The China Southern Power Grid: Solutions to Operation Risks and Planning Challenges

The China Southern Power Grid LTD (CSG) is a unique power system, featuring long-distance, largecapacity transmission by extra-high-voltage (EH V)/ultra HV (UH V) parallel ac and dc. Half of the load is located in the Pearl River Delta of Guangdong province in the east, while 90% of the primary energy resources are concentrated in Yunnan and Guizhou provinces in the west. CSG has 16 transmission lines (eight ac and eight dc) with a total transmission capacity over 35 GW to transmit power from west to east. All HVdc inverter stations are located closely in the receiving grid, of which the average location distance is fewer than 100 km. This structure of parallel ac/dc system and multi-infeed dc has brought a unique risk of system operation and control. In this article, operation challenges and planning solutions of CSG are presented.