Influence of Different Factors on Fault Current Under DC Side Fault of Photo voltaic Grid Connected System

Modular multilevel converter (MMC) has many advantages, such as low loss, flexible control and so on, which has been widely used in photovoltaic grid connected system. However, the photovoltaic output has some instability, and the damping of the flexible DC system is also low, which puts forward a severe test for the stable operation of the power grid. Firstly, this paper describes the basic structure of the photovoltaic system connected by MMC. Secondly, the photovoltaic grid connected system model based on PSCAD illustrates the fault current characteristics under DC side fault, and simulates and analyzes the influence of different factors in the system on the fault current.