Aerial photo taken on May 17, 2019 shows a view of the 750-KV North Xi'an substation in Gaoling District of Xi'an City, northwest China's Shaanxi Province. The substation has been put into operation recently, marking the completion of the second 750-KV transmission line project from Shanbei to Guanzhong area in Shaanxi Provinece. (Xinhua/Liu Xiao)