Confronting combined cyber-attacks on collaborative DC microgrids using a communication protocols-based distributed unscented Kalman filter

Abstract

The functioning of microgrids (MGs), which represent a contemporary arrangement of distribution networks featuring local control over generation and consumption, necessitates telecommunication infrastructure for transmitting and receiving measurement data and control commands. This reliance on telecommunication infrastructure renders MGs vulnerable to the threat of cyber-attacks. The existing methods for identifying cyber-attacks have been restricted solely to MG modeling. However, identifying and restoring a cyber-attack lack dependability and feasibility in a practical application without the concurrent modeling of MGs and their communication protocols. Therefore, this study aims to identify hybrid cyber-attacks (simultaneous false data injection and time delay attacks) to flow sensors and cyber links in direct flow MGs by considering the communication protocols between them, as well as extracting and reconstructing real measurement data. In order to achieve this objective, a generalized unscented Kalman filter (UKF) is introduced in conjunction with communication protocols incorporating an augmented state space to estimate the power of nonlinear loads. For this purpose, two measurement models have been developed to prevent data collisions and reduce the communication load. These models are based on the round-robin scheduling protocol and the try-once-discard weighted protocol. They aim to establish a specific order for data transfer from sensors to the filter. The article concludes by presenting a stability analysis of the protocol-based generalized UKF, which aims to ensure the convergence and limitation of the estimation error. The study presents simulation results on the resilient reconstruction of hybrid cyber-attacks involving unknown constant power loads and noise. The proposed approach utilizes the protocol-based generalized UKF and exhibits superior performance.