Abstract: This paper takes the dynamic reactive power compensation system of a photovoltaic power station cluster in Jiangsu Province as the research object and explores the optimal design and application of the dynamic characteristics of magnetic control reactors. The research objective is to solve the problems of lagging dynamic response, excessive harmonic pollution, and poor economic operation of existing magnetic control reactors in photovoltaic grid-connected systems. Through innovative designs such as self-excited topology systems, dual-stage magnetic valve core nonlinear harmonic suppression, adaptive CFn-I resonant excitation control strategies, low-loss winding topology design, and split modular structures, the performance of magnetic control reactors has been optimized. Measured results show that the optimized scheme has shortened the dynamic response time of magnetic control reactors from 180 ms to 28 ms, reduced the voltage fluctuation suppression lag rate to 4.7%, significantly decreased the harmonic current distortion rate, and effectively controlled the system′s operating losses.