提高集中电源外送系统输电能力的发电机励磁系统协调优化

能源基地电源通过交流线路远距离送至负荷中心，电力系统发生N－1故障后系统阻尼不足，造成输电能力降低。为提高动态稳定水平，改善机组开机出力受限的现状，对发电机励磁控制系统开展协调优化策略的研究。首先对发电机进行了励磁系统AVR主环、附加调差及PSS参数优化，优化后发电机及励磁系统滞后时间减小，无补偿相频特性滞后角度减小了约10°。然后对PSS参数进行相位补偿研究，使有补偿特性更接近-90°，具有更优的相位补偿特性，同时PSS提供的增益显著提高。结果表明，发电机励磁系统、PSS对电网的动态特性有重要影响，在原始参数配置下，外送通道的送出能力不能满足送端发电机组满出力的要求。通过试验验证了机组在优化参数配置下负载试验结果满足机组和电网安全稳定运行需求，优化参数具有可行性，N－1故障后的送出能力得到提高。此优化策略的研究和实施，可以安全、高效、经济地提高集中电源的外送能力。

Coordinated Optimization of Generator Excitation System for Improving Transmission Capacity of Power System

For long-distance AC transmission system from energy base to load center, the system damping is insufficient when N-1 fault occurs, which leads to the reduction of transmission capacity. In order to enhance the dynamic stability of the transmission system and improve the constrained generating capacity of the generator units, the paper studies the coordinated optimization strategy of the generator excitation control system in disturbance. Aiming at above-mentioned problems, we firstly optimize the excitation system AVR main loop, the reactive current compensation and PSS parameters of generators, which reduces the lag time of generators and excitation system, decreasing the non-compensation phase frequency characteristic hysteresis by 10 degrees. And then we studies the phase compensation for PSS parameters, which brings the compensation characteristics closing to -90 degrees, substantially increasing the AC gain provided by PSS. The results show that the excitation system and PSS have important influence on the dynamic characteristics of the power grid, and under the existing parameter configuration, the delivery capacity of the power system cannot meet the full power generation requirements of generator units at the sending end. Tests have proved that under the optimized parameter configuration, the loading test results of generator units can meet the safe operation requirements of generator units and power grids, and the capacity of transmission system can be improved after N-1 fault occurs. Implementation of the optimization strategy will improve the delivery capacity of power grids for centralized power sources with high efficiency, safety and economy.