Search Results (2)

The sloping ceiling tailrace tunnel is a novel tailrace tunnel system for hydropower plants. The design, operation, and maintenance of hydropower plants with sloping ceiling tailrace tunnels are based on the calculation and analysis of hydraulic transients and dynamic behavior. Research achievements have provided guidance and a basis for the safe, stable, and efficient operation of hydropower plants with sloping ceiling tailrace tunnels. Based on research achievements, sloping ceiling tailrace tunnels have been applied to more and more hydropower plants. This review paper gives a systematic literature investigation on the hydraulic transient and dynamic behaviors of hydropower plants with sloping ceiling tailrace tunnels. First, the appearance and development of sloping ceiling tailrace tunnels are stated. Key issues in the hydraulic transient and dynamic behaviors of hydropower plants with sloping ceiling tailrace tunnels are illuminated. Then, research achievements on six issues (i.e., the working principles of sloping ceiling tailrace tunnels, the shape design of sloping ceiling tailrace tunnels, the free surface pressurized flow characteristics in sloping ceiling tailrace tunnels, numerical simulations of transient processes for hydro-turbine governing systems with sloping ceiling tailrace tunnels, the stability of hydro-turbine governing systems with sloping ceiling tailrace tunnels, and the transient process control of hydro-turbine governing systems with sloping ceiling tailrace tunnels) are elaborated. Finally, future research trends are presented. In future research, fluid–solid coupling of the tunnel wall and free surface pressurized flow in sloping ceiling tailrace tunnels is worth studying. For hydropower plants with sloping ceiling tailrace tunnels, a combined operating scheme with thermal power and wind power should be explored. Full article

For hydropower stations with sloping ceiling tailrace tunnel (SCTT), the regulation quality of hydro-turbine governing system (HTGS) under the proportional-integral-derivative (PID) strategy is poor. In order to improve the regulation quality of HTGS, the nonlinear disturbance decoupling control (NDDC) based on differential geometry theory is firstly applied into the HTGS with SCTT. The rigorous and complete construction method of nominal output function is proposed. Based on the obtained nominal output function, a novel NDDC strategy for HTGS with SCTT is designed. The application and performance of NDDC strategy on HTGS with SCTT are revealed. The results indicate that the regulation quality of the HTGS with SCTT under NDDC strategy is obviously better than that under PID strategy. The NDDC strategy has a favorable applicability on SCTT. The robustness of the HTGS with SCTT under NDDC strategy is excellent. In real engineering cases, the NDDC strategy can be adopted to optimize the design of the governor and improve the power supply quality of hydropower station. Full article