Cyber intrusion detection for line current differential relays in DC distribution system

Line current differential relays (LCDRs) are used as a promising solution for DC system protection. Such relays rely on communication channels (for remote end data) for decision and therefore, are susceptible to cyber intrusions. The false data injection (FDI) based cyber attack is one of the prominent threats, which may cause unintentional tripping of LCDRs. This paper presents a cyber intrusion detection algorithm based on the change in slope of the superimposed component of current in both ends of the line segment. The proposed algorithm distinguishes cyber attacks from the internal faults. The case studies are carried out on an IEEE 37 bus distribution system modified into a DC distribution test system in a real-time OPAL-RT environment. The performance of the proposed method is tested for different conditions including high resistance fault, FDI attack, load change, switching effect and signal with noise.