What Is a Smart Grid?

Smart grid is the intelligence of the power grid (smart electricity), also known as " grid 2.0 " . It is based on an integrated, high-speed two-way communication network. The application of advanced control methods and advanced decision support system technology to achieve the goals of reliability, security, economy, efficiency, environmental friendliness and safe use of the power grid. Its main characteristics include self-healing, motivating and protecting users, resisting attacks, providing The power quality that meets the needs of users in the 21st century, allows access to various forms of power generation, starts the power market and optimizes the efficient operation of assets.

U.S. Department of Energy's "Grid 2030": a fully automated power transmission network that can monitor and control each user and grid node, ensuring bidirectional flow of information and power between all nodes in the entire transmission and distribution process from the power plant to the end user .

China IoT School-enterprise Alliance: Smart grid is composed of many parts, which can be divided into: smart substations, smart distribution networks, smart energy meters, smart interactive terminals, smart dispatching, smart appliances, smart buildings, smart city power grids , Intelligent power generation system, new energy storage system.

European Technology Forum: A power transmission network that integrates all behaviors connected to grid users to effectively provide sustainable, economical and safe power.

State Grid China Electric Power Research Institute: Based on the physical grid (China's smart grid is based on a strong grid with UHV grids as the backbone and coordinated development of grids of all voltage levels). It uses modern advanced sensor measurement technology, Communication technology, information technology, computer technology and control technology are highly integrated with the physical power grid. It aims at fully satisfying the user's demand for electricity and optimizing resource allocation, ensuring the safety, reliability and economy of power supply, meeting environmental protection constraints, ensuring power quality, and adapting to the development of electricity marketization, etc., to achieve reliable and economical for users , Clean, interactive power supply and value-added services.

In terms of grid development foundations, the power needs of countries are becoming saturated. After years of rapid development, the grid has stabilized its structure.

Compared with the existing power grid, the smart grid reflects the remarkable characteristics of a high degree of integration of power flow, information flow and business flow. Its advancedness and advantages are mainly reflected in:

(1) It has a strong power grid basic system and technical support system, which can resist various external interferences and attacks, and can adapt to large-scale access to clean energy and renewable energy. The strength of the power grid has been consolidated and improved.

(2) The organic integration of information technology, sensor technology, and automatic control technology with the power grid infrastructure can obtain panoramic information of the power grid to discover and anticipate possible failures in a timely manner. When a fault occurs, the power grid can quickly isolate the fault and realize self-recovery, thereby avoiding a large-scale power outage.

(3) Extensive application of flexible AC / DC transmission, network plant coordination, intelligent dispatching, power storage, and distribution automation technologies makes the operation control of the power grid more flexible and economical, and it can adapt to a large number of distributed power sources, microgrids and electric Access to car charging and discharging facilities.

(4) The comprehensive use of communication, information and modern management technology will greatly improve the efficiency of power equipment use, reduce power loss, and make the operation of the power grid more economical and efficient.

(5) To achieve a high degree of integration, sharing and utilization of real-time and non-real-time information, to display a comprehensive, complete and detailed grid operation status chart for operation management, and to provide corresponding auxiliary decision-making support, control implementation plans and response plans.

(6) Establish a two-way interactive service model, users can understand the power supply capacity, power quality, electricity price status and power outages in real time, and reasonably arrange the use of electrical appliances; electric power companies can obtain detailed information on electricity consumption by users to provide them with more value-added services . ^[1]

The role of smart grids in promoting economic and social development in the world. The construction of smart grids plays an important role in coping with global climate change and promoting sustainable development of the world economy and society. Mainly manifested in: ^[5]

(1) In terms of grid construction, the grid structure has been continuously strengthened and improved. The UHV AC test demonstration project and the UHV DC demonstration project have been successfully put into operation and stable operation. The core technology of UHV transmission and transformation has been fully grasped. The development of the power grid has laid a solid foundation.

(2) In the aspect of large grid operation control, it has the advantages of uniform dispatching and rich experience in operation technology. It has advanced internationally in the level of dispatching technology and equipment. Independently developed dispatching automation systems and relay protection devices have been widely used.

(3) In the construction of communication information platform, a "three vertical and four horizontal" power communication backbone network has been established, forming a communication network pattern that mainly uses optical fiber communication and coexistence of multiple communication methods such as microwave and carrier; the stage of SG186 project acquisition Results, ERP, marketing, production and other business application systems have completed pilot construction and started large-scale promotion and application.

(4) In terms of test and detection methods, according to the needs of smart grid technology development, research and testing centers for large-scale wind power grids, solar power generation, and power technology have been established.

(5) In terms of smart grid development practice, the pilot work in all links has been fully carried out. Pilot projects such as smart grid dispatching technology support systems, smart substations, power consumption information collection systems, electric vehicle charging facilities, power distribution automation, and power fiber to the home Progressing well.

(6) In the field of large-scale renewable energy grid connection and energy storage, in-depth research on key technologies such as centralized grid connection and electrochemical energy storage, the establishment of a wind power grid simulation analysis platform, and the establishment of wind farm power access Related technical standards of the system.

(7) In the field of electric vehicle charging and discharging technology, China has carried out a lot of research on access, monitoring and billing of charging and discharging facilities, and has established electric vehicle charging operation sites in some cities.

(8) In terms of the development mechanism of the power grid, the business scope of China's power grid enterprises covers all links from power transmission, transformation, distribution to power consumption. There are obvious advantages in terms of unified planning, unified standards, and rapid advancement.

In 2005,

In recent years, the state has successively introduced policies to support the development of smart grids. In 2011, China's smart grid entered a comprehensive construction phase. The development of smart grids has promoted the smart bidding and procurement activities of smart meters and accelerated the growth of China's smart meter market. The development of global smart grid requires the use of new types of electricity meters to bring opportunities to Chinese enterprises. Driven by national policies and stimulated by foreign markets, China's smart meter market will maintain a growth trend in the next few years. The industry forecasts that shipments of smart meters in 2016 will reach 9.78 million.

Smart Power Grids (SmartPowerGrids)

In a broad sense, smart grids include smart dispatching systems that can prioritize the use of clean energy, smart metering systems that can be dynamically priced, and smart technology systems that optimize load balancing by adjusting power generation and electricity equipment power. The following figure 1-1 shows the basic structure of the smart grid in the future. Electric energy not only flows from centralized power plants to the transmission grid and distribution network to users. At the same time, various forms of new and clean energy are distributed throughout the power grid: solar, wind, Fuel cells, electric vehicles, etc. In addition, the high-speed, two-way communication system realizes the information exchange between the control center and grid equipment, and advanced analysis tools and decision-making system ensure the safe, stable and optimized operation of the smart grid.

The goal of the smart grid is to achieve reliable, safe, economic, efficient, environmentally friendly and safe use of the grid. If the grid can achieve these goals, it can be called a smart grid.

The smart grid must be more reliablethe smart grid can provide a reliable power supply no matter when and where users are. It provides sufficient warning of possible problems with the power grid and can tolerate most grid disturbances without power failure. It can take effective corrective measures before users are affected by power outages to protect grid users from power interruptions.

Smart grids must be more securesmart grids can withstand physical and cyber attacks without extensive blackouts or high recovery costs. It is even less vulnerable to natural disasters. Smart grids must be more economical-smart grids operate under the basic law of supply and demand balance, with fair prices and adequate supplies. Smart grids must be more efficient-smart grids use investment, control costs, reduce losses in power transmission and distribution, and make power production and asset utilization more efficient. By controlling the power flow method to reduce transmission power congestion and allow access to low-cost power sources including renewable energy.

Smart grids must be more environmentally friendlySmart grids reduce their environmental impact through innovation in power generation, transmission, distribution, energy storage, and consumption. Further expand access to renewable energy. Where possible, in future designs, the assets of the smart grid will occupy less land and reduce the actual impact on the landscape. The smart grid must be safe to usethe smart grid must not harm the public or grid workers, which means that the use of electricity must be safe.

The smart grid includes six main features. These features functionally describe the characteristics of the grid, rather than the specific technology of the final application. They form a complete picture of the smart grid.

The IEEE is committed to formulating a set of standards and interoperability principles for the smart grid (IEEE P2030). The main content lies in the following three aspects: power engineering, information technology, and communications. .

In addition to the IEEE, the International Electrotechnical Commission (IEC) also plays an important role. The National Institute of Standards and Technology (NIST) coordinates the cooperation between various departments. The 15 institutions involved in standard setting are responsible for different aspects of standard setting.

The IEEE is mainly committed to standards for interworking into the network, such as how each energy source is linked to the entire smart grid, access to metering equipment (such as electricity meters), and time synchronization standards. The American Society of Automotive Engineers (SAE) focuses on standards for access to the network of motor vehicles, while IEC is responsible for information automation models and environmental standards.

On May 18, 2009, US Secretary of Commerce Luo Jiahui and Secretary of Energy Zhu Yiwen jointly announced the first standards for smart grid construction in the United States (see Table 1).

Table 1 The first 16 smart grid industry standards

standard	application
AMI-SEC system security requirements	Advanced Measurement Infrastructure (AMI) and Smart Grid End-to-End Security
ANSI C12.19 / MC1219	Revenue measurement information model
BACnet ANSI ASHRAE 135-2008 / ISO 16484-5	Building automation
DNP3	Substation and Feeder Automation
IEC 60870-6 / TASE.2	Internal control center communication
IEC 61850	Substation Automation and Protection
IEC 61968/61970	Application level energy management system interface
IEC 62351 Parts 1-8	Information security for power system control operations
IEEE C37.118	Phasor measurement (PMU) communication
IEEE 1547	Physical and electrical interconnection between power companies and distributed generation (DG)
IEEE 1686-2007	Security of Intelligent Electronic Devices (IEDs)
NERC CIP 002-009	Cybersecurity standards for large power systems
NIST Special Publication (SP) 800-53, NIST SP 800-82	Cybersecurity standards and guidelines for Federal Information Systems, including large power systems
Open ADR (Open Automatic Demand Response)	Price responsive and direct load control
Open HAN	Home area network (HAN) device communication, measurement and control
ZigBee / Home Plug Smart Energy Profile	Home Area Network Device Communication and Information Model

The development of a new model must be based on reality, better use, more convenient, more efficient, and based on the development of China's own standards. You must not fancy the concept, pick a new term, and put together a few functions. This is not a new technology.

Because the smart grid contains a lot of content, each grid and equipment manufacturer must adopt the overall planning and step-by-step implementation strategy to gradually realize the smart grid according to the actual situation.

Smart Grid Smart Substation

The intelligent substation is an advanced, reliable, integrated, low-carbon, and environmentally-friendly intelligent device. With the basic requirements of information digitization of the entire station, networking of the communication platform, and standardization of information sharing, it automatically completes information collection, measurement, control, protection, metering, and monitoring. And other basic functions, and can support advanced functions such as real-time automatic control of the power grid, intelligent adjustment, online analysis and decision-making, and collaborative interaction. The key technologies involved: smart transformers and circuit breakers, electronic transformers, a unified information platform for substations.

Smart Grid Smart Energy Meter

The intelligent energy meter can realize the two-way metering function under the two-way interactive power supply mode, the fast response of the electricity price under the dynamic floating electricity price, fast switching, and real-time settlement of electricity prices.

Smart Grid Smart Interactive Terminal

The intelligent interactive terminal is a key device for realizing intelligent power consumption services in the home. It uses advanced information and communication technology to uniformly monitor and manage household power equipment, and collects and analyzes data such as power quality and household power consumption information. Users make reasonable use of electricity, adjust the peak and valley load of the power grid, and realize intelligent interaction between the power grid and users. In addition, through intelligent interactive terminals, water and gas meter reading can be realized, reducing the cost of meter reading for water and gas companies, and providing users with value-added services such as home security, community services, and Internet services. ^[11]