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Enron Mail |
Cc: bill.rust@enron.com, james.steffes@enron.com, richard.shapiro@enron.com,
christi.nicolay@enron.com, lloyd.will@enron.com, steve.walton@enron.com, andy.rodriquez@enron.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Bcc: bill.rust@enron.com, james.steffes@enron.com, richard.shapiro@enron.com, christi.nicolay@enron.com, lloyd.will@enron.com, steve.walton@enron.com, andy.rodriquez@enron.com X-From: Charles Yeung X-To: Kevin M Presto X-cc: Bill Rust, James D Steffes, Richard Shapiro, Christi L Nicolay, Lloyd Will, Steve Walton, Andy Rodriquez X-bcc: X-Folder: \Richard_Shapiro_June2001\Notes Folders\All documents X-Origin: SHAPIRO-R X-FileName: rshapiro.nsf Kevin Here is a summary of the work of this task force. Bill Rust has been attending the meetings and I have been closley coordinating our positions. The PFTF set out to develop a means to capture native load impacts (not tagged) in load flow models to ensure that parallel flows resulting from native load dispatch are accounted for accurately to assess system security. This has largely been ignored in the past since most TLRs hit only non-firm PTP transactions. However, the NERC TLR procedures (in line with FERC OATT) requires a pro-rata curtailment of native and network service with Firm point-to-point (PTP). Since more and more TLRs at Level 5 (Firm) have been utilized and is expected to rise, providers are being forced by the MIC to demonstrate comparability at these TLR levels. In order to demonstrate comparability - a transparent calculation of Native and Network impacts is needed. In past, this was left to the discretion of each control area. The task force reviewed 7 methods on how to model native gen to native load dispatch. These seven methods can be grouped into three categories: 1) Continue with the existing method that does not consider counterflows. 2) Inlcude counterflows for NNL (Native/Network Load) and PTP and assign to sink control area. 3) Assign NNL counterflows to the control area and PTP counterflows to the purchasing selling entitiy (PSE). Each method tries to simulate real-time dispatch realizing that an interconnection-wide state estimator is not available nor a nodal dispatch model. The simplest methods (group 1) adjust each generator individually to a set of load points in its control area and repeats until all the units in the control area are accounted for. The problem for the transmission owners with this approach is that the netting effects of the real-time dispatch are not captured therfore exaggerating the impacts a control area has on its neighbors. Group 1 solutions were rejected because the task force beleived that its parent, the Security Subcommittee (Dick Ingersoll member) insisted on a new procedure that included counterflows - for security reasons. The initial proposal to include netted effects (Group 2) allows control areas to net NNL flows within the control area and PTP to net flows that are grouped by sink control area. Group 2 solutions were rejected because PSEs would not get credit for off-setting transactions that sink in other control areas, e.g. I have a PTP that sinks in TVA that off-sets a PTP that sinks in SOCO. Group 2 solutions would not give credit for this. The most complex method (group 3) allows the native load dispatch to net their impacts with all internal gen-load pairings AND nets the contributions of point-to-point tagged transactions by PSE. This is the most equitable solution for the market, however it is the most costly and demanding solution for the transmission owner/operators. Group 3 solutions were acceptable to all parties because it assigned credit to those who are sponsoring transactions that relieve the flow gate loading. Lately, I have been pushed in NERC activities to make calls that boil down to what is fair and equitable between native loads and point-to-point service vs. what increased burden and accountability on providers is needed to provide for that level of comparability. We should always hold providers to the higher standard. That is - it is not easy to facilitate market transactions, and yes - real people and real dollars are needed to be expended by providers to continue facilitating an increasingly complex and evolving marketplace. Providers cannot be let off the hook and be allowed to do what is easy and least cost - this has proven over and over to have negative impact on the market.
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