Communication Networks for Smart Grids - Making Smart Grid Real

In its Framework and Roadmap for Smart Grid Interoperability Standards, US National Institute of Standards and Technology declares that a 21st century clean energy economy demands a 21st century electric grid [NIST12]. The start of the 21st century marked the acceleration of the Smart Grid evolution. The goals of this evolution are broad, including promotion of widespread and distributed deployment of renewable energy sources, increased energy efficiency, peak power reduction, automated demand response, improved reliability, lower energy delivery costs, and consumer participation in energy management. This evolution will touch each and every aspect of the electric power grid, a system that has changed little since its inception at the end of 19th century. Realizing the goals of the Smart Grid evolution will require modernization of grid components, introduction of new control and monitoring technologies and on-going research and development of new technologies. The "intelligence" of the Smart Grid relies upon the real-time exchange of measurement and control data among a vast web of devices installed in homes, businesses, within the distribution and transmission grids, at substations, control centers, generations stations, and other facilities. Thus, a high performance, reliable, secure, and scalable communication network is an integral part of the Smart Grid evolution. However, the communication networks of many utilities today are ill-equipped to meet the challenges created by the Smart Grid evolution. These communications networks are largely purpose-built for the support of individual applications: an individual network for Supervisory Control and Data Acquisition (SCADA), an individual network for video surveillance, an individual network for Land Mobile Radio backhaul, and so on. The networks rely heavily on circuit-based transport technologies. The ever expanding growth of network endpoints and applications as Smart Grid takes hold makes these current practices untenable. A new, integrated network architecture is required, one which will carry traffic from all applications while meeting their disparate reliability, security, and performance requirements. This book is a contribution to this growing body of knowledge. It is based both on our research into Smart Grid communications and the consulting services we have provided electric power companies on transforming their existing communications networks to meet the challenges of Smart Grid evolution. This book will be of interest to those engaged in the planning, deployment, engineering, operation, and regulation of Smart Grids, including strategists, planners, utility practitioners, communication network technology providers, communication network service providers, Smart Grid product vendors, regulators, and academics. This book will also be a resource for upper-level undergraduate and graduate courses covering the Smart Grids. We have taken an application-centric approach to the development of the Smart Grid communication architecture and network transformation based on that architecture. Therefore, a significant part of the book is devoted to describing the evolving Smart Grid applications such as Advanced Metering Infrastructure (AMI), Distribution Automation (DA), and traditional utility applications like Supervisory Control and Data Acquisition (SCADA.) We begin in Chapter 1 with characterizing the Smart Grid in the broadest sense. Electric power grid consists of power plants of bulk electric energy generation connected to a system of high voltage transmission lines to deliver power to the consumers through electric distribution systems. Communication networks have been used for grid monitoring in the latter part of the 20th century but were limited to the substation-based SCADA and Teleprotection systems. The need for clean energy with large-scale deployment of renewable sources of energy, advantages of peak power reduction for environmental and economic reasons, grid modernization, and consumer participation in energy management are some of the motivations for the evolution of Smart Grid. While Smart Grid is a natural evolution of the electric power grid, the evolution has taken a sense of urgency in the last decade. Topics in power systems and grid operations relevant to the book are presented in Chapter 2 for the benefit of the readers with little background in power systems. After presenting the definitions of basis electrical quantities like power and energy, a quick overview of alternate current systems and phasors is presented. Elements of power generation, transmission, and distribution systems are briefly described to provide background relevant to the book. In Chapter 3, topics in communication networks relevant to the book are presented for the benefit of the readers with little background in networking. After a brief presentation of the data communication network architecture framework of t he Open System Inter connection (OSI) architecture, networking layers pertinent to Smart Grid network are presented in more detail. Introduction to many wireless and wireline technologies are included. Since IP will be the network protocol of choice for the evolving smart networks, relevant IP networking features are described in more details. Multi-Protocol Label Switching (MPLS) technology is also included in this review since MPLS is expected to provide many important features needed in the Smart Grid communication network. Before the Smart Grid evolution began, networking for utility operations was generally limited to applications like SACDA and Teleprotection. Utility mobile workforce use communication networks for their operations - mostly for push-to-talk voice communications. Some utilities have deployed networks video surveillance with Closed Circuit Television cameras (CCTV). All these applications will continue to be supported in the Smart Grid network. In Chapter 4, these applications and their communication network requirements, networking protocols and networking technologies are presented. The Smart Grid network will be an integrated network supporting all existing utility applications presented in Chapter 4 as well as the as the Smart Grid applications that are being introduced and that will be introduced in the future. In Chapter 5 we present comprehensive description of many of these new utility applications that can be attributed to the Smart Grid evolution. In addition to presenting their communication network requirements, we briefly discuss network protocols and network technology options for some of these applications. Applications included in this chapter are AMI, DA, Distributed Generation (DG), Distributed Storage, Electric Vehicles (EV), microgrids, Home Area Networks, Retail Energy Markets, Automated Demand Response, Wide Area Situation Awareness and SynchroPhasors, Flexible AC Transmission System, and Dynamic Line Rating (DLR). Contributions of the application of Chapter 4 and Chapter 5 to one or more of the four broad characteristics of the Smart Grid are summarized in a table at the end of this chapter. In Chapter 6, the Smart Grid communication network architecture is developed. A core-edge network architecture is well-suited for the Smart Grid network with many utility endpoints communicating with the application endpoints located in utility Data and Control Center (DCC). The concept of the Wide Area Network (WAN) is formalized for the Smart Grid network as an interconnection of aggregation routers- called WAN Routers. Other utility endpoints connect to the WAN at the WAN routers over access networks - called Field Area Networks (FAN) in the utility community. While IP will be the overall network protocol, the architecture will support legacy applications and protocols for a period of time as desired by a utility. In addition to the physical network architecture, the logical network architecture is described with the use of many examples. At the outset, it is important to understand that the networking requirements for the a utility network are different in many aspects compared to those for a Network Service Provider (NSP) network used for data services offered to its customers as well as for data networks in most enterprises. The NSP networks are primarily designed to support their customers' multi-media applications while the Smart Grid network must support mission critical applications like SCADA, Teleprotection, DA, and SynchroPhasors. Most enterprise data network requirements on reliability, security, and performance that are less stringent than those for the Smart Grid networks. Therefore, the network design paradigm for Smart Grid network is different in many respects from that for the more established data network design practices. Chapter 7 begins with characterization of Smart Grid logical connectivity and network traffic that are the inputs to network design. Design considerations are provided for support of the requirements on routing, quality of service (QoS), and network reliability. While security is briefly included in Chapter 7, in the context of network design, Network security deserved a detailed treatment. Chapter 8 is on network security in the Smart Grid communication networks. Cyber security of the power grid has become as important as the physical security. There has been a concerted effort by utilities, regulators, and standard bodies to implement highest level of communication network security that will not only make the networks secure but also minimize the possibility of security attacks on the grid and provide means of mitigating and eliminating security threats. Further, a comprehensive approach is required where network security must be complemented by security policies and procedures. Chapter 9 provides an overview of communication network technologies appropriate for the WAN and the FANs. For the WAN, optical networks are discussed in detail since many utilities already own or plan to deploy significant fiber infrastructure with Optical Ground Wire. Both wireline and wireless networking technologies are considered with special emphasis of their use as FANs. A more detailed treatment is provided for Power Line Communication (PLC) technology since it is not a very commonly deployed technology in carrier (service provider) or most enterprise networks. Similarly, the Long Term Evolution (LTE) technology is described in detail in this chapter, since LTE has the promise of the most appropriate network technology for Smart Grid endpoints that need to be connected over wireless networks. Benefits and drawbacks of all technologies for their use in the FANs are summarized in a table. The chapter ends with a discussion on benefits and drawbacks of utility ownership of one or more of these network components in comparison to using carrier data networking services. Smart Grid brings with it an enormous growth in data that must be managed for use by an ever-growing number of utility applications. Smart Grid data management is discussed in Chapter 10 in the context of data collection, storage, and access across the communication network. The traditional practice of client-service communication between individual application and individual data source (such as a smart meters, Intelligent Electronic Devices, and SynchroPhasor) is not scalable. Further, this end-to-end communication has inherent security and data privacy risks. There have been recent advances in secure data management that are particularly suitable in the Smart Grid data management environment with network based data storage and the corresponding middleware that affords highly secure and low delay access to the data. In this chapter, secure data-centric data management architecture is discussed. Chapter 11 brings together the concepts, technologies, and practices in realization of the communication networks for the Smart Grid. In this chapter, we present network transformation from the present mode of utility operation - of supporting all utility applications over multiple desperate networks to an integrated network based on the Smart Grid architecture framework developed in this book. The network transformation process must weigh all available alternatives towards optimal network architecture and design that is sustainable for a period of 5-20 years depending on the utility's planning horizon. Planning for long-term network transformation described in the book is based on reasonable assumptions of the future developments in new network technologies, their availability to the utility in its service area, possibilities of using networking services from Network Service Providers and costs. While some of these futuristic elements and traits were considered in earlier chapters, a more focused discussion is presented in Chapter 12.