[en] At present, most of the diesel generating units in domestic nuclear power plants have adopted the PA machine as the original motive. This model has the characteristics of reliable operation and convenient maintenance. However, in recent years, the failure of the unit has been frequent. During the field delivery test of a domestic nuclear power plant and a diesel generator set, serious accidents such as starting air pipeline burning and opening of crankcase explosion proof doors have occurred. After site exploration, and through the fault tree, all factors that caused the accident were investigated, and the root causes and solutions of the accident were finally determined, which played a guiding role in the late manufacture and on-site commissioning of the crew. (authors)