> Cc: - (052)estradam(a)sce.com; Roome, Jane; - (052)MSL6(a)pge.com; -
> (052)hillrm(a)sce.com; - (052)garciah1(a)sce.com; -
> (052)colwella(a)sce.com; - (052)JECo(a)pge.com; -
> (052)diane.rihn(a)lgeenergy.com; - (052)dciruli(a)energyinteractive.com;
> - (052)tom.lofgren(a)cellnet.com; - (052)VJM3(a)pge.com; -
> (052)dirksjd(a)sce.com; - (052)ddc2(a)pge.com; Vanderlinde, H. John; -
> (052)pswg3web(a)dra1.cpuc.ca.gov; - (052)pswg(a)dra1.cpuc.ca.gov
> Subject: Re: Questions about Interval VEE rules
>
> <<File: PowerOut.doc>>
> I agree with Kathy's response to Question 2, but I believe that there is
> still some
> ambiguity with respect to my first question. I have developed some
> examples of what
> we could do when there is a power outage adjacent to the period requiring
> estimation. They are shown in the attached Word document (saved in Word
> 6.0, but
> let me know if you cannot read it).
>
> Having now given some thought about how to approach implementation, I
> would argue
> for dropping the statement "Intervals containing a power failure cannot be
> used as
> end points for interpolation" from the rules. The genesis of this
> statement was our
> agreement not to use days with power outages as reference days for
> creating average
> profiles for estimation. I think it makes sense not to use days with
> power outages
> as reference days for estimation because those days may not represent
> typical
> usage. But not using these intervals for interpolation suggests that the
> usage
> during the power outage does not represent actual usage, which is not
> consistent
> with our treatment of power outages in the remaining data.
>
> Since the goal here is one interpretation of the rules, I would appreciate
> knowing
> how others are implementing this rule.
>
> Thanks,
> Valerie Nibler
> Energy Interactive
> 510-704-8777
> valerie@energyinteractive.com
>
> kathy.smith@USTRA.mail.abb.com wrote:
>
> > Valerie Nibler sent me the following questions regarding interval VEE
> rules.
> > I've attached my thoughts to her questions. Please let me know if you
> agree or
> > have a different interpretation by COB Friday, 7/31. I assume we can
> > disseminate the clarifications through the UDC/MDMA and MUG
> groups.....thanks!
> > (No, the VEE work never finishes!)
> >
> > Kathy Smith, ABB
> > 919-250-5429
> > kathy.smith@ustra.mail.abb.com
> >
> > Questions:
> > 1) Regarding the statement: "Intervals containing a power failure
> > cannot be used as end points for interpolation." What intervals should
> > be used as the first and second points for interpolation in the case
> > where there is a power failure adjacent to the period needing
> > estimation?
> >
> > Proposed answer:
> > My understanding is that an interval with a power failure would be
> > treated the same way as an interval that isn't valid. You would find
> the
> > closest valid interval that is not a power failure to use as the end
> point.
> >
> > 2) Point of clarification on estimating holidays. It is my
> > understanding that you should look for holidays in the current and
> > historical periods, and if you do not find three holidays, you should
> > look for as many additional Sundays as required to supplement the
> > holidays. Average the holidays and the Sundays (a total of three days)
> > to create the average profile. A contrasting interpretation is: look
> > for holidays first, if you find only one, use that as the "average", but
> > if you don't find any, then look for Sundays.
> >
> > Proposed answer:
> > I think you should always try for three days. This may end up being a
> > combination of holidays and Sundays, and current period and historical.
> I
> > think the priority should be:
> > 1. Holidays in current period
> > 2. Holidays in historical data
> > 3. Sundays in current period
> > 4. Sundays in historical data
> > If you can't find three holidays or Sundays after all this, then you
> would
> > back off to two days or one day, depending on what you can find.
> >
> > For example, if the current billing period had no holidays, and
> historical data
> > had one holiday - use the holiday from historical data, and the two
> Sundays from
> > the current billing period that are closest chronologically to the day
> needing
> > estimation. (Assumes all the reference days are "good" data.)
>
>
>
.