Adaptive Log-Fractional Terminal Sliding Mode Control for Residual Current Compensation in Bushfire-Prone Power Networks

This paper proposes a novel adaptive log-fractional terminal sliding mode controller (ALFTSMC) for enhancing safety and reliability in bushfire-prone power distribution networks. The controller is integrated within a residual current compensation inverter system, coordinated with an active arc suppression coil, to mitigate single-line-to-ground faults that can lead to bushfire ignition if not rapidly suppressed. The proposed ALFTSMC employs a hybrid terminal sliding surface that combines fractional-order, logarithmic, and exponential nonlinearities with an adaptive fractional-based reaching law. This structure ensures finite-time convergence, improved transient smoothness, and robustness against system parameter variations. The controller dynamically regulates the injected neutral current to maintain residual current below the critical fire-safe threshold of 0.5 A within 2 s of fault onset. Simulation results under both low- and high-impedance fault conditions demonstrate that ALFTSMC achieves a reduction in steady-state fault current by up to 94%, a 21% improvement in voltage regulation, and a 35% faster settling time compared to a benchmark global terminal sliding mode controller. These findings confirm the ALFTSMC's effectiveness in achieving fire-safe operation under fault disturbances and highlight its practical applicability for real-time fault mitigation in resonant grounded distribution networks.