The torsional interaction from the electrical couplings among the generating sets is presented and the influence of the natural torsional frequency of the generating sets on the torsional oscillation characteristics is described . the torsional dynamics between identical parallel turbine - generators are deduced as well as that between non - identical parallel turbine - generators . then the basic principle of equivalent simplification of generating units for different operational condition is summarized ( 2 )介绍了多机电力系统机组间电气耦合对轴系扭振特性的影响，以及机组自然频率与机组扭振相互作用的关系，并对复杂系统中并列运行的相同发电机和不同发电机间的扭振相互作用进行了分析，归纳了不同运行条件下机组等值简化的基本原则。
