In view of the problem that the new generation of 300 Mvar Synchronous Condenser has no actual data of loss of excitation operation to support loss of excitation protection's cast or cancel strategy and relay protection setting calculation at present.Through the development of loss-of-excitation protection test in the start-up and commissioning process of a new generation of 300 Mvar Synchronous Condenser.The key data obtained from the loss-of-excitation protection test during the start-up and debugging of a new generation of synchronous condenser are presented.The corresponding relay protection setting adjustment and protection cast or cancel strategy of loss-of-excitation protection in the starting and running stages of synchronous condenser are studied.The loss-of-excitation protection test method in the start-up and debugging project of a new generation of synchronous condenser is described in detail, and the experimental conditions required in the loss-of-excitation protection test process are introduced.Combined with the experiment of rated leading phase operation and complete loss of excitation operation, the maximum leading phase depth, excitation current and terminal voltage of the new generation of condenser are obtained.Through the analysis and research of the data, the recommended setting value of the excitation low voltage setting value of the loss of excitation protection and the on-off strategy of each section of the loss of excitation protection in the start-up stage and operation stage are obtained, which provides a reference for the future production of the condenser.