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SMART GRID – AN INTRODUCTION
M. N. O. Sadiku and S.M. MusaCollege of Engineering Prairie View A&M University
Prairie View, TX 77446 Sudarshan R. Nelatury
School of Engineering and Engineering Technology Pennsylvania State University
Erie, PA 16563-1701 ABSTRACT
Electricity is a necessity in the modern world. In the traditional power system, electricity is being generated and transmitted through a one-way transmission and distribution system called the grid. The smart grid is an intelligent power grid designed to handle distributed resources using communication technology employing smart meters and control system. It promises more efficient, secure and climate friendly power system.
Key words: Smart Grid, Micro Grid, Power Grid
Cite this Article: M. N. O. Sadiku, S.M. Musa and Sudarshan R. Nelatury, Smart Grid – An Introduction. International Journal of Electrical Engineering & Technology, 7(1), 2016, pp. 35-44.
http://www.iaeme.com/IJEET/issues.asp?JType=IJEET&VType=7&IType=1
1. INTRODUCTION
To sustain our modern society, we need an uninterrupted supply of electricity. The world’s annual electricity generation was 20,250 TWh in the year 2012 and is expected to be 25,500 TWh in the year 2020 [1].
The existing power grid provides one-way distribution of electricity from the power generator to consumers. The basic structure has not changed for about 100 years. It is known to be inefficient and unreliable. As a result of its low efficiency, the power industry is faced with unprecedented challenges and opportunities. Experiences have shown that it is not suitable for 21st century.
The word “smart” in smart grid refers to the notion of a power grid with intelligence. The main objective of the smart grid is to bring reliability, flexibility, efficiency, and robustness to the power system. Smart grid does this by introducing two-way data communications into the power grid. Thus the smart grid consists of
the power infrastructure and communication infrastructure, which correspond to the flow of power and information respectively. This enables intelligent operation of the smart grid. But this introduces security-related challenges.
Key benefits of smart grid include uninterrupted supply of power, reduced transmission and distribution loss, secure grid, and market based electricity pricing [2].
2. CONCEPT OF SMART GRID
The term “grid” is traditionally used for electricity generation, electricity transmission, electricity distribution, and electricity control. A “smart grid” is an enhancement of the traditional electric power grid. It is the modernization of the power delivery system. It is a transformation of the legacy unidirectional electric grid into automatic intelligent system of bidirectional exchange of electric power and information. A smart grid may be defined as any combination of enabling technologies, hardware, software, or practices that collectively make the delivery infrastructure (or the grid) more reliable, more versatile, more secure, more accommodating, more resilient, and ultimately more useful to consumers [3].
A smart grid basically consists of overlaying the physical power system with the information system. A brief comparison between the existing power grid and the smart grid is provided in Table 1. A conceptual model of smart grid developed by the National Institute of Standards and Technology (NIST) is shown in Figure 1.
Table 1 Comparison between traditional power grid and the smart grid [4].
Existing Grid Smart Grid
Electromechanical Digital
One-way communication Two-way communication
Centralized generation Distributed generation
Few sensors Advanced sensors throughout
Manual monitoring Self-monitoring
Manual restoration Self-healing
Failures and blackouts Adaptive and islanding
Limited control Pervasive control
Few customer choices Many customer choices
From the technical point of view, the smart grid can be divided into three major systems [4]:
Smart infrastructure system: This is the energy, information, and communication infrastructure underlying the smart grid. This allows two-way flow of electricity and information. This implies that the users may put back electricity into the grid. The system enables multiple entities (such as intelligent devices, dedicated software, control center, etc.) to interact.
Smart management system: This provides advanced management and control services. Efficient management is fundamental for efficient operation of smart grids. Management of smart grid includes the development and implementation of smart metering, real time pricing, efficient management of renewable energy sources, and management of transmission and distribution networks.
Smart protection system: This provides advanced reliability analysis, fault protection, and security services. The existing infrastructure has become vulnerable to several security threats.
The smart grid is made possible by applying sensors, smart meters, and field automated devices to the electrical power grid. The grid can predict, adapt, and reconfigure itself reliably and efficiently. It will be able to handle uncertainties in schedules, power transfer across regions, managing and resolving unpredictable events, and meeting the demand for reliable supply [5]. In doing so, the smart grid offers several benefits to both the power grid and the energy consumers such as: reduction in transmission congestion, reduced blackouts and forced outages, self-diagnosis, self-healing, peak demand shaving, increased system capacity, increased power system security and reduced vulnerability, and ease in managing hybrid and electric vehicles. Indispensable to the functioning of a smart grid are considerations dealing with: energy storage, advanced meters and sensors, grid-friendly plug-in hybrids, grid-friendly loads, substation and distribution automation, communications, data-intensive analysis, visualization and human interface, and renewable energy integration involving weather prediction and control [7]. Load shaping is one of the important and challenging issues in power grid. Smart grids employ novel load shaping strategies based on energy storage and dynamic pricing. A consumer would sign up for a nominal quota of energy from the grid. If the usage exceeds the quota,
the consumer is faced with a higher electricity price. With energy storage in place, the consumer can optimize the energy consumption by varying charging and discharging flow depending on the demand and price. This accomplishes optimal load shaping. If these strategies are implemented with low complexity and in a distributed fashion, scalability to large number of consumers is possible [8].
3. SECURITY
As we move from legacy power systems to more modern smart grid systems, security will be a big issue. For any new system, security has to be part of system design [6]. Security has been a major concern from the advent of the smart grid concept.
It is the key factor in system design at each level of smart grid from metering to remote sensing and control networks.
The most valuable promise of smart grid is the reliability and security of the power system. Disruptions to the system can be due to weather or natural disasters. Security detects whether the system is in a secure state or an alert state. The system is secure when there are no limit violations. It is alert when particular limits are violated [5].
4. CONCLUSION
The smart grid is the latest development for the electric power system. Although the term “smart grid” does not have a precise, uniformly accepted definition, it is commonly regarded as a digital upgrade of the existing power system. It promotes clean energy, controls energy consumption pattern and brings security to the grid. The future smart grid should enhance the security and reliability of the power system. The implementation of smart grid will be a long continuous process because it involves technological and financial investment. It also involves international effort. The government of each nation will need to develop a policy for implementing smart grid. As the smart grid moves in people’s living room, the focus will significantly change to marketing to consumers. A good source of information about smart grid is the
IEEE Transactions on Smart Grid (2010 – present).
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[9] Sharun John and Brinta N.R, Active Power Electronic Transformer A Standard Building Block for Smart Grid. International Journal of Electrical Engineering & Technology, 5(12), 2014, pp. 178-184.
[10] M.Saisesha, V.S.N.Narasimharaju, R.Madhu Sudanarao and M.Balaji, Control of Power Inverters in Renewable Energy and Smart Grid Integration. International Journal of Electrical Engineering & Technology, 4(1), 2013, pp. 200-207.
ABOUT THE AUTHORS
MATHEW N.O. SADIKU is a professor at Prairie View A&M University, Texas. He is the author of several books and papers. He is an IEEE fellow.
SARHAN M. MUSA is an associate professor in the Department of Engineering Technology at Prairie View A&M University, Texas. He has been the director of Prairie View Networking Academy, Texas, since 2004. He is an LTD Spring and Boeing Welliver Fellow.
SUDARSHAN R. NELATURY is an associate professor at the Penn State University, Erie, PA. He is the author of several research papers. He is a senior member, IEEE.
