This paper presents the complete design, mathematical modelling, simulation implementation, and rigorous performance analysis of a Static Synchronous Compensator (STATCOM) for dynamic power factor correction in a three-phase 415 V, 50 Hz AC distribution system. A fully designed LCL output filter (L1=5 mH, C=10 µF, L2=2 mH, Rd=4 ?, f_res=1.3 kHz), cascaded dual-loop dq-frame PI control architecture, and Synchronous Reference Frame Phase-Locked Loop (SRF-PLL) are incorporated and validated using MATLAB/Simulink R2021b with Simscape Electrical. Simulation results demonstrate: reactive power compensation from Q_Grid=100 kVAR to 0–5 kVAR (>95% efficiency); power factor improvement from 0.894 lagging to unity (1.0); load-side current THD of 0.01% and load voltage THD of 0.02%. P_Stat ? 0 kW confirming purelyreactive operation; DC bus stable at ~700 V; and dynamic step-change response within 2–3 AC cycles (60–80 ms).