According to a research on the 30kVA simulation experimental platform of hydraulic wind tur- bine, its basic structure, composition and operation principle are expounded in this paper. An in- verter motor is used to s...According to a research on the 30kVA simulation experimental platform of hydraulic wind tur- bine, its basic structure, composition and operation principle are expounded in this paper. An in- verter motor is used to simulate the wind turbine, while a similarity calculation method is applied be- tween the small and large wind turbine. A fixed displacement pump-variable motor closed loop is used as the main transmission system, and a self-excited synchronous generator generates electricity through the grid connection. The experiment and simulation study on the speed and power control of the hydraulic wind turbine is conducted, based on the experimental platform, thus correctness and progressiveness of the experiment platform is further verified. The experimental platform study lays a foundation for further research on the characteristics of hydraulic wind turhln~展开更多
The main technical problems that should be considered in the design of hydro-turbine generating units of Three Gorges Project (TGP) are analyzed;the key technical researches performed are summarized,and the parameters...The main technical problems that should be considered in the design of hydro-turbine generating units of Three Gorges Project (TGP) are analyzed;the key technical researches performed are summarized,and the parameters of hydro-turbine generating units are optimized through the study on key technical problems.The unit operation indicates that the performance of the hydro-turbine generating units is excellent,and the units can operate in a safe,stable and highly efficient mode for a long term.Therefore,it is verified effectively that the general technical design of units is scientific and rational.展开更多
This paper presents small-signal study based on eigenvalue analysis as a preliminary study to observe the interaction between multimass turbine-generator system and inverter-based distributed generation in a microgrid...This paper presents small-signal study based on eigenvalue analysis as a preliminary study to observe the interaction between multimass turbine-generator system and inverter-based distributed generation in a microgrid. The multimass turbine model is included in the overall distributed generation system model. Two case studies are demonstrated to observe the interaction between turbine-generator set and power electronics-based distributed generation system. Both case studies are in stand-alone and grid-connected operation. It can be shown that under stand-alone operation, unstable oscillatory modes may occur and be highly influenced by the operating points of the system.展开更多
The performance of a reversible pump turbine with S-shaped characteristics is of great importance to the transition processes such as start-up and load rejection. In order to predict the S-shaped curve accurately and ...The performance of a reversible pump turbine with S-shaped characteristics is of great importance to the transition processes such as start-up and load rejection. In order to predict the S-shaped curve accurately and develop a reliable tool for design improvement, a shear stress transport model (SST) with various numerical schemes for pressure term in the governing equation was investigated in a whole pump turbine including spiral casing, stay vanes, guide vanes, runner and draft tube. Through the computation, it was shown that different zones in the curve should employ different schemes to get the solution converged. Comparison of discharge-speed performance showed that good correspondence is got between experimental data and CFD results. Based on this, internal flow analysis was carried out at three typical operating points representing turbine mode, shut-off mode and reversible pump mode, respectively. According to the flow field concerned, the mechanism for the speed-no-load instability was explained, which provides good guidelines to take countermeasures in future design.展开更多
Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow w...Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.展开更多
基金Supported by the National Key Basic Research Development Program of China(No.2014CB046405)the National Natural Science Foundation of China(No.51475406,51405423)the Hebei Youth Fund(No.QN20132017)
文摘According to a research on the 30kVA simulation experimental platform of hydraulic wind tur- bine, its basic structure, composition and operation principle are expounded in this paper. An in- verter motor is used to simulate the wind turbine, while a similarity calculation method is applied be- tween the small and large wind turbine. A fixed displacement pump-variable motor closed loop is used as the main transmission system, and a self-excited synchronous generator generates electricity through the grid connection. The experiment and simulation study on the speed and power control of the hydraulic wind turbine is conducted, based on the experimental platform, thus correctness and progressiveness of the experiment platform is further verified. The experimental platform study lays a foundation for further research on the characteristics of hydraulic wind turhln~
文摘The main technical problems that should be considered in the design of hydro-turbine generating units of Three Gorges Project (TGP) are analyzed;the key technical researches performed are summarized,and the parameters of hydro-turbine generating units are optimized through the study on key technical problems.The unit operation indicates that the performance of the hydro-turbine generating units is excellent,and the units can operate in a safe,stable and highly efficient mode for a long term.Therefore,it is verified effectively that the general technical design of units is scientific and rational.
文摘This paper presents small-signal study based on eigenvalue analysis as a preliminary study to observe the interaction between multimass turbine-generator system and inverter-based distributed generation in a microgrid. The multimass turbine model is included in the overall distributed generation system model. Two case studies are demonstrated to observe the interaction between turbine-generator set and power electronics-based distributed generation system. Both case studies are in stand-alone and grid-connected operation. It can be shown that under stand-alone operation, unstable oscillatory modes may occur and be highly influenced by the operating points of the system.
基金supported by the National Natural Science Foundation of China (Grant No. 50979095)
文摘The performance of a reversible pump turbine with S-shaped characteristics is of great importance to the transition processes such as start-up and load rejection. In order to predict the S-shaped curve accurately and develop a reliable tool for design improvement, a shear stress transport model (SST) with various numerical schemes for pressure term in the governing equation was investigated in a whole pump turbine including spiral casing, stay vanes, guide vanes, runner and draft tube. Through the computation, it was shown that different zones in the curve should employ different schemes to get the solution converged. Comparison of discharge-speed performance showed that good correspondence is got between experimental data and CFD results. Based on this, internal flow analysis was carried out at three typical operating points representing turbine mode, shut-off mode and reversible pump mode, respectively. According to the flow field concerned, the mechanism for the speed-no-load instability was explained, which provides good guidelines to take countermeasures in future design.
文摘Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.
