Workshop on Energy Supply-demand Networks with Renewables
based on Integration of Economic Models and Physical Models
-Toward international collaborations between NSF, RCN and JST CREST projects-

November 19-20, 2015

Large Meeting Room, "Raiosha" building,
Hiyoshi-Campus, Keio University, Yokohama, Kanagawa, Japan

The NSF, DFG, RCN and JST CREST have held three international workshops in Hawaii, Washington D.C., and Japan to encourage international research collaborations. The present workshop aims at further explore ways to encourage potential collaborative researches between the researchers from NSF, RCN and JST CREST program and is proposed by the two research teams from the CREST EMS program led by Jun-ichi Imura and Kenko Uchida. The path to the next generation energy management system is unique for each country, but interlinked through shared knowledge and research. The topics of the workshop cover wind energy, photovoltaic systems, energy storage, energy systems/smart girds and economic aspects of the energy systems. We thank for your participation and look forward to having an informative and productive workshop. The workshop is financially supported by the JST Supplemental Funding toward Promotion of International Collaborative Activities in CREST EMS Research Area.

Program (tentative) : Download (pdf, doc)

November 19

10:00-10:05 (Opening remarks) : Kenko Uchida (Waseda University)

Chair: Takeshi Hatanaka (Tokyo Institute of Technology)

Lucy Y. Pao (University of Colorado at Boulder)
Integration of Large Amounts of Wind Energy While Maintaining Utility Grid Reliabilityh

Abstract: Wind energy is recognized worldwide as cost-effective and environmentally friendly and is among the world's fastest-growing sources of electrical energy. Despite the amazing growth in global wind power installations in recent years, science and engineering challenges still exist. For instance, since electrical power supply and demand must match on the grid, wind's variability creates challenges to integrating large amounts of wind energy on the utility grid. Recently, systems and control techniques have begun to demonstrate that it is possible to actively control the power generated by wind turbines and wind farms to help stabilize the grid frequency. In this talk, we will first provide an overview of wind energy systems by introducing the primary structural components and operating regions of wind turbines. The operation of the utility grid will be briefly reviewed by discussing the electrical system, explaining the importance of preserving grid reliability through controlling the grid frequency (which is a measure of the balance between electrical generation and load), and describing the traditional methods of providing ancillary services for frequency support using conventional generation utilities. We will then outline how wind turbines and wind farms can be controlled to help stabilize and balance the frequency of the utility grid. Results of simulation studies as well as experimental field tests will be presented to show the promise of the techniques being developed. We will also present some of our new research directions in exploring the scheduling optimization of power generation and reserves when the capabilities of wind power plants in providing ancillary services are incorporated. We shall close by discussing continuing challenges and future research avenues that can facilitate the widespread adoption of active power control services provided by wind farms, and how advanced distributed capabilities can reduce the integration cost of wind energy and enable much higher wind energy penetrations while simultaneously maintaining and possibly increasing the reliability of the utility grid.

Toru Namerikawa (Keio University)
gPower Network Stabilization by Direct Load Control Based on Mechanism Designh

Abstract: This talk proposes a novel direct load control method to stabilize the system frequency of the power network. The proposed method utilizes the consumersf controllable loads for load frequency control. By solving an optimization problem to maximize the social welfare function, the input required for the frequency control is allocated among the controllable loads and the load frequency control generator in an economically rational manner. To introduce the direct control program for smooth operation of the power system, preventing consumers from cheating and guaranteeing their benefits are required. Thus, strategy-proofness and individual rationality based on the Groves and Clarke mechanism are used to design the electricity charge. Each consumer bids on the utility functions truthfully to the independent system operator and gains from participating in the proposed direct load control program. The effectiveness of the proposed method is demonstrated through some numerical experimental results.


Chair: Kenji Hirata (Nagaoka University of Technology)

Olav Bjarte Fosso (NTNU)
gElectric Vehicle Storage Capacity and Smart Grids as Means for Integrating Larger Amounts of Renewable Energy in Norwayh

Abstract: Norway has a rapidly increasing number of Electrical Vehicles due to favourable incentive schemes. We have passed more than one EV per 100 capita. This will represent a challenge for the distribution grid but also many opportunities when it comes to distributed storage. This will provide flexibility and can contribute til ancillary services. The presentation will address more detailed how this can be implemented and the challenge of coordination when there may be local intermittent energy resources and limited transmission capacity.

Jun-ichi Imura (Tokyo Institute of Technology)
gTowards System Theory for Harmonized Power System Control Based on Photovoltaic Power Predictionh

Abstract: This talk presents after a brief introduction of JST CREST research project "System Theory for Harmonized Power System Control Based on Photovoltaic Power Prediction (HARPS)", three topics on power systems control that my group has recently studied. The first is the economic dispatch control under uncertainty of PV power prediction, the next is control of batteries in the demand-side, and the third is a kind of wide-area frequency load control.

Coffee break

Chair: Toshiyuki Ohtsuka (Kyoto University)

Aranya Chakrabortty (North Carolina State University)
gModeling and Analysis of Dynamic Oscillation Patterns in Power Systems with High Wind Penetrationh

Abstract: Over the past few decades the operating characteristics of the North American power grid have changed substantially due to increasing penetration of renewable energy resources such as wind. The impact of increased levels of wind penetration on grid stability and dynamics, and in particular on inter-area oscillations, has also been the subject of a number of recent studies. Methods have been proposed to control these effects by regulating the wind farm power output, and by controlling doubly fed induction generators (DFIGs) to increase oscillation damping. However, a detailed, rigorous analytical framework for evaluating the impact of wind penetration on power system oscillations has yet to be developed. Specifically, there is very limited understanding of how wind injection may affect the time-scale separation or coherency properties of conventional grid models. In this talk I will present several illustrative results on spectral analysis of oscillations arising in power systems with high wind penetration, and study how the conventional coherency properties of this system changes as a function of the wind generation dynamics. I will first explain the mathematical model for the dynamics of a power network consisting of synchronous generators, loads, transmission lines and wind generator. Assuming the network to be divided into coherent clusters, I will use singular perturbation theory to derive a multi-time-scale dynamic model of the system, showing the impact of wind penetration on the slow oscillatory modes or interarea oscillation modes. I will present a detailed case study illustrating how the spatial distribution of wind power plants, as well as their relative proximity to the load centers, may result in power flow dynamics that alter the frequency and damping of interarea oscillatory modes. In the final part of the talk I will describe the design of a supplementary control system for a Static VAr Compensator (SVC) using synchronized phasor measurements for damping these interarea oscillations in face of rising wind power penetration. Real-world examples drawn from the US west coast grid as well as the New England power system will be presented to substantiate our results.

Kenji Hirata (Nagaoka University of Technology)
gReal-time Pricing Leading to Optimal Operation and its Application Case Studiesh

Abstract: We consider interactions between an independent entity, called a utility, and multiple agents, which correspond to generators or consumers. The utility wants to realize the socially optimal solution that fulfills power supply demand balancing. Each agent is allowed to determine its desired set-point according to the individual profit. In order to align the individual decision makings with the socially optimal solution, the utility is allowed to provide an additional price, which conceptually represents tax or subsidy. We propose a real-time pricing strategy of the utility and show three application case studies: a distributed voltage regulation of a distribution power gird in which a voltage rise occurs due to revers power flow from PV generators of households, a distributed voltage regulation for a large scale PV system with experimental case study results, a distributed management of EV/PHEV storage charging to fulfill the power flow balancing between a prediction based power supply and actual demands.

Vijay Gupta (University of Notre Dame)
gMarket Design for the Aggregator-Prosumer Interfaceh

Abstract: Designing new markets that align the interests of prosumers with the system objectives will be crucial to realize large scale penetration of renewable generation at the distribution level. To tame the complexity arising from a large number of interacting prosumers and to mitigate variability so that the unpredictable energy supply from renewables can be matched to the reliable on-demand power we expect from the grid, systematic aggregation will play a critical role. In particular, work is needed to design fair and efficient sharing mechanisms to allocate among strategic and empowered prosumers the risks and rewards of participating through an aggregator in various markets for both energy transfer (usually at time scales ranging from day ahead to 15 minutes) and power transfer (for ancillary service provision). In this talk, we develop some such markets and mechanisms for the aggregator-prosumer interface that will be crucial for large scale renewable integration when these sources are owned by a large number of strategic prosumers at the distribution level.

November 20

Chair: Hideaki Ishii (Tokyo Institute of Technology)

Isamu Matsukawa (Musashi University)
gThe Effects of an In-Home Display on Electricity Consumptionh

Abstract: I use panel data on how frequently households use in-home displays (IHD) in a randomized field experiment to investigate how acquiring information from IHDs affects electricity usage through consumption salience and learning. Providing IHDs, which enables households to see a graph of their half-hourly electricity consumption in real time, is a promising policy intervention that corrects for consumption biases associated with inattention and limited information-processing capacity by promoting salience and learning. Contrary to the energy-conservation literature, I find that IHD usage consistently raised electricity consumption through salience. I further find that learning through attention enhanced IHDsfenergy-using effect.

Anuradha Annaswamy (MIT)
gTransactive Control: A New Paradigm for Smart Grid Designh

Abstract: As we move deeper into the 21st century, critical infrastructures related to energy, and transportation are becoming smart-monitor themselves, communicate, and most importantly self-govern. Various drivers have enabled this transition, including sustainability concerns, scarcity in resources, economic considerations, and explosive growth in enabling technologies of sensor networks, and computational and communication systems. Two ideal illustrations of such infrastructures include smart grid and smart cities.
  The smart grid infrastructure has come into sharp focus with the arrival of renewable sources such as wind and solar energy, global concerns of sustainability and greenhouse gas emissions, and dwindling resources of fossil fuels. The idea behind a Smart Grid is the creation of a dynamic, cyber-physical infrastructure that meets the challenges of intermittency and distributed availability of renewables, and realize the advantages of reduced operational costs and emissions, via a flexible, intelligent, and networked grid that plans, controls, and delivers power to meet demand over an entire region. The concept of Smart City is gaining popular attention driven by goals of sustainability and efficiency, the needs of enhancing quality and performance, and the explosion of technological advances in communication and computation. Given that 50% of the worldfs population lives in urban regions, critical infrastructures of transportation, energy, healthcare, and food as well as their growing interdependencies have to be collectively analyzed and designed to provide the substrate for the realization of the Smart City Concept.
  A common emerging concept in both of these smart infrastructures is Transactive Control, that pertains to the use of economic incentives to manage demand in the presence of scarce resources. With its beginnings in electricity markets, the idea of a Transactive Control architecture is to combine economic incentives together with an understanding of the underlying structure of the infrastructure. In this talk, instantiations of various scenarios that exemplify the role of transactive control, the associated research challenges, and recent illustrations will be presented.
  Solutions already exist for many individual challenges facing the adoption of smart grid technology, yet full realization still requires a vision for dynamic control with coordination of numerous processes and constituents across the spectrum of energy activities.

Shinji Hara (The University of Tokyo)
gGlocal (Global/Local) Controller Synthesis for Hierarchical Dynamical Systemsh

Abstract: This talk is concerned with how to develop a new system control theory for providing systematic design methods of hierarchical networked dynamical systems composed of various kinds of subsystems from the glocal (global/local) control view point. "Glocal Control" means that both desired global and local behaviors are achieved by local actions of measurement and control. One of key control system framework for realizing glocal control is hierarchical networked dynamical systems with multiple resolutions in time and space. Through examinations of energy network control we first explain the idea and concept of glocal control and propose a structure of glocal control system consisting multi-resolved sensor, glocal predictor, and glocal controller. We then provide methods of designing glocal controller, or hierarchical decentralized controller with glocal adaptor for adjusting multiple objectives and constraints in different layers, and show that the structure completely fits our proposed one and satisfies the properties of certain confidentiality and flexibility required in glocal control through numerical examples.


Chair: Toru Namerikawa (Keio University)

Salvatore D'Arco (SINTEF)
gVirtual Synchronous Machines for Grid Integration of Energy Storage and Renewablesh

Abstract: The increasing power generation from renewable energy sources is reducing the share of production with conventional synchronous machines (SM) and, thus, the physical inertia of the power system. This trend can lead in the future to challenges in frequency regulation and to potential instabilities. The virtual synchronous machine (VSM) concept has been introduced in the last decade as a form of control of power converters to replicate the functional behavior of SM. The presentation offers an overview of the VSM concept including examples of implementations schemes and applications.

Takao Tsuji (Yokohama National University)
gTransient Stability of Japanese Power System with Large Amounts of Wind Power Plantsh

Abstract: Recently, renewable energy integration such as wind power and photovoltaics has been largely progressed worldwide. With a large amount of the renewable energy, stabilization of power system becomes more important issue: for example, power flow control, frequency regulation, and voltage management. Synchronous transient stability is also one of those keywords. If a part of conventional generating plants are replaced with the renewable energy, there is a possibility that the transient stability is worsened by the reduction of equivalent inertia constant and damping coefficient. In addition, the change of power flow profile also gives an impact on the stability when the generation output of the renewable energy is not uniformed in the power system configuration. By taking into consideration these effects, system operators must analyze the transient stability carefully not to decrease power supply reliability significantly. In Japan, the main target of the renewable energy integration has been ever treated as photovoltaics while wind power has been the mainstream worldwide. However, the wind power integration can be also expected to realize the sustainable energy society after the great east Japan earthquake followed by the nuclear power issue. The transient stability is one of dominant constraints in Japanese power system to determine the available transfer capability. Here, the wind power plants can contribute to improve the transient stability based on the concept of inertia control by mitigating the reduction of the equivalent inertia constant. Hence, in this study, the transient stability analysis is performed supposing the wind power penetration with the inertia control mechanism. In particular, the maximization of the inertia control effect will be discussed considering the unique characteristics of Japanese power system.

15:00- (Closing remarks) : Jun-ichi Imura (Tokyo Institute of Technology)