V2G Networks Research Articles

Influence of electric vehicle distributed energy storage access on safety and stability of distribution network

This paper proposes a distributed energy storage control strategy for electric vehicles to improve the security and stability of distribution network when electric vehicles are connected. Firstly, the load characteristics of electric vehicles are investigated, and the optimal power flow model including energy storage power station, electric vehicle charging station considering V2G and distribution network is established. The objective function is established to minimize network loss, voltage deviation and load peak to peak. The problem is transformed into a mixed integer second-order cone optimization problem for solution, and based on the analysis of distributed energy storage model and constraints, the distributed energy storage control strategy of electric vehicle is established. Through the solution analysis in IEEE33 node system, it can be concluded that using this strategy can improve the power quality of distribution network and effectively improve the security and stability of distribution network.

Intimacy and Influence Based Scheduling Algorithm for Vehicle-to-Grid Network

The increasing number of Electric Vehicles (EVs) makes vehicle communication and vehicle charging linked together to form a part of the intelligent transportation system, which promotes the development of Vehicle-to-Grid (V2G) and Vehicular Ad Hoc Network (VANET). At the same time, the charging behavior of electric vehicles affects the energy distribution and storage of each charging pile. Scheduling technology plays an important role in the field of power and communication. The charging behavior is closely related to vehicle communication and will eventually affect vehicle scheduling. Therefore, analyzing the relationship between user charging and user communication is the basis of vehicle scheduling. In order to solve the problem, Intimacy and Influence based Connected Dominating Set Scheduling Algorithm (IICDSA) is proposed in this paper to adjust the charging behavior of users to realize vehicle scheduling: Firstly, V2G network model is constructed to describe the vehicle communication network, and then, Intimacy Measurement algorithm based on Relationship of Attribute (IMRA) is designed to analyze the relationship between users; secondly, Influence Walk algorithm based on the Intimacy between Users (IWIU) is designed to measure the user influence; at last, Connected Dominated Set Scheduling algorithm based on user Influence and user Location (CDSSIL) is designed to schedule users in groups. Furthermore, the simulation results show that the algorithm reduces the system scheduling cost and improves the utilization of charging pile.

A comprehensive survey on security issues in vehicle-to-grid networks

Vehicle to grid (V2G) is the most hopeful approach to transfer energy as well as information in the bidirectional way. V2G network is formed by electric vehicles which connect with smart metres for information and energy transfer in a wireless manner. Even though many security preserving schemes developed in V2G networks, they were prone to enormous number of security breaches. A countless deal of works has been done towards it, but security mechanisms in V2G networks are not effective. This survey work provides a summary about the V2G network characteristics, significance, security services and the security challenges. Moreover, this work offers a summary of some foremost security attacks on various security services such as accessibility, confidentiality, authentication, integrity and non-repudiation and the related countermeasures to make the V2G communications more protected.

An Efficient Blockchain-Based Authentication Scheme for Energy-Trading in V2G Networks

Vehicle-to-grid (V2G) networks have been emerged as a new technology in the smart grid (SG). These networks allow a two-way flow of energy-trading between electric vehicles (EVs) and charging stations (CSs) in the SG. EVs are regarded as one of the most effective tools to reduce energy demands. It will bring a great impact on our society and human life. Thus, during energy trading between EVs and CSs, various security, and privacy challenges occur in V2G networks. Although several proposals have been proposed, still there are many issues like lack of integrity, mutual authentication, and identity privacy-preservation make the system more vulnerable. Researchers have used the centralized system in V2G networks which may act as a single point of failure. So, for deploying secure V2G networks in the SG, we propose an energy-trading scheme having blockchain between three communicating parties, i.e., EVs, CSs, utility center. The proposed system is divided into three phases, first, the registration process provides identity privacy-preservation to the EVs and CSs, second, the searching process makes the registration and key-generation steps faster, and third, the authentication process provides mutual authentication between them and a blockchain network is used to execute transactions using Merkle Root Hash. The security analysis result shows that the proposed scheme is secure for energy-trading in V2G networks. The performance evaluation results illustrate that our scheme has less communication cost and computation time as compared to the existing proposals.

Vehicle-to-Grid (V2G) as line-side energy storage for support of DC-powered electric railway systems

Two predominant areas of ongoing transport electrification are the uptake of electric vehicles (EVs) in personal transportation and electrically powered trains for mass transportation - both significantly increase demand stresses on the electric power grid. In this research, a novel V2G application to support electrically powered rail transport is proposed. A local V2G network can reduce peak demand stresses on the power grid arising from electrified rail traffic and enable brake energy recovery from DC-powered electric trains. A case study examining an existing third-rail DC-powered rail system in England supported by a simulated population of aggregated parked EVs is presented. Simulation results for 24 h of V2G supported rail traffic from the view of a single train station with nearby V2G enabled car park are discussed. Therein the EV population size, charging rate limits per EV and the overall power made available from the power grid are variables. The V2G network's ability to absorb power from regenerative braking on the rail system was found to be more sensitive to changes in EV charging rates than its ability to provide traction power. In particular, careful power management is required to avoid charging EVs ‘too quickly’ during periods without rail traffic.

PADP: Efficient Privacy-Preserving Data Aggregation and Dynamic Pricing for Vehicle-to-Grid Networks

With the fast development of Internet of Things (IoT) especially for smart grid and electric vehicle (EV) networking, vehicle-to-grid (V2G) communications have been increasingly studied and recognized as one of the most convincing tools for general road transportation, to effectively reduce the oil demands and gas emissions. Unfortunately, a series of security and privacy issues have significantly impeded its wide adoption. The existing work mainly focused on the static environment, which cannot be directly applied to the mobile setting where EVs travel across regions. The dynamic pricing metric in V2G networks depends on the real-time electricity usage aggregation in one region. To address this issue, in this article, an efficient privacy-preserving data aggregation and dynamic pricing service PADP in V2G IoT is proposed, by designing an identity-based sequential aggregate signed data (SASD) based on factoring and a threshold homomorphic encryption. In the proposed threshold homomorphic encryption, a legal ciphertext can be generated if and only if no less than threshold k individual illegal ciphertexts are aggregated. Therefore, the aggregated power consumption data can be successfully decrypted while the individual power consumption privacy of honest EV users can be well protected against even the collusion between a malicious power charging station and compromised EVs. Furthermore, the technique of SASD guarantees entity authentication with a minimized amount of transmitted data. Finally, formal security proof and extensive performance evaluation demonstrate the effectiveness and practicability of our proposed PADP.

Certificateless Privacy Protection Scheme based on Fog Computing in V2G Network

With large-scale electric vehicles connected to the power grid, the security and operating efficiency of V2G networks are facing severe challenges. Aiming at the shortcomings of the existing V2G privacy protection schemes, this study proposes a certificateless privacy protection scheme based on fog computing in V2G network. This scheme applies the elliptic curve certificateless public key signcryption algorithm to the V2G network, avoiding the bilinear pairing operation. At the same time, we introduce the fog calculation model into the charging and discharging data transmission process to design a new V2G network architecture, and used data aggregation technology, which can effectively improve the calculation efficiency. This study compares the security and computational overhead with other existing V2G privacy protection scheme. Compared with other schemes, the security and computational efficiency of the scheme proposed in this article are better.

Differential privacy EV charging data release based on variable window.

In the V2G network, the release and sharing of real-time data are of great value for data mining. However, publishing these data directly to service providers may reveal the privacy of users. Therefore, it is necessary that the data release model with a privacy protection mechanism protects user privacy in the case of data utility. In this paper, we propose a privacy protection mechanism based on differential privacy to protect the release of data in V2G networks. To improve the utility of the data, we define a variable sliding window, which can dynamically and adaptively adjust the size according to the data. Besides, to allocate the privacy budget reasonably in the variable window, we consider the sampling interval and the proportion of the window. Through experimental analysis on real data sets, and comparison with two representative w event privacy protection methods, we prove that the method in this paper is superior to the existing schemes and improves the utility of the data.

Effective charging identity authentication scheme based on fog computing in V2G networks

Vehicle to Grid (V2G) networks are facing many security problems, such as privacy protection and identity authentication for electric vehicle (EV) users. To solve these problems of identity authentication in V2G networks, we propose a charging identity authentication scheme based on fog computing in this paper. In our proposed scheme, when each EV user finished his registration, all related servers must authenticate the users’ identities; also, when an EV user needs to start charging, the related fog server must authenticate his identity and save the related electricity information after charging. Further, the electricity server (ES) can periodically audit the electricity consumption from the fog servers in our scheme. Based on fog computing, the efficiency of our proposed V2G network charging scheme is improved by reducing the number of interactions between EV users and cloud servers. Also, we analyze the security of our proposed scheme, where our proposed scheme can use group signatures to protect the privacy of EV users. The experimental results show that our proposed scheme is effective and efficient.

Privacy Protection Strategy of Vehicle-to-Grid Network Based on Consortium Blockchain and Attribute-based Signature

V2G(vehicle-to-grid) is an integral part of the smart grid. To deploy a V2G network on a large scale, it is necessary to solve network security and trustworthiness and privacy protection of electric vehicle users (EV). Therefore, this paper proposes a privacy protection strategy for V2G networks based on consortium blockchain and attribute-based signature and designs an overall implementation scheme including system initialization, EV registration, anonymous authentication, optimized scheduling, local services, block construction and consensus mechanism. The strategy also uses the K-anonymity to protect the privacy of the EV’s geographic location, making it well compatible with charging and discharging services. Finally, security and performance analysis proved the feasibility of design scheme.

A Secure and Decentralized Blockchain Based EV Energy Trading Model Using Smart Contract in V2G Network

In this work, a secure and decentralized Blockchain based energy trading model for electric vehicles (EVs) using Smart contract that achieves Peer-to-Peer (P2P) transactions between EVs in Vehicle to Grid networks is designed. The traditional energy trading model is a centralized structure based on trusted third parties, and there may an issue of single-point failure and leakage of privacy. In this way, a blockchain-based framework offers a secure, efficient and transparent trading model. Initially, the participating EVs and aggregator in the trading process should register at the trusted authority. Once the registration is successfully completed, both EVs and aggregator authenticate each other mutually in an anonymous manner. Moreover, only authorized EVs (charging and discharging EVs) participate in the contrary auction mechanism to exchange power/money based on their demand. Simulation conducted for the proposed scheme shows that our scheme has high speed (i.e., less computational time and execution time) which improves the market efficiency. In-addition, the transactions are non tamperable, when compared to the conventional scheme.

Efficient privacy-preserving authentication for V2G networks

Vehicle-to-grid (V2G) networks, as a crucial subsystem of smart grid, can potentially help the grid to improve stability, save generation cost and reduce energy consumption. However, how to ensure the security and privacy of V2G networks, especially to realize secure communication between electric vehicles (EVs) and the grid, is extremely challenging. In order to overcome the challenge, we design an efficient privacy-preserving authentication scheme for V2G networks. In the proposed scheme, EV can securely access services provided by smart grid using an authenticated key agreement protocol established between them, which can support mutual authentication and generate a secure common session key for further communication. Security analysis and performance evaluation show that the proposed scheme not only protects the privacy of EV, but also reduces the computation cost of charging station and EV. Experimental results demonstrate that our scheme is fit for the application of V2G networks.

Resource Efficient Vehicle-to-Grid (V2G) Communication Systems for Electric Vehicle Enabled Microgrids

Intelligent vehicular communication is fundamental to manage vehicle-to-grid (V2G) interaction, where electric vehicles (EVs) provide energy to balance demand of critical loads (CLs). We propose resource efficiency (RE) to exploit the tradeoff between spectral efficiency (SE) and cost efficiency (CE) of EVs in a V2G communication network. The CE is the data rate of the V2G channel between EVs and base station (BS) over the operating cost of EVs to supply energy to CLs. We consider maximizing the RE in the downlink of a V2G communication network, where EVs are served by a BS and associated with CLs, while satisfying energy demand and charging station constraints. As the proposed RE problem is inherently non-convex and known to be NP-hard, we develop a suboptimal scheme based on a two-phase algorithm. Phase 1 derives optimum EV-CL association using a heuristic approach, while phase 2 finds optimum power allocation using geometric programming. We then derive upper and lower bounds to the optimal RE as a benchmark to study the performance gap of the suboptimal scheme. Simulation results demonstrate that the proposed suboptimal scheme is close to the optimal solution, while its complexity is relatively low, making it promising for V2G applications.

A Lightweight Authentication Scheme for V2G Communications: A PUF-Based Approach Ensuring Cyber/Physical Security and Identity/Location Privacy

Vehicle-to-grid (V2G) technology has become a promising concept for the near future smart grid eco-system. V2G improves smart grid resiliency by enabling two-way communication and electricity flows while reducing the greenhouse gases emission. V2G practicality and stability is strongly based on the exchanged data between electrical vehicles (EVs) and the grid server (GS). However, using communication protocols to exchange vital information leads grid to being vulnerable against various types of attack. To prevent the well-known attacks in V2G network, this paper proposes a privacy-aware authentication scheme that ensures data integrity, confidentiality, users’ identity and location privacy, mutual authentication, and physical security based on physical unclonable function (PUF). Furthermore, the performance analysis shows that the proposed scheme outperforms the state-of-the-art, since EVs only use lightweight cryptographic primitives for every protocol execution.

Impact of V2G Communication on Grid Node Voltage at Charging Station in a Smart Grid Scenario

This article discusses the impact of realistic communication systems on charging stations at multiple nodes of the subfeeder in an electricity grid distribution system. A vehicle to grid (V2G) system is modeled in this article comprising of the electricity grid, aggregators, controllers, charging station, electric vehicles, and communication channels. Fuzzy logic controllers are at two levels; one at the distribution level and the other at the charging station level. Two types of communication channels are considered between the entities of the V2G network with charging stations at multiple nodes of the electricity grid. The basic access method of the IEEE 802.11 MAC protocol using the distributed coordination function is used by electric vehicles to transmit their data packets to a charging station aggregator. An in-depth analysis of the system is carried out using MATLAB/Simulink environment by varying the bit error rate, timeout required to send a packet in the WiFi channel for multiple retransmissions, and the number of electric vehicles on the distribution grid node voltage. Root-mean-square error of node voltage is calculated for different values of the mentioned parameters to propose a real-time V2G infrastructure with an integrated communication system.

Robust session key generation protocol for social internet of vehicles with enhanced security provision

Social internet of things (SIoT) is an emerging concept that enables the autonomous interactions between social networks and internet of things (IoT). Vehicle-to-grid (V2G) networks are one of the instances of the SIoT. To mitigate privacy and security issues exist in the V2G networks, it is crucial to employ proper security solutions. One of the most important and popular security solutions is the key exchange protocol. During the last decade, several key exchange schemes have been proposed considering the specific requirements of V2G networks. However, the existing schemes have not reached a proper balance between security and efficiency. Therefore, in this paper, after the security assessment of a recent work, we propose a key exchange protocol, which can provide the desired performance and security properties. Rigorous formal security analyses besides the security features, communication overhead, and computational complexity comparisons indicate that the proposed scheme is a robust one to be employed in the V2G networks. To be more specific, in comparison to one of the most secure schemes, the proposed protocol has 84% improvement in execution time and 54% improvement in communication overhead. Furthermore, experiments on realistic platform indicate that the proposed protocol only takes 3 s to be executed by the computationally constrained onboard unit of electric vehicle.

A Blockchain-Based Framework for Lightweight Data Sharing and Energy Trading in V2G Network

The Vehicle-to-Grid (V2G) network is, where the battery-powered vehicles provide energy to the power grid, is highly emerging. A robust, scalable, and cost-optimal mechanism that can support the increasing number of transactions in a V2G network is required. Existing studies use traditional blockchain as to achieve this requirement. Blockchain-enabled V2G networks require a high computation power and are not suitable for micro-transactions due to the mining reward being higher than the transaction value itself. Moreover, the transaction throughput in the generic blockchain is too low to support the increasing number of frequent transactions in V2G networks. To address these challenges, in this paper, a lightweight blockchain-based protocol called Directed Acyclic Graph-based V2G network (DV2G) is proposed. Here blockchain refers to any Distributed Ledger Technology (DLT) and not just the bitcoin chain of blocks. A tangle data structure is used to record the transactions in the network in a secure and scalable manner. A game theory model is used to perform negotiation between the grid and vehicles at an optimized cost. The proposed model does not require the heavy computation associated to the addition of the transactions to the data structure and does not require any fees to post the transaction. The proposed model is shown to be highly scalable and supports the micro-transactions required in V2G networks.

Multi-Layer Event-Based Vehicle-to-Grid (V2G) Scheduling With Short Term Predictive Capability Within a Modular Aggregator Control Structure

In this work, a novel method of event-based V2G scheduling is devised that is suitable for dynamic real time aggregator control in large scale V2G applications within centrally controlled EV car parks. The method is applicable in deterministic systems where a V2G network provides or receives electricity in reoccurring and predictable patterns (events). The scheduling strategy shown is based on a robust modular high-level aggregator control structure and a proposed communications and data management system. The scheduling consists of three algorithm layers, differentiating between predictive scheduling for in-event periods, smart charging for out-of-event periods and reactive scheduling for ongoing adjustments in real-time to account for uncertainty. The scheduling process is described in terms of its underlying rules for prioritising EVs to be either charged or discharged. It's behaviour is then analysed using a simulated car park of up to one thousand connected EVs for an example application in which a V2G network is used to support nearby electrified rail infrastructure, providing power for train acceleration and accepting power from regenerative braking. The departure or arrival of a train of known type and speed pattern can be regarded as a reoccurring event and its effect on the V2G network is therefore predictable due to train schedules and tracking.

Integration of electric vehicle user charging preferences into Vehicle-to-Grid aggregator controls

Vehicle-to-Grid (V2G) describes the concept of using the battery packs of parked electric vehicles (EVs) as distributed battery energy storage to support the power grid. The bi-directional power flow in a V2G network is managed by a so-called aggregator which has to consider the needs of both the power grid and connected EVs. ‘Range anxiety’ is a major factor holding back the EV market as many drivers consider range limitations as a major disadvantage of EVs over more traditional vehicles with internal combustion engines. Implementing V2G could potentially worsen this perception as connected EVs could actually lose charge over short periods when providing grid services. Enabling EV owners/users to state charging preferences via simple user interfaces might increase the acceptance of V2G and reduce range anxiety.The inclusion of user charging preferences puts further constraints on an aggregator and complicates charge/discharge scheduling. Taking such preferences into account and weighting them against (potentially conflicting) needs of the power grid is a major challenge for V2G scheduling and adds computational costs through increased complexity. However, depending on its application, the responsiveness of a V2G network is crucial and the scheduling process is hence time-sensitive. In this research, a method of capturing user charging preferences and accounting for the resulting constraints is presented. The impact of added complexity on the execution time of the scheduling process is addressed by resolving user inputs prior to the actual scheduling. The ability of each EV to either charge or discharge is scored taking into account user inputs and the current state of the battery pack. This scoring system informs the selection of suitable EVs before the scheduling process.

Provably Secure Escrow-Less Chebyshev Chaotic Map-Based Key Agreement Protocol for Vehicle to Grid Connections With Privacy Protection

Security and privacy concerns necessitate the careful management of shared keys in the vehicle to grid (V2G) networks. To do so, in recent years, several interesting key agreement protocols have been proposed to be employed in the context of V2G networks. As the efficiency is of prime significance in V2G networks, many of these protocols have been designed to be as light as possible. Nevertheless, review of the previous works indicates that the existing lightweight schemes cannot provide the desired security properties. Furthermore, the existing secure protocols are not so proper to be used by computationally limited devices in the V2G networks. Therefore, in this article, by utilizing the efficient Chebyshev chaotic map-based public key cryptosystem, we propose an anonymous key agreement scheme, which can not only provide the expected security requirements, but also has a proper level of performance. To demonstrate the security of the proposed scheme, we present a rigorous formal security proof using the random oracle model. In addition, to show its outperformance, we both compare it with several recently published well-known schemes and perform the experimental study. In general, the results indicate the efficiency of the proposed protocol in comparison to the related ones.