Denton Municipal Electric
Distribution Modeling Considerations
DREAM Task Force
Lance Cunningham, Ph.D., PENovember 2015
Frisco, TX
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Transmission Modeling
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Transmission Modeling
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Distribution Substation
5This 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 552.101, 552.104, 552.110 and/or 552.133, and may be protected from required public disclosure.
Load Serving Transformers
Distribution Circuits
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The distribut-ion system is much more complex.
FRISCO
Panther Creek
Roman Juarez
Bridges
Yellow might equal blue
Distribution Operations
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Pole top switches to balance circuits, back-feed or sectionalize for problems, etc.
Direction ….. ?
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• If the direction is to reflect all distributed resources back to their respective transmission buses, then all is done.
Direction ….. ?
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• 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
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• 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/MWo 138 kV: $3,500/MWo 69 kV: $2,800/MWo <69 kV: $????
Distributed Resources modeled at the distribution level
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• 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
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CIM # of Switches
CIM # of breakers
CIM # of Settlement Points
33,928 13,293 599
Planning Case# of
Loads
Planning Case# of
Substations with Loads
Planning Case# of Buses with an Area Loads
5,649 3,164 3,782
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• 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 schemeso Automatic sectionalizing schemes
Outage scheduling of distribution level equipment Potentially longer SCED solution times
Distributed Resources modeled at the distribution level
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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?