# A Review of Edge Computing Technology and Its Applications in Power Systems
## 1 Introduction  
Edge computing is a transformative approach in the field of distributed computing, designed to bring data processing closer to the data source, such as sensors, Internet of Things (IoT) devices, or local servers. It emerged from the increasing demand for real-time data processing capabilities, as it minimizes the need for data transmission over long distances. To fully understand the role of edge computing, it is essential to address its relationship with cloud computing. Cloud computing has been one of the most popular topics in the information technology area over the past decades. In October 2007, IBM and Google announced a collaboration in cloud computing [1; 2], which marked a significant milestone. Since then, cloud computing has been widely discussed and used. Typically, the cloud computing paradigm is based on transmission control protocol (TCP)/internet protocol (IP) and involves the high integration of configurable computing resources [3]. It encompasses data storage, management software, data transmission network, cloud center, and related applications. Cloud computing operates as a computational paradigm that collects data from the end devices and sends it to a centralized cloud server for further processing and computation. It boasts advanced characteristics such as being service-oriented, loosely coupled, and strongly fault-tolerant [1]. Cloud servers usually possess supercomputing power capable of handling various large-scale computing tasks. Conventionally, cloud computing is implemented using three cloud computing services: Software-as-a-service (SaaS) is responsible for running, managing, and maintainingthe applications and the infrastructure on which the applications run; Platform-as-a-service (PaaS) provides customers with cloud resources such as hardware to develop, run and manage consumer-created applications without building and maintaining these resources; Infrastructure-as-service(IaaS) delivers computing, storage, virtual machines, and other fundamental resources to consumers. With the development of network-connected intelligent devices and the growing needs of end users, intelligence has become integrated into various aspects of the industry and people's daily lives [4]. The significantly increasing number of smart edge devices has led to a larger data scale. According to Cisco's statistics, there were 17.1 billion devices on the Internet in 2016 [5]. The Cisco Annual Internet Report (2018-2023) White Paper published in 2020 [6] indicated that there were 18.4 billion devices connected to the Internet, projected to rise to 29.3 billion by the end of 2023. Dell Technologies also predicts that there will be 41.6 billion IoT devices in 2025, producing 79.4 zettabytes (ZB) of data [7]. These statistics highlight the growing data scales and increasing complexity of data processing tasks. The limitations of cloud-based architectures are becoming evident. Firstly, intelligent devices are often used for real-time data processing. For example, an IoT-enabled intelligent automobile [8] generates a significant amount of data [9], necessitating servers to receive and handle the data. The response speed of these servers is critical. Secondly, end devices are often placed across a wide range of geographical locations. The failure of some end devices and the long transmission distance increase resource consumption. Thirdly, ensuring the security of end devices' data is another significant concern. Typically, cloud centers collect and store vast amounts of user personal data, including private information. Information leakage can lead to unacceptable consequences. To address these challenges, an alternative solution that can process the massive data instantly, efficiently, and safely is necessary. Consequently, edge computing has emerged and gained popularity in recent years. It represents a variant of distributed computing architecture designed to process data at the grid edge with the end devices [10].