Publications 2017

Thursday, April 20, 2017
"Advanced Control in Modern Power Grids"

Shahab Mehraeen
Associate Professor
Louisiana State University

38-138 Engr. IV
Time: 3:00 pm – 4:00 pm

Abstract: Modern grids are different than the traditional power networks in various aspects. They interconnect different types of energy sources and loads. They comprise ac and dc components and circuits. Finally, they are designed to operate independently or connected to the large power networks. The dc micro grids have attracted much attention recently due to the advances in dc components. Stability of such systems is an attractive area of research especially when nonlinear components such as constant-power loads (CPLs) exist. In this presentation, dynamic modeling, stability, and safe operation of dc network powered by solar power is introduced. The destabilizing effect of CPL is considered and an advanced adaptive control mechanism is introduced to mitigate it. Hardware tests on an interconnected dc network is presented to support theoretical conjectures.

Biosketch: Dr. Shahab Mehraeen received his B.S. and M.S. degrees in electrical engineering from Iran University of Science and Technology and Esfahan University of Technology, Iran, respectively. He received his Ph.D. in electrical engineering from the Missouri University of Science and Technology, Rolla, Missouri, in 2009. He joined Louisiana State University, Baton Rouge, Louisiana, as assistant professor, in 2010. He conducts research on power system control, renewable energy integration, fault and stability analysis, and micro grids. He also conducts research in decentralized, and adaptive control of dynamical systems. Shahab Mehraeen is a recipient of the National Science Foundation CAREER Award and a holder of a US patent.

Wednesday, March 15, 2017
"Data-Driven Learning in Power Distribution Networks"

Ram Rajagopal
Assistant Professor
Civil & Environmental Engineering
Stanford University

37-124 Engr. IV
Time: 3:00 pm – 4:00 pm

Abstract: Increase in supply side variability due to increases in renewable generation require demand side management strategies to reduce electricity delivery costs. Smart grid technologies provide opportunities for measuring and controlling distributed energy resources such as loads and storage at an unprecedented scale reducing the electricity delivery cost. Enabling this solution requires accurate models of the power distribution network and how consumer loads respond to various signals. This talk introduces data driven tools to resolve these two challenges. VISDOM (Visualization and Insight for Demand Operations and Management) is an open source framework to learn consumer behavior utilizing real experiments and observing smart meter data. The proposed methodology utilizes features derived from the data to postulate behavior models, and various algorithms to characterize consumption statistics, segment consumers and target the appropriate ones to programs. VADER (Visualization and Analytics for Distributed Energy Resources) is a platform that learns models of the distribution network fusing traditional utility data such as from SCADA with novel sources of information such as measurements from inverters and smart meters. We demonstrate how machine learning and statistical analysis can yield theoretical sound and more accurate models of the system as compared to traditional approaches. We conclude with an overview of future challenges, in particular how to learn models of electricity markets and aggregators from data.

Biosketch: Ram Rajagopal is an Assistant Professor of Civil and Environmental Engineering at Stanford University, where he directs the Stanford Sustainable Systems Lab (S3L), focused on large scale monitoring, data analytics and stochastic control for infrastructure networks, in particular power networks. His current research interests in power systems are in integration of renewables, smart distribution systems and demand-side data analytics. Prior to his current position he was a DSP Research Engineer at National Instruments and a Visiting Research Scientist at IBM Research. He holds a Ph.D. in Electrical Engineering and Computer Sciences and an M.A. in Statistics, both from the University of California Berkeley, Masters in Electrical and Computer Engineering from University of Texas, Austin and Bachelors in Electrical Engineering from the Federal University of Rio de Janeiro. He is a recipient of the NSF CAREER Award, Powell Foundation Fellowship, Berkeley Regents Fellowship and the Makhoul Conjecture Challenge award. He holds more than 30 patents and several best paper awards from his work, and has advised or founded various companies in the fields of sensor networks, power systems and data analytics.


Friday, December 2, 2016
"Novel Controls of PV Solar Farms in Night and Day for Benefit to Utilities"

Rajiv K. Varma
The University of Western Ontario
London, ON, Canada

47-124 Engineering IV
Time: 10:00 - 11:00 AM

Abstract: PV solar farms are idle in the nights with their entire inverter capacity remaining unutilized. This seminar will present a set of novel patent-protected technologies for both nighttime and daytime control of PV solar farms as a dynamic reactive power compensator STATCOM, termed PV-STATCOM, for providing several benefits to both power transmission and distribution systems. These novel technologies on solar farms are 50-100 times lower in cost compared to conventional devices such as Flexible AC Transmission System (FACTS) used by electric utilities for providing the same functionalities in power systems.

The following night and day applications of the PV-STATCOM technology will be described:

  • Power Transfer Improvement in Transmission lines Through Increased Transient Stability and Enhanced Power Oscillation Damping
  • Mitigation of Subsynchronous Resonance in Synchronous Generators Connected to Series Compensated Lines
  • Increasing the Connectivity of Neighboring Wind Farms
  • Stabilizing Critical Induction Motor Loads
  • Decreasing Line Losses in Distribution Lines
  • Increasing the connectivity of PV Solar Farms
This PV-STATCOM technology leads to better network performance for utilities through 100% utilization of PV solar farms. It further opens up new revenue making opportunities for solar farms for providing various grid support functions during night and day.

This seminar will also present the nature and causes of series and parallel resonances in distribution/transmission networks. Harmonic amplification caused by these resonances can potentially result in maloperation or failures of utility/ customer owned equipment. Actual case studies will be presented of network and harmonic resonances, and their potential adverse impacts. It will be illustrated that harmonic resonances can constitute one of the major challenges in restricting the connectivity of inverter based renewable sources such as wind plants, PV solar plants and Plug-in Electric Vehicles.

Biosketch: Dr. Rajiv Varma is currently a Professor and past Hydro One Research Chair in Power Systems Engineering in the Electrical and Computer Engineering Department at The University of Western Ontario (UWO), London, Ontario, Canada. Before joining Western in 2002, he was a Faculty Member at Indian Institute of Technology Kanpur (IITK), India, for 11 years. He is also an Adjunct Professor at University of Waterloo.

Dr. Varma has received thirteen teaching excellence awards at the University and Faculty levels at UWO. He is the principal co-author of the book "Thyristor-Based FACTS Controllers for Electrical Transmission Systems"published by IEEE Press and John Wiley & Sons in 2002. His research interests include Flexible AC Transmission Systems (FACTS), power systems stability, and grid integration of PV solar and wind power systems. He has led multi-university researchprojects funded by Ontario Centres of Excellence and several utilities totaling $8.2 Million in the development of pioneering technologies aimed at low-cost PV control strategies to improve grid voltages and stability. Dr. Varma has developed a new technology for "Nighttime Utilization of PV Solar Farms as STATCOM" for which six patents have been issued in US, Canada and China, and several other international patents are pending. For this research, he received the Prize Paper Award from IEEE Power and Energy Society (PES) in 2012 and the First Place Poster Award in 7th International IRED Conference in 2016.

He led the first IEEE Tutorial on "Smart Inverters for Distributed Generators"; and co-delivered several Tutorials on "Static Var Compensator (SVC)" conducted by the IEEE Substations Committee. He is a Senior Member of IEEE. He is the Secretary of the IEEE PES "HVDC and FACTS Subcommittee", and the Chair of IEEE Working Group on "HVDC and FACTS Bibliography". He is also a Member of the IEEE P1547 Revision Working Group and Standard Technical Panel UL 1741. Dr. Varma obtained B.Tech. and Ph.D. degrees in Electrical Engineering from IIT Kanpur, India, in 1980 and 1988, respectively.

Thursday, October 27, 2016
"Optimizing the Coordinated Control of Distributed Generation, Storage and Demand Response on Decision Trees"

Panayiotis Moutis
Postdoctoral Research Associate
Carnegie Mellon University

47-124 Engineering IV
Time: 12:00 PM - 1:00 PM

Abstract: The questions regarding the provision of firm capacity by Distributed Generation (DG) as also the coordinated control of its de-loading, so that it can mitigate over-frequency phenomena, may be answered by incorporating DG under the Virtual Power Plant (VPP) paradigm. A VPP represents an abstract organizational concept of generation, storage and demand units that can cater for the procurement of ancillary services at Power System (PS) level, while ensuring optimality for the units involved. Taking into account the stochastic nature of PS load demand, as also of a great number of DG units based on Renewable Energy Sources, the uncertainty implied requires for solutions that (i) are characterized by flexibility, (ii) may not be optimal, but represent the best available approach, and (iii) can be realized in a short-time-ahead horizon, so that they exploit the most current information.

To this end, binary decision trees (DT) based on the Shannon entropy metric of information gain are used. Although the progress concerning DTs has been vast and in-depth, there are features of the aforementioned version of the tool that have not been clearly identified and exploited, previously. Thus, a DT-based methodology is suggested which can either re-dispatch the assets of a VPP, so that they cover for a considerable loss of power and, thus, provide firm capacity, or reduce the total output of the VPP, in order to support the mitigation of some over-frequency in the PS. In both cases, the optimality of the dispatching is ensured regardless of the stochastic nature of the VPP components, while the hour-ahead horizon of the realization exploits the current data. The time tedious process of generating the learning set of the DT can be minimized by splitting the burden among the microprocessors of the units of the VPP.

During the talk, the focus will be on (without being limited to) the characteristics of the binary DTs as a tool which can approach an optimization problem from the viewpoint of actual applicability; especially, when emergency (contingency) measures are required. Based on experience, a more generic discussion on the Smart Grid concepts and their deployment in modern PSs may follow and is encouraged.

Additional info on the recent work and publications concerning the talk can be found in

Biosketch: I received my Diploma and Phd in Electrical and Computer Engineering (ECE) from the National Technical University of Athens (NTUA), Greece, in November 2007 and January 2015, respectively. I have been involved in R&D projects in collaboration with native and European research institutes, industries and universities in the field of renewable energy sources, microgrids and energy efficiency. I have offered teaching assistance in the Power System Analysis courses of ECE NTUA and was involved as a lecturer on Smart Grid applications in the Energy Academy of the Ios-Aegean Energy Agency. Since 2006 I am involved in technical consulting to the sectors of photovoltaic investments and sustainability in Greece from various posts. In 2014 I was a Research Fellow on Microgrids at the University of Greenwich, in collaboration with Arup. Since February 2016 I am Postdoctoral Research Associate at Carnegie Mellon University, in the framework of the SHINES program of R&D projects. My research interests lie in the field of renewable sources integration, virtual power plants, microgrids and application of artificial intelligence to power system management and control. I am a member of the Power & Energy, Industrial Electronics, Computational Intelligence and Computer IEEE Enesocieties and a registered member of the Technical Chamber of Greece.


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44-120 Engr. IV, 420 Westwood Plaza, Los Angeles, CA. 90095