But according to Popovi -Gerber et al. (2012), the concept of smart grid involves the future
evolution of the entire power network much more than adding ICT and smart metering to the existing grids. It will do this by continuing to deploy three fundamental building blocks: distributed intelligence, digital communications, and decision software (Collier, 2010). Consequently, Santacana et al. (2010) have proposed the representation of the four essential building blocks of the smart grid using a layered diagram as shown in Figure 4.6. According to them, an analoguey can be drawn between these layers and those that make up the human body. The bottom layer is analogueous to the body’s muscles; the sensor/actuator layer corresponds to the body’s sensory and motor nerves, which perceive the environment and control the muscles; the communication layer corresponds to the
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nerves that transmit perception and motor signals; and the decision intelligence layer corresponds to the human brain.
Figure 4.6 Smart grid technology layers (Santacana et al., 2010)
Gao et al. (2012) agree with Santacana et al. (2010) on the four major components of smart grid but disagree on the individual composition of these groups as shown in Figure 4.7. Therefore, according to Gao et al. (2012) smart grid is composed of:
Sensing and Measurement
Advanced Control Methods
Improved Interfaces and Decision Support
Advanced Components
The crucial role played by advanced control methods in smart grid through integrated communications (IC) is very clear from Figure 4.7. According to IEC (2010) common to most of the Smart Grid technologies is an increased use of communication and IT technologies, including an increased interaction and integration of formerly separated systems. Equally Noam et al. (2013) submit that an essential building block of smart grids is a communications and control system integrated with the existing power grid which enables end-to-end communication and thus improved coordination. Furthermore, through the use of broadband networks, sensors, smart meters, and software, this layer enables the two-way flow of electricity and information to provide superior performance at lower costs. At the
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same time, greenhouse gas emissions would be reduced as an improved coordination of energy supply and demand increases efficiency.
Figure 4.7: Smart grid key technology areas (Gao et al., 2012)
Figure 4.8: Main component of a smart grid (Agarwal and Tsoukalas, 2011)
From a technical components perspective, the smart grid is a highly complex combination and integration of multiple digital and non-digital technologies and systems (Agarwal and Tsoukalas, 2011). The authors have noted that these individual grid components do not need to be centralised, but can have more control stations and be more highly integrated. Figure 4.8 shows the five key technology areas emerging to achieve the principal characteristics of smart grid. According to NETL (2007) these technologies have been proven in other industries and are essential to realising the modern grid vision. They are briefly explained as follows (Agarwal and Tsoukalas, 2011; NETL, 2007; US-DOE, 2012):
Fully integrated two-way, and possibly high-speed, communication technologies will make the modern grid a dynamic, interactive “mega-infrastructure” for real-time
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information and power exchange. Open architecture implementation of these technologies will create a plug-and-play environment that securely networks grid components to talk, listen and interact. Such technologies include Broadband over Power Line (BPL), digital wireless communications or hybrid fibre coax;
Sensing and measurement, including advanced protection systems, wireless, intelligent system sensors for condition information on grid assets and system status, and Advanced Metering Infrastructure (AMI). These technologies will enhance power system measurements and enable the transformation of data into information. They evaluate the health of equipment and the integrity of the grid and support advanced protective relaying; they eliminate meter estimations and prevent energy theft. They also enable consumer choice and demand response, and help relieve congestion;
Advanced components play an active role in determining the grid’s behaviour. The next generation of these power system devices will apply the latest research and development in materials, superconductivity, energy storage, power electronics, microelectronics, Unified Power Flow Controllers (UPFC), Plug‐in Hybrid Electric Vehicles and Direct Current micro‐grids. This will produce higher power densities, greater reliability and power quality, enhanced electrical efficiency producing major environmental gains and improved real-time diagnostics;
Advanced control methods will involve application of new methods to monitor essential components, enabling rapid diagnosis and timely, appropriate response to any event to ensure high quality supply and for Smart Grids to become self‐healing. They will also support market pricing and enhance asset management and efficient operations. Such technologies include advanced Supervisory Control and Data Acquisition (SCADA) systems, load and short‐term weather forecasting, and distributed intelligent control systems;.
Improved interfaces and decision support: In many situations, the time available for operators to make decisions has shortened to seconds. Thus, the modern grid will require wide, seamless, real-time use of applications and tools that enable grid operators and managers to make decisions quickly. Decision support with improved interfaces will amplify human decision making at all levels of the grid to reduce significant amounts of data to actionable information. These include online transmission optimisation software, enhanced GIS mapping software and support tools to increase situational awareness.
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Berst (2009) has represented the smart grid as a sector chart as shown in Figure 4.9. He has clumped core technologies at the top as a group because he believes the Smart Grid starts with those core technologies and they deserve more visibility in all considerations. According to him the chart serves at least one important purpose: it underscores the value and role of core technologies. Most high-tech industries have understood this for decades and they treat core technologies as foundations or “platforms.” Once the platform is in place, they amortize its cost by building as many applications on top of it as possible.
Figure 4.9: Smart Grid sector chart (Berst, 2009)
Berst (2009) relying on the fact that in reality, the pinnacle of intelligence is the ability to express complex ideas in simple terms – a lesson preached for at least the last 2,400 years by notables ranging from Aristotle to Abraham Lincoln to Albert Einstein – is convinced that consumers will never ask for something until they understand it. So in his opinion to make the case to consumers, we must simplify and he believes the best approach is to describe the Smart Grid as three pieces:
Smart devices
Two-way communications
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Santacana et al. (2010) have noted that the objective of transforming the current power grid into a smart grid will be achieved through the application of a combination of existing and emerging technologies for energy efficiency, renewable energy integration, demand response, wide-area monitoring and control, self-healing, HVDC, flexible ac transmission systems (FACTS), and so on. According to IEC (2010) HVDC and FACTS – both are actuators, e.g. to control the power flow – improve the controllability of the transmission grid. It notes that the controllability of the distribution grid is improved by load control and automated distribution switches. Devices and systems developed independently by many different suppliers, operated by many different utilities, and used by millions of customers, must work together (EC, 2010; NIST, 2012) to provide a smart power system (EC, 2010). Moreover these systems must work together not just across technical domains but across smart grid “enterprises” as well as the smart grid industry as a whole (NIST, 2012). For such a system to operate and the desired services and functionalities to be provided, these components will need to be linked together. In this context, interoperability becomes of major importance, not least in the interest of ensuring greater competition. However, the relationship between interconnection and interoperability is often a source of confusion for engineers just as between interconnection and integration as explained in Section 3.3. According to Siira (2014) during the development of the IEEE 2030-2011 Smart Grid standard, it was a personal struggle for him to “get” the concept of interoperability and how it related to power systems interconnection until he understood the perspectives of Information Technology (IT) and Communication Technology (CT). Then he realised that the systems-of-systems view employed and recommended in the IEEE 2030-2011 Smart Grid guide standard was extremely powerful.
Based on EC (2010) interoperability can be defined as the ability of a system or a product to work well with other systems or products. It notes that while there are many ways to achieve interoperability, one common way is via interface standards. A good example of this is the set of standards developed for the World Wide Web, including TCP/IP, HTTP and HTML, by which information is seamlessly exchanged over the Internet between devices of all sorts and brands, for the benefit of users and businesses. Equally, interoperability can be achieved through standardisation of communications in terms of interfaces, signals, messages and workflows. However, this does not mean unifying all data protocols or applications to a single technology but defining them in a detailed and unambiguous manner
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and agreeing on the usage and interpretation of standards in such a way as to ensure interoperability between systems and devices.
NIST (2012) and IEEE (2011b) have proffered solutions to interoperability challenges. Particularly IEEE (2011b) focuses on a systems-level approach to understanding and the guidance for interoperability components of communications, power systems, and information technology platforms as shown in Figure 4.10. Besides, there exist other factors frustrating smart grid transition as highlighted in Section 4.2. Siira (2014) asserts that the most recent developments that lay a path to improving interoperability are included in the IEEE 2030 series of standards, with IEEE 2030-2011 being the cornerstone. This guide standard introduces the Smart Grid Interoperability Reference Model (SGIRM) that organizes all the functions and interconnections of a Smart Grid in terms of three separate perspectives that together comprise the Smart Grid:
The Power Systems (PS-IAP) Perspective defines the Smart Grid in terms of power entities and their interoperability.
The Communications Technology (CT-IAP) Perspective defines the Smart Grid in terms of communications paths.
The Information Technology (IT-IAP) perspective describes the Smart Grid in terms of information flows, entities, and protocols used to exchange that information.
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Therefore, according to him interoperability is the capability of multiple networks, systems, devices, applications, or components to exchange and use information securely and effectively.
But, the standardisation of solutions and interoperability of technologies will help reduce deployment costs, essential to establish a positive business case (WEC, 2012). Therefore, interoperability between devices and equipment is crucial, as the introduction of smart grids and smart metering should not create a barrier to competition or unnecessary cost (EC, 2010).