This paper introduces the basic situation, the power grid connection mode, and the DC control and protection function of Zhoushan VSC-MTDC transmission demonstration project, and analyzes the application of fast restart and start/stop of a single converter station, together with the operation effect of the project. Combined with the practical operation and maintenance experience, the main equipment problems such as DC control and protection, converter valve submodule, DC circuit breaker and DC measuring device are analyzed, and the direction of technical perfection is given.