Supporting ARPA-E Competition on Optimal Power Flow

PNNL – Feng Pan, Stephen Elbert UW-Madison – Christopher DeMarco ASU – Hans Mittelmann

March 30, 2016

Optimal Power Flow Competition

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Support Team and Competition Components

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DEEP Support – Design, Execute, Evaluate and Promote

– Optimization problem – Data sets – Competition platform

• Website • Back-end server and evaluation system • Hardware

– Evaluation procedure and scoring metrics

– Resources • Solvers, programming languages, forum

– Outreach

Open Competition

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‣ Open to everyone – Almost everyone

‣ Open formulation – Up to competitors to formulate the problem

‣ Open data sets – Release hidden data sets after announcing winner – Yes, we can handle proprietary data

‣ Open discussion – Communication through forum

‣ Open to suggestions and feedback – To release RFI

Selecting Optimization Problem ‣ Selection criteria – industry relevance, reasonable learning curve for

general participants, specific and broad impact on applications, problem assumptions.

‣ Security-constraint is a must. ‣ Potential problems

– SCOPF + participation factor/droop. A two stage problem with additional state variables for each contingency.

– SCOPF + redispatch. It becomes a two stage problem with additional control variables (generation dispatch) for each contingency.

– SCOPF + demand flexibility – SCOPF with added discrete controls: transformer taps, switching capacitors

and reactors, phase shifter actions (likely drastically increase run time and will require different approaches.)

– Stochastic SCOPF with added scenarios and their probabilities. ‣ Need your inputs … ‣ We selected SCOPF with participation factor as the starting problem and

a starting point for discussion.

Optimization Problem

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Security constrained optimal power flow with participation factor

Minimize total dispatch cost

power flow balance system limit

Open formulation, solutions will be verified through forward evaluation

Objective

Base-case

Contingency case power flow balance system limit

voltage set point droop control

Subject to

SCOPF-PF

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Power-voltage polar coordinate formulation as an illustration

Base Case

Flow Balance

Power Flow on (i,j)

System Limits

Generation Cost

Contingencies

SCOPF-PF

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Fixed voltage when reactive power within limit. PV->PQ

Active power adjustment with Participation Factor

Data Sets

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‣ Three types – Training data for developing algorithms – Public data for monitoring progress (leaderboard) – Hidden data (will be made public afterwards) for final award

scoring ‣ Each data set will include these elements

– System model: power system description – Scenario: realization of exogenous variables, e.g., instantaneous

demand, generator data (cost, capacity and participation factor), line availability, …

– Contingency list ‣ Data format

– Current: PSS/E RAW and CSV – Other suggestions?

Data Sources and Coordination ‣ RTS96 (UW-Madison) ‣ Small system (~100 buses), medium system (X100-X1,000

buses), large system (X10,000 buses) ‣ Coordinate with GRID DATA teams

– Format – Phased supply of data sets – What to include in a data set – Feasibility check - whether there exists a feasible solution to

SCOPF ‣ Coordination

– Suggestions on timeline, format, transfer method, feedback method?

Evaluation

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‣ Output of an algorithm run will include two files: – competitor's solution file – system file, including computation time.

‣ Solution file – Competitor is required to output solution to specified variables

in a standard format – For example, objective value, generation dispatches, state

variables in power-voltage polar coordinates (p,q,v,θ) for the base case and all contingency cases.

‣ Forward evaluation – Check each constraint in a standard formulation and each

limit. – Calculate the total cost. – Record violation.

‣ Elapsed Time of entire run captured by system

Scoring

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‣ Goal is to evaluate quality of an algorithm while preventing gaming

– Transparent – Clear – Easy to understand

‣ Three main metrics – Time – Objective value – Constraint violations

‣ Evaluation and scoring is generally an automatic process. Human-in-the-loop process is reserved for a small number of cases.

Automated Evaluation and Scoring

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CEES – compile, execute, evaluate and score

Interface with Participants

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‣ Participants will participate this competition through the competition platform (to be introduced next)

‣ Through the platform, participants can – Download data sets. – Submit algorithms to be evaluated and scored during the training

stage. – Use standardized input and output files. – Receive log file showing algorithm performance. – Make requests. – Discuss with the support team and other competitors.

‣ The platform is for evaluation and NOT a development environment.

‣ It is important to have sufficient data sets for participants to understand their algorithm performance and leave out surprises.

‣ The platform is a fair playground – same resource, same software version, and same environment.

Participation Modes

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‣ Competitor – individuals and teams

‣ Industry sponsors – support competitor, provide data sets

‣ Contributor/sponsor – provide supporting materials and licensed software, join forum discussion

– CPLEX – Gurobi – Knitro – Xpressmp

– MATLAB & MATPOWER – GAMS – …more to come

Questions and Suggestions?

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