基于综合性能指标的交直流混合系统直流调制研究

Study on DC modulation for AC/DC hybrid transmission system based on comprehensive performance index

通常的直流调制研究,只考虑其对系统功率振荡阻尼的改善。直流调制改变系统功率振荡阻尼同时,对频率特性和功角特性也会有影响。把频率偏差连同功角和功率偏差一起作为综合性能指标,在直流调制研究时,对功率响应进行Prony分析,选灵敏度最高的备选交流线路作为调制信号。以综合性能指标作为衡量标准,用分层寻优方法对反馈增益进行优化;并与未考虑频率偏差的指标作为标准的优化增益进行比较,结果表明前者对频率稳定更为有利。最后以四川电网为例,验证了提出方法的有效性。

In the usual researching of DCM （DC Modulation）, the improvement of system damping of power oscillation is only considered. The DCM can improve the system damping ratio of power oscillation, and meanwhile it will affect swing-angle stability and frequency stability. So the frequency deviation is added in comprehensive performance index with swing-angle deviation and power deviation. In the studying ofthe DCM in the AC/DC hybrid transmission system, the most sensitive AC circuit signal is chosen to be the modulation signal by Prony analysing, and the comprehensive performance index is used to be the index to optimize the feedback gain based on hierarchical search. The gain got by using the comprehensive performance index is compared with the one got by using the index that does not consider frequency deviation, it＇s proved that the frequency stability of the former is better. Finally, Sichuan power system is utilized to illustrate the effort of this method mentioned in this papar.