Definition: Smart Grid is a new electricity network, which highly integrates the advanced sensing and measurement technologies, information and communication technologies (ICTs), analytical and decision-making technologies, automatic control technologies with energy and power technologies and infrastructure of electricity grids.
Some important aspects of what ‘smart’ are listed below:
- Observability: It enables the status of the electricity grid to be observed accurately and timely by using advanced sensing and measuring technologies;
- Controllability: It enables the effective control of the power system by observing the status of the electricity grid;
- Timely analysis and decision-making: It enables the improvement of the intelligent decision-making process;
- Self-adapting and self-healing: It prevents power disturbance and breakdown via self-diagnosis and fault location.
- Renewable energy integration: It enables to integrate the renewable energy such as solar and wind, as well as the electricity from micro-grid and supports efficient and safe energy delivery services for an electric vehicle, smart home, and others.
Goals and Objectives of Smart Grid
In many countries, regulators and liberalization are forcing utilities to reduce costs for the transmission and distribution of electrical energy. Therefore, new methods (mainly based on the efforts of modern information and communication techniques) to operate power systems are required to guarantee a sustainable, secure and competitive energy supply.
The general goals of Smart Grid are to ensure a transparent, sustainable and environmental-friendly system operation that is cost and energy efficient, secure and safe.
Objectives of developing the Smart Grid are quite different from country to country for their various demands and start points.
However, the common objectives of a Smart Grid are clear and listed below:
- Robustness: The Smart Grid shall improve resilience to disruption to provide continuous and stable electricity flows, avoiding wide-area breakout accidents. It shall guarantee the normal and secure run off the electricity grid even under the instance of emergency issues, such as natural disasters, extreme weather, and man-made breakage, and provides self-healing abilities;
- Secured operation: The Smart Grid shall enhance communication networks and information security of the electricity grid;
- Compatibility: The Smart Grid shall support the integration of renewable electricity such as solar and wind, has the capacity of distributed generation access and micro-grids, improve demand response functions, implement the effective two-way communication with consumers and satisfy various electricity demands of consumers;
- Economical energy usage: The Smart Grid shall have the capacity of more efficient electricity markets and electricity trades, implement the optimized configuration of resources, increase the efficiency of the electricity grid, and reduce electricity grid wastage;
- Integrated system: The Smart Grid shall highly integrate and share information and data of an electricity grid, utilize the uniform platform and model to provide standardized and refined management;
- Optimization: The Smart Grid shall optimize assets, reduce costs and operate efficiently;
- Green energy: The Smart Grid shall solve problems of energy security, energy saving, carbon dioxide emission and etc.
The utilities of the Smart Grid shall address the following challenges:
- High power system loading;
- Increasing distance between generation and load;
- Fluctuating renewables;
- New loads (hybrid/electric vehicles);
- Increased use of distributed energy resources;
- Cost pressure;
- Utility unbundling;
- Increased energy trading;
- Transparent consumption & pricing for the consumer;
- Significant regulatory push.
The key market drivers behind Smart Grid solutions are:
- Need for more efficient use of energy;
- Increased use of renewable energy resources;
- Competitive energy prices;
- Security of supply;
- Aging infrastructure and workforce.
The priority of local drivers and challenges might differ from place to place.
Conceptual Model and Reference Diagram for Smart Grid
Figure 1, extracted from the NIST Framework, shows a conceptual model of Smart Grid, consisting of seven major functional area call domains and the information flows between these domains, as well as the flow of electricity from power sources through transmission and distribution system to the customers. Table 1 gives a brief definition of these domains.
An important new capability for Smart Grid not explicitly shown in this model is the distributed power generation that may occur in the Customer, Distribution, and Transmission domains.
If the generation facility exists in the Customer domain, new paths for electrical and communication flows need to be shown; similarly for generation capabilities in the Transmission and Distribution domains.
Figure 1. A conceptual model of Smart Grid
Table 1. Domains and Actors in the Smart Grid conceptual model
|Domain||Actors in the Domain|
|Customers||The end users of electricity. May also store, and manage the use of energy. Traditionally, three customer types are discussed, each with its own domain: residential, commercial, and industrial.|
|Markets||The operators and participants in electricity markets.|
|Service Providers||The organizations providing services to electrical customers and utilities.|
|Operations||The managers of the movement of electricity.|
|Bulk Generation||The generators of electricity in bulk quantities. May also store energy for later distribution.|
|Transmission||The carriers of bulk electricity over long distances. May also store and generate electricity.|
|Distribution||The distributors of electricity to and from customers. May also store and generate electricity.|
Figure 2 is a conceptual reference diagram for Smart Grid Information Network from the NIST document, showing the interconnections of networks between various domains.
Some of networking clouds have been moved outside of individual domains to emphasize the communication functions between the domains.
The major component is a backbone network or Wide Area Network (WAN) that distributes messages between domains. There is another network cloud that aggregates/de-aggregates local traffics in some domains to/from the WAN, similar to Access Networks such as optical, cable or DSL.
In the Smart Grid environment, the access network is needed for connection to smart meters and customer premises and is called Neighborhood Network in this context as they form the networking infrastructure within each neighborhood.
The clouds labeled “Internet/e-Business” refers to the existing Internet access to the public, and is shown separately to indicate logical separation due to security considerations.
Within each domain, there are network infrastructures to serve the need of the domain. Of special interest to Smart Grid is the Home Area Network (HAN) in the Customer domain for Smart Grid applications, connecting various devices, such as home appliances, sensors, electric vehicle chargers, and local generators.
The HAN may or may not be the same network as the existing Local Area Network (LAN) in the homes for access to the Internet, depending on the security considerations of the Smart Grid.
Figure 2. Conceptual Reference Diagram for Smart Grid