IEMI Vulnerability Analysis for Different Smart Grid-enabled Devices

The smart grid concept aims to improve power systems’ robustness, efficiency, and reliability. The transition from conventional power grids to smart grids has been achieved mainly by integrating Smart Electronic Devices (SEDs) and advanced automatic control and communication systems. On the one hand, electronic devices have been integrated to make the system more decentralised from the national electrical grid. On the other hand, from the point of view of protection and control equipment, there is a growing tendency to replace arrays of analog devices with single digital units that perform multiple functions in a more integrated and efficient way. Despite the perceived benefits of such modernisation, security issues have arisen with substantial concern as electronic devices can be susceptible to Intentional Electromagnetic Interference (IEMI). The number of IEMI sources has grown significantly in recent decades. In 2014, 76 different types were reported, in which 21 sources were conducted, and 55 were irradiated. From a technical perspective, they can present different features, including band type, average / centre frequency, peak voltage (for conducted sources), or peak field (for irradiated sources). These sources also differ in technology level, associated cost, and mobility in approaching the target system. Therefore, they can be characterized by the easiness of occurrence in a given scenario and the increased probability of successful attacks on a target system. Under this perspective, a self-built jammer built with off-the-shelf components is more likely to be employed by an offender than a High-Power Electromagnetic (HPEM) source. On the other hand, despite being less probable on account of higher technological level, cost and mobility, a HPEM source may have a higher success rate to affect the target system than the self-built jammer. Coupled with this, based on the different characteristics of the IEMI sources, the electronic devices may present distinct effects, which may trigger severe impacts on a smart grid at a higher level.
Therefore, this study compares the IEMI vulnerability of three devices used in smart grid applica tions. The first device is a Wi-Fi-based smart home meter. It can read voltage and current signals of consumer units and remotely display real power, reactive power, and power factor. These mea surements can be used in-house or transmitted to a Supervisory Control and Data Acquisition (SCADA) system from Distribution System Operators (DSOs). The second device is a Power Line Communication (PLC) unit, which enables data to be carried over conductors intended primarily for electrical power transmission. This technology is used in buildings to reduce the communication network’s material and installation costs and provide flexibility and faster data communication. The final device considered is a digital protection relay designed to trip circuit breakers when faults are detected. The latest digital relay units feature many protection functionalities, including overload and under-voltage/over-voltage protection, temperature monitoring, fault location, self-reclosure, among others. The three devices are subjected to self-built low-power jamming signals. As an extension, the protection relay is also subjected to a narrowband High Power Electromagnetic (HPEM) source.