This paper analyses the non full phase of the main switch in a fossil fueled power unit with the method of symmetry ponderance in theory.

• 利用对称分量法,对火电单元发电机组主开关非全相运行从理论上加以详细分析,并结合电厂实际情况,分析其现象、危害,最后提出相应的处理方法。