Transient Stability Assessment of a Grid-Connected Micro-Hydro Power Plant Using MATLAB/Simulink Under Multiple Fault Conditions with Controller Performance Analysis

Abstract

The issue of transient stability demands careful attention when integrating micro-hydro power plants into the utility grid, since synchronous generating units of small capacity are highly sensitive to electrical disturbances, particularly short-circuit faults of varying severity. Rigorous dynamic modeling is therefore essential to capture the coupled interactions among the hydraulic, electrical, and control subsystems under disturbed operating conditions. This paper develops a MATLAB/Simulink-based transient stability model of a grid-connected run-of-river micro-hydro power plant comprising a hydraulic turbine-governor, a synchronous generator, an automatic voltage regulator and excitation system, a step-up transformer, connected loads, and an infinite-bus grid, rated at 100 kVA, 11 kV, 50 Hz. The system is subjected to four distinct fault types, namely a Symmetrical Three-Phase-to-Ground (3LG) fault, a Single Line-to-Ground (SLG) fault, a Line-to-Line (LL) fault, and a double Line-to-Ground (LLG) fault, each applied at 0.1 s and cleared at 0.2 s, together with a parametric study covering different fault-clearing times and load variation conditions. Terminal voltage, rotor speed, stator current, and field voltage are analyzed across all scenarios. In addition, a comparative evaluation of controller performance is carried out, contrasting the conventional governor and IEEE Type-1 AVR configuration with an optimized PID governor and a fuzzy-logic-based excitation controller. The results demonstrate that synchronism is maintained across all fault types and operating conditions. The comparative controller analysis confirms that optimized and intelligent control strategies reduce post-fault settling time by approximately 45% relative to the conventional baseline. The findings establish the presented framework as a reliable basis for fault-type-dependent stability assessment, controller benchmarking, and grid-integration planning of micro-hydro generation systems.