Smart Grids and Their Communication Systems

The smart grid that is a new concept introduced at the beginning of the 2000s intends to include bidirectional communication infrastructure to conventional grids in order to enable information and communication technologies (ICTs) at any stage of generation, transmission, distribution, and even consumption sections of utility grids. This chapter introduces essential components and novel technologies of smart grids such as sensor networks, smart metering and monitoring systems, smart management systems, wired and wireless communication technologies, security requirements, and standards and regulations for this concept. First of all, this chapter focuses on the main components of smart grids such as smart sensors and sensor networks, phasor measurement unit (PMU), smart meters (SMs), and wireless sensor networks (WSNs). Then, smart grid applications and main requirements are explained on the basis of advanced metering infrastructure (AMI), demand response (DR), station and substation automation, and demand-side management (DSM). Later, communication systems of smart grid are presented in which the communication systems are classified into two groups as wired and wireless communication systems, and they are comprehensively analyzed. Furthermore, the area networks related to smart grid concept such as home area network (HAN), building area network (BAN), industrial area network (IAN), neighborhood area network (NAN), field area network (FAN), and wide-area network (WAN) are presented in a logical way beginning from generation systems to the user side.

The electricity delivery infrastructure—consisting of power plants, transmission lines, and distribution systems—is known as the power grid. The power grid in its present form is one of the most remarkable engineering developments. The grid infrastructure has played a critical role in making electric power reach the common people in a reliable and economic way. The National Academy of Science, USA, has ranked the power grid as the most beneficial engineering innovation of the twentieth century. Power grid is a complicated and highly meshed network. The complexity of the grid has been ever increasing with the increase in electricity demand. The high reliability and power quality requirement for the digital society are challenging. The smart grid is a power grid that uses real-time measurements, two-way communication, and computational intelligence. The smart grid is expected to be safe, secure, reliable, resilient, efficient, and sustainable. Measuring devices like phasor measurement units (PMUs) can radically change the monitoring way of the grids. However, there are several challenges like deployment of sufficient number of PMUs and managing the huge amount of data. Two-way communication is an essential requirement of the smart grid. A communication system that is secure, dedicated, and capable of handling the data traffic is required. The integration of renewable sources will alter the dynamics of the grid. This situation calls for better monitoring and control at the distribution level.

This chapter deals with novel technologies in terms of power electronics, power converters, information and communication technologies (ICTs), energy storage systems (ESSs), electric vehicles (EVs), and microgeneration systems in the context of smart grid applications. Although the smart grid was a concept defining ICT-enabled conventional grid at the beginning, it has now improved its own infrastructure with particularly tailored applications and technologies. During this improvement stage; researchers, engineers, and technology improving alliances have overcome many technical challenges. This chapter presents a number of innovative solutions enhanced against challenges met during improvement era. They have been introduced in terms of power electronics and power converters, integration of communication systems to power devices; improved microgrid, generation and transmission systems, the demand side management (DSM) policies, smart home management systems, ESSs and EVs. The surveyed device topologies and technologies are particularly selected in order to present a set of recent application in smart grid infrastructure. Therefore, widely known devices, systems, and methods that can be found in any regular textbook are not considered in this section.

In recent years, the electricity grid has experienced a significant transformation in the generation side, with an increasing use of energy sources (renewable) that have a more decentralized structure and unpredictable availability than conventional ones. Similarly, the expected penetration of electric vehicles would considerably change the consumption patterns. These new circumstances require an improved monitoring and control of the electricity grid assets, and smart metering is a key element to achieve both ends. While there are many communication technologies for smart metering applications, power line communications (PLCs) have proven to be a cost-effective solution in a large number of scenarios. Moreover, it provides distribution system operator (DSO) a proprietary communication network and innately integrates the sensing and communication functionalities. Consequently, it has become the predominant smart metering technology in the EU and China, among others. In the last decade, several industrial alliances and standardization bodies have developed a number of narrowband PLC (NB-PLC) systems particularly tailored for smart metering applications. They implement a relay network that connects the smart meters to the data concentrator located in the medium voltage to low voltage (MV/LV) transformer stations. The latter are connected to the management center using different technologies, among which broadband PLC (BB-PLC) has proven to be a suitable one. The bit rate of the resulting shared medium provided by NB-PLC ranges from tens to hundreds of kilobit/s, which currently suffices for reading the energy consumption of 100 smart meters in less than 15 min.

Frequency is one of the most significant parameters in the smart grid systems. Thus, accurate frequency estimation becomes an essential task for monitoring, controlling and protecting a real-time smart grid system. In this chapter, we present an overview of the frequency estimation methods in the smart grid system with a focus on real-time adaptive estimation algorithms. Primarily, in Sects. 5.1 and 5.2, the importance of the frequency estimation in the smart grid systems and the challenges encountered in its real-time applications are introduced in detail. In Sect. 5.3, a three-phase power system is then formulated as a two-phase system in the complex domain by using the well-known Clarke’s transformation so as to be able to estimate the frequency of the smart grid system in the real time. For this purpose, the adaptive real-time frequency estimation algorithms are comparatively presented as strictly and widely linear algorithms in Sect. 5.4. The strictly linear algorithms yield optimal solutions only under balanced three-phase systems, whereas the widely linear algorithms give a better solution under both balanced and unbalanced conditions due to the fact that they take into account all statistical information of the system. Considering smart grid applications in real time, the mentioned properties of these algorithms under both balanced and unbalanced conditions are proven in Sect. 5.5.

Demand-side management (DSM) and a market mechanism involving demand response (DR) receive significant attention. The DSM is an emerging initiative which is one of the key elements of restructured power systems. An objective of any DSM program could be peak load clipping instead of adding generation supply, by simply shifting timing from the peak load period to off-peak period. The DR seeks to adjust load demand instead of adjusting generation supply. Different types of load shaping objectives, such as peak clipping, valley filling, load shifting, produce the DR. A compensation for the DR is triggered by diverse policies, market mechanism and implementation models. The integration of DR resources in electric power system becomes worldwide due to advent of communication technologies and metering infrastructure. With the evolving restructured electricity market, aggregator as a mediator between market operator and end-user customers. This chapter discusses six major DSM aspects: (1) the DR resources, (2) possible DR program models, (3) enabler technology framework and policy, (4) role of DR exchange (DRX) market, (5) optimization algorithms used and (6) a few implementation issues like end-users engagement, privacy preservation, and DR rebounding. An optimization algorithm for specific DRX market structures and how the market participants interact is described in detail.

In recent years, a massive number of inverter-based distributed generations (DGs) and battery-based storage devices have been penetrated in domestic residential areas, and real-time pricing (RTP) schemes of electricity are adopted in many nations. In such context, the residents are able to deploy the domestic energy management system to provide an efficient energy dispatch in advance (e.g. one-day ahead) through appropriate control and scheduling of power loads and energy storage units based on the predicted system operational states. This chapter presents an algorithmic solution to investigate the potential economic benefits of improving matching between domestic DG generation and power loads with explicitly consideration of the real-time pricing information. The proposed energy dispatch solution is evaluated and validated using a set of operational scenarios through numerical simulations. The obtained experimental result clearly demonstrates that the domestic energy can be appropriately controlled to meet the required domestic demand with significantly improved resource utilization efficiency and reduced purchase cost. The robustness of the solution under inaccurate prediction information is also validated considering the presence of inaccurate prediction of RTP and DG generation.

The major goal of the power industry is to serve the demand of electricity consumers as reliable as possible but at an affordable cost. Toward the goal, however, the industry faces substantial barriers such as aging infrastructures, growing demand, and limited budgets for reinforcements. A great portion of infrastructures which were built decades ago need to be retired. The growing demand needs system reinforcement and expansion. These, in turn, require considerable amounts of investment which is in contradiction with highly limited budget of the power industry. This critical situation forces the industry to utilize the existing system more efficiently and wisely. To this end, the concept of smart grid has been recently proposed by the area researchers to enhance the performance of power systems. Smart grid refers to an electricity grid which is equipped with advanced technologies dedicated to managing the system in a sustainable, reliable, and economic manner. Smart grids have several aspects which have to be thoroughly investigated before their implementation in the real world. Demand response is one of the key integral parts of a smart grid. It refers to any voluntary change in electricity usage in response to signals from the grid operator. Demand response provides system operators with an opportunity to modify the normal consumption pattern when electricity procurement prices are higher, or service reliability is jeopardized. The focus of this chapter is on potential impacts of demand response on the operation of power systems. Although demand response may have significant impacts on generation and transmission levels, its impacts on the operation of distribution networks are studied here. This is due to the fact that distribution networks have captured the least attention and experienced the minimum advancements during the past decades, and thus, they are the appropriate place to be improved when efficiency enhancement is the objective. The first and foremost goal of this chapter is to quantify potential benefits of demand response to distribution network operation. To do so, brief definition of demand response is followed by explanations about different demand response programs. Then, demand response benefits are counted. Thereafter, a distribution network hosting several residential customers is utilized to quantify the benefits of demand response in the operation of distribution networks. Disaggregated load profiles associated with residential customers and their flexibility are employed to modify the total load profile. Then, by applying the modified load profile to the network, impacts of demand response on the network losses, voltage profiles, and loading levels are studied. It is demonstrated that even activating demand response potential of a portion of customers can lead to significant improvements in the parameters. Finally, demand response barriers and associated solutions are described.

The present-day power system is rapidly progressing in the fields of generation, transmission, and distribution of energy. Factors such as diverse and distributed nature of power consumption, increased use of the renewable energy that enables the consumer to also be an energy provider have exacerbated the complexity of the power grid. A glitch or a failure in one part of this complex network, unless espied and curtailed, can translate into a major power outage. This requirement has led to the inception of the smart grid. A smart grid consists of several intelligent sensors with advanced communication capabilities that collect, communicate, and monitor the real-time information pertaining to the grid dynamics. Apart from fault detection and outage prevention, there are several other applications of the smart grid such as electric substation automation, distributed energy resource management, automatic metering infrastructure (AMI), electrical vehicles (EVs), home automation. These applications require efficient communication technologies for transfer of information. This chapter presents a comprehensive description of the various smart grid communication systems and standards from the perspective of their application in smart grid. The future technologies and the challenges they pose are also discussed for the benefit of the research groups working on smart grid communications.

Wireless and mobile communication technologies exhibit remarkable changes in every decade. The necessity of these changes is based on the changing user demands and innovations offered by the emerging technologies. This chapter provides information on the current situation of fifth generation (5G) mobile communication systems. Before discussing the details of the 5G networks, the evolution of mobile communication systems is considered from first generation to fourth generation systems. The advantages and weaknesses of each generation are explained comparatively. Later, technical infrastructure developments of the 5G communication systems have been evaluated in the context of system requirements and new experiences of users such as 4K video streaming, tactile Internet, and augmented reality. After the main goals and requirements of the 5G networks are described, the planned targets to be provided in real applications by this new generation systems are clarified. In addition, different usage scenarios and minimum requirements for the ITU-2020 are evaluated. On the other hand, there are several challenges to be overcome for achieving the intended purpose of 5G communication systems. These challenges and potential solutions for them are described in the proceeding subsections of the chapter. Furthermore, massive multiple-input multiple-output (MIMO), millimeter wave (mmWave), mmWave massive MIMO, and beamforming techniques are clarified in a detail which are taken into account as promising key technologies for the 5G networks. Besides, potential application areas and application examples of the 5G communication systems are covered at the end of this chapter.

Future wireless communication systems should have the ability to accommodate large number of mobile users increasing day by day. Moreover, various high-speed mobile applications such as online video streaming and online gaming, interconnection of different wireless devices for Internet of Things (IoT) are also some of the key requirements must be fulfilled. Hence, next-generation 5G wireless communication systems and smart grid (SG) communication systems requires high data rate, low latency, high spectral efficiency, low out-of-band (OOB) radiation, low power consumption, secure connectivity and ability to accommodate more number of users as well as diversified wireless devices distributed in large geographical regions for different mobile applications with maintaining uninterrupted connectivity at high speed. More sophisticated signaling schemes are required to overcome the limitations of orthogonal frequency-division multiplexing (OFDM), which is widely accepted by many researchers as one of the potential modulation schemes for 3.5G and 4G wireless standards. Even some of the multicarrier modulation schemes suitable for 5G applications, which work well at the frequency range of around 28 GHz, may not be suitable for millimeter wave (mmWave) frequency range of 60–90 GHz. Hence, in this chapter a comprehensive analysis of various types of potential waveforms such as generalized frequency-division multiplexing (GFDM), filter bank multicarrier (FBMC), universal filtered multicarrier (UFMC), and some of the extended version of OFDM, which can be used in 5G wireless communication systems. Some single-carrier modulation schemes suitable for mmWave are studied and discussed. Various issues for implementing these new waveforms and their advantages and disadvantages are also discussed. Smart grid (SG) communication technologies can be more reliable, secure and faster by using some of the modern signaling schemes. Finally, some of the standards of SG and its applications are discussed.

Wired and wireless communication technologies are widely leveraged for bilateral communications between the utility and end user in smart grid environments. With mobile technologies evolving, optical communications are projected to play an essential role in emerging fifth-generation (5G) networks. In this chapter, we first introduce fiber-optic communications and briefly address optical attenuation, dispersion, and nonlinear effects for a variety of modulation devices in present and future fiber-optic transmission and multiplexing technologies. Second, the development of optical wireless communications is introduced, including free-space optical communication and visible-light communication (VLC) systems. Third, waveform designs and modulation techniques in 5G for the smart grid are addressed, including amplitude shift keying (ASK), differential phase shift keying (DPSK), quadrature phase shift keying (QPSK), multiple quadrature amplitude modulation (MQAM), polarization shift keying (PolSK), plus other digital modulation and pulse modulation formats, as well as coding technologies. Finally, an overview of the prospects is given for future development, application fields, and socioeconomic influence.

The giant information exchange enabled by the Internet of Things (IoT) paradigm, i.e. by a “network of networks” of smart and connected devices, will likely exploit electrical lines as a ready-to-use infrastructure. Power Line Communications (PLC) have received a significant attention in the last decade, as electrical lines are not used as simple energy supply media, but as information carriers. Among the different aspects of PLC-based architectures, an interesting and important analysis have to be reserved to security aspects that should be adopted in similar infrastructures, having that they are crucial to deliver trustworthy and reliable systems and, hence, to support users relying on available services, especially in case in which they should be inherently secure at the physical level (e.g. against unauthorised signal removal/interruption and eavesdropping, since they are difficult and dangerous). Motivated by the relevant impact of PLC on IoT, in this chapter we investigate experimentally the performance of IoT systems on PLC in indoor environments, considering a vendor-provided application tool and a self-developed Java library. The experimental tests are carried out on both cold and hot electrical lines, evaluating both fixed-size and variable-length power lines. Our results show that IoT-oriented PLC can reach a throughput of 8 kbps on a 300-m cold line and of 6 kbps on a 300-m hot line. Further experimental efforts will be oriented to performance analyses in presence of the adoption of security measures.

Nowadays, the growth of the Internet of things makes necessary to improve systems in terms of reliability, autonomy, and adaptation. Some research lines are focused on these issues to be part of new necessities. The main idea of this chapter is to go further than a wide extended communication among devices or remote control focusing on decision making of cooperative systems. Voting algorithms are widespread in this kind of applications since they allow to combine multiple outputs to generate the final solution. The simplest voting methodology is majority but, in this case, past classifications do not affect the following ones. However, weighted majority can make the system adaptive since weights are calculated according to the previous behavior of each device. Two different weighted methods are analyzed in this chapter. The first one establishes the definition of how weights have to evolve depending on the matches between the solution of each device and the final cooperative solution. In contrast, the second weighted approach estimates weights using a stochastic-based method which gives weight assignments after analyzing multiple combinations. Rewards and penalties will be different every time. Final weights are not given by a specific combination; they are calculated according to all the valid combination distribution (i.e., geometric center of all of them). The way to define the valid combinations will determine the system reliability. Additionally, in order to verify the performance of each method, a case of use is also presented. Results demonstrate the adaptation of both methods and how the system reliability is also improved comparing to the simple majority solution.

In recent years, wireless sensor networks (WSNs) have received growing attention owing to their remarkable advantages, and they are widely being utilized in various metering and monitoring application areas such as Internet of things (IoT), smart grids, smart cities, smart homes, cloud computing, healthcare monitoring, military investigation, environmental surveillance systems. The most widely utilized standard in the WSN applications is IEEE 802.15.4 that is developed to enable short-range applications with low data rates and low power consumption features. This chapter aims to provide comprehensive information concerning of the WSNs, general specifications of the IEEE 802.15.4 standard, recently developed new technologies based on this standard, and several practical WSN applications performed for smart grid concept. This chapter firstly introduces the fundamentals, application areas, and advantages of the WSNs in a detail. Later, the chapter continues by explaining technical backgrounds of the WSNs where IEEE 802.15.4 standard is examined in terms of layer stacks. The physical (PHY) and media access control (MAC) layers of the IEEE 802.15.4 standard are comprehensively analyzed since these layers are the basis of new technologies such as ZigBee, WirelessHART, ISA100.11a, 6LoWPAN, and 6TiSCH. Afterward, these novel technologies are introduced and analyzed by considering open systems interconnection (OSI) reference model. Finally, practical examples of the WSNs regarding metering and monitoring applications of smart grids are presented at the end of this chapter.

This chapter provides a comprehensive discussion on fault tolerance and reliability for advanced metering infrastructure (AMI) communication. The AMI is one of the main applications in smart grids, and several references have discussed performance requirements for its correct functioning. While, in isolation, the requirements for each user are not high, the scale and density of the network make meeting them a challenge. Moreover, any downtime for this network is harmful, which strongly suggests the need for some degree of fault tolerance. In this chapter, we will discuss the main enabling technologies and architectures for AMI communication, highlighting the currently dominating architecture, based on wireless communication between meters and data aggregation points (DAPs). In this architecture, we will discuss fault tolerance and reliability under the prism of routing (e.g., choosing reliable paths, fast reroute in case of failures, and multipath routing). We will also show how those routing approaches depend on particular topological characteristics of the communication network, which can be guaranteed by proper network planning.

When we talk about smart grid we refer to the next generation of power systems that should and will replace existing power system grids through intelligent communication infrastructures, sensing technologies, advanced computing, smart meters, smart appliances, and renewable energy resources. Features of the smart grid must meet requirements as high efficiency, reliability, sustainability, flexibility, and market enabling. But, the growing dependency on information and communication technologies (ICT) with its applications and uses has led to new threats to discuss and to try to resist against them. On the one hand, the most important challenges for smart grid cyber security infrastructure are finding and designing optimum methods to secure communication networks between millions of inter-connected devices and entities throughout critical power facilities, especially by preventing attacks and defending against them with intelligent methods and systems in order to maintain our infrastructures resilient and without affecting their behavior and performances. On the other hand, another main challenge is to incorporate data security measures to the communication infrastructures and security protocols of the smart grid system keeping in mind the complexity of smart grid network and the specific cyber security threats and vulnerabilities. The basic concept of smart grid is to add control, monitoring, analysis, and the feature to communicate to the standard electrical system in order to reduce power consumption while achieving maximized throughput of the system. This technology, currently being developed around the world, will allow to use electricity as economically as possible for business and home user. The smart grid integrates various technical initiatives such as wide-area monitoring protection and control systems (WAMPAC) based on phasor measurement units (PMU), advanced metering infrastructure (AMI), demand response (DR), plug-in hybrid electric vehicles (PHEV), and large-scale renewable integration in the form of wind and solar generation. Therefore, this chapter is focused on two main ideas considering modern smart grid infrastructures. The first idea is focused on high-level security requirements and objectives for the smart grid, and the second idea is about innovative concepts and methods to secure these critical infrastructures. The main challenge in assuring the security of such infrastructures is to obtain a high level of resiliency (immunity from various types of attacks) and to maintain the performances of the protected system. This chapter is organized in seven parts as follows. The first part of this chapter is an introduction in smart grid related to how it was developed in the last decades and what are the issues of smart grid in terms of cyber security. The second part shows the architecture of a smart grid network with all its features and utilities. The third part refers to the cyber security area of smart grid network which involves challenges, requirements, features, and objectives to secure the smart grid. The fourth part of this chapter is about attacks performed against smart grid network that happens because the threats and vulnerabilities existing in the smart grid system. The fifth part refers to the methods and countermeasures used to avoid or to minimize effects of complex attacks. The sixth part of the chapter is dedicated to presenting an innovative methodology for security assessment based on vulnerability scanning and honeypots usage. The last part concludes the chapter and draws some goals for future research directions. The main purposes of this chapter are: to present smart grid network architecture with all its issues, complexities, and features, to explore known and future threats and vulnerabilities of smart grid technology, to show how a highly secured smart grid should look like and how this next generation of power system should act and recover against the increasing complexity of cyber-attacks.