Presentation on theme: "Transmission planning in Vermont Past, present and future Docket 7081 workshop By Dean LaForest 9/19/05."— Presentation transcript:
Transmission planning in Vermont Past, present and future Docket 7081 workshop By Dean LaForest 9/19/05
9/19/05 Docket 7081 Workshop Dean LaForest 2 What is transmission planning? Transmission planning examines the need for changes to the transmission network as load and power sources change through time in an area The transmission network consists of all electric transmission lines and substations, typically built and constructed at 115,000 volts or above Vermont has an underlying subtransmission network with significant facilities built and operated at 34,500 and 46,000 volts that often parallel the transmission network VELCO owns and operates the transmission grid in Vermont, while the Vermont distribution companies own and operate the subtransmission network
5 What tools and key sets of data are needed and necessary for transmission planning? Need software to model the behavior and performance of the power system Need accurate model of the power system to capture existing system performance and predict future system performance Model needs input on network characteristics (t-lines / transformers), reactive power sources (generators / caps / sync condensers / FACTs devices), real power sources (generators / HVDC), and loads Model needs sets of this data for each condition examined (load level / generation dispatch, etc. Need a set of reliability standards against which to measure the system performance and determine whether reinforcements are needed
9/19/05 Docket 7081 Workshop Dean LaForest 6 What are VELCO’s sources for these sets of tools / data? VELCO uses a widely utilized power flow analysis software, allowing high productivity and data interrogation capabilities VELCO provides modeling information for the power system network to ISO-NE, who collects information from the rest of New England and the eastern US / Canada VELCO gets load information from the distribution companies and the DPS for VT, and from the database provided by ISO-NE for areas outside of VT
9/19/05 Docket 7081 Workshop Dean LaForest 7 What are the regional reliability standards? NERC (North American Electric Reliability Council) Standards found on NERC website (http://www.nerc.com/~filez/standards/Reliability_Standards.html#Transmission_Planning)http://www.nerc.com/~filez/standards/Reliability_Standards.html#Transmission_Planning These are the minimum level of standards the system must meet NPCC (Northeast Power Coordinating Council) Standards found on NPCC website (http://www.npcc.org/criteria.asp)http://www.npcc.org/criteria.asp New England by way of the ISO-NE reliability standards is and must be compliant with these criteria, which are more specific than NERC’s criteria
9/19/05 Docket 7081 Workshop Dean LaForest 8 What are the regional (NPCC) reliability standards?
9/19/05 Docket 7081 Workshop Dean LaForest 9 What are the New England (ISO-NE) reliability standards? ISO-NE’s planning criteria are located at http://www.iso- ne.com/rules_proceds/isone_plan/index.html http://www.iso- ne.com/rules_proceds/isone_plan/index.html Planning Procedure #3 is the key document
9/19/05 Docket 7081 Workshop Dean LaForest 10 Reliability Standards Evolve NERC’s Standards will be more stringent, become mandatory, and will include penalties The FERC will put in place an ERO – and Energy Reliability Organization
9/19/05 Docket 7081 Workshop Dean LaForest 11 The type of system under study matters Vermont system characteristics Importer of electrical power Two large sources relative to the load Minimal reserves Winter and Summer peaking Sparse transmission network Located at one end of the New England system
9/19/05 Docket 7081 Workshop Dean LaForest 12 Planning design example... the problem Question – feed 50 MW of load (Addison county) from a 50 MW generator (McNeil) 40 miles away Choices 46 kV line (can look like a distribution circuit) Single conductor Double conductor 115 kV line (standard VELCO h-frame) The issues Provide adequate voltage for customers (within 5% of nominal) Provide coverage for expected outages
9/19/05 Docket 7081 Workshop Dean LaForest 13 The first test... Can 46 kV work?
9/19/05 Docket 7081 Workshop Dean LaForest 14 The first test... Can 46 kV REALLY work?
9/19/05 Docket 7081 Workshop Dean LaForest 15 The first test... Can 46 kV work with two conductors (or bundled conductors)?
9/19/05 Docket 7081 Workshop Dean LaForest 16 40 miles...
9/19/05 Docket 7081 Workshop Dean LaForest 17 The second test... Can 115 kV work over 40 miles?
9/19/05 Docket 7081 Workshop Dean LaForest 18 To meet a N-1 design standard (be able to suffer the loss of one element)...
9/19/05 Docket 7081 Workshop Dean LaForest 19 VELCO’s design standard for transmission planning... Conforms to NERC, NPCC and ISO-NE planning standards We consider the unavailability of system elements that have potential long duration outages (more than one load cycle) Highgate DC converter Underground (or underwater) cables Transformers Generators After system adjustment following first outage, VELCO tests all other potential outages
9/19/05 Docket 7081 Workshop Dean LaForest 20 What has VELCO done in the past for long range transmission planning VELCO’s recently performed long range studies include the “Twenty Year Plan” (1987), the “Long Range Transmission Plan” (1992), and “A Strategic Planning Study” (2001) Each considered, and included, distribution company projects / plans and current regional system information Each effort used the latest tools and system models available The earlier two efforts included examination of power source location and its influence on transmission expansion Each effort built on the past using better tools, and utilized a more thorough understanding of the transmission network (with less predictable performance as time went on).
9/19/05 Docket 7081 Workshop Dean LaForest 21 What VELCO projects included analysis of future system performance? Those projects included the Essex STATCOM (filed June 1999 – docket 6252), the Rutland Region Reliability Project (filed March 2001 – docket 6479), the Northern Loop Project (filed December 2002 – docket 6792) and the Northwest Reliability Project (filed June 2003 – docket 6860)
9/19/05 Docket 7081 Workshop Dean LaForest 22 What peak loads did VELCO experience during these planning efforts?
9/19/05 Docket 7081 Workshop Dean LaForest 23 What will VELCO provide to comply with Act 61? VELCO will perform a study examining system performance 10 years from the present (i.e. 2015). The analysis will likely consider: All facilities available, and with one facility out due to a long term outage Stressed transfer conditions The continued availability of energy from Highgate and how it might influence transmission system design A reduced load growth scenario and how that might influence the timing of transmission system reinforcements Proposed in-state generation projects and how they may influence transmission system design VELCO will provide a draft report early in 2006 and hold public meetings to promote discussion and elicit comments before publishing a final report by July 1, 2006
9/19/05 Docket 7081 Workshop Dean LaForest 24 What activities will take place within the Long Range Planning process? Involve the Vermont distribution companies (via the Vermont Utility Planning Group) in review of interim results and proposed solutions Make certain that distribution utility issues / projects are considered and properly reflected in the analysis Involve ISO-NE through collaborative meetings to review results, refine modeling of beyond Vermont conditions / assumptions and provide / seek input on the transmission system design necessary to address system deficiencies that do not meet design criteria Propose a series of alternatives to any discovered system wide deficiency Provide planning grade cost estimates for the alternatives to allow ranking
9/19/05 Docket 7081 Workshop Dean LaForest 25 Questions?
9/19/05 Docket 7081 Workshop Lawrence Kirby 26 A probabilistic reliability guideline for subtransmission planning, based on the equal slope criterion