Gu Dongkou hydropower plant is located in Xingshan county, Yichang city, Hubei province, the first generating unit was put into commission in September 9th 1999, the total output is 3×15MW, the turbine models is HLA153-LJ-150. Since the operation, the cavitations on the back of runner blade is very serious, almost every year has to carry out repair welding and grinding, caused inconvenience to the maintenance and operation.
The runner replacement is carried out in Nov. 2013 by Getai, new runner model is HLGT153A-LJ-150, and the second time relative efficiency test finished successfully on Sept. 16th 2014, the test results show that the efficiencies in all range of loads increased higher than the original one (HLA153-LJ-150), the efficiency on rated point increased by 5%, the original runner maximum output is 15.13MW at water level on the dam EL311.00m and the new runner maximum output is 16.17MW at EL310.42m (tail water maintained).
HLGT153A model serious is featured by "X" type blade with bigger wrap angle, the blade inlet side extended appropriately with optimization of blade inlet, outlet angle and thickness regulation. The blade area of HLGT153A increased much larger than HLA153, the optimal unit speed decreased by 3 rpm after upgrades to improve the hydraulic properties and cavitations performance largely at high head condition. According to the CFD analysis, the HLGT153A runner blade back pressure value was significantly higher than HLA153 so as to bring a significant improvement to the cavitations performance.