As a multi-band PSS, PSS4B draws wide attention for its great potential in constraining the ultra-low frequency oscillations. In this paper, the crossbreed operation in genetic algorithm is introduced to particle swarm optimization (PSO) algorithm to form a hybrid PSO, so as to optimize PSS4B parameters. According to the single machine infinite system model, the phase frequency characteristic of excitation system without compensation is calculated by Heffron-Philips model. Based on phase frequency characteristic, the PSS4B parameters are tuned ...