Impact of UPFC on Power System Reliability Considering its Cyber Vulnerability

The unified power flow controller (UPFC) has attracted much attention recently because of its capability in controlling the active and reactive power flows. The normal operation of UPFC is dependent on both its physical part and the associated cyber system. Thus malicious cyber attacks may impact the reliability of UPFC. As more information and communication technologies are being integrated into the current power grid, more frequent occurrences of cyber attacks are possible. In this paper, the cyber architecture of UPFC is analyzed, and the possible attack scenarios are considered and discussed. Based on the interdependency of the physical part and the cyber part, an integrated reliability model for UPFC is proposed and analyzed. The impact of UPFC on the overall system reliability is examined, and it is shown that cyber attacks against UPFC may yield an adverse influence.