National Grid Local System Plan 2012 Place your chosen image here. - - PowerPoint PPT Presentation

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national grid local system plan 2012

National Grid Local System Plan 2012 Place your chosen image here. - - PowerPoint PPT Presentation

Oct 27, 2023 174 likes •505 views

National Grid Local System Plan 2012 Place your chosen image here. The four corners must just cover the arrow tips. For covers, the three pictures should be the same size and in a straight line. PAC Presentation September 20, 2012

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National Grid Local System Plan 2012

PAC Presentation – September 20, 2012 Melissa Scott, presenter

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Purpose of Local System Plan

Per Attachment K – Local, the LSP is a report that:  Describes projected improvements to non-PTF that are needed to maintain system reliability  Reflects:  LSP Needs Assessments  Corresponding transmission system planning and expansion studies  Identifies:  Local Planning Process (See Appendix)  Criteria, Data, and Assumptions (See Appendix)

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LSP Communication

National Grid’s contact:

Brian Hayduk Interim Mgr Transmission Planning, New England National Grid 40 Sylvan Road Waltham, MA 02451-1120 781-907-3060 Brian.Hayduk@nationalgrid.com The ISO-NE RSP project list links to each individual TO’s LSP project list National Grid’s project list is located at:

http://www.nationalgridus.com/oasis/filings_studies.asp

"LSP Project List 2012”

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LSP Project List

 The LSP Project List is a cumulative listing of proposed regulated transmission solutions that may meet LSP needs  Lower voltage facilities contained in the LSP Project List pertain to facilities supplying our wholesale municipal customers  The LSP Project List contains the status of each project:

 Concept  Proposed  Planned  Under Construction  In Service

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LSP Project List Definitions

Project Status Descriptions (may vary slightly from RSP definitions) Concept Project is under consideration as possible solution to a need, but little or no analysis is available Proposed National Grid has internally determined that the project is an appropriate solution to a need, but has not yet obtained Proposed Plan Approval (PPA) from ISO-NE (1.3.9 ISO-NE approval) Planned PPA has been approved (if required) and has internal approval. Under Construction Project has PPA approval and has internal approval. In Service Project is complete

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2012 LSP Projects

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LSP – Massachusetts

(Fonts in Red are new or updates)

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LSP – Massachusetts Continued

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LSP – Massachusetts Continued

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LSP – Massachusetts Continued

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LSP – Massachusetts Continued

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LSP – Massachusetts Continued

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LSP – Massachusetts Continued

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LSP – New Hampshire

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LSP – Vermont

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LSP – Rhode Island

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LSP – Rhode Island

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LSP – Rhode Island

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LSP – Removed From List

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2012 Study Example –

Sandy Pond Tertiary Removal Project – Ayer, MA

Project Example – Sandy Pond Tertiary Removal Project – Ayer, MA

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Needs Assessment

 The tertiary winding of the 345/115/23 kV 448 MVA autotransformer T2 at Sandy Pond #236 substation supplies approximately 21 MW of sub-transmission load – summer peak.  Two autotransformers at Sandy Pond/West Farnum substations supplying sub-transmission feeders through their tertiary windings experienced significant faults and outages due to faults on the sub-transmission system served off the tertiary windings. Both transformers required replacement on an emergency basis.  In summer 2000, Sandy Pond T2 failed due to faults on the sub- transmission system. T2 was immediately taken out of service and replaced with the existing spare transformer. National Grid undertook analysis to determine the best course of action to prevent failure of the new transformer T2.

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Alternative 1 (preferred solution) – Install a 115/23 kV transformer

 Remove 23 kV load from existing transformer  Install 115/23 kV 24/32/40 MVA-rated transformer at Sandy Pond  Install new 115 kV and 23 kV breakers and associated control equipment, expand control house  Expected cost $4.3m (+50%, -25%)

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Alternative 2 – Construct New 115/13.2 kV Substation

 Construct new 115/13.2 kV substation on National Grid-owned land in Chelmsford, MA  Install two 33/44/55 MVA- rated 115/13.2 kV transformers at proposed Turnpike Road substation  Tap the 115 kV L-138E and I-161 lines to supply each transformer  Install 115 kV 40 kA circuit switchers for transformer protection  Install 115 kV in-line sectionalizing  Expected cost $10.4m

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Alternative 3 – 2nd Spare Auto

 Buy additional spare 345/115/23 kV 448 MVA autotransformer  Delivery lead time for a new T2 autotransformer is ~18 months or more  Approximate cost of a new T2 is $3.7m. (Installation of the new spare inside Sandy Pond substation is not included in this estimate.)  Replacement still leaves the possibility of outages and damage due to distribution system faults  Replacement time = outages of approximately 2 weeks

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Preferred Solution Assessment

 Alternative 1 chosen as the preferred solution since it provides:  Elimination of problem – removes 23 kV sub-transmission load from transformer tertiary winding  Most economical – Spare autotransformer cost does not include installation costs  When combined with the Sandy Pond control house replacement project, costs savings are possible

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Questions

Questions

PAC, Transmission Customers, and other Stakeholders have 30 days to provide any written comments for consideration by National Grid.

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Appendix

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Criteria

 All National Grid facilities that are part of the interconnected National Grid system shall be designed in accordance with the National Grid Transmission Planning Guide (TGP28)  The National Grid Transmission Planning Guide is posted on our website under: http://www.nationalgridus.com/transmission/c3-8_standocs.asp as: Transmission Planning Guide

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Local System Planning Process

 Local studies can result from:  Load Growth  Area Reliability Assessments  Point of Delivery Request from Customer  Asset Replacement

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Local System Planning Process

 A Planner –

 summarizes the results from the needs assessment and provides: criteria, data and assumptions used in study  builds study cases with proposed alternatives  determines the most effective solution  summarizes the results of the solutions study

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Data and Assumptions

Resources for studies:  NEPOOL Library cases for load flow and ASPEN short circuit studies  CELT Report Load forecasts for NE wide loads  Customer provided forecasted loads for local areas