RC Meeting August 28, 2009 Marianne Perben Senior Engineer, FCM & Tariff Administration

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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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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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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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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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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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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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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Clustering Results with 20% Distance Threshold

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Clustering Results with 40% Distance Threshold

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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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Questions

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RC Meeting August 28, 2009 Marianne Perben Senior Engineer, FCM & Tariff Administration

Documents

Transcript of RC Meeting August 28, 2009 Marianne Perben Senior Engineer, FCM & Tariff Administration