(230604) -- GOLMUD, June 4, 2023 (Xinhua) -- A worker conducts routing inspection of power transmission lines at Tanggulashan Township of Golmud City in the Mongolian-Tibetan Autonomous Prefecture of Haixi, northwest China's Qinghai Province, June 3, 2023. Since 2012, the State Grid's Qinghai Electricity Power Company would conduct its annual centralized maintenance of the Qinghai-Tibet grid interconnection project, whose grid lines are laid at the plateau with an average altitude of 4,500 meters. Low temperatures, lack of oxygen and strong winds on the plateau challenge the operation and maintenance of the grid. Over 420 workers would finish this year's maintenance work of 608-kilometer-long power transmission lines as well as the Qaidam Converter Station in 15 days recently. Over 10.5 billion kWh of electricity has been transferred to Tibet through the Qinghai-Tibet grid interconnection project, which was put into operation in 2011. (Xinhua/Zhang Hongxiang)