Hall Spoofing: A Non-Invasive DoS Attack on Grid-Tied Solar Inverter

Grid-tied solar inverters continue to proliferate rapidly to tackle the growing environmental challenges. Nowadays, different smart sensors and transducers are tightly integrated with the grid-tied inverter. This integration opens the "Pandora's Box" of unknown threats that could come from very unconventional ways. This paper demonstrates a noninvasive attack that could come by spoofing the Hall sensor of an inverter in a stealthy way by using an external magnetic field. We demonstrate how an attacker can camouflage his/her attack tool and place it near a target inverter. In doing so, he/she can intentionally perturb grid voltage and frequency and can inject false real and reactive power to the grid. We also show the consequences of the attack on a scaled-down testbed of a power grid with a commercial 140 W grid-tied inverter from Texas Instruments. We are able to achieve a 31.52% change in output voltage, 3.16x (-6dB to -11dB) increase in low-frequency harmonics power, and 3.44x increase in real power. Moreover, we introduce a duty-cycle variation approach for a noninvasive adversarial control that can change the inverter voltage up to 34% and real power up to 38%. We discuss the feasibility of using a 100 kW inverter through discussion. This provides insights behind the generalization of the attack model. In addition, the commercial power system simulation tool Etap 19.0.1 is used to simulate the impact of the attack on a 2.3 MW power grid. To the best of our knowledge, this is the first methodology that highlights the possibility of such an attack that might lead to grid blackout in a weak grid.