The S-type tubular turbine unit is a common form of tubular turbine, where the main shaft extends out of the turbine flow passage and is directly connected to the generator. This type of unit is typically used in hydropower stations with low head and high flow. It features a simple structure, low material consumption, and lower manufacturing costs. Additionally, the construction scale of the civil engineering is small, making it particularly suitable for small and medium-sized hydropower stations with a shorter payback period. The S-type tubular turbine unit is an ideal choice for low-head resource development, offering high efficiency and low costs. However, it has higher requirements for water quality, head range, and manufacturing accuracy.