Infinitesimal-Attack-High-Impact Phenomena: Cyber-Attack Bifurcation in Two-Terminal HVDC Power Delivery Systems

Voltage-source converters (VSC) and current-source converters (CSC) are two predominant techniques in high-voltage direct-current (HVDC) power delivery systems. They are crucial for inter-regional power exchange. The cyber vulnerabilities of HVDC systems have been physically demonstrated, threatening their secure operation. To this end, this study investigates the closed-form bifurcation hyperplanes in the cyber-attack injection space of both the VSC HVDC system and the CSC HVDC system. By considering the inherent nonlinearity in intra-station switching control and inter-station coordination control, this study formulates different clusters of attack-induced equilibrium points in HVDC systems. Closed-form sufficient conditions are then derived for triggering small-attack-high-impact and even infinitesimal-attack-high-impact phenomena, in which an infinitesimal cyber-attack can activate rapid power reversal by altering the DC current polarity in VSC HVDC systems or DC voltage polarity in CSC HVDC systems. These attack-induced properties are experimentally validated by establishing a hardware-in-the-loop HVDC cybersecurity testbed, incorporating a Real Time Digital Simulator (RTDS) and a STM32F429-based cyber-attack prototype. The video demonstration and the first-of-its-kind open-source HVDC cybersecurity testbed are attached.