Lance Cunningham, Ph.D., PE November 2015

Frisco, TX 2

Transmission Modeling 3

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Distribution Substation 5 This document and that is confidential, commercially-sensitive, proprietary, and/or public power utility competitive and financial information in accordance with the provisions of Texas Government Code, Section , , and/or , and may be protected from required public disclosure. Load Serving Transformers

Distribution Circuits 6 The distribut- ion system is much more complex. FRISCO Panther Creek Roman Juarez Bridges Yellow might equal blue

Distribution Operations 7 Pole top switches to balance circuits, back- feed or sectionalize for problems, etc.

Direction ….. ? 8 If the direction is to reflect all distributed resources back to their respective transmission buses, then all is done.

Direction ….. ? 9 If the direction is to model all distributed resources to a distribution bus AND to compute a “distribution based locational marginal price” ……. Then the following modeling and operational parameters need to be overcome.

Distributed Resources modeled at the distribution level 10 How should an effective “Transmission Constraint Shadow Price Cap in SCED” be reflected to the distribution level?  Existing N-1 Constraint Violation Caps o 345 kV: $4,500/MW o 138 kV: $3,500/MW o 69 kV: $2,800/MW o <69 kV: $????

Distributed Resources modeled at the distribution level 11 How should the “Texas Two Step” locational market power test be applied at the distribution level? DERs modeled in ERCOT and receiving price signals from SCED should be subject to the Constraint Competitiveness Test in SCED (Protocols section 3.19)  Non-Competitive Constraint Definition A contingency and limiting Transmission Element pair or group of Transmission Elements associated with a GTC that is not determined to be a Competitive Constraint under the process defined in Section 3.19, Constraint Competitiveness Tests.

Current CIM and Planning Models 12 CIM # of Switches CIM # of breakers CIM # of Settlement Points 33,92813, Planning Case # of Loads Planning Case # of Substations with Loads Planning Case # of Buses with an Area Loads 5,6493,1643,782

13 Additional modeling considerations  1,000 DERs could result in 1,000 more modeling points  More SCADA points communicating with ERCOT  Define distribution level contingencies?  More automatic distribution switching schemes o Automatic load rollover schemes o Automatic sectionalizing schemes  Outage scheduling of distribution level equipment  Potentially longer SCED solution times Distributed Resources modeled at the distribution level

14 How much time AND money do we want to take for implementation? Generally, that is directly related to the level of complexity.  How much personnel & equipment?  Regulatory impacts?  Staffing impacts?