The coordinated voltage control meets imperfect communication system.

High penetration of Distributed Generations (DGs) will have impact on the development of power systems. Due to the uncertainty of the DG output, it becomes extremely difficult to control the system voltage profile. This paper proposes a coordinated decentralized voltage control method, together with a self-excited inverter, that can control the voltage level by reactive power injection/absorption. The time-delay introduced by communications among DGs is considered to validate the proposed control approach. Simulation results show that the coodinated control approach is sensitive to the time-delay in a 33-bus medium-voltage distribution network (MVDN)

Energy Efficient Massive MIMO System Design for Smart Grid Communications

Communication technologies are critical in achieving potential advantages of smart gird (SG), as they enable electric utilities to interact with their devices and customers. This paper focuses on the integration of a massive multiple-input multiple-output (MIMO) technique into a SG communication architecture. Massive MIMO has the benefits of offering higher data rates, whereas operating a large number of antennas in practice could increase the system complexity and energy consumption. We propose to use antenna selection to preserve the gain provided by the large number of antennas, and investigate an energy efficient massive MIMO system design for SG communications. Specifically, we derive a closed-form asymptotic approximation to the system energy efficiency function in consideration of channel spatial correlation, which exhibits an excellent level of accuracy for a wide range of system dimensions in SG communication scenarios. Based on the accurate approximation, we propose a novel antenna selection scheme aiming at maximizing the system energy efficiency, using only the long-term channel statistics. Simulation results show that the proposed antenna selection scheme can always achieve an energy efficiency gain compared to other selection schemes or baseline systems without antenna selection, and thus is particularly valuable for enabling an energy efficient communication system of the SG

A survey on information and communications technology infrastructure for smart grids

Abstract: _Smart Grids (SGs) aim to improve the aging power system grid into a modernized grid with the utilization of the advanced communication technologies in the industry. The incorporation of communications technology in power systems enables two-way flow of electricity and information within the grid system. SGs emerge as the next generation technology in power systems, as a result of the increasing demand of upgrading the conventional grid into the more modernized grid, with the aim of resolving some of the major crisis such as the environmental and energy crisis posed by the existing grid. In order, to deploy this intelligent grid, a sustainable, energy efficient, flexible, scalable, and secure communication infrastructure need to be designed and implemented to address these issues. There are several surveys and studies on the Information and communication technologies (ICT) architectures to develop a suitable protocol of applying the proposed advanced and up-to-date communication and networking technologies into the power system, to enable the intelligence features of the grid system. This paper reviews the works on communications technologies on SGs, with the objective of addressing the issues related to ICT infrastructure, and the recent communication technologies with their corresponding communication requirements

A review of cognitive smart grid communication infrastructure system

Abstract: The reliance on obsolete communication infrastructure and outdated technologies, in order to meet increasing electricity demand, consists of major challenges confronting traditional power grids. Therefore, the concept of smart grids (SGs) has been adopted as an ideal solution. This concept entails the integration of advanced information and communication technologies (ICTs) into power grids, as well as allowing a two-way flow of communication. However, recent development in cognitive technologies internet of things (IoT) smart devices particularly in home area network (HAN) as well rapid growth in wireless applications have enabled the traffic of huge data volumes across SGs. Data gathered in SGs are distinguished by quality of service (QoS) requirements such as; latency, security, bandwidth, etc. In order to support the level of QoS requirements in SGs, stable and secure communication infrastructure is of great importance. Therefore an in-depth review of the stateof- the-art of existing and emerging communication architectures of SGs is conducted. Therefore, this work proposes communication architecture based on fifth-generation (5G) and cognitive radio networks (CRN)

CRB-RPL: A Receiver-based Routing Protocol for Communications in Cognitive Radio Enabled Smart Grid

As a tool of overcoming radio spectrum shortages in wireless communications, cognitive radio technology plays a vital role in future smart grid applications, particularly in Advanced Metering Infrastructure (AMI) networks with Quality of Service (QoS) requirements. This paper focuses on the investigation of the receiver-based routing protocol for enhancing QoS in cognitive radio-enabled AMI networks, due to their potentials of enhancing reliability and routing efficiency. In accordance with practical requirements of smart grid applications, a new routing protocol with two purposes is proposed: one is to address the realtime requirement while another protocol focuses on how to meet energy efficiency requirements. As a special feature of cognitive radio technology, the protocol have the mechanism of protecting primary (licensed) users whilst meeting the utility requirements of secondary (cognitive radio) users. System-level evaluation shows that the proposed routing protocol can achieve better performances compared with existing routing protocols for cognitive radio-enabled AMI networks

Relay aided smart meter to smart meter communication in a microgrid

In this paper, a new approach is considered for relay aided smart meter to smart meter communication in a microgrid. In the considered framework, a group of smart meters (SMs) simultaneously exchange pricing data with each other for selling or purchasing energy. At the same time, another group of SMs forward load demand and generation information tothe control centre as these are the most important states of microgrid for balancing power. The data exchange between SMs and from SM to control centre are aided by a multi-antenna wireless relay, which acts as the communication gateway for the SMs. For the considered system model, the error performance, a key indicator for the reliability of smart grid communication, is analytically derived at the SMs and at the control centre. The analysis indicates that the error performance at the controlcentre degrades if a large number of SMs communicate with the control centre simultaneously, while the error performance at the SMs does not degrade with increasing number of SMs exchanging data with each other. Finally, the analytically derived error performance is verified using numerical simulations

On the Design of Cognitive-Radio-Inspired Asymmetric Network Coding Transmissions in MIMO Systems

In this paper, a cognitive-radio-inspired asymmetric network coding (CR-AsNC) scheme is proposed for multiple-input-multiple-output (MIMO) cellular transmissions, where information exchange among users and base-station (BS) broadcasting can be accomplished simultaneously. The key idea is to apply the concept of cognitive radio (CR) in network coding transmissions, where the BS tries sending new information while helping users' transmissions as a relay. In particular, we design an asymmetric network coding method for information exchange between the BS and the users, although many existing works consider the design of network coding in symmetric scenarios. To approach the optimal performance, an iterative precoding design for CR-AsNC is first developed. Then, a channel-diagonalization-based precoding design with low complexity is proposed, to which power allocation can be optimized with a closed-form solution. The simulation results show that the proposed CR-AsNC scheme with precoding optimization can significantly improve system transmission performance

Internet of Things-aided Smart Grid: Technologies, Architectures, Applications, Prototypes, and Future Research Directions

Traditional power grids are being transformed into Smart Grids (SGs) to address the issues in existing power system due to uni-directional information flow, energy wastage, growing energy demand, reliability and security. SGs offer bi-directional energy flow between service providers and consumers, involving power generation, transmission, distribution and utilization systems. SGs employ various devices for the monitoring, analysis and control of the grid, deployed at power plants, distribution centers and in consumers' premises in a very large number. Hence, an SG requires connectivity, automation and the tracking of such devices. This is achieved with the help of Internet of Things (IoT). IoT helps SG systems to support various network functions throughout the generation, transmission, distribution and consumption of energy by incorporating IoT devices (such as sensors, actuators and smart meters), as well as by providing the connectivity, automation and tracking for such devices. In this paper, we provide a comprehensive survey on IoT-aided SG systems, which includes the existing architectures, applications and prototypes of IoT-aided SG systems. This survey also highlights the open issues, challenges and future research directions for IoT-aided SG systems

Cooperative Communications in Smart Grid Networks

The conventional grid system is facing great challenges due to the fast growing electricity demand throughout the world. The smart grid has emerged as the next generation of grid power systems, aimed at providing secure, reliable and low cost power generation, distribution and consumption intelligently. The smart grid communication system within the smart grid network is of fundamental importance to support data transfer and information exchange within the smart grid system. The National Institute of Standards and Technology has identified wireless communications as an important networking technology to be employed in power systems. The reliability of the data transmission is essential for the smart grid system to achieve high accuracy for the power generation, distribution and consumption. In this thesis, we investigate cooperative communications to improve transmission reliability in smart grid networks. Although many issues within cooperative communication have already been addressed, there is a lack of research efforts on cooperative communication for the wireless smart grid communication system which has its own network features and different transmission requirements. In our research, the smart grid communication networks were studied, and cooperative communications in smart grid networks were analysed. The research work mainly focuses on three problems: the application of cooperative relay communications to modern smart grid communication networks, the cooperative relay-based network development strategy, and the optimization of cooperative relay communication for smart grids. For the first problem, the application of cooperative relay communication to a home area network (HAN) of smart grid system is presented. The wireless transmission reliability is identified as the issue of most concern in wireless smart grid networks. We model the smart grid HAN as a wireless mesh network that deploys cooperative relay communication to enhance the transmission reliability. We apply cooperative relay communication to provide a user equipment selection scheme to effectively improve the transmission quality between the electricity equipment and the smart meter. For the second problem, we address the network design and planning problem in the smart grid HAN. The outage performance of direct transmission and cooperative transmission was analysed. Based on the reliability performance metric that we have defined, we propose a HAN deployment strategy to improve the reliability of the transmission links. The proposed HAN deployment strategy is tested in a home environment. The smart meter location optimization problem has also been identified and solved. The simulation results show that our proposed network deployment strategy can guarantee high reliability for smart grid communications in home area networks. For the third problem, the research focuses on the optimization of the cooperative relay transmission regarding the power allocation and relay selection in the neighbourhood area network (NAN) of the smart grid system. Owing to the complexity of the joint optimization problem, reduced-complexity algorithms have been proposed to minimize the transmission power, at the same time, guarantee the link reliability of the cooperative communications. The optimization problem of power allocation and relay selection is formulated and treated as a combinatorial optimization problem. Two sub-optimal solutions that simplify the optimization process are devised. Based on the solutions, two different algorithms are proposed to solve the optimization problem with reduced complexity. The simulation results demonstrate that both two algorithms have good performance on minimizing the total transmission power while guaranteeing the transmission reliability for the wireless smart grid communication system. In this thesis, we consider cooperative communications in a smart grid scenario. We minimize the outage probability and thus improve the reliability of the communications taking place in the smart grid by considering the optimization problem of power control, relay selection and the network deployment problem. Although similar problems might have been well investigated in conventional wireless networks, such as the cellular network, little research has been conducted in smart grid communications. We apply new optimization techniques and propose solutions for these optimization problems specifically tailored for smart grid communications. We demonstrate that, compared to naively applying the algorithms suitable for conventional communications to the smart gird scenario, our proposed algorithm significantly improves the performance of smart grid communications. Finally, we note that, in future work, it will be possible to consider more complex smart grid communications system models. For example, it is worthwhile considering hetregeneous smart communications by combining HAN and wide area networks (WAN). In addition, instead of assuming that all communications have the equal priority, as in this thesis, more comprehensive analysis of the priority of the smart grid communication can be applied to the research