Technische Universität München
Distributed Optimization for Smart Grids Jose Rivera , Christoph - - PowerPoint PPT Presentation
Distributed Optimization for Smart Grids Jose Rivera , Christoph - - PowerPoint PPT Presentation
Technische Universitt Mnchen Distributed Optimization for Smart Grids Jose Rivera , Christoph Goebel, and Hans-Arno Jacobsen Smart Buildings and Smart Grids Dagstuhl Seminar, February 22 27 , 2015 Department of Computer Science Chair for
Technische Universität München
Scenario
- Very large number of (new) devices
- Smart grid allows control
Can we actively integrate them into power system operations in a scalable, efficient and reliable manner? This usually involves solving optimization problems
Department of Computer Science, Chair for Application & Middleware Systems
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[energiewende-sta.de]
[frauenhofer-esk]
[ionexusa.com] [smartgridsmartcity_com_au]
Technische Universität München
Centralized optimization
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Data Computation
Control center (Aggregator) Devices 1. All data to one solver 2. Solver optimizes 3. Results are send back 4. Done! Challenging to scale up to large number of devices !
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Hierarchical optimization
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Data Computation
Control center (Aggregator) Devices Scales better than centralized, but offers suboptimal results 1. Each solver gets part
- f the data
2. Each solver optimizes 3. Each solver sends result back 4. Done! Idea: Simplify problem by splitting or creating a hierarchy of problems
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Distributed optimization
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Data Computation
Aggregator coordinator Devices subproblems Scalable and optimal !
1. Each subproblem gets local data 2. Coordinator sends coordination signal 3. Each solver optimizes 4. Each solver sends result to coordinator 5. Coordinator updates coordination signal 6. If no convergence go to 2 7. Done!
Idea: Divide into subproblems and one coordinator
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An example: EV ADMM
- General algorithmic framework for aggregator convex optimization
(use case: EV charging)
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General aggregator optimization problem
ADMM
Technische Universität München
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Using distributed optimization for the smart grid
- Some issues
– Efficiency: Can have expensive network and cpu usage* – Reliability: No results until convergence (important for communication delays)
- Needed
– Killer app – Platform for simple formulation and deployment
*MapReduce/Bigtable for Distributed Optimization: http://videolectures.net/nipsworkshops2010_guestrin_kml/
Technische Universität München
DOPS: Distributed Optimization Pub/Sub
Publish/Subscribe middleware for EV aggregation
- Performance improvement
based on DOs characteristics
- Communication with
coordinator is a bottleneck
- Idea: In-network
computation
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In-network computation: 2 x faster distributed optimization!
www.msrg.org/padres/
Technische Universität München
Reliability: EV charging control
Problem: Real-time capability of distributed
- ptimization
Idea: Anytime algorithms Result: EV charging control can run in milliseconds instead of minutes
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Distributed optimization feasible on each iteration
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Overview: Distributed optimization for smart grids
- High potential for the definition of control protocols and practicable
system-wide optimization
- Currently it may introduce more problems than it solves
- Becomes interesting when centralized approach starts to be
intractable
- Suitable for planning tasks, but close-loop control remains a
challenge
- A lot of theory but very limited actual implementation
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Technische Universität München
Crowdsourcing grid data
Collection Verification Inference Analysis
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EnergyMap.info
Transformer? Generator?
Expert in the loop
Technische Universität München
References (1/2)
- C. Goebel et al., “Energy Informatics,” Business & Information Systems Engineering,
2013. Matt Kraning, Eric Chu, Javad Lavaei and Stephen Boyd, "Dynamic Network Energy Management via Proximal Message Passing", Foundations and Trends in Optimization: Vol. 1: No. 2, pp 73-126. Boyd, Stephen, et al. "Distributed optimization and statistical learning via the alternating direction method of multipliers." Foundations and Trends in Machine Learning 3.1 (2011): 1-122.
- L. Gan, U. Topcu, and S. Low. Optimal decentralized protocol for electric vehicle
- charging. IEEE Transactions on Power Systems, 2013.
Omid Ardakanian, Catherine Rosenberg, and S. Keshav. 2013. Distributed control of electric vehicle charging. In Proceedings of the fourth international conference on Future energy systems (e-Energy '13). ACM, New York, NY, USA, 101-112.
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Technische Universität München
References (2/2)
- J. Rivera, M. Jergler, A. Stoimenov, C. Goebel, H.-A. Jacobsen. Using
Publish/Subscribe Middleware for Distributed EV Charging Optimization. Conference on Energy Informatics, Zürich, Switzerland, 2014.
- J. Rivera, H.-A. Jacobsen. A Distributed Anytime Algorithm for Network Utility
Maximization with Application to Real-time EV Charging Control. 53rd Conference
- n Decision and Control (CDC2014), Los Angeles, USA. 2014.
- J. Rivera, P. Wolfrum, S. Hirche, C. Goebel, and H.-A. Jacobsen. "Alternating
direction method of multipliers for decentralized electric vehicle charging control." In 52nd Conference on Decision and Control (CDC2013), Florence, Italy, 2013.
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Technische Universität München
Thank you, questions or comments …
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Jose Rivera j.rivera@tum.de
Contact
Technische Universität München
Outline: Power system operations
What is the status quo? Why do we need to do things differently? Our contribution Searching for a killer-app Summary and future work
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Technische Universität München
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Power system operations are complex
[gettyimages]
Technische Universität München
Power system operations
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Monitoring
- Status & Analog
Retrieval (SAR)
- Network Model Builder
(NMB)
- Scheduler Function
(SF)
- State Estimation (SE)
- Network Sensitivity
(NS)
Analysis
- Dispatcher Power
Flow (DPF)
- Security Analysis (SA)
- Short Circuit Analysis
(SCA)
Operation enhancement
- Optimal Power Flow
(OPF)
- Security Constrained
Dispatch (SCD)
- Voltage Stability
Analysis (VSA)
- Thermal Security
Analysis (TSA)
- Available
Transmission Capacity (ATC=VSA+TSA)
- Equipment Outage
Scheduler (EOS)
- Bad Topology
Detection (BTD)
- Network Parameter
Update (NPU)
- Network Modeling
Assistant (NMA)
Decision support
- Interlocking with LF &
SA
- Study data base
- Network save cases
[G. Björkman, ABB]
Technische Universität München
Power system operations & time scales
Real-Time Operations (msec – 10s of minutes)
- Protection (msec)
- Frequency governors (sec)
- Automatic Generation Control (AGC) (seconds)
- State estimation and contingency analysis
(minutes)
- Economic dispatch (~15 minutes)
Operation planning (days - years)
- Load forecasting – days (short term) to years
(long term)
- Unit commitment (day ahead markets)
- Maintenance planning (weeks - year)
- Generation and transmission planning ( up to 25
years)
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Monitoring Analysis Operation enhancement Decision support
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In simple words
Power system operations = Optimization
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Methods
Conventional
- ptimization
methods
Nonlinear Programming (NLP) Linear Programming (LP) Quadratic Programming (QP) Generalized reduced gradient method Newton method Network Flow Programming (NFP) Mixed - Integer Programming (MIP) Interior Point (IP) methods
Intelligence search methods
Neural Network (NN) Evolutionary Algorithms (EAs) Tabu Search (TS) Particle Swarm Optimization (PSO)
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Conventional is preferred
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Why not heuristics?
- No guaranteed good results
- Also…
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Technische Universität München
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- An aggregator bundles the services of many small
devices
- Every cent counts
- Need:
– Scalability – Optimality – Privacy Aggregator Co.
Aggregator problem as a killer app?
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Example: The EV charging problem
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Munich
Technische Universität München
If we control EVs
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Munich
Technische Universität München
Distributed vs centralized optimization
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We can scale up using Distributed Optimization (DO)
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What about 1 Mio EVs in Germany
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Germany
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In search of a ….
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killer app of DO in power systems
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What is the current killer app of DO?
Machine learning at Google scale
Training with massive amounts of data
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Large Scale Distributed Deep Networks Jeffrey Dean, Greg S. Corrado, Rajat Monga, Kai Chen, Matthieu Devin, Quoc V. Le, Mark Z. Mao, Marc’Aurelio Ranzato, Andrew Senior, Paul Tucker, Ke Yang, and Andrew Y. Ng
Technische Universität München
What is another current killer app of DO?
Optimization problems over large scale networks
– Lack of centralized coordinator or information access – Time-varying system characteristics
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Rate control in communication networks Wireless sensor networks: Data gathering/estimation/localization
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Bringing it all together
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Distribution networks Data in smart grids
Killer app: Combine big data and the distribution grid. Automation and control? Predictive analytics?
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Summary
- Power system operations require scalable, efficient and
reliable optimization
- Distributed optimization offers scalability
- Progress towards efficiency and reliability for distributed
- ptimization
- Killer app still required
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Future work
Move towards a platform for DO tailored to power systems
- peration problems
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