由于电网建设与电源建设、负荷发展存在时间差，现有网架结构和地区用电负荷可能难以满足大型能源基地电能送出的需求。为了解决这一问题，提出了1套电力系统稳定器(power system stabilizer, PSS)的参数优化方案。在综合考虑系统需求及机组稳定性的基础上，通过增加1级超前滞后环节来改善本机PSS的频率特性，找出影响电能送出的振荡模式，针对该模式对机组励磁系统进行重点相位补偿。优化参数比原始参数具有更平缓的幅频特性和较大的临界增益。采用电力系统综合分析程序，分别通过时域仿真和现场试验的方法，验证了该电站开机极限功率在2010年夏季丰水期方式下可以由1 765 MW提高到2 900 MW。研究结果表明：优化并网机组PSS的参数可有效改善系统的动态稳定水平，提高电网的外送能力。

Because there is a time lag among power grid construction, power sources construction, and load development, the existing power grid structure and regional power consumption load may not meet the demands of outward power transmission by some new large-scale power plants. In order to solve this problem, a parameters optimization scheme of power system stabilizer (PSS) was presented. Based on the comprehensive consideration of the grid demands and generator stability, the frequency characteristic of PSS has been improved through adding a lead-lag link in compensation section, founding out the oscillation mode which restricted the ability of power transmission, as well as particularly implementing phase compensation for unit’ s excitation system under this oscillation mode. The optimized PSS has better frequency characteristic and larger gain. Through time-domain simulation and field testing, it has been verified that the ultimate power during the station starting up process can be increased from 1 765 MW to 2 900 MW in the wet season in 2010 summer, based on the power system analysis software package (PSASP). The research results show that parameters optimization of grid-connected unit’s PSS can improve the dynamic stability level of system and enhance the capacity of power transmission .