Vulnerability assessment of high-voltage direct current transmission systems to cyberattacks

High-voltage direct current (HVDC) transmission systems demonstrate significant advantages in long-distance and high-capacity power transmission. Voltage-source converter-based HVDC (VSC-HVDC), with its flexible power flow control and independent active/reactive power regulation capabilities, has been increasingly adopted in large-scale transmission projects. However, the stable operation of HVDC systems relies heavily on reliable communication and control systems, making their cybersecurity vulnerabilities a critical concern. This study focuses on the cyberattacks targeting two-terminal VSC-HVDC systems. We systematically analyze the control architecture and identify vulnerable attack points, and then conduct experimental attacks including denial-of-service (DoS), time-delay, false data injection (FDI), and hybrid attacks, targeting these vulnerable nodes. To enhance the experimental authenticity, the real-time simulation experiments were performed on the OPAL-RT OP5707 XG platform. The experiments involved both individual and simultaneous cyberattacks on the two converter stations, yielding a series of attack-induced effects. The results demonstrate that cyberattacks can induce severe consequences including DC over-voltage, power transmission failure, and system oscillations, all of which pose substantial threats to grid security and stable operation. These findings highlight the urgent need for further cybersecurity enhancement in HVDC control systems.