Abstract: With the development of renewable energy, the demand for external reactive voltage support in power systems has been steadily increasing. This paper establishes the mathematical model of the phasor excitation system, analyzing the influence of the time constants T_a, T_b, T_c of the PID controller and the gain K_e of the automatic voltage regulator (AVR) on the voltage and reactive power response at the grid connection point. In response to the traditional particle swarm optimization (PSO) algorithm's tendency to prematurely converge and its slow convergence rate, a Logistic-chaos-initialized PSO is proposed. The controller parameters of the excitation system are optimized using the time-weighted absolute error integral (ITEA) as the fitness function. Simulation results demonstrate that the optimized synchronous condenser achieves superior dynamic performance after the clearance of three-phase short-circuit faults in the power system. Faster recovery of voltage and reactive power, smaller overshoot, and mitigated oscillations are observed, which further improves system stability.