Fault Characteristics Analysis of Transmission Lines in High Proportion New Energy System

In order to build a new power system with new energy generation as the main body, promoting clean energy such as wind power has entered a stage of rapid development. The grid connection of a high proportion of new energy through flexible High voltage DC transmission (HVDC) has become a typical scenario of the power system. Since both ends of the new energy transmission line connected by flexible HVDC grids are power electronic devices, the current fault characteristics are completely different from those of synchronous power source, so it is of certain research significance and extensive application value to study the fault characteristics of the flexible HVDC transmission system in the new energy access scenario. In this paper, based on offshore wind power grid-connected flexible DC transmission project, the corresponding simulation model is built in the PSCAD/EMTDC software platform, and the characteristics of short circuit current provided by the flexible direct system are analyzed when different fault scenarios occur on the system outgoing line. Through the waveform analysis and comparison of the simulation experiment, it is found that the fault characteristics of the flexible and direct system change essentially under the scenario of a new energy grid connection, and the short-circuit current characteristics provided by the flexible and direct system are significantly different from those of the conventional power supply. The simulation experiment clarified the fault characteristics of the energy-flexible HVDC outgoing system and provided a strong basis for the protection of the new energy outgoing transmission line.