AESO Response

Comments from Stakeholders on Settlement Zone Accuracy (POD Aggregation)
AESO Response
Name
EPCOR
Utilities Inc.
Carmen Piercey
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
Conceptual Framework
Responses to be published soon.
The accuracy and reliability of system level data is impacted at a number of levels, given
the physical nature of the system. Meters are used to calculate zone load. Zone load in
each time period is then disaggregated into components consisting of classes of data,
resulting in the series of calculations that is load settlement. Since those meters that
measure the total load in a zone are relatively few, their effect on load settlement
accuracy is much greater than other data.
June 28, 2005
Given these interrelationships and linkages, EPCOR suggests it would be instructive and
helpful to group the various issues related to system level data into three general
categories as follows.
1. Physical Reality of Electric System – There are metering devices connected at
various points to energized wires. The wiring itself determines the utility of
related meter data. A number of physical facts impact the use of meter data,
including required meter types, loss compensation, PT and CT ratios, redundant
wires, check and backup meters.
2. Status of Meter Devices – Each meter point used in the context of transmission
is represented by a single line drawing, often represented in a generally accepted
industry model called a Meter Point Definition Record (“MPDR”). These
models establish agreed conventions on how physical reality will be reflected in
data use. It is noteworthy that the MPDR model does not extend to include
distributed generation, distribution interchange and other constructs not directly
related to transmission tariffs.
Meter Data Provision – Meter pulses are converted to “readings” data by software
systems. Meter readings are aggregated according to MPDR rules by software systems.
Meters are assigned “system level” status and a system level model of each interval is
constructed by software systems. Software systems create load settlement from these
data. This is the domain of “meter data management”, if the above two classifications
are right, and of lost effort if they are not. System level meter data is used both to
describe load shapes and load magnitudes as well as to provision data for transmission
tariff purposes.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 1 of 19
Name
EPCOR
Utilities Inc.
(continued)
Issue
Settlement
Zone Accuracy
(POD
Aggregation)
Comments
The relationships among these categories, and the degree to which they depend on and
affect one another, can also be viewed as follows:
Meter Data Provision
Carmen Piercey
Status of Meter Devices
June 28, 2005
Physical Reality of Electric
System
AESO Response
Responses to be published soon.
This layer indicates the data provided to market
business processes. This layer is useful only if the
layers below are sound.
This layer contains standards for meter accuracy,
reading frequency, and rules for measurements. This
layer is sound only if it accurately reflects reality
At this level are the physical characteristics of the
measurement devices, including PT/CT ratios, actual
point at which measurements are taken, and resulting
totalizations. This layer is right if engineering is
sound relative to the purpose and intent of
measurements needed.
Within this framework, it is evident that failures can have a cascading effect in that data
problems within any level may create difficulties at any of the three (or all three) levels.
Categorization of Issues
The three “strata” described above can be used to drive a table-based review of the
matter. In the table in Appendix A we have captured each of the issues listed in the
Settlement Zone Accuracy issue paper, and then mapped it into this general conceptual
model. The issues list from the issue paper is extensive, and due to the need to be
comprehensive, it contains numerous repetitions. EPCOR has attempted to restate these
issues organized according to the three categories described above in order to enhance
the understanding of the problem.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 2 of 19
Name
EPCOR
Utilities Inc.
(continued)
Carmen Piercey
June 28, 2005
Issue
Settlement
Zone Accuracy
(POD
Aggregation)
Comments
Physical Electric System
1.
Responsibility for data veracity is ambiguous where MDM and LSA are
separate parties.
2.
Distributed Generation metering standards are inadequate.
3.
Distribution Interchange metering standards are inadequate.
AESO Response
Responses to be published soon.
Status of Meter Devices
4.
Data exchange standards have weaknesses where both TA and LS streams
are used.
5.
A need exists for generally agreed business process rules for some metering
constructs. MPDR – like disciplines have a TA focus insufficient to
describe LS needs.
6.
System Level data are not reconciled or validated on a daily basis.
7.
There are many timing problems. Timing is an issue:
a.
Where TA and LS system level data are reporting on different
schedules.
b.
Where SL meter data are permitted to be restated but load shapes are
required to freeze.
c.
Where SL estimations are permitted to be used.
Meter Data Provision
8.
Distributed Generation data standards are inadequate.
9.
Distribution Interchange data standards are inadequate.
10.
System level data restatements are in conflict with profile freezing
requirements.
11.
Data validation, in the sense of QA analysis and data controls is not
standardized, not transparent, and apparently not adequate. Validating TA
measurements against LS data streams (or the reverse) will not add value
until timing and data rules are coordinated.
Other
12.
Accountability does not exist without enforcement adequate to change
behaviour.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 3 of 19
Name
EPCOR
Utilities Inc.
(continued)
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
It was not clear that “POD Aggregation” was related to the published issues in any direct
way, except in areas affected by distributed generation or distribution interchange.
EPCOR believes the issues above reflect the primary issues and factors relating to
settlement zone accuracy that ought to be considered in this process. With respect to
these issues, EPCOR further believes that continued and intensified standards work is
directly indicated as a least-cost approach to resolution.
Carmen Piercey
Concluding Comments
June 28, 2005
The paper seems to presume that direct operational involvement with meter data by the
AESO might be of value. EPCOR proposes that the issues listed above be resolved
before any consideration is given to moving the responsibility to the AESO. Moving the
current processes at this time would likely exacerbate, rather than resolve the problem.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
AESO Response
Responses to be published soon.
Page 4 of 19
Name
Issue
Direct Energy
Settlement Zone
Accuracy (POD
Aggregation)
Christina
Davidson
July 4, 2005
Comments
The AESO has requested feedback on the following:
AESO Response
Responses to be published soon.
“Comments and input to clarify the issue stated in this document, any corrections to
issues information”
DEML notes that the issue as identified: “To improve the accuracy, reliability, and
dependability of the settlement zone totals used by the LSA’s for settlement” is actually
not an issue but an action item or objective required as a result of a number of
outstanding settlement issues. DEML respectfully submits that in order to comment
appropriately, the AESO provide the LSBAC members a flowchart of the current
settlement zone reconciliation process and highlight the key issues that are currently
affecting the AESO’s ability to facilitate this reconciliation. Once the issues have been
clearly identified DEML proposes that the LSBAC committee members will be in a far
better position to add value in terms of addressing these issues and moving ahead with
effective resolution.
“Comments and input to clarify the scope and objectives of this initiative”
Please see comments above.
“Comments and input on the process, timelines, and schedules. Provide suggestions on
the proposed TBD windows”
DEML notes with some concern that the proposed dates appear to extend well into
October 2005. DEML respectfully suggests that the issues as detailed in this discussion
paper are not new issues for the AESO. They are a continuation of a host of issues raised
by industry since the beginning of electricity deregulation in 2001. As a result, DEML
proposes that the AESO is well equipped to provide LSBAC members the information
requested above well before the end of August.
“Additional comments”
DEML has recognized this issue as a priority for industry and commits to working with
the AESO in determining the best steps on moving these items effectively forward.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 5 of 19
Name
ATCO
Electric
Blair Morton
Issue
Comments
Settlement Zone
Accuracy (POD
Aggregation)
Although the referenced document requests specific feedback, ATCO Electric believes
that a more general issue needs to be addressed before specific feedback can be
constructively provided. The issue, as described in the referenced document is very
similar to an issue currently being addressed by the Metering Service Providers group
also lead by the AESO. Confusion and unproductive efforts will result if the initiative
called, “Daily System Measurement Implementation Plan” is not coordinated with the
referenced issue. The DSM Implementation Plan has progressed to a point where a
solution is defined. The referenced issue is yet to be defined.
AESO Response
Responses to be published soon.
June 28, 2005
Based on this new information, ATCO Electric believes that the referenced issue
should be deferred until the DSM Implementation is completed and that the Load
Settlement Group should support the implementation of this initiative. Once it has
been implemented, should the AESO still believe there is an issue, the Load
Settlement Group should address it at that time.
The following is ATCO Electric’s response to the specific requests made in the
referenced document.
Requested Action: “Comments and input to clarify the issue stated in this document, any
corrections to issues information.”
ATCO Electric does not have any specific feedback for reasons stated previously.
Requested Action: “Comments and input to clarify the scope and objectives of this
initiative.”
ATCO Electric believes that the scope and objectives should be revisited once the DSM
Implementation has been completed.
Requested Action: “Comments and input on the process, timelines and schedules.
Provide suggestion on the proposed TBD windows.”
ATCO Electric believes the DSM implementation should precede any action with
respect to this issue.
Requested Action: “Comments and input to clarify or correct any of the reference
information included in this document.”
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 6 of 19
Name
Issue
Comments
ATCO Electric
(continued)
Settlement Zone
Accuracy (POD
Aggregation)
ATCO Electric would like to respectfully clarify their position on the priority of this
issue. Based on the new knowledge as noted in the opening paragraphs, ATCO Electric
believes this issue to be a “low” priority. Also note that ATCO Electric does support
the DSM Implementation Plan initiative.
Blair Morton
June 28, 2005
AESO Response
Responses to be published soon.
Requested Action: “Comments and concerns for supporting or not supporting moving
forward.”
As stated earlier, ATCO Electric does not support moving forward at this time and
believes that the “DSM Implementation Plan” initiative should be completed before any
more effort goes into this initiative.
Requested Action: “Any other comments related to this issue or the process.”
ATCO Electric has no further issues.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 7 of 19
Name
Issue
EnCana Power
Settlement Zone
Accuracy (POD
Aggregation)
Comments
Item # 1 and Item # 2 - Issue Clarity; Scope and Objectives
AESO Response
Responses to be published soon.
EnCana supports the AESO in that the issue is not physical metering but an absence of
comprehensive consistent and enforceable standards for gathering, transferring and
processing settlement zone meter data.
Marie Gallant
Item # 3 - Process and Timelines
June 16, 2005
EnCana encourages the AESO to expedite addressing this issue as much as possible.
There has been a great deal of progress already made in identifying feasible options with
the System Level MDMs. The LSBAC is now in the enviable position to take advantage
of work already done and move quickly towards the solution stage.
Items # 4, # 5 and # 6 - Support for Moving Forward
EnCana is a strong proponent of moving this issue forward. Zone level measurement
accuracy is fundamental to a system that provides for over $3 Billion annually in
financial settlement.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 8 of 19
Name
FortisAlberta
Nguyen Tran
June 29, 2005
Issue
Comments
Settlement Zone
Accuracy (POD
Aggregation)
FortisAlberta supports the AESO’s Settlement Zone Accuracy initiative to have timely,
consistent and reliable system level data. FortisAlberta submits that the following
clarifications are necessary in order to support this market data accuracy initiative.
AESO Response
Responses to be published soon.
Issue
FortisAlberta agrees with the issues as presented and submits the following:
1.
Late updates to system level data are an issue. If system level data is delayed to
the extent that such data is not received prior to the creation of such period’s
frozen profile, there is the potential for a divergence between the profile as
created and what the profile should have been had such system level data been
present. This divergence results in a difference between the zone load and
settled load and is allocated as UFE.
2.
Accuracy of system level data is an issue. The current classification of
transmission meter points as either Point of Delivery (POD) or Point of Supply
(POS), precludes the capability to recognize that the meter point may act as one
or the other given the meter point’s proximity to distributed generators at any
one point in time. Such classification results in an inability to accurately define
the Settlement Zone Load. The potential for this situation to intensify grows as
the trend towards ever larger distributed generators continues. Initiatives such
as the Daily System Measurement (DSM), while being beneficial to the
accuracy of system level data, does not address this fundamental inconsistency
as presently defined.
3.
Inconsistent treatment of distributed and interchange points between LSAs
needs to be addressed with the intent of defining a single standard.
4.
Inconsistent system level data between transmission and settlement needs to be
addressed to determine the root cause of any such differences, with the intent of
eliminating those differences.
5.
There is a need for clarification of the ‘Need to better assign aggregate
wholesale zones’ issue as raised.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 9 of 19
Name
FortisAlberta
(continued)
Nguyen Tran
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
Current Developments
FortisAlberta submits that it is of benefit to coordinate initiatives identified by MDM
stakeholders (DSM, standardization of distributed generation/interchange, single data
stream for system level data, etc.) as they each have an impact on Settlement Zone
Accuracy.
AESO Response
Responses to be published soon.
Objectives
FortisAlberta agrees with the objectives as presented.
June 29, 2005
Scope
FortisAlberta submits that resolution of the Settlement Zone Accuracy issue would be
best achieved through a holistic approach that includes discussion of all factors,
including physical metering standards and processes and appropriate revisions to the
SSC as well as the Daily System Measurement (DSM) transaction. A synchronized
approach would allow the market to leverage proposed transaction standards and ensure
that they are best utilized to provide the market with an accurate settlement zone. This
approach would also reduce the costs associated with any potential changes to system
implementations.
Schedule
FortisAlberta submits that it is beneficial to include two additional processes; the first
before Activity 6: Seek input from industry on potential alternatives / solutions to issues
labeled ‘Validation of the specific concerns’, so that the concerns contributing to the
issue are explored to provide a basis for more effective alternatives / solutions; and after
Activity 11: Development of a final recommendation and business case labeled
‘Stakeholder review of final recommendation and business case’, in order that all
stakeholders have the opportunity to evaluate the proposal for completeness, prior to the
development of an implementation plan.
FortisAlberta agrees with all other scheduled time frames as proposed and suggests that
it is practical to exclude actual dates at this time as this is an iterative process whereby
the completion of each milestone is dependent on the one before it.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 10 of 19
Name
FortisAlberta
(continued)
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
Concerns
FortisAlberta submits that there exists an inconsistency between the Daily System
Measurement Implementation Plan v2.0, June 21, 2005 (DSM transaction sent to all
parties directly) and that of the stakeholder view on Settlement Zone Accuracy as
presented to the LSBAC on March 23,
2005:
AESO Response
Responses to be published soon.
Nguyen Tran
June 29, 2005
‘AESO to handle the responsibility for all System Level Metering transactions
between the MSPs, MDMs and the LSAs’
This inconsistency has the potential to impair the development of a complete solution,
and may cause additional systems development and/or manual processes to
circumvent any limitations in the inherent design.
In closing, FortisAlberta asserts that the key goals of timeliness, accuracy, data
integrity and audit visibility is better managed through a central entity that is
responsible for the control and publishing of all system level data. FortisAlberta
supports this approach to improving Settlement Zone Accuracy.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 11 of 19
Name
Issue
MIDAS
Metering
Services Ltd.
(MIDAS)
Settlement Zone
Accuracy (POD
Aggregation)
Tim Raines
June 29, 2005
Comments
Intent
This document is the MIDAS Metering Services Ltd. (MIDAS) response to the Alberta
Electric System Operator (AESO) request for input relative to their Settlement Zone
Accuracy (POD Aggregation) issue definition document dated June 8, 2005.
AESO Response
Responses to be published soon.
Executive Summary
Prior to the opening of the retail market the Transmission Administrator (initially GridCo
and later, in 1998, ESBI Alberta Ltd.) received transmission system interface
measurement point data (IMP, EXP, GEN and LOD) from what it termed, in it’s
Measurement System Standard documentation, to be Metering Data Providers (namely
transmission facility owners, transmission-connected generators, etc…) so that it could
administer it’s mandate, apply it’s tariffs and pass an extract of this data on the Power
Pool Of Alberta for wholesale energy settlement purposes. When the retail market
opened up in 2001, the Transmission Administrator (then ESBI Alberta Ltd.) took no real
interest or role in the retail load settlement process and so a somewhat redundant and
non-cohesive set of ‘system level’ metering and data standards was developed as part of
the System Settlement Code (SSC). Unfortunately, as with most process failures, the
issues began to arise at the interfaces, most notably the common transmission –
distribution interface.
Both transmission and distribution (retail) reconciliation and settlement processes depend
upon the transmission-to-distribution point-of-delivery measurement point interval data
as it represents the energy that crosses this important interface. The reconciliation of the
net flows across the bulk transmission system or the establishment of distribution system
settlement zone totals cannot be completed without the timely delivery and use of
consistently accurate point-of-delivery measurement data. Since all downstream load and
financial settlement processes depend upon settlement zone totals it is imperative that the
calculation of the settlement zone totals not only be correct, accurate and complete but
that the settlement zone total data be made available for load settlement in a timely
manner.
Unfortunately, and largely as the result of the nature of what has been a relatively longterm evolution of industry change, the transmission and distribution data management
standards and processes relative to that mutual interface have been developed in isolation
resulting in a non-cohesive collective. The establishment of the AESO and it’s mandate
to address load settlement
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 12 of 19
Name
Issue
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Settlement Zone
Accuracy (POD
Aggregation)
Tim Raines
Comments
AESO Response
presents an opportunity for this industry to rectify this situation by addressing what we
contend are the two fundamental issue categories:
o
o
Responses to be published soon.
metering data path issues
metering data management issues
It is our contention that until all settlement zone totals are calculated and provided to the
LSAs by the AESO that this industry will never be able to complete reliable energy
reconciliations across the bulk electrical system or overcome the crippling data
management issues that have lead to the problems that continue to plague load and
financial settlement in this industry.
June 29, 2005
Issues
Metering Data Path Issues
The multiple metering data path effect occurs when two separate internal, or distinct
external, processes are used to manage transmission interface metering data for the
purposes of transmission administration from that used to manage system-level metering
for the purposes of retail load settlement.
Meter Data Management Processes
Meter Data Management Processes
Transmission
Data Management Process
X
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Distribution
Data Management Process
AESO
Y
Page 13 of 19
Name
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Tim Raines
June 29, 2005
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
One would expect both data paths/processes to produce the same end results given that
they both have as their basis the original raw interval metering data and yet, either as the
result of processing or timing differences, they very often do not. These differences are
difficult, if not impossible, to resolve and have resulted in significant reconciliation
issues between what appears to be energy delivered from the transmission system and
what appears to be energy consumed by the distribution system.
AESO Response
Responses to be published soon.
The WO/WSP organizations, in most cases, undertake a number of roles within the
industry, namely that of MDP, MDM, LSA. When dealing with these organizations it is
difficult, if not impossible, to differentiate between these roles. In addition, because of
internal non-standard, non-transparent data processes it is not altogether possible to
examine the constituent data that forms the basis for the aggregate settlement zone total
data utilized by the LSA associated with that organization.
Metering Data Management Issues
The Measurement System Standard (formerly the Gridco G302 document) has been
developed since 1995 to define all of the metering system and data management
standards associated with the transmission system interfaces. The System Settlement
Code was developed in response to the opening of the retail market in 2001 to define all
of the data management standards associated with the distribution system interfaces.
There is a significant over/underlap between these two standards with respect to what
the SSC terms as the system-level meters. Differences in file formats, time stamps,
delivery frequencies, validation methodology exist among many others. It is these
differences that create confusion between market participants affected by, or subject to,
such standards.
The SSC document is, in many respects, written in a manner that leaves significant
discretion to the WO/WSP as to how, or if, they interpret/implement the standards
leaving the rest of the industry (or those that must interface with them) to deal with
numerous data management exceptions. Besides creating a barrier to entry for new
market participants, this situation fosters the development and use of non-standard
‘work-around’ processes that fragment the integrity of the overall data management
effort. If the AESO, in keeping with it’s load settlement oversight mandate, is going to
monitor and enforce compliance to the SSC then this industry needs to clearly and
unambiguously define the standards so that they apply to all market participants equally.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 14 of 19
Name
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
Resolution
AESO Response
Responses to be published soon.
Metering Data Path Issue Resolution
The metering data path issues can be addressed by:
o
o
o
eliminating the potential for multiple data paths, and
creating data and data path transparency, and
centralizing settlement zone total calculations.
Tim Raines
Appendix I provides a data flow diagram that meets the above criteria.
June 29, 2005
Appendix II provides an overview of all of the applicable electrical system metering
interfaces.
Appendix III provides the calculation methodology needed to complete the settlement
zone totals.
Appendix IV provides the rough timing for the delivery of the constituent data and final
settlement zone total data.
Metering Data Management Issue Resolution
The metering data standards issues can be addressed by:
o
o
o
consolidating the ‘system level’ metering data management standards, and
eliminating ambiguity within the consolidated metering data management
standards, and
enabling the AESO to monitor and enforce compliance to the consolidated
standard.
Appendix I: Measurement Point & Settlement Zone Total Data Flow
The following diagram illustrates the data flow required to translate raw metering point
data into the settlement zone total data required for load settlement purposes:
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 15 of 19
Name
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Issue
Settlement Zone
Accuracy (POD
Aggregation)
Comments
M1
Mx
·
MDM1
DSM
MDMy
MPDR
·
·
·
SZDR
AESO
Metering point interval data collected , verified, validate
estimated, edited and stored by MDM/MDPs.
Measurement point interval data calculated , in accorda
with Measurement Point Definition Records (MPDR) d
and provided by the AESO, using validated/estimated
metering point data.
Measurement point data transferred to the AESO in DS
format.
DSM
Tim Raines
June 29, 2005
·
AESO Response
SZDR
·
SZT
SZT
LSA1
LSAz
·
Measurement point interval data received , verified and
stored by the AESO.
Settlement zone total interval data calculated , in accor
with Settlement Zone Definition Records (SZDR) deve
and managed by the AESO, using verified measureme
point interval data.
Settlement zone total interval data transferred to the LS
SZT file format.
LSAs use settlement zone total data for load settlemen
processing.
Appendix II - Alberta Electrical System Metering Interfaces
The following diagram is a depiction of the Alberta interconnected electrical system that
shows all of the possible ‘system-level’ measurement point 1 interfaces.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 16 of 19
Responses to be published soon.
Name
Issue
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Settlement Zone
Accuracy (POD
Aggregation)
Comments
AESO Response
1
A distinction is made between a ‘metering point’ (a physically realizable point on the electrical
system where a meter exists) and a ‘measurement point’ (a point that may or may not be physically
realizable on the electrical system where the data for that point is derived from the algorithmical
manipulation of the data from one or more metering points)
Distribution
Connected
Generator
Transmission
Connected
Generator
Tim Raines
June 29, 2005
2
Non-AIES
Transmission
System
1
6
4
Transmission
System
3
Distribution
System
(ZoneX)
8
Non-AIES
Distribution
System
7
5
Distribution
System
(ZoneY)
Transmission
Direct-Connect
Facility
1.
2.
3.
4.
5.
6.
7.
8.
Import/export interconnection with the bulk transmission system
Transmission connected (co)generation facility
Transmission connected, direct connect load facility
Transmission to distribution point of delivery (ZoneX)
Transmission to distribution point of delivery (ZoneY)
Distribution connected generation facility
Distribution system interchange point
Import/export interconnection with the bulk distribution system
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 17 of 19
Responses to be published soon.
Name
Issue
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Settlement Zone
Accuracy (POD
Aggregation)
Comments
AESO Response
System-level measurement points 1, 2 and 3 have nothing to do with the calculation of settlement
zone totals.
System-level measurement points 4, 6, 7 and 8 are required to complete the calculation of the
settlement zone X total while measurement points 5 and 7 are required to complete the calculation
of the settlement zone Y total.
1
Tim Raines
A distinction is made between a ‘metering point’ (a physically realizable point on the electrical
system where a meter exists) and a ‘measurement point’ (a point that may or may not be physically
realizable on the electrical system where the data for that point is derived from the algorithmical
manipulation of the data from one or more metering points)
June 29, 2005
Appendix III: Settlement Zone Total Calculations
The following diagram is that of a hypothetical settlement zone:
Generation (GEN)
~
Import (IMP)
Settlement Zone
Export (EXP)
~
Load + Loss (LOD)
where the net load (including distribution system losses) can be calculated as:
LOD = IMP + GEN – EXP
where IMP and EXP represent the collective effect of both point-of-delivery and point-ofinterchange energy exchanges.
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
Page 18 of 19
Responses to be published soon.
Name
Issue
Comments
MIDAS
Metering
Services Ltd.
(MIDAS)
(continued)
Settlement Zone
Accuracy (POD
Aggregation)
Appendix IV: Settlement Zone Total Data Delivery Timing
Timing must be such that settlement zone totals are delivered to the LSAs prior to their using those
to ‘back-stop’ their load settlement processes. Conceptually, this could look as follows:
0
Tim Raines
Day Of Flow
June 29, 2005
Comments – Settlement Zone Accuracy (POD Aggregation), Created on July 6, 2005
1
...
AESO Response
n-2
n-1
n
Metering
Data Delivery
For The Day
Of Flow For
All
Settlement
Zone
Interfaces
From MDMs
To The
AESO
Settlement
Zone Total
Processing &
Delivery
For The Day
Of Flow By
The AESO
To The LSAs
Load
Settlement
Processing
For The Day
Of Flow By
The LSAs
Page 19 of 19
Responses to be published soon.