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Figure 1.1 Traditional electricity delivery system.
Source: [DOE 2015a]. Public Domain.
As illustrated in Figure 1.1, the electricity sector is composed of four distinct functions: generation, transmission, distribution, and system operations. Once electricity is generated, it is generally sent through high‐voltage, high‐capacity transmission lines to local electricity distributors. Once there, electricity is transformed into a lower voltage and sent through local distribution lines for consumption by industrial plants, businesses, and residential consumers.
Because electric energy is generated and consumed almost instantaneously, the operation of an electric power system requires that a system operator constantly balance the generation and consumption of power. Figure 1.2 shows additional functional systems (transmission system, system operations, distribution system) and substation connected to different customers (offices, residential customers, and industrial customers). Information including basic definitions of terms and concepts related to the electrical power grid can be also found in the references and glossaries included in Appendix B.
Figure 1.2 Functions of the electricity sector.
Source: [GAO 2011]. Public Domain.
1.2.1.1 Key Players
In the US electric sector, the key players include utilities and system operators [GAO 2011]:
Utilities own and operate electricity assets, which may include generation plants, transmission lines, distribution lines, and substations including structures often seen in residential and commercial areas that contain technical equipment such as switches and transformers to ensure smooth, safe flow of current and voltage. Utilities may be owned by investors, municipalities, and individuals (as in cooperative utilities).
System operators are sometimes affiliated with a particular utility or sometimes independent and responsible for managing the electricity flows in multiple utility areas. The system operators manage and control the generation, transmission, and distribution of electric power using control systems, IT information systems, and network‐based systems that monitor and control sensitive processes and physical functions, including opening and closing circuit breakers (see definitions in Appendix B). Therefore, the effective functioning of the electricity industry is highly dependent on these control systems.
However, for many years, the US electricity network lacked opportunities such as [GAO 2011]:
Adequate technologies (e.g. sensors) to allow system operators to monitor how much electricity was flowing on distribution lines.
Communication networks to further integrate parts of the electricity grid with control centers.
Computerized control devices to automate system management and recovery.
1.2.1.2 Electric Grid Design of the Future
As the electric grid transitions from the traditional design to the design of the future, new features and technologies must be incorporated. Increasing communications and computing capabilities are transforming power grid from the traditional centralized model to an integrated hybrid centralized/decentralized system. Therefore, society and the power industry in particular are challenged by the transformation of the power grid, as introduced by Nikola Tesla about 120 years ago, into a Smart Grid.
Figure 1.3 depicts an electric power grid that is evolving to include more distributed control, two‐way flows of electricity and information, more energy storage, and new market participants including consumers as energy producers.
Figure 1.3 Evolution of the electric power grid.
Source: [DOE 2015a]. Public Domain.
1.2.2 Smart Grid Definitions
The definition of a Smart Grid is broad and encompasses many aspects of electric grid operation and management. A Smart Grid is an improved electrical power grid, a network of transmission lines, substations, transformers, and more that deliver electricity from suppliers to consumers by using two‐way digital technology to communicate with end loads and appliances at industrial, commercial, and residential premises to save energy and reduce capital and operational cost by improving reliability, security, and efficiency of current power grid. The Smart Grid enables greater use of electricity generated from renewable resources.
Smart Grids are typically described as electricity systems complemented by communication networks, monitoring and control systems, smart devices, and end‐user interfaces [OECD 2010], [OECD 2009].
Another Smart Grid definition blends both functions and components [OECD 2012b] and refers to an electricity network that uses digital and other advanced technologies to monitor and manage the transport of electricity from all generation sources to meet the varying electricity demands of end users. Smart Grids coordinate the needs and capabilities of all generators, grid operators, end users, and electricity market stakeholders to operate all parts of the system as efficiently as possible, minimizing costs and environmental impacts while maximizing system reliability, resilience, and stability [IEA 2011].
The Smart Grid is a vision of the future electricity delivery infrastructure that improves network efficiency and resilience while empowering consumers and addressing energy sustainability concerns [Gartner IT].
The SmartGrids Platform was started by the Directorate‐General for Research of the European Commission in 2005 [SmartGrids 2006]. This initiative aims at boosting the competitive situation of the European Union in the field of electricity networks, especially smart power grids. The establishment of a European Technology Platform (ETP) in this field was for the first time suggested by the industrial stakeholders and the research community at the first International Conference on the Integration of Renewable and Distributed Energy Resources [Conference 2004].
Although there is no formal definition of a Smart Grid based on its features proposed in the literature, the Smart Grid may be considered as a power grid in which modern sensors, communication links, and computational power are used to improve the efficiency, stability, and flexibility of the system [Rihan 2011].
The 2006 report of European Commission [SmartGrids 2006] describes the vision of the “Future: operation of system will be shared between central and distributed generators. Control of distributed СКАЧАТЬ