Underground powerhouse chamber design of ERTAN hydroelectric project

ERTAN hydroelectric project is located on the lower reaches of Yalong river in the southwest part of China’s Sichuan province and at a distance approximately 46 km from Panzhihua city. The multi-purpose hydroelectric project is developed mainly for power generation. The main features consist of a 240 m high double curvature concrete arch dam, left bank underground powerhouse complex, log passing facilities, right bank spillway tunnel etc. There are 6 sets of units installed in the powerhouse. The capacity is 550MW for each. The design waterhead is 165m, the unit inflow is 370mνs and annual output is 17,000GWh. The left bank underground powerhouse complex is comprised of a power intake penstocks, underground powerhouse, main transformer chamber, tailrace surge chambers. The powerhouse size is 280.3x25.5x65.38m (Length x width x height).