Denial of Service Attack on Tie-Line Bias Control in a Power System With PV Plant

The use of synchrophasor networks consisting of phasor measurement units (PMUs) makes it possible to monitor, analyzes, and control the electric power grid in real-time. PMU measurements of frequencies, currents, voltages, and phase angles are transmitted to system control centers through synchrophasor networks. Delayed or missing measurements from PMUs in closed-loop applications could lead to power system instability. Although the use of virtual private network (VPN) tunnels eliminates many security vulnerabilities, VPNs are still vulnerable to denial of service (DoS) attack that exploits a side-channel vulnerability. In this paper, the authors detail their analysis of DoS attack on a two-area four machine power system with a utility-scale photovoltaic (PV) plant. Automatic generation control (AGC) is used to implement a tie-line bias control in one of the areas. The impact of PMU packet dropping on AGC operation and countermeasures are presented in this paper. Cellular computational network (CCN) prediction of PMU data is used to implement a virtual synchrophasor network (VSN). The data from VSN is used by the AGC when the PMU packets are disrupted by DoS attacks. Real-time experimental results show the CCN based VSN effectively inferred the missing data and mitigated the negative impacts of DoS attacks.