Robust Fault Compensation in Bushfire-Prone Distribution Networks Using Prescribed Performance-Based Hybrid Nonlinear Controllers

This paper propose a robust hybrid nonlinear control strategy—termed the prescribed performance-based backstepping adaptive nonsingular integral terminal sliding mode controller (PP-BSA-NITSMC), designed for enhancing fault compensation performance in residual current compensation (RCC) inverters used in bushfire-prone compensated distribution networks. A second-order dynamical model is adopted to jointly regulate neutral voltage and current, allowing fault compensation without dependence on leakage parameters. A prescribed performance function shapes the transient and steady-state tracking behavior within predefined bounds, while a nonsingular integral terminal sliding mode structure ensures finite-time convergence and robustness against disturbances. Comparative simulation studies with a first-order model-based controller (PP-ANITSMC) under both low-impedance ($150~\Omega$) and high-impedance (25.4 k$\Omega$) single line-to-ground faults demonstrate significant improvements: the proposed controller reduces the steady-state rms fault current from 0.1696 A to 0.1588 A under low-impedance and from 0.0025 A to 0.0019 A under high-impedance conditions—achieving approximately 6.35% and 24% improvements, respectively. Additionally, the system settles more quickly, prevents overshoot during neutral current injection, and enhances neutral voltage stability, fully meeting bushfire mitigation standards. These outcomes clearly demonstrate that PP-BSA-NITSMC provides superior accuracy, responsiveness, and reliability in handling various fault conditions.