Large Language Models for Detecting Cyberattacks on Smart Grid Protective Relays
Ahmad Mohammad Saber, Saeed Jafari, Zhengmao Ouyang, Paul Budnarain, Amr Youssef, Deepa Kundur
TL;DR
Addressing FDIA threats against transformer current differential relays (TCDRs), the paper develops an on-site LLM-based detector that texts six-channel TCDR measurements into prompts and fine-tunes compact models. The main result is that DistilBERT achieves $97.6\%$ true-positive rate for cyberattack detection with latency below $<6\mathrm{ms}$ per sample, while preserving fault-detection reliability; GPT-2 and DistilBERT+LoRA offer comparable performance. The framework provides interpretable decisions via self-attention maps and maintains robustness under complex attacks and measurement noise, with a fully reproducible dataset released. This work demonstrates practical, edge-deployable, privacy-preserving cybersecurity augmentation for smart grids.
Abstract
This paper presents a large language model (LLM)-based framework for detecting cyberattacks on transformer current differential relays (TCDRs), which, if undetected, may trigger false tripping of critical transformers. The proposed approach adapts and fine-tunes compact LLMs such as DistilBERT to distinguish cyberattacks from actual faults using textualized multidimensional TCDR current measurements recorded before and after tripping. Our results demonstrate that DistilBERT detects 97.6% of cyberattacks without compromising TCDR dependability and achieves inference latency below 6 ms on a commercial workstation. Additional evaluations confirm the framework's robustness under combined time-synchronization and false-data-injection attacks, resilience to measurement noise, and stability across prompt formulation variants. Furthermore, GPT-2 and DistilBERT+LoRA achieve comparable performance, highlighting the potential of LLMs for enhancing smart grid cybersecurity. We provide the full dataset used in this study for reproducibility.
