Cyber Threats to Line Current Differential Relays: Analysis and Impact of False Data Injection Attacks

With the integration of Information and Communication Technology (ICT) into modern power grids, Line Current Differential Relays (LCDRs) have become an essential component for ensuring fast, selective, and sensitive protection, particularly for critical transmission lines. However, their resilience on digital communication networks has introduced significant cybersecurity risks, making them potential targets for cyberattacks on smart power systems. To strengthen the resilience of the smart grid against cyber-physical intrusions, it is crucial to examine the various impacts that cyberattacks can have on LCDRs. Among these threats, False Data Injection Attacks (FDIAs) are particularly concerning, as they can manipulate relay data and cause unintended tripping. This paper categorizes FDIAs into two main types: Fault Masking Attacks and Fault Mimicking Attacks, which include Noise Attacks, Ramp Induced Attacks, Step Attacks, Time Delay Attacks, and Replay Attacks. By analyzing their effects on LCDR performance using IEEE test systems, this study provides a comprehensive foundation for understanding cyber threats and conducting systematic risk assessments. This insight is essential for developing effective security strategies and algorithms to safeguard power systems from cyber threats.