Abstract: Abstract: In recent years, with the rapid development of hydropower, wind and solar power generation, renewable energy installed capacity has more than 60% of the total installed capacity in Qinghai, Yunnan, Sichuan, Tibet and other power grid. With the transmission of power in the provinces is increasing year by year, the ultra-high voltage AC/DC hybrid power grid is developing to multi-DC asynchronous grid like Yunnan. Based on Yunnan province as an example, this article studied the operational problems of the multi-DC asynchronous source side grid with high proportion of renewable energy, proposed the security and stability technology, analyzed the actual case and evaluated the effect.