To optimize the length of the penstock branch of a high-head pumped storage power station

 sensitivity analysis is conducted to determine the reasonable range of penstock branch length where the hydraulic transient process calculation values can simultaneously satisfy the maximum pressure at the spiral case inlet and the minimum pressure at the draft tube inlet. The study results show that the pressure values of JFS and DLH pumped storage power stations exhibit the same trend with the change of the penstock branch length. When the hydraulic transient process calculation values meet the code-specified control values

the variable range of the penstock branch length is between 6.5%~7.8%of the length from the upstream surge tank to the ball valve.