China's new energy generation is undergoing rapid large-scale development. UHVDC links are required to transmit new energy from resource-rich areas to load centers over long distances. For large power gri containing massive amounts of power electronic equipment, electromagnetic transient simulation techniques must be employed for research. This presentation focuses on the construction of electromagnetic transient simulation models for big grids with large-scale new energy generation and UHVDC link, as well as issues and solutions related to the system operational characteristics of large-scale new energy transmitted via UHVDC link.