Dynamic Modelling and Analysis of Power System Stability with HVDC Transmission Using MATLAB/Simulink

Abstract

High-voltage direct current (HVDC) transmission systems are critical for integrating renewable energy and transmitting power over long distances, yet they face challenges such as transient instability and poor power quality, particularly in regions with aging infrastructure like the Inga-Kolwezi line in the Democratic Republic of Congo. These issues, including voltage oscillations and harmonic distortions exceeding IEEE standards (THD > 5%), lead to frequent outages and economic losses, necessitating advanced control strategies to enhance grid reliability and support sustainable development goals. This study aims to address these challenges by developing and evaluating a hybrid Differential Evolution (DE)-optimised Proportional-Integral-Derivative (PID) control framework for the Inga-Kolwezi HVDC system, focusing on improving transient stability and power quality under diverse fault conditions. The methodology involves mathematical modelling of the HVDC system in MATLAB/Simulink, implementing a DE-optimised PID controller to regulate DC voltage, current, and power flow, and simulating performance across fault scenarios such as DC short circuits and three-phase faults. Results indicate a significant reduction in Total Harmonic Distortion from 24.82% to 0.05%, a 4.3% improvement in voltage response time (from 0.833 s to 0.797 s), and a 3% increase in current tracking accuracy (from 73.19% to 76.19%), demonstrating enhanced fault ride-through and damping capabilities. These findings validate the proposed approach, offering a replicable solution for optimising HVDC systems in developing regions, though further refinements in steady-state voltage tracking are recommended for future research as of September 10, 2025.