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Forward Capacity Market (FCM) Zonal Issues Discussion. RC Meeting August 28, 2009 Marianne Perben Senior Engineer, FCM & Tariff Administration. Purpose of the Discussion. This discussion will primarily focus on the third item of the Issues List: Zonal Issues - PowerPoint PPT Presentation
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Forward Capacity Market (FCM)Zonal Issues Discussion
RC MeetingAugust 28, 2009
Marianne PerbenSenior Engineer, FCM & Tariff Administration
Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Purpose of the Discussion
• This discussion will primarily focus on the third item of the Issues List: Zonal Issues
• At the 08/04/09 RC meeting the ISO presented a potential methodology to identify “pure” capacity reliability zones
• Today, the ISO is providing an illustration of the application of such a methodology using FCA_2011_2012 data
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Definition of Capacity Reliability Zones
• There are two approaches to the definition of capacity reliability zones1. Top to Bottom approach
• Review zones used in current ISO’s processes– Reliability zones, load zones, reserve zones, capacity zones, dispatch
zones, RSP zones
• Establish pros and cons of using each of them as a potential capacity reliability zone
2. Bottom to Top approach• Start with blank sheet of paper and identify “pure” capacity
reliability zones
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Definition of Capacity Reliability Zones, cont.
• The ISO reviewed both approaches and favored the second one– Technically more rigorous– Unbiased by market related or settlement/software related
considerations– May offer a systematic approach to defining zones
• For the purpose of this discussion, a “pure” capacity reliability zone is defined as a geographic region within which resources (new and existing) have a very high probability of substitutability
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
General Methodology to Identify “Pure” Capacity Reliability Zones
• In power system terms, a “pure” capacity reliability zone is a zone where all generators behave in a very similar way towards key system constraints
• Consequently, the identification of such zones is a two-step process1. Identify key system constraints
2. Group generation into zones based on key constraints identified in step 1
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Identification of “Pure” Capacity Reliability Zones
• Step 1: Identification of Key System Constraints:– In this analysis, the ISO simulated the individual de-list of every
generator in New England and gathered the critical flowgates that prevented some delists from occurring
– For simplicity purposes, the impact of only one delist at a time was considered (did not model several sequential delist requests)
– Around 60 key system constraints were identified
• Some were regional
• Some were very local
– All system constraints were used to group generation
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Identification of “Pure” Capacity Reliability Zones, cont.
• Step 2: Generation grouping– The ISO relied on clustering algorithms to group generators into zones (also
called clusters)
– All generators in the same cluster have similar or identical DFAXs on all critical flowgates
• Two generators with substantially different DFAXs should belong to different clusters (distance between generators in a given cluster should be electrically small)
– The distance function chosen for this analysis was the maximum of all absolute DFAX differences over all key constraints
• Distance between Gen1 and Gen2 = Max. | DFAX1-DFAX2 |
• The choice of a threshold is independent of the number of key constraints
• The final clustering is independent of the choice of a reference for DFAX calculation
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Identification of “Pure” Capacity Reliability Zones, cont.
• The clustering analysis was performed using two different distance thresholds– 20%: if the DFAX of two generators is more than 20% apart, generators
are placed into two different clusters
– 40%: if the DFAX of two generators is more than 40% apart, generators are placed into two different clusters
• The clusters resulting from the generation grouping step were geographically mapped using PowerWorld
• A larger threshold tends to make a regional cluster (cluster resulting from regional constraints) bigger
• A larger threshold does not tend to affect very small, marginal clusters resulting from very local constraints
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Clustering Results with 20% Distance Threshold
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Clustering Results with 40% Distance Threshold
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Further Requirement Considerations
• All internal and external transmission constraints were modeled in this analysis
– Used updated network model topology created for FCA_2011_2012 and determined in accordance with Section 3 of Planning Procedure 10
• A transmission security based requirement could be determined for the previous clusters/zones
– Assumptions used to set the transmission security based requirement should be the same as the assumptions used for the delist analysis performed to identify key constraints
– The transmission security based requirement may be inferred directly from the delist analysis that is performed to identify key constraints
• Depending on the DFAX differences between all buses within the clusters (and the distance threshold applied), analysis may identify a range of requirements for a given cluster
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Zonal Issues – August 28, 2009© 2009 ISO New England Inc.
Questions
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