The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this article, we survey the literature till 2011 on the enabling technologies for the Smart Grid. We explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system. We also propose possible future directions in each system. colorred{Specifically, for the smart infrastructure system, we explore the smart energy subsystem, the smart information subsystem, and the smart communication subsystem.} For the smart management system, we explore various management objectives, such as improving energy efficiency, profiling demand, maximizing utility, reducing cost, and controlling emission. We also explore various management methods to achieve these objectives. For the smart protection system, we explore various failure protection mechanisms which improve the reliability of the Smart Grid, and explore the security and privacy issues in the Smart Grid.

/pdf/smart-grid-the-new-and-improved-power-grid-a-survey-4jypbbgv3j.pdf

Smart Grid — The New and Improved Power Grid: A Survey

Smart Grid - The New and Improved Power Grid:

This paper presents a conceptual framework to successfully integrate electric vehicles into electric power systems. The proposed framework covers two different domains: the grid technical operation and the electricity markets environment. All the players involved in both these processes, as well as their activities, are described in detail. Additionally, several simulations are presented in order to illustrate the potential impacts/benefits arising from the electric vehicles grid integration under the referred framework, comprising steady-state and dynamic behavior analysis.

/pdf/integration-of-electric-vehicles-in-the-electric-power-t2rcksyr69.pdf

Integration of Electric Vehicles in the Electric Power System

As the number of plug-in hybrid vehicles (PHEVs) increases, so might the impacts on the power system performance, such as overloading, reduced efficiency, power quality, and voltage regulation particularly at the distribution level. Coordinated charging of PHEVs is a possible solution to these problems. In this work, the relationship between feeder losses, load factor, and load variance is explored in the context of coordinated PHEV charging. From these relationships, three optimal charging algorithms are developed which minimize the impacts of PHEV charging on the connected distribution system. The application of the algorithms to two test systems verifies these relationships approximately hold independent of system topology. They also show the additional benefits of reduced computation time and problem convexity when using load factor or load variance as the objective function rather than system losses. This is important for real-time dispatching of PHEVs.

Coordinated Charging of Plug-In Hybrid Electric Vehicles to Minimize Distribution System Losses

We propose a decentralized algorithm to optimally schedule electric vehicle (EV) charging. The algorithm exploits the elasticity of electric vehicle loads to fill the valleys in electric load profiles. We first formulate the EV charging scheduling problem as an optimal control problem, whose objective is to impose a generalized notion of valley-filling, and study properties of optimal charging profiles. We then give a decentralized algorithm to iteratively solve the optimal control problem. In each iteration, EVs update their charging profiles according to the control signal broadcast by the utility company, and the utility company alters the control signal to guide their updates. The algorithm converges to optimal charging profiles (that are as “flat” as they can possibly be) irrespective of the specifications (e.g., maximum charging rate and deadline) of EVs, even if EVs do not necessarily update their charging profiles in every iteration, and use potentially outdated control signal when they update. Moreover, the algorithm only requires each EV solving its local problem, hence its implementation requires low computation capability. We also extend the algorithm to track a given load profile and to real-time implementation.

/pdf/optimal-decentralized-protocol-for-electric-vehicle-charging-3fb91gvn7z.pdf

Optimal decentralized protocol for electric vehicle charging

This paper presents investigations into various aspects of how plug-in hybrid electric vehicles (PHEVs) could impact the electric power system. The investigation is focused on impacts on the power system infrastructure and impacts on the primary fuel utilizations due to PHEV charging. The investigation is presented in terms of examples of typical systems. Methodologies are presented for computing loss of life of distribution transformers, which sets the basis for needed expansion or upgrades of systems with PHEV penetration. In addition, a methodology is presented for evaluating the impact on primary fuel source utilization considering all the operating constraints of an electric power system. Examples of fuel utilization impact are presented for various levels of PHEV penetration. In general, PHEVs cause a shift of fuel utilization from petroleum to less expensive fuels utilized by electric power utilities.

/pdf/power-system-level-impacts-of-phevs-1x47ds93cb.pdf

Power System Level Impacts of PHEVs

This paper presents an investigation into an aspect of how plug-in hybrid electric vehicles (PHEVs) could impact the electric power system The investigation is focused on the impact of the additional electrical load PHEV charging will have on primary energy source utilization and subsequent environmental air pollution (EAP) as emissions are transferred from vehicle tailpipes to powerplants A methodology is presented for evaluating the impact on primary energy source utilization, considering all the operating constraints of an electric power system, as well as, the realistic operation of PHEVs Examples of energy source utilization impacts are presented for various levels of PHEV penetration on a specific power system In general, PHEVs cause a shift of fuel utilization from gasoline to, a more diversified fuel source, utilized by electric power utilities The results are particularly sensitive to the generation mix of the specific power system simulated

Power System Level Impacts of Plug-In Hybrid Electric Vehicles Using Simulation Data

A residential energy management system (REMS) is an amalgamation of hardware and software that performs monitoring, planning, and control functions of the energy utilization within a residence. The REMS system is designed to provide desirable demand response (DR) to price or system condition utility signals. This paper presents simulated results of a proposed REMS system to provide automated DR. The simulation test bed is structured as a discrete event simulation of a single household for a full day. Four scenarios with varying levels of automation are compared. The application of the proposed REMS results in reduced average power and energy use during the DR service time. These services are achieved by delaying the use of controllable electric appliances (clothes dryer, clothes washer, dishwasher, and plug-in electric vehicle) prior to and during the DR service time. Finally, simple payback time computations for the considered scenarios are presented.

Simulated demand response of a residential energy management system

This paper presents an investigation into the impact that plug-in hybrid electric vehicles (PHEVs) could have to mitigate the effects of fault-delayed voltage recovery. The energy storage and conversion system in PHEVs, given potentially high levels of future market penetration, represent a sizable dispersed energy storage resource or reactive power source that electric utilities could leverage to their benefit. In this investigation the impact of PHEVs utilized as reactive power resources on fault delayed voltage recovery on distribution systems is analyzed. It is known that fault delayed voltage recovery can cause serious problems on distribution circuits resulting in stalled air-conditioners, motor tripping and other load disruption events. The impact of these phenomena on the performance of distribution systems is documented with and without PHEVs present.

/pdf/fault-delayed-voltage-recovery-control-with-plug-in-hybrid-4qf5b3eoou.pdf

Curtis Roe

Papers

Power System Level Impacts of PHEVs

Power System Level Impacts of Plug-In Hybrid Electric Vehicles Using Simulation Data

Simulated demand response of a residential energy management system

Fault-Delayed Voltage Recovery Control with Plug-In Hybrid Electric Vehicles