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What is a Smart Grid?

A Smart Grid is a grid of modern electricity transmission lines that uses communication technology to detect and collect digital or analog information on the status of consumer power usage, and uses this information to coordinate electric power supply within the system. This information can be used to adjust the production, transmission, and distribution of electricity, or adjust the power consumption of household appliances and enterprise users, saving energy, reducing losses, and enhancing the reliability of the power grid.

The recent development of smart grids:

Promoting "smart meter infrastructure", "planning smart grid" and "smart power service" is the focus of smart grid development. Taiwan has carried out smart meter testing and demonstration programs in recent years, and actively assists Taipower in promoting smart grid. Communication technologies that will be used include 3G/4G, RF Mesh, (Radio Frequency mesh),PLC (power-line communication), Wi-SUN, (Wireless Smart Ubiquitous Network), Wi-Fi, wired optical fiber, etc. In recent years, the technology of Low-Power Wide-Area Network (LPWAN) has gradually matured. The low data volume requirements of smart grids make them very suitable for using LPWAN communication systems, such as LoRa, NB-IoT, and other technologies. With its high-speed transmission, huge capacity, low latency, network slicing, edge computing, and other communication potentials, 5G will bring more diversified applications to smart grids.

5G smart grid application scenarios and communication requirements:

The 5G system uses three main types of slicing technologies; eMBB (Enhanced Mobile Broadband), URLLC (Ultra-reliable and Low Latency Communications), mMTC (massive Machine Type Communications), and other applications, which can respectively meet the application requirements of various power services in the smart grid. 5G network slicing technology can be used to provide diversified services for various needs of the power grid.

The power grid can be transformed from a traditional transmission/distribution/transformation system into a smart grid. Small and decentralized energy systems are effectively managed by analyzing power consumption patterns to determine the most effective method of providing safe and efficient power transmission and transformation, and flexible power distribution. Each communication network has its own characteristics so must be coordinated with the entire power system. 5G's network slicing technology can accommodate different transmission levels. Whether it is an image monitoring application that requires a large bandwidth, or a power distribution management that requires a small bandwidth and low latency, 5G can support the different requirements of each application. 

The international trend of energy generation is towards a higher and higher proportion of renewable energy, moving from centralized power plants to small, decentralized, diverse energy systems. Household solar power generation, electric scooters, and home energy management systems are becoming more mainstream. The amount of decentralized energy continues to increase, and the global DER capacity is expected to grow from 132.4 GW in 2017 to 528.4 GW in 2026. To meet the 2025 domestic energy ratio target of 30% coal, 50% gas, 20% renewable energy, maintaining the balance of supply and demand in the power system is a problem that power companies will need to face and solve. As renewable energy power generation is especially uncertain, difficult to predict accurately, and difficult to control, these challenges will present opportunities for breakthrough in 5G technology.

To coordinate diverse and small-scale distributed energy sources, Taipower will need to introduce virtual power plant technology. By using a 5G high-efficiency and a low-latency network with smart and real-time management, its overall power availability and reliability can be made equivalent to that of a traditional power plant.  

In the past, low-latency requirements were met by TV stations through self-built optical fiber networks. 91ÊÓƵ¹ÙÍøever, with decentralized energy, the cost of self-distributed optical fiber solutions is too high. Therefore, 5G network slicing and edge computing technologies can be used to establish communication. VPP (Virtual Power Plant) intelligent control is established on the edge cloud to ensure stable transmission and low latency. Through network slicing, Taipower helps establish a private network with the participating party on the existing communication network to ensure the security of the power grid and avoid malicious attacks.

In its early stages, the distribution network only had a simple protection circuit design for overcurrent and overvoltage. No communication network or back-end computer management systems were built, so it was difficult to achieve segmental isolation. Distribution automation (DA) is a powerful information management system that accurately monitors the power distribution network, locates faults, and obtains information from adjacent power distribution terminal equipment which can be used to quickly isolate and eliminate these faults.

Feeder automation (FA) refers to automation of substation transformer equipment, to automatically detect, isolate or correct feeder faults. It is an important part of distribution automation. The reliability of the power system is very high, with the accident isolation time shortened to milliseconds, ensuring the uninterrupted supply of power. To meet the very high requirements for distribution/feeder automation, and low transmission delay between base stations and distribution/feeder terminal equipment, 5G URLLC technology is required. 5G technology can replace the existing fiber-optic infrastructure, providing millisecond-level network transmission delay.  5G offers a better solution for wireless communications on the distribution/feeder automation grid, enabling faster and more accurate grid control.

Possible applications of ultra-high-speed 5G technology in smart grids include high-quality video inspection of grid equipment and structures. High-quality image and voice inspections inside and outside the substation are mainly performed using audio-visual inspection robots. The inspection robot can be integrated with multi-channel, high-definition cameras and various IoT environment sensors, to instantly return high-definition images and IoT-related inspection data to the control center in the substation.

Audio and video inspection of the power distribution room in the substation, and multi-channel high-definition audio and video monitoring can be achieved by installing the appropriate equipment in the power distribution room. Relevant information such as the operating status, and image and equipment status can be sent back to the control center to improve the automation of inspection in substations. Applications outside the substation mainly include unmanned aerial vehicle (UAV) inspections of transmission lines, etc. UAV inspections of transmission lines are mainly aimed at line inspections of high-voltage transmission networks.

With the increase in demand, all countries are actively promoting the construction of smart grids, hoping to promote the optimal allocation and operation of power resources through real-time control and demand-side management, achieve the goals of energy conservation and carbon reduction, and improve the installation and operation of smart meters. Most of the electricity meters are installed in basements and other places with poor reception, and the density of electricity meters in urban areas is high. In addition, the general public will cause a backlash against the installation of obvious communication devices. At present, the technology adopted by most manufacturers in the world is to deploy RF Mesh with PLC. RF Mesh must be installed with a large number of concentrators, which requires a large space, but the space is not easy to obtain. The power system has high stability. To meet the requirements of security and confidentiality, using slicing technology, a wireless private network can be virtualized to perform higher-strength security isolation and improve the security, stability, and flexibility required by smart meter reading.

5G technical features will accelerate the realization of the smart grid:

5G networks and smart grids are both important trends for the future development of the IT industry. In addition to optical fiber networks, the application of 5G network low-latency characteristics in control applications can bring new communication solutions to smart grids. Extensive, slicing technology can simultaneously provide eMBB, URLLC, mMTC, and other different application scenarios. Network-Function Virtualization (NFV) can be used for a secure isolation network like a private network for smart grids, and bring better security for the transmission of grid data. In response to the diverse application scenarios of smart grids, 5G networks also provide different levels of network access, providing users with more flexible configurations, and enabling smart grids to accelerate the pace of implementation.

The smart grid, with all its smart technologies, tools, and equipment, will have a positive impact on the national grid in terms of efficiency, reducing emissions, and improving its durability and safety. Any new technology, especially disruptive technology, will have difficulties that must be overcome, and so does the smart grid. A reliable, safe, and cost-effective grid are expected in everyday life, and smart grids are gradually meeting this demand.