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Redact Gen Ties + 6 stations


									 ERCOT/IMM/PUCT Proposal for
Redaction of State Estimator Data
        Wholesale Market Subcommittee
               January 12, 2011

January 12, 2011      1       ERCOT Wholesale Market Subcommittee
  Original Nodal Protocol Language (Nov. 2009)
•The original Protocol language in Section, Data Inputs and Outputs for the
Real-Time Sequence and SCED, generated stakeholder discussion over the items in red

(4) Every hour, ERCOT shall post on the MIS Secure Area the following information:
          (b) Transmission flows and voltages from the State Estimator;
          (d) Transformer flows, voltages and tap position from the State Estimator;

•Disclosing all of this information in Real-Time could threaten the confidentiality of
resource-specific outputs and bids/offers.

•Nodal Protocol Revision Request (NPRR) 209 and Project No. 38470 were initiated to
resolve confidentiality concerns in both the PUC Substantive Rules and ERCOT

       January 12, 2011                     2               ERCOT Wholesale Market Subcommittee
Project No. 38470 – Commission’s Order Adopting Amendment to
  § 25.505 As Approved at the October 22, 2010 Open Meeting
Highlights of the new PUC Substantive Rule changes impacting State Estimator (SE) data include the

(E) After the start of operation of the market under a nodal market design, ERCOT shall begin
    posting transmission flows, voltages, transformer flows, voltages and tap positions (i.e., State
    Estimator data) 60 days after the day for which the data were accumulated or other time interval
    as established in clause (ii) of this subparagraph. The data released shall be made available
    simultaneously to all market participants.
           (ii) … ERCOT shall, by the start of the nodal market, develop and post a redacted version
    of State Estimator data, as soon as reasonably practicable after collection of the data, so long as
    a redacted version excludes information (including but not limited to, voltages, transmission
    flows and transformer flows) from which resource-specific output levels or offer curves could
    continually and systematically be derived. Concurrently, in conjunction with the Independent
    Market Monitor and the commission Staff, ERCOT, through its stakeholder process, shall develop
    protocols that detail, at a minimum, the methodology, duration and posting requirement of a
    redacted version of the State Estimator data. The redacted report methodology developed
    through the stakeholder process shall be completed within 90 days of the start of the nodal
Continues on next slide….
          January 12, 2011                          3                  ERCOT Wholesale Market Subcommittee
                          Project No. 38470 (cont.)
      If ERCOT is unable to develop a cost effective protocol for the redaction process of the State
      Estimator data within 90 days of the start of the nodal market, then the following information
      shall be released as soon as reasonably practicable:
       (I) Current commercially significant constraints (CSCs) and closely related elements (CREs) line
             flows that are embodied in the competitive constraint list from the Competitive Constraint
       (II) For phase shifting transformers, tap positions and line flows;
       (III) Voltages at all buses;
       (IV) Line flows on lines that make up interfaces (import, export, flow gate, or stability); and
       (V) Line flows on DC ties.

•     Regarding “backstop” data, ERCOT is currently posting items (I), (II), most of (IV) and (V) above.

•     By March 1, 2011, ERCOT will post item (III) above to comply with the Rule.

•     On November 16, 2010, the ERCOT Board of Directors approved NPRR209 incorporating the
      Commission’s changes in the PUC Substantive Rules into the EROCT Protocols.

           January 12, 2011                           4                  ERCOT Wholesale Market Subcommittee
            The Continuum of SE Data
Real-Time Data:                                         (Op Day + 60) Data:
38 lines,                                               *everything*
7 transformers                                          5,643 lines,
(phase shifters)                                        1,511 transformers

                               “Compromise Region”

    Max security                                                     Max information
    Min information                                                  Min security

                      Redact                         Disclose

  January 12, 2011                       5              ERCOT Wholesale Market Subcommittee
         ERCOT Proposed Redaction Methodology
                                 A                B                     C
                        G               T1                  T2                      T3

LineID    FromSt          ToSt   ToMW    ToMVAR       FromMW FromMVAR

A         G               T1     xxx     xxx          xxx        xxx

B         T1              T2     xxx     xxx          xxx        xxx

C         T2              T3     xxx     xxx          xxx        xxx

    Redaction is based on lines’ proximity to stations containing resources. Lines are
    redacted based on their “electrical distance” from generating stations.

    Gen ties only: Redact only gen ties (all lines incident at gen stations)
    Gen ties + 1 station: Redact gen ties plus all lines at next stations
    Gen ties + 2 stations: Redact gen ties, plus all lines at next two stations

              January 12, 2011                     6                   ERCOT Wholesale Market Subcommittee
      Breakdown of Methodology Results
*Total lines in ERCOT: 5,643

                              # Lines   # Stations
                             Excluded   Excluded                # Lines Included

Redaction Method                                      345KV      138KV         69KV       Total

Gen Lines Only                 854         231         157         3035         1597      4789

Gen Lines + Next Station       2047        726         27          2219         1350      3596

Gen Lines + 2 Stations         3302        1489         3          1362         976       2341

Gen Lines + 3 Stations         4394        2335         0          661          588       1249

Gen Lines + 4 Stations         5079        3028         0          290          274        564

Gen Lines + 5 Stations         5420        3442         0          109          114        223

Gen Lines + 6 Stations         5574        3659         0           31           38        69

          January 12, 2011                        7           ERCOT Wholesale Market Subcommittee
       Redact Gen Ties + 6 stations

January 12, 2011     8      ERCOT Wholesale Market Subcommittee
       Redact Gen Ties + 5 stations

January 12, 2011     9      ERCOT Wholesale Market Subcommittee
       Redact Gen Ties + 4 stations

January 12, 2011     10     ERCOT Wholesale Market Subcommittee
       Redact Gen Ties + 3 stations

January 12, 2011     11     ERCOT Wholesale Market Subcommittee
Failure of 3-station method at WHTTAIL

   January 12, 2011   12   ERCOT Wholesale Market Subcommittee
  WHTTAIL looks OK w/ 4-station

January 12, 2011   13   ERCOT Wholesale Market Subcommittee
• In order to comply with the Commission’s Order in Project No.
  38470 and PUC Subst. R. 25.505(E)(ii), ERCOT will sponsor a
  Nodal Protocol Revision Request (NPRR) in the near future
  that formalizes the proposed methodology, duration and
  posting requirement of a redacted version of the State
  Estimator data.
   – Methodology: ERCOT recommends using the proposed methodology to exclude all
     transmission lines up to a point where resource-specific output levels or offers could not
     continually and systematically be derived.
   – Duration: ERCOT recommends that the redacted version of SE data be posted no sooner
     than 24 hours after the Operating Day.
   – Posting Requirement: ERCOT recommends that the redacted version of SE data be
     posted on the MIS Secure Area.
• Questions?

     January 12, 2011                         14                 ERCOT Wholesale Market Subcommittee

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