Demand Response and Smart Buildings: A Survey of Control, Communication, and Cyber-Physical Security
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paper_title: Standard load models for power flow and dynamic performance simulation

paper_content:

The authors recommend standard load models for power flow and dynamic simulation programs. The goal of this paper is to promote better load modeling and advanced load modeling, and to facilitate data exchange among users of various production-grade simulation programs. Flexibility of modeling is an important consideration. For transient stability, longer-term dynamics, and small-disturbance stability programs, the authors recommend the structure of multiple load types connected to a load bus. Load types are static including discharge lighting, induction motors, synchronous motors, and transformer saturation. For each load type, multiple models may be connected to the bus. For longer-term dynamics programs, a model for LTC transformers is also recommended.
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paper_title: Experimental Study of Grid Frequency Regulation Ancillary Service of a Variable Speed Heat Pump

paper_content:

This paper describes an analysis of a variable speed heat pump (VSHP), which responds to direct load control (DLC) signals to provide grid frequency regulation (GFR) ancillary service, while ensuring the comfort of building occupants. A data-driven dynamic model of the VSHP is developed through real-time experimental studies with a time horizon ranging from seconds to hours. The model is simple, yet still sufficiently comprehensive to analyze the operational characteristics of the VSHP. The DLC scheme is then experimentally applied to the VSHP to evaluate its demand response (DR) capability. Two control methods are considered for a practical implementation of the DLC-enabled VSHP and a further improvement of the DR capability, respectively. Additionally, a small-signal analysis is carried out using the aggregated dynamic response of a number of DLC-enabled VSHPs to analyze their contribution to GFR in an isolated power grid. For experimental case studies, a laboratory-scale microgrid is then implemented with generator and load emulators. We show that the DLC-enabled VSHP can effectively reduce grid frequency deviations and required reserve capacities of generators.
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paper_title: Test bed implementation of 380V DC distribution system using isolated bidirectional power converters

paper_content:

The test bed implementation of a 380V DC distribution system using smart power converters is proposed. The proposed test bed system is composed of DC home appliances modified from conventional AC components, a grid-interactive AC-DC converter for regulating bus voltage, a bidirectional converter for battery power interface, a renewable energy simulator, DC distribution panel board, and its monitoring system. This paper will focus on three power converters: bi-directional AC-DC rectifier, bidirectional DC-DC converter, and unidirectional DC-DC converter for the DC distribution system. Those converters are designed using dual active bridge (DAB) converter and resonant topologies of CLLC and LLC. The performance of the proposed converters was evaluated using prototypes of a 5 kW bidirectional AC-DC converter, a 3 kW bidirectional DC-DC converter, and a 3 kW unidirectional DC-DC converter. Finally, the test bed system has been verified through DC load connecting experiments employing the prototype converters.
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paper_title: Stabilization of Grid Frequency Through Dynamic Demand Control

paper_content:

Frequency stability in electricity networks is essential to the maintenance of supply quality and security. This paper investigates whether a degree of built-in frequency stability could be provided by incorporating dynamic demand control into certain consumer appliances. Such devices would monitor system frequency (a universally available indicator of supply-demand imbalance) and switch the appliance on or off accordingly, striking a compromise between the needs of the appliance and the grid. A simplified computer model of a power grid was created incorporating aggregate generator inertia, governor action and load-frequency dependence plus refrigerators with dynamic demand controllers. Simulation modelling studies were carried out to investigate the system's response to a sudden loss of generation, and to fluctuating wind power. The studies indicated a significant delay in frequency-fall and a reduced dependence on rapidly deployable backup generation.
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paper_title: Provision of Load Frequency Control by PHEVs, Controllable Loads, and a Cogeneration Unit

paper_content:

This paper presents a method for tracking a secondary frequency control (Load Frequency Control) signal by groups of plug-in hybrid electric vehicles (PHEVs), controllable thermal household appliances under a duty-cycle coordination scheme, and a decentralized combined-heat-and-power generation unit. The distribution of the control action on the participating units is performed by an aggregator utilizing a Model Predictive Control strategy which allows the inclusion of unit and grid constraints. In addition to the individual dynamic behavior, the varying availability of the units during the day is taken into account. The proposed methodology, easily extendable to larger networks, is evaluated on a four-bus system corresponding to a medium-voltage distribution grid and illustrates a possible operation mode of an aggregator in the power system.
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paper_title: An Evaluation of the Water Heater Load Potential for Providing Regulation Service

paper_content:

This paper investigates the possibility of providing aggregated regulation services with small loads, such as water heaters or air conditioners. A direct-load control algorithm is presented to aggregate the water heater load for the purpose of regulation. A dual-element electric water heater model is developed, which accounts for both thermal dynamics and users' water consumption. A realistic regulation signal was used to evaluate the number of water heaters needed and the operational characteristics of a water heater when providing 2-MW regulation service. Modeling results suggest that approximately 33, 000 water heaters are needed to provide a 2-MW regulation service 24 hours a day. However, if water heaters only provide regulation from 6:00 to 24:00, approximately 20, 000 will be needed. Because the control algorithm has considered the thermal setting of the water heater, customer comfort is maintained. Therefore, the aggregated regulation service provided by water heater loads can become a major source of revenue for load-serving entities when the smart grid enables the direct load control.
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paper_title: Load modeling for power flow and transient stability computer studies

paper_content:

A novel method is presented for preparing load models for power flow and stability studies. The LOADSYN load model synthesis software package transforms data on load class mix, composition, and characteristics into the form required for commonly used flow and transient stability simulation programs. Typical default data have been developed for load composition and characteristics. The load-modeling techniques used in this software and results of initial testing are described. Significant improvements in simulation accuracy are demonstrated. >
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paper_title: Low-Voltage Bipolar-Type DC Microgrid for Super High Quality Distribution

paper_content:

Microgrid is one of the new conceptual power systems for smooth installation of many distributed generations (DGs). While most of the microgrids adopt ac distribution as well as conventional power systems, dc microgrids are proposed and researched for the good connection with dc output type sources such as photovoltaic (PV) system, fuel cell, and secondary battery. Moreover, if loads in the system are supplied with dc power, the conversion losses from sources to loads are reduced compared with ac microgrid. As one of the dc microgrids, we propose “low-voltage bipolar-type dc microgrid,” which can supply super high quality power with three-wire dc distribution line. In this paper, one system for a residential complex is presented as an instance of the dc microgrid. In this system, each house has a cogeneration system (CGS) such as gas engine and fuel cell. The output electric power is shared among the houses, and the total power can be controlled by changing the running number of CGSs. Super capacitors are chosen as main energy storage. To confirm the fundamental characteristics and system operations, we experimented with a laboratory scale system. The results showed that the proposed system could supply high-quality power under several conditions.
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paper_title: Decentralized Demand-Side Contribution to Primary Frequency Control

paper_content:

Frequency in large power systems is usually controlled by adjusting the production of generating units in response to changes in the load. As the amount of intermittent renewable generation increases and the proportion of flexible conventional generating units decreases, a contribution from the demand side to primary frequency control becomes technically and economically desirable. One of the reasons why this has not been done was the perceived difficulties in dealing with many small loads rather than a limited number of generating units. In particular, the cost and complexity associated with two-way communications between many loads and the control center appeared to be insurmountable obstacles. This paper argues that this two-way communication is not essential and that the demand can respond to the frequency error in a manner similar to the generators. Simulation results show that, using this approach, the demand side can make a significant and reliable contribution to primary frequency response while preserving the benefits that consumers derive from their supply of electric energy.
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paper_title: Demonstration of HVAC chiller control for power grid frequency regulation—Part 1: Controller development and experimental results

paper_content:

Secondary frequency regulation is a necessary electric grid ancillary service that balances electric power system supply and demand on short time intervals of seconds to minutes. HVAC chillers may be well positioned to provide secondary frequency regulation as a demand side resource. This article describes the experimental development and performance of a practical controller that modifies chiller power demand to provide secondary frequency regulation. Chiller characteristics are identified through testing of a 200-ton (703-kWth) chiller serving a commercial building in Boston. Appropriate control strategies are subsequently determined. Controller demonstrations using standard electric system operator test routines show the chiller power response to exceed qualification requirements while providing up to ±25% of chiller nameplate power in secondary frequency regulation capability. The controller is further demonstrated to provide secondary frequency regulation continuously for several hours, during which ...
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paper_title: Total and Peak Energy Consumption Minimization of Building HVAC Systems Using Model Predictive Control

paper_content:

This article addresses the challenge of realizing the building automation and control system using a distributed network of embedded computers. A specification methodology and design space exploration framework are proposed to raise the level of abstraction at which building control systems are designed, to reduce design effort, and to lower implementation cost.
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paper_title: Analysis and Experimental Implementation of Grid Frequency Regulation Using Behind-the-Meter Batteries Compensating for Fast Load Demand Variations

paper_content:

This paper proposes a new grid frequency regulation (GFR) scheme using behind-the-meter battery energy storage systems (BESSs). The fast dynamic responses of the electrical BESSs enable buildings to compensate for the high-frequency components of load demand variations, through direct load control (DLC). An electrical system in a building, along with its building-level and device-level controllers, is considered to address the difficulties in the application of DLC, especially in communicating with several small-scale BESSs. A small-signal analysis is carried out using the aggregated responses of the generators and the DLC-enabled buildings to investigate the proposed GFR scheme, particularly with respect to the feedback controllers for the buildings. Simulation studies are performed using a test grid for various penetrations of the DLC-enabled buildings, and the test grid is implemented using a laboratory-scale microgrid. The proposed GFR is effective in reducing the frequency deviations and required reserve capacity of the generators, which is achieved by making small variations in the state-of-charge of the behind-the-meter battery.
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paper_title: DC Microgrids—Part II: A Review of Power Architectures, Applications, and Standardization Issues

paper_content:

DC microgrids (MGs) have been gaining a continually increasing interest over the past couple of years both in academia and industry. The advantages of dc distribution when compared to its ac counterpart are well known. The most important ones include higher reliability and efficiency, simpler control and natural interface with renewable energy sources, and electronic loads and energy storage systems. With rapid emergence of these components in modern power systems, the importance of dc in today's society is gradually being brought to a whole new level. A broad class of traditional dc distribution applications, such as traction, telecom, vehicular, and distributed power systems can be classified under dc MG framework and ongoing development, and expansion of the field is largely influenced by concepts used over there. This paper aims first to shed light on the practical design aspects of dc MG technology concerning typical power hardware topologies and their suitability for different emerging smart grid applications. Then, an overview of the state of the art in dc MG protection and grounding is provided. Owing to the fact that there is no zero-current crossing, an arc that appears upon breaking dc current cannot be extinguished naturally, making the protection of dc MGs a challenging problem. In relation with this, a comprehensive overview of protection schemes, which discusses both design of practical protective devices and their integration into overall protection systems, is provided. Closely coupled with protection, conflicting grounding objectives, e.g., minimization of stray current and common-mode voltage, are explained and several practical solutions are presented. Also, standardization efforts for dc systems are addressed. Finally, concluding remarks and important future research directions are pointed out.
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paper_title: Supplementary Load Frequency Control by Use of a Number of Both Electric Vehicles and Heat Pump Water Heaters

paper_content:

A large integration of renewable energy sources such as wind power generation and photovoltaic generation causes some problems in power systems, e.g., distribution voltage rise and frequency fluctuation. Battery energy storage system (BESS) is one of the effective solutions to these problems. Due to a high cost of the BESS, an application of controllable loads such as electric vehicle (EV) and heat pump water heater (HPWH) to the power system control is considered in this paper for reduction of the required capacity of the BESS. This paper proposes a new supplementary load frequency control (LFC) method by use of a number of both the EVs and the HPWHs as controllable loads. The effectiveness of the proposed LFC method is shown by numerical simulations conducted on the power system model with a large integration of wind power generation and photovoltaic generation.
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paper_title: Design Considerations of a Centralized Load Controller Using Thermostatically Controlled Appliances for Continuous Regulation Reserves

paper_content:

This paper presents design considerations for a centralized load controller to control thermostatically controlled appliances (TCAs) for continuous regulation reserves (CRRs). The controller logics for setting up the baseline load, generating priority lists, issuing dispatch commands, and tuning the simplified forecaster model using measurement data are described. To study the impacts of different control parameter settings on control performance and device lifetimes, a system consisting of 1000 heating, ventilating, and air-conditioning (HVAC) units in their heating modes is modeled to provide a CRR 24 hours a day. Four cases are modeled to evaluate the impact of forecasting errors, minimum HVAC turn-off times, response delays, and consumer overrides. The results demonstrate that a centralized TCA load controller can provide robust, good quality CRRs with reduced communication needs for the two-way communication network and inexpensive load control devices. Most importantly, because the controller precisely controls the aggregated HVAC load shapes while maintaining load diversity, the controllable and measurable load services that it provides can be used for many other demand response applications, such as peak shaving, load shifting, and arbitrage.
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paper_title: Deployment of Behind-The-Meter Energy Storage for Demand Charge Reduction

paper_content:

This study investigates how economically motivated customers will use energy storage for demand charge reduction, as well as how this changes in the presence of on-site photovoltaic power generation, to investigate the possible effects of incentivizing increased quantities of behind-the-meter storage. It finds that small, short-duration batteries are most cost effective regardless of solar power levels, serving to reduce short load spikes on the order of 2.5% of peak demand. While profitable to the customer, such action is unlikely to adequately benefit the utility as may be desired, thus highlighting the need for modified utility rate structures or properly structured incentives.
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paper_title: Modeling and Analysis of a Variable Speed Heat Pump for Frequency Regulation Through Direct Load Control

paper_content:

This paper presents a dynamic model of a variable speed heat pump (VSHP) in a commercial building that responds to direct load control (DLC) signals, updated every 4 s, for the improvement of grid frequency regulation (GFR). The model is simplified for real-time simulation studies with the time horizon ranging from seconds to hours, but still sufficiently comprehensive to analyze the operational characteristics such as the heat rate and coefficient of performance. A variable speed drive-controlled induction motor model is also established for the adjustment of the VSHP input power. A dynamic model of an experimental room is then developed to estimate the effect of the DLC application to the VSHP on its indoor air temperature for two different cooling systems. Furthermore, small signal analysis is performed to evaluate both the transient response of the DLC-enabled VSHP and its contribution to GFR. Finally, with an isolated microgrid implemented with Matlab/Simulink, simulation studies demonstrate that the VSHP can be effectively exploited as the DLC-enabled load while still ensuring building occupant comfort and long-term device performance.
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paper_title: Demand as Frequency Controlled Reserve

paper_content:

Relying on generation side alone is deemed insufficient to fulfill the system balancing needs for future Danish power system, where a 50% wind penetration is outlined by the government for year 2025. This paper investigates use of the electricity demand as frequency controlled reserve (DFR), which has a high potential and can provide many advantages. Firstly, the background of the research is reviewed, including conventional power system reserves and the demand side potentials. Subsequently, the control logics and corresponding design considerations for the DFR technology have been developed and analyzed, based on which simulation models have been built using the DIgSILENT Power Factory. The simulation studies of different scenarios confirm that the DFR can provide reliable performance of frequency control. Furthermore, relevant issues regarding implementing DFR in reality have been discussed.
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paper_title: Load control of a wind-hydrogen stand-alone power system

paper_content:

A new generation of load controllers enable stand-alone power systems (SAPS) to use one or many standard (grid connected) wind turbines. The controllers use fuzzy logic software algorithms. The strategy is to use the control loads to balance the flow of active power in the system and hence control system frequency. The dynamic supply of reactive power by a synchronous compensator maintains the system voltage within the limits specified in EN50160. The resistive controller loads produce a certain amount of heat that is exchanged down to the end user (hot water). It was decided to investigate the implementation of a hydrogen subsystem into the SAPS that can work in parallel with the Distributed Intelligent Load Controller (DILC). The hydrogen subsystem can then function as energy storage on long-term basis and an active load controller on short-term basis.
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paper_title: DC Microgrids—Part I: A Review of Control Strategies and Stabilization Techniques

paper_content:

This paper presents a review of control strategies, stability analysis, and stabilization techniques for dc microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control, which relies only on local measurements, some line of communication between units needs to be made available in order to achieve the coordinated control. Depending on the communication method, three basic coordinated control strategies can be distinguished, i.e., decentralized, centralized, and distributed control. Decentralized control can be regarded as an extension of the local control since it is also based exclusively on local measurements. In contrast, centralized and distributed control strategies rely on digital communication technologies. A number of approaches using these three coordinated control strategies to achieve various control objectives are reviewed in this paper. Moreover, properties of dc MG dynamics and stability are discussed. This paper illustrates that tightly regulated point-of-load converters tend to reduce the stability margins of the system since they introduce negative impedances, which can potentially oscillate with lightly damped power supply input filters. It is also demonstrated that how the stability of the whole system is defined by the relationship of the source and load impedances, referred to as the minor loop gain. Several prominent specifications for the minor loop gain are reviewed. Finally, a number of active stabilization techniques are presented.
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paper_title: Evaluation of commercial building HVAC systems as frequency regulation providers

paper_content:

The heating, ventilating and air-conditioning (HVAC) systems of large commercial office buildings consume a significant amount of electric power. Instead of passively consuming energy, these systems can provide frequency regulation (FR) services to the electric grid by adjusting the power consumption in response to a signal sent by the electric grid operator. This paper has four primary goals: First, it provides the theoretical support and states the need for using HVAC systems to provide FR. Second, it proposes two methods of using HVAC systems for providing FR – a direct method and an indirect method; these two methods are developed as models and tested in simulation. Third, it addresses the challenges of using commercial building HVAC systems for FR; this motivates the development of a new supervisory control method to support the HVAC system for providing FR service. Fourth, it evaluates the simulated results based on the performance based regulation (PBR) rules proposed by the PJM regional transmission organization; thus, it provides the reference for the future field-testing
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paper_title: Model predictive control for energy efficient cooling and dehumidification

paper_content:

Thesis (Ph. D. in Building Technology)--Massachusetts Institute of Technology, Dept. of Architecture, 2013.
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paper_title: Modeling and Analysis of a Variable Speed Heat Pump for Frequency Regulation Through Direct Load Control

paper_content:

This paper presents a dynamic model of a variable speed heat pump (VSHP) in a commercial building that responds to direct load control (DLC) signals, updated every 4 s, for the improvement of grid frequency regulation (GFR). The model is simplified for real-time simulation studies with the time horizon ranging from seconds to hours, but still sufficiently comprehensive to analyze the operational characteristics such as the heat rate and coefficient of performance. A variable speed drive-controlled induction motor model is also established for the adjustment of the VSHP input power. A dynamic model of an experimental room is then developed to estimate the effect of the DLC application to the VSHP on its indoor air temperature for two different cooling systems. Furthermore, small signal analysis is performed to evaluate both the transient response of the DLC-enabled VSHP and its contribution to GFR. Finally, with an isolated microgrid implemented with Matlab/Simulink, simulation studies demonstrate that the VSHP can be effectively exploited as the DLC-enabled load while still ensuring building occupant comfort and long-term device performance.
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paper_title: Deploying Systems Interoperability and Customer Choice within Smart Grid

paper_content:

Deploying Systems Interoperability and Customer Choice within Smart Grid Girish Ghatikar, Lawrence Berkeley National Laboratory Ed Koch, Akuacom/Honeywell November 2012
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paper_title: Design of parallel sources in DC distributed power systems by using gain-scheduling technique

paper_content:

In this work, the issue of load sharing between parallel-connected three-phase PWM boost rectifiers is analyzed. In order to achieve independence between the rectifiers to facilitate standardized module design, the droop method is adopted. Traditionally, the method involves a trade-off between voltage regulation and load sharing. After parametric analysis, a novel droop method is proposed to avoid those limitations by using the gain scheduling technique. The analysis shows that the proposed method can achieve both good voltage regulation and good load sharing. The source output impedance of the proposed method is also proven to be better than that of the commonly used master/slave method.
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paper_title: Hierarchical Control of Droop-Controlled AC and DC Microgrids—A General Approach Toward Standardization

paper_content:

DC and AC Microgrids are key elements to integrate renewable and distributed energy resources as well as distributed energy storage systems. In the last years, efforts toward the standardization of these Microgrids have been made. In this sense, this paper present the hierarchical control derived from ISA-95 and electrical dispatching standards to endow smartness and flexibility to microgrids. The hierarchical control proposed consist of three levels: i) the primary control is based on the droop method, including an output impedance virtual loop; ii) the secondary control allows restoring the deviations produced by the primary control; and iii) the tertiary control manage the power flow between the microgrid and the external electrical distribution system. Results from a hierarchical-controlled microgrid are provided to show the feasibility of the proposed approach.
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paper_title: Mode-Adaptive Decentralized Control for Renewable DC Microgrid With Enhanced Reliability and Flexibility

paper_content:

A mode-adaptive decentralized control strategy is proposed for the power management of a dc microgrid with multiple renewable distributed generators and energy storage systems. In the presented solution, the dc bus voltage signal is used not only to enable power sharing among different sources, but also to designate microgrid operation modes and facilitate seamless mode transitions. With this mode-adaptive operation mechanism, a greater control freedom can be achieved than the conventional dc voltage droop control scheme. More importantly, this approach features fully self-disciplined regulation of distributed converters without an extra control center or communication link. Therefore, both reliability and flexibility can be enhanced. Meanwhile, a novel mode definition criterion is also provided to highlight the special characteristics of the dc microgrid which is different from an ac one. Three typical operation conditions are summarized according to which type of sources are dominating the power balance. Finally, the effectiveness of the proposed technique is verified experimentally based on a composite dc microgrid test system.
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paper_title: DC Microgrids—Part I: A Review of Control Strategies and Stabilization Techniques

paper_content:

This paper presents a review of control strategies, stability analysis, and stabilization techniques for dc microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control, which relies only on local measurements, some line of communication between units needs to be made available in order to achieve the coordinated control. Depending on the communication method, three basic coordinated control strategies can be distinguished, i.e., decentralized, centralized, and distributed control. Decentralized control can be regarded as an extension of the local control since it is also based exclusively on local measurements. In contrast, centralized and distributed control strategies rely on digital communication technologies. A number of approaches using these three coordinated control strategies to achieve various control objectives are reviewed in this paper. Moreover, properties of dc MG dynamics and stability are discussed. This paper illustrates that tightly regulated point-of-load converters tend to reduce the stability margins of the system since they introduce negative impedances, which can potentially oscillate with lightly damped power supply input filters. It is also demonstrated that how the stability of the whole system is defined by the relationship of the source and load impedances, referred to as the minor loop gain. Several prominent specifications for the minor loop gain are reviewed. Finally, a number of active stabilization techniques are presented.
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paper_title: A Distributed Control Strategy Based on DC Bus Signaling for Modular Photovoltaic Generation Systems With Battery Energy Storage

paper_content:

Modular generation system, which consists of modular power conditioning converters, is an effective solution to integrate renewable energy sources with conventional utility grid to improve reliability and efficiency, especially for photovoltaic generation. A distributed control strategy based on improved dc bus signaling is proposed for a modular photovoltaic (PV) generation system with battery energy storage elements. In this paper, the modular PV generation system is composed of three modular dc/dc converters for PV arrays, two grid-connected dc/ac converters, and one dc/dc converter for battery charging/discharging and local loads, which is available of either grid-connected operation or islanding operation. By using the proposed control strategy, the operations of a modular PV generation system are categorized into four modes: islanding with battery discharging, grid-connected rectification, grid-connected inversion, and islanding with constant voltage (CV) generation. The power balance of the system under extreme conditions such as the islanding operation with a full-charged battery is taken into account in this control strategy. The dc bus voltage level is employed as an information carrier to distinguish different modes and determine mode switching. Control methods of modular dc/dc converters, battery converter, and grid-connected converter are addressed. An autonomous control method for modular dc/dc converters is proposed to realize smooth switching between CV operation and maximum power point tracking operation, which enables the dc bus voltage regulation capability of modular dc/dc converters. Seamless switching of a battery converter between charging and discharging and that of a grid-connected converter between rectification and inversion are ensured by the proposed control methods. Experiments verify the practical feasibility and the effectiveness of the proposed control strategies.
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paper_title: An Evaluation of the Water Heater Load Potential for Providing Regulation Service

paper_content:

This paper investigates the possibility of providing aggregated regulation services with small loads, such as water heaters or air conditioners. A direct-load control algorithm is presented to aggregate the water heater load for the purpose of regulation. A dual-element electric water heater model is developed, which accounts for both thermal dynamics and users' water consumption. A realistic regulation signal was used to evaluate the number of water heaters needed and the operational characteristics of a water heater when providing 2-MW regulation service. Modeling results suggest that approximately 33, 000 water heaters are needed to provide a 2-MW regulation service 24 hours a day. However, if water heaters only provide regulation from 6:00 to 24:00, approximately 20, 000 will be needed. Because the control algorithm has considered the thermal setting of the water heater, customer comfort is maintained. Therefore, the aggregated regulation service provided by water heater loads can become a major source of revenue for load-serving entities when the smart grid enables the direct load control.
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paper_title: Fast linear iterations for distributed averaging

paper_content:

We consider the problem of finding a linear iteration that yields distributed averaging consensus over a network, i.e., that asymptotically computes the average of some initial values given at the nodes. When the iteration is assumed symmetric, the problem of finding the fastest converging linear iteration can be cast as a semidefinite program, and therefore efficiently and globally solved. These optimal linear iterations are often substantially faster than several simple heuristics that are based on the Laplacian matrix of the associated graph.
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paper_title: Optimal demand response based on utility maximization in power networks

paper_content:

Demand side management will be a key component of future smart grid that can help reduce peak load and adapt elastic demand to fluctuating generations. In this paper, we consider households that operate different appliances including PHEVs and batteries and propose a demand response approach based on utility maximization. Each appliance provides a certain benefit depending on the pattern or volume of power it consumes. Each household wishes to optimally schedule its power consumption so as to maximize its individual net benefit subject to various consumption and power flow constraints. We show that there exist time-varying prices that can align individual optimality with social optimality, i.e., under such prices, when the households selfishly optimize their own benefits, they automatically also maximize the social welfare. The utility company can thus use dynamic pricing to coordinate demand responses to the benefit of the overall system. We propose a distributed algorithm for the utility company and the customers to jointly compute this optimal prices and demand schedules. Finally, we present simulation results that illustrate several interesting properties of the proposed scheme.
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paper_title: Smart Grid Communications: Overview of Research Challenges, Solutions, and Standardization Activities

paper_content:

Optimization of energy consumption in future intelligent energy networks (or Smart Grids) will be based on grid-integrated near-real-time communications between various grid elements in generation, transmission, distribution and loads. This paper discusses some of the challenges and opportunities of communications research in the areas of smart grid and smart metering. In particular, we focus on some of the key communications challenges for realizing interoperable and future-proof smart grid/metering networks, smart grid security and privacy, and how some of the existing networking technologies can be applied to energy management. Finally, we also discuss the coordinated standardization efforts in Europe to harmonize communications standards and protocols.
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paper_title: Optimal Real-Time Pricing Algorithm Based on Utility Maximization for Smart Grid

paper_content:

In this paper, we consider a smart power infrastructure, where several subscribers share a common energy source. Each subscriber is equipped with an energy consumption controller (ECC) unit as part of its smart meter. Each smart meter is connected to not only the power grid but also a communication infrastructure such as a local area network. This allows two-way communication among smart meters. Considering the importance of energy pricing as an essential tool to develop efficient demand side management strategies, we propose a novel real-time pricing algorithm for the future smart grid. We focus on the interactions between the smart meters and the energy provider through the exchange of control messages which contain subscribers' energy consumption and the real-time price information. First, we analytically model the subscribers' preferences and their energy consumption patterns in form of carefully selected utility functions based on concepts from microeconomics. Second, we propose a distributed algorithm which automatically manages the interactions among the ECC units at the smart meters and the energy provider. The algorithm finds the optimal energy consumption levels for each subscriber to maximize the aggregate utility of all subscribers in the system in a fair and efficient fashion. Finally, we show that the energy provider can encourage some desirable consumption patterns among the subscribers by means of the proposed real-time pricing interactions. Simulation results confirm that the proposed distributed algorithm can potentially benefit both subscribers and the energy provider.
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paper_title: Consensus problems in networks of agents with switching topology and time-delays

paper_content:

In this paper, we discuss consensus problems for networks of dynamic agents with fixed and switching topologies. We analyze three cases: 1) directed networks with fixed topology; 2) directed networks with switching topology; and 3) undirected networks with communication time-delays and fixed topology. We introduce two consensus protocols for networks with and without time-delays and provide a convergence analysis in all three cases. We establish a direct connection between the algebraic connectivity (or Fiedler eigenvalue) of the network and the performance (or negotiation speed) of a linear consensus protocol. This required the generalization of the notion of algebraic connectivity of undirected graphs to digraphs. It turns out that balanced digraphs play a key role in addressing average-consensus problems. We introduce disagreement functions for convergence analysis of consensus protocols. A disagreement function is a Lyapunov function for the disagreement network dynamics. We proposed a simple disagreement function that is a common Lyapunov function for the disagreement dynamics of a directed network with switching topology. A distinctive feature of this work is to address consensus problems for networks with directed information flow. We provide analytical tools that rely on algebraic graph theory, matrix theory, and control theory. Simulations are provided that demonstrate the effectiveness of our theoretical results.
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paper_title: Quantifying the Effect of Demand Response on Electricity Markets

paper_content:

It is widely agreed that an increased participation of the demand side in the electricity markets would produce benefits not only for the individual consumers but also for the market as a whole. This paper proposes a method for quantifying rigorously the effect that such an increase would have on the various categories of market participants. A new centralized complex-bid market-clearing mechanism has been devised to take into consideration the load shifting behavior of consumers who do submit price-sensitive bids. The effects of the proportion of demand response on the market are illustrated using a test system with ten generating units scheduled over 24 periods.
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paper_title: Consensus and Cooperation in Networked Multi-Agent Systems

paper_content:

This paper provides a theoretical framework for analysis of consensus algorithms for multi-agent networked systems with an emphasis on the role of directed information flow, robustness to changes in network topology due to link/node failures, time-delays, and performance guarantees. An overview of basic concepts of information consensus in networks and methods of convergence and performance analysis for the algorithms are provided. Our analysis frame- work is based on tools from matrix theory, algebraic graph theory, and control theory. We discuss the connections between consensus problems in networked dynamic systems and diverse applications including synchronization of coupled oscillators, flocking, formation control, fast consensus in small- world networks, Markov processes and gossip-based algo- rithms, load balancing in networks, rendezvous in space, distributed sensor fusion in sensor networks, and belief propagation. We establish direct connections between spectral and structural properties of complex networks and the speed of information diffusion of consensus algorithms. A brief introduction is provided on networked systems with nonlocal information flow that are considerably faster than distributed systems with lattice-type nearest neighbor interactions. Simu- lation results are presented that demonstrate the role of small- world effects on the speed of consensus algorithms and cooperative control of multivehicle formations.
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paper_title: Smart Grid Technologies: Communication Technologies and Standards

paper_content:

For 100 years, there has been no change in the basic structure of the electrical power grid. Experiences have shown that the hierarchical, centrally controlled grid of the 20th Century is ill-suited to the needs of the 21st Century. To address the challenges of the existing power grid, the new concept of smart grid has emerged. The smart grid can be considered as a modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability, and so on. While current power systems are based on a solid information and communication infrastructure, the new smart grid needs a different and much more complex one, as its dimension is much larger. This paper addresses critical issues on smart grid technologies primarily in terms of information and communication technology (ICT) issues and opportunities. The main objective of this paper is to provide a contemporary look at the current state of the art in smart grid communications as well as to discuss the still-open research issues in this field. It is expected that this paper will provide a better understanding of the technologies, potential advantages and research challenges of the smart grid and provoke interest among the research community to further explore this promising research area.
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paper_title: Energy-saving decision making framework for HVAC with usage logs

paper_content:

Abstract Commercial and residential buildings account for 40% of total energy usage in the United Sates. Efforts have been made to better manage energy through the implementation of building energy management systems. In particular, heating, ventilating, and air conditioning consume 50% of energy used in buildings. The system air-conditioner, an individually as well as centrally controlled HVAC system, is widely used across Asia. As energy cost increases, building managers often take building-wide energy saving measures, such as intermittent indoor unit shut-down and setting units to uncomfortable temperatures. In this paper, we argue that a smarter approach is possible. Analyzing a large amount of data collected from indoor units, we see that these units have varying levels of energy consumption and that we can identify those that consume more energy than others, resulting in individual measures for each. We propose a business intelligence framework that allows us to see why certain rooms consume more energy than others through three variables: hours of power-on, hours of thermo-on, and a timeframe of power-on. All variables are visualized, providing building managers with an intuitive understanding of their buildings’ energy consumption. We used real-world data to validate the framework and received positive feedbacks from domain experts.
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paper_title: Smart Grid Technologies: Communication Technologies and Standards

paper_content:

For 100 years, there has been no change in the basic structure of the electrical power grid. Experiences have shown that the hierarchical, centrally controlled grid of the 20th Century is ill-suited to the needs of the 21st Century. To address the challenges of the existing power grid, the new concept of smart grid has emerged. The smart grid can be considered as a modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability, and so on. While current power systems are based on a solid information and communication infrastructure, the new smart grid needs a different and much more complex one, as its dimension is much larger. This paper addresses critical issues on smart grid technologies primarily in terms of information and communication technology (ICT) issues and opportunities. The main objective of this paper is to provide a contemporary look at the current state of the art in smart grid communications as well as to discuss the still-open research issues in this field. It is expected that this paper will provide a better understanding of the technologies, potential advantages and research challenges of the smart grid and provoke interest among the research community to further explore this promising research area.
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paper_title: A Survey of Communications and Networking Technologies for Energy Management in Buildings and Home Automation

paper_content:

With the exploding power consumption in private households and increasing environmental and regulatory restraints, the need to improve the overall efficiency of electrical networks has never been greater. That being said, the most efficient way to minimize the power consumption is by voluntary mitigation of home electric energy consumption, based on energy-awareness and automatic or manual reduction of standby power of idling home appliances. Deploying bi-directional smart meters and home energy management (HEM) agents that provision real-time usage monitoring and remote control, will enable HEM in “smart households.” Furthermore, the traditionally inelastic demand curve has began to change, and these emerging HEM technologies enable consumers (industrial to residential) to respond to the energy market behavior to reduce their consumption at peak prices, to supply reserves on a as-needed basis, and to reduce demand on the electric grid. Because the development of smart grid-related activities has resulted in an increased interest in demand response (DR) and demand side management (DSM) programs, this paper presents some popular DR and DSM initiatives that include planning, implementation and evaluation techniques for reducing energy consumption and peak electricity demand. The paper then focuses on reviewing and distinguishing the various state-of-the-art HEM control and networking technologies, and outlines directions for promoting the shift towards a society with low energy demand and low greenhouse gas emissions. The paper also surveys the existing software and hardware tools, platforms, and test beds for evaluating the performance of the information and communications technologies that are at the core of future smart grids. It is envisioned that this paper will inspire future research and design efforts in developing standardized and user-friendly smart energy monitoring systems that are suitable for wide scale deployment in homes.
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paper_title: Survey in Smart Grid and Smart Home Security: Issues, Challenges and Countermeasures

paper_content:

The electricity industry is now at the verge of a new era—an era that promises, through the evolution of the existing electrical grids to smart grids, more efficient and effective power management, better reliability, reduced production costs, and more environmentally friendly energy generation. Numerous initiatives across the globe, led by both industry and academia, reflect the mounting interest around not only the enormous benefits but also the great risks introduced by this evolution. This paper focuses on issues related to the security of the smart grid and the smart home, which we present as an integral part of the smart grid. Based on several scenarios, we aim to present some of the most representative threats to the smart home/smart grid environment. The threats detected are categorized according to specific security goals set for the smart home/smart grid environment, and their impact on the overall system security is evaluated. A review of contemporary literature is then conducted with the aim of presenting promising security countermeasures with respect to the identified specific security goals for each presented scenario. An effort to shed light on open issues and future research directions concludes this paper.
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paper_title: Privacy Concerns in Upcoming Residential and Commercial Demand-Response Systems

paper_content:

We explore the privacy concerns arising from the collection of power consumption data in current and future demand-response systems. We claim that in a lax regulatory environment, the detailed household consumption data gathered by advanced metering projects can and will be repurposed by interested parties to reveal personally identifying information such as an individual's activities, preferences, and even beliefs. To develop this claim, we begin with an overview of demand- response technologies and their deployment trends, mentioning both the parties interested in the data and their motivations. We proceed to formalize the notion of privacy and list the types of personal information which can be estimated with current and upcoming monitoring technologies. To support our list, we conduct a small-scale monitoring experiment on a private residence. Our results show that personal information can be estimated with a high degree of accuracy, even with relatively unsophisticated hardware and algorithms. We discuss the impli- cations of our results for future demand-response projects. Our paper concludes with guidelines for data-handling policies which ensure the protection of privacy. Index Terms—NG-SCADA, Protection, Privacy.
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paper_title: Smart Grid Privacy via Anonymization of Smart Metering Data

paper_content:

The security and privacy of future smart grid and smart metering networks is important to their rollout and eventual acceptance by the public: research in this area is ongoing and smart meter users will need to be reassured that their data is secure. This paper describes a method for securely anonymizing frequent (for example, every few minutes) electrical metering data sent by a smart meter. Although such frequent metering data may be required by a utility or electrical energy distribution network for operational reasons, this data may not necessarily need to be attributable to a specific smart meter or consumer. It does, however, need to be securely attributable to a specific location (e.g. a group of houses or apartments) within the electricity distribution network. The method described in this paper provides a 3rd party escrow mechanism for authenticated anonymous meter readings which are difficult to associate with a particular smart meter or customer. This method does not preclude the provision of attributable metering data that is required for other purposes such as billing, account management or marketing research purposes.
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paper_title: Attribute-based encryption for fine-grained access control of encrypted data

paper_content:

As more sensitive data is shared and stored by third-party sites on the Internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data, is that it can be selectively shared only at a coarse-grained level (i.e., giving another party your private key). We develop a new cryptosystem for fine-grained sharing of encrypted data that we call Key-Policy Attribute-Based Encryption (KP-ABE). In our cryptosystem, ciphertexts are labeled with sets of attributes and private keys are associated with access structures that control which ciphertexts a user is able to decrypt. We demonstrate the applicability of our construction to sharing of audit-log information and broadcast encryption. Our construction supports delegation of private keys which subsumesHierarchical Identity-Based Encryption (HIBE).
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paper_title: Secure enrollment and practical migration for mobile trusted execution environments

paper_content:

Smartphones can implement various security services from mobile banking to security tokens used for physical access control. System-wide trusted execution environments (TEEs), like ARM TrustZone, allow implementation of these services that withstand malware and operating system compromise. While researchers and developers have focused on secure storage and processing of credentials on such mobile TEEs, secure and practical bootstrapping of security services has been overlooked. The goal of this paper is to put forward the problem of secure user enrollment in the context of mobile system-wide TEEs. We explain why user identity binding to a mobile device is challenging on current smartphone platforms, and argue that current mobile device architectures do not facilitate secure enrollment and migration for such TEEs. We outline possible architecture changes that would enable the realization of secure and practical enrollment, and thus enable more widespread secure deployment of various mobile security services.
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paper_title: Hierarchical Control of Droop-Controlled AC and DC Microgrids—A General Approach Toward Standardization

paper_content:

DC and AC Microgrids are key elements to integrate renewable and distributed energy resources as well as distributed energy storage systems. In the last years, efforts toward the standardization of these Microgrids have been made. In this sense, this paper present the hierarchical control derived from ISA-95 and electrical dispatching standards to endow smartness and flexibility to microgrids. The hierarchical control proposed consist of three levels: i) the primary control is based on the droop method, including an output impedance virtual loop; ii) the secondary control allows restoring the deviations produced by the primary control; and iii) the tertiary control manage the power flow between the microgrid and the external electrical distribution system. Results from a hierarchical-controlled microgrid are provided to show the feasibility of the proposed approach.
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paper_title: Experimental Study of Grid Frequency Regulation Ancillary Service of a Variable Speed Heat Pump

paper_content:

This paper describes an analysis of a variable speed heat pump (VSHP), which responds to direct load control (DLC) signals to provide grid frequency regulation (GFR) ancillary service, while ensuring the comfort of building occupants. A data-driven dynamic model of the VSHP is developed through real-time experimental studies with a time horizon ranging from seconds to hours. The model is simple, yet still sufficiently comprehensive to analyze the operational characteristics of the VSHP. The DLC scheme is then experimentally applied to the VSHP to evaluate its demand response (DR) capability. Two control methods are considered for a practical implementation of the DLC-enabled VSHP and a further improvement of the DR capability, respectively. Additionally, a small-signal analysis is carried out using the aggregated dynamic response of a number of DLC-enabled VSHPs to analyze their contribution to GFR in an isolated power grid. For experimental case studies, a laboratory-scale microgrid is then implemented with generator and load emulators. We show that the DLC-enabled VSHP can effectively reduce grid frequency deviations and required reserve capacities of generators.
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paper_title: Smart Grid Communication: Its Challenges and Opportunities

paper_content:

The necessity to promote smart grid (SG) has been recognized with a strong consensus. The SG integrates electrical grids and communication infrastructures and forms an intelligent electricity network working with all connected components to deliver sustainable electricity supplies. Many advanced communication technologies have been identified for SG applications with a potential to significantly enhance the overall efficiency of power grids. In this paper, the challenges and applications of communication technologies in SG are discussed. In particular, we identify three major challenges to implement SG communication systems, including standards interoperability, cognitive access to unlicensed radio spectra, and cyber security. The issues to implement SG communications on an evolutional path and its future trends are also addressed. The aim of this paper is to offer a comprehensive review of state-of-the-art researches on SG communications.
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paper_title: Benefits and challenges of electrical demand response: A critical review

paper_content:

Advances in IT, control and forecasting capabilities have made demand response a viable, and potentially attractive, option to increase power system flexibility. This paper presents a critical review of the literature in the field of demand response, providing an overview of the benefits and challenges of demand response. These benefits include the ability to balance fluctuations in renewable generation and consequently facilitate higher penetrations of renewable resources on the power system, an increase in economic efficiency through the implementation of real-time pricing, and a reduction in generation capacity requirements. Nevertheless, demand response is not without its challenges. The key challenges for demand response centre around establishing reliable control strategies and market frameworks so that the demand response resource can be used optimally. One of the greatest challenges for demand response is the lack of experience, and the consequent need to employ extensive assumptions when modelling and evaluating this resource. This paper concludes with an examination of these assumptions, which range from assuming a fixed linear price–demand relationship for price responsive demand, to modelling the highly diverse, distributed and uncertain demand response resource as a single, centralised negative generator, adopting fixed characteristics and constraints.
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paper_title: Demonstration of HVAC chiller control for power grid frequency regulation—Part 1: Controller development and experimental results

paper_content:

Secondary frequency regulation is a necessary electric grid ancillary service that balances electric power system supply and demand on short time intervals of seconds to minutes. HVAC chillers may be well positioned to provide secondary frequency regulation as a demand side resource. This article describes the experimental development and performance of a practical controller that modifies chiller power demand to provide secondary frequency regulation. Chiller characteristics are identified through testing of a 200-ton (703-kWth) chiller serving a commercial building in Boston. Appropriate control strategies are subsequently determined. Controller demonstrations using standard electric system operator test routines show the chiller power response to exceed qualification requirements while providing up to ±25% of chiller nameplate power in secondary frequency regulation capability. The controller is further demonstrated to provide secondary frequency regulation continuously for several hours, during which ...
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paper_title: Frequency droop control with scheduled charging of electric vehicles

paper_content:

Vehicle-to-grid (V2G) control of electric vehicles (EVs) has the potential to provide frequency regulation for power system operation. The authors study the frequency droop control with EVs’ participation. The challenge is to simultaneously suppress frequency fluctuation and satisfy transportation usages of EV owners. A V2G control consisting of frequency droop control and scheduled charging is developed to overcome this challenge. Frequency droop control can suppress frequency fluctuation by responding to frequency deviation signal, while scheduled charging can achieve the charging demands of EV owners. Although uncertain regulation may result in deviation of the battery energy levels from the expected, the scheduled charging made based on the departure time, the real-time, the real-time battery energy levels, and the expected battery energy levels can compensate this change in real time. The proposed V2G control can ensure different types of charging demands such as holding battery energy levels and elevating battery energy levels, unlike existing methods in which different V2G control strategies have to be developed. Simulations on a two-area interconnected power grid using real power grid data in China validate the effectiveness of the proposed V2G control in suppressing frequency fluctuation and achieving the charging demands of EV owners.
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paper_title: Total and Peak Energy Consumption Minimization of Building HVAC Systems Using Model Predictive Control

paper_content:

This article addresses the challenge of realizing the building automation and control system using a distributed network of embedded computers. A specification methodology and design space exploration framework are proposed to raise the level of abstraction at which building control systems are designed, to reduce design effort, and to lower implementation cost.
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paper_title: Ancillary Service to the Grid Through Control of Fans in Commercial Building HVAC Systems

paper_content:

The thermal storage potential in commercial buildings is an enormous resource for providing various ancillary services to the grid. In this paper, we show how fans in Heating, Ventilation, and Air Conditioning (HVAC) systems of commercial buildings alone can provide substantial frequency regulation service, with little change in their indoor environments. A feedforward architecture is proposed to control the fan power consumption to track a regulation signal. The proposed control scheme is then tested through simulations based on a calibrated high fidelity non-linear model of a building. Model parameters are identified from data collected in Pugh Hall, a commercial building located on the University of Florida campus. For the HVAC system under consideration, numerical experiments demonstrate how up to 15% of the rated fan power can be deployed for regulation purpose while having little effect on the building indoor temperature. The regulation signal that can be successfully tracked is constrained in the frequency band $[1/\tau_{0},1/\tau_{1}]$ , where $\tau_{0}\approx 3$ minutes and $\tau_{1}\approx 8$ seconds. Our results indicate that fans in existing commercial buildings in the U.S. can provide about 70% of the current national regulation reserve requirements in the aforementioned frequency band. A unique advantage of the proposed control scheme is that assessing the value of the ancillary service provided is trivial, which is in stark contrast to many demand-response programs.
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paper_title: Decentralized Vehicle-to-Grid Control for Primary Frequency Regulation Considering Charging Demands

paper_content:

Vehicle-to-grid (V2G) control has the potential to provide frequency regulation service for power system operation from electric vehicles (EVs). In this paper, a decentralized V2G control (DVC) method is proposed for EVs to participate in primary frequency control considering charging demands from EV customers. When an EV customer wants to maintain the residual state of charge (SOC) of the EV battery, a V2G control strategy, called battery SOC holder (BSH), is performed to maintain the battery energy around the residual SOC along with adaptive frequency droop control. If the residual battery energy is not enough for next trip, the customer needs to charge the EV to higher SOC level. Then, a smart charging method, called charging with frequency regulation (CFR), is developed to achieve scheduled charging and provide frequency regulation at the same time. Simulations on a two-area interconnected power system with wind power integration have shown the effectiveness of the proposed method.
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paper_title: Smart Grid Communications: Overview of Research Challenges, Solutions, and Standardization Activities

paper_content:

Optimization of energy consumption in future intelligent energy networks (or Smart Grids) will be based on grid-integrated near-real-time communications between various grid elements in generation, transmission, distribution and loads. This paper discusses some of the challenges and opportunities of communications research in the areas of smart grid and smart metering. In particular, we focus on some of the key communications challenges for realizing interoperable and future-proof smart grid/metering networks, smart grid security and privacy, and how some of the existing networking technologies can be applied to energy management. Finally, we also discuss the coordinated standardization efforts in Europe to harmonize communications standards and protocols.
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paper_title: Demand side management: Benefits and challenges ☆

paper_content:

In this paper, the major benefits and challenges of electricity demand side management (DSM) are discussed in the context of the UK electricity system. The relatively low utilisation of generation and networks (of about 50%) means that there is significant scope for DSM to contribute to increasing the efficiency of the system investment. The importance of the diversity of electricity load is discussed and the negative effects of DSM on load diversity illustrated. Ageing assets, the growth in renewable and other low-carbon generation technologies and advances in information and communication technologies are identified as major additional drivers that could lead to wider applications of DSM in the medium term. Potential benefits of DSM are discussed in the context of generation and of transmission and distribution networks. The provision of back-up capacity by generation may not be efficient as it will be needed relatively infrequently, and DSM may be better placed to support security. We also present an analysis of the value of DSM in balancing generation and demand in a future UK electricity system with significant variable renewable generation. We give a number of reasons for the relatively slow uptake of DSM, particularly in the residential, commercial and small business sectors. They include a lack of metering, information and communication infrastructure, lack of understanding of the benefits of DSM, problems with the competitiveness of DSM when compared with traditional approaches, an increase in the complexity of system operation and inappropriate market incentives.
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paper_title: Vehicle-to-Grid Control for Supplementary Frequency Regulation Considering Charging Demands

paper_content:

Electric vehicles (EVs) as distributed storage devices have the potential to provide frequency regulation services due to the fast adjustment of charging/discharging power. In our previous research, decentralized vehicle-to-grid (V2G) control methods for EVs were proposed to participate in primary frequency control. In this paper, our attention is on bringing a large number of EVs into the centralized supplementary frequency regulation (SFR) of interconnected power systems. An aggregator is the coordinator between EVs and the power system control center. The aggregator calculates the total frequency regulation capacity (FRC) and expected V2G (EV2G) power of EVs based on the data communicated between the aggregator and individual EVs or EV charging stations. With FRC and EV2G power, a V2G control strategy is proposed for the aggregator to dispatch regulation requirements to EVs and EV charging stations. In individual EV charging stations, the FRC is calculated on the basis of the V2G power at present time, and EV2G power is presented considering both frequency regulation and charging demands. Besides, V2G control strategies are developed to distribute regulation requirements to each EV. Simulations on an interconnected power grid based on a practical power grid in China have demonstrated the effectiveness of the proposed strategies.
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paper_title: Benefits and challenges of electrical demand response: A critical review

paper_content:

Advances in IT, control and forecasting capabilities have made demand response a viable, and potentially attractive, option to increase power system flexibility. This paper presents a critical review of the literature in the field of demand response, providing an overview of the benefits and challenges of demand response. These benefits include the ability to balance fluctuations in renewable generation and consequently facilitate higher penetrations of renewable resources on the power system, an increase in economic efficiency through the implementation of real-time pricing, and a reduction in generation capacity requirements. Nevertheless, demand response is not without its challenges. The key challenges for demand response centre around establishing reliable control strategies and market frameworks so that the demand response resource can be used optimally. One of the greatest challenges for demand response is the lack of experience, and the consequent need to employ extensive assumptions when modelling and evaluating this resource. This paper concludes with an examination of these assumptions, which range from assuming a fixed linear price–demand relationship for price responsive demand, to modelling the highly diverse, distributed and uncertain demand response resource as a single, centralised negative generator, adopting fixed characteristics and constraints.
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paper_title: Approximate Inference in Additive Factorial HMMs with Application to Energy Disaggregation

paper_content:

This paper considers additive factorial hidden Markov models, an extension to HMMs where the state factors into multiple independent chains, and the output is an additive function of all the hidden states. Although such models are very powerful, accurate inference is unfortunately difficult: exact inference is not computationally tractable, and existing approximate inference techniques are highly susceptible to local optima. In this paper we propose an alternative inference method for such models, which exploits their additive structure by 1) looking at the observed difference signal of the observation, 2) incorporating a “robust” mixture component that can account for unmodeled observations, and 3) constraining the posterior to allow at most one hidden state to change at a time. Combining these elements we develop a convex formulation of approximate inference that is computationally efficient, has no issues of local optima, and which performs much better than existing approaches in practice. The method is motivated by the problem of energy disaggregation, the task of taking a whole home electricity signal and decomposing it into its component appliances; applied to this task, our algorithm achieves state-of-the-art performance, and is able to separate many appliances almost perfectly using just the total aggregate signal.
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paper_title: Residential demand response behavior analysis based on Monte Carlo simulation: The case of Yinchuan in China

paper_content:

Demand response to time-varying pricing of electricity is critical to a smart grid's efficient management of electrical resources. This paper presents a new approach to quantify residential demand responsiveness to (time-of-use) TOU rates, which does not entail an econometric estimation of TOU demand equations. Based on one of the four smart grid pilots in China, our approach uses the survey data collected in 2011 from 236 residents in Yinchuan to implement a Monte Carlo simulation to obtain the minimum, expected and maximum demand responsiveness to four TOU rate designs. We find that residents do not respond to TOU pricing when the TOU rate design only causes a 10% increase in their existing electricity bills under non-TOU rates. However, their estimated peak demand responsiveness is 8.41% (21.26%) when the peak-time price increases by 20% (40%). Based on these findings, we conclude that suitably designed TOU rates are useful to the efficient operation of a smart grid.
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Title: Demand Response and Smart Buildings: A Survey of Control, Communication, and Cyber-Physical Security

Section 1: INTRODUCTION
Description 1: Discuss the evolving grid architecture, renewable generation integration, and the critical need for effective demand response and smart buildings from both the power system and consumer perspectives.

Section 2: SMART LOADS AND POWER ARCHITECTURE
Description 2: Describe the roles of energy storage resources, load models, HVAC systems, and the integration of renewable energy sources in smart buildings.

Section 3: Thermal Dynamics Control Within a Building
Description 3: Address HVAC systems and building thermal dynamics controlled through device-specific and supervisory control strategies to provide ancillary services.

Section 4: Electric Dynamics Control Within a Building
Description 4: Explore hybrid centralized and decentralized control strategies, droop control methods, and hierarchical control architecture for building microgrids.

Section 5: Human-in-the-Loop Control
Description 5: Examine occupant-centered HVAC system control, occupants' real-time participation in energy management, and challenges in human-in-the-loop control.

Section 6: Distributed Coordination Among Buildings
Description 6: Discuss the coordination of multiple buildings for demand-side management and the use of consensus-based algorithms for distributed control.

Section 7: Communication Technologies
Description 7: Review various communication technologies such as Wi-Fi, Cellular Communications, Powerline Communications, and Digital Subscriber Lines for smart building implementation.

Section 8: Communication Network Architecture
Description 8: Describe the hierarchical communication network architecture, including Home Area Networks (HAN), Neighborhood Area Networks (NAN), and Wide-Area Networks (WAN).

Section 9: CYBER-PHYSICAL SECURITY
Description 9: Identify cyber-physical security challenges in demand response and smart buildings, including enhancing security at both cyber and physical layers.

Section 10: Enhancing Cyber Layer Security
Description 10: Discuss specific cybersecurity mechanisms to protect smart buildings, such as trusted system architectures, access control models, secure communications, and privacy measures.

Section 11: Enhancing Physical Layer Security
Description 11: Explore fault-tolerant capabilities, plug-and-play features, and enhancements to building-level control architecture for security against physical threats.

Section 12: BENEFITS, COSTS, AND CHALLENGES
Description 12: Summarize the benefits, costs, and implementation challenges of demand response and smart buildings, including distributed transactive control, communication networks, data analytics, and predicting end-user behaviors.

Section 13: United States
Description 13: Provide an overview of demand response adoption and programs in the United States, including statistics on AMI penetration and peak reduction potential.