IoT-Based Monitoring and Protection Applications in Power Substations: A Critical Review

Abstract: This review paper presents a comprehensive analysis of recent research on IoT based monitoring and protection systems in electrical power substations published between 2019 and 2025. The reviewed studies indicate that IoT technology have been extensively adopted to enhance real-time monitoring, condition assessment, data acquisition and remote supervision of substation equipments. A major portion of the existing literature focuses on monitoring-oriented applications such as transformer health monitoring, smart metering and substation surveillance where IoT mainly serves as a data collection and communication platform. In contrast, fewer studies address protection-related functions, including fault detection, overcurrent, earth fault, differential protections and coordination concept. In many of these studies, the protection logic is either simplified or still heavily dependent on conventional protective relays, with IoT used primarily to support communication or centralized decision-making instead of acting as a core protection element. This review classifies the selected studies into monitoring-based, protection supported and intelligent or AI- based approaches, and compares them in terms of application scope, role of IoT, level of protection functionality and validation methods. Depending on this analytics, key limitations and research gaps are identified, highlighting the need for practical and standard-aware IoT-based protection schemes that can be effectively deployed in real substation environments.