ReThink: Reveal the Threat of Electromagnetic Interference on Power Inverters

TL;DR

This paper reveals electromagnetic interference vulnerabilities in photovoltaic inverters' sensors, demonstrating how carefully crafted EMI can disrupt, damage, or disable them, and proposes countermeasures to enhance their security.

Contribution

It uncovers EMI vulnerabilities in PV inverter sensors, demonstrates practical attack methods, and offers hardware and software defenses to improve security in renewable energy systems.

Findings

EMI can cause DoS and physical damage to PV inverters

Vulnerabilities exist despite electromagnetic compatibility measures

Countermeasures can mitigate EMI threats effectively

Abstract

With the boom of renewable energy sources (RES), the number of power inverters proliferates. Power inverters are the key electronic devices that transform the direct current (DC) power from RES to the alternating current (AC) power on the grids, and their security can affect the stable operation of RES and even power grids. This paper analyzes the security of photovoltaic (PV) inverters from the aspects of internal sensors since they serve as the foundation for safe power conversion. We discover that both the embedded current sensors and voltage sensors are vulnerable to electromagnetic interference (EMI) of 1 GHz or higher, despite electromagnetic compatibility (EMC) countermeasures. Such vulnerabilities can lead to incorrect measurements and deceiving the control algorithms, and we design ReThink that could produce three types of consequences on PV inverters by emitting carefully crafted EMI, i.e., Denial of Service (DoS), damaging inverters physically or damping the power output. We successfully validate these consequences on 5 off-the-shelf PV inverters, and even in a real-world microgrid, by transmitting EMI signals at a distance of 100-150cm and a total power within 20W. Our work aims to raise awareness of the security of power electronic devices of RES, as they represent an emerging Cyber-Physical attack surface to the future RES-dominated grid. Finally, to cope with such threats, we provide hardware and software-based countermeasures.