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 370m 3 /s 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).