Canal lock variable speed hydropower turbine design and control

Abstract

The design of a novel submerged hydraulic turbine for producing electricity by converting the available hydropower on canal locks during raising and lowering ships, but with the minimum overall impact on the facility, is being considered. The hydraulic head in such applications is low (few meters) and varies over time (from its maximum value down to zero) resulting in a low potential conversion of hydraulic head in electrical energy. The study involves the modification of the hydraulic transient system, the design and performance estimation of a hydraulic turbine. Based on the performance curves, a permanent magnet Vernier generator is designed. The models of hydraulic turbine and generator are added to the system model and simulations results of the whole system are presented.

Maximum power extraction from a hydrokinetic energy conversion system

“…V dc, k and P k are the values of the rectifier voltage and the power at time t k and S is the convergence speed coefficient. According to (20), the voltage V dc is perturbed and the resulting power P is measured. For a specific perturbation of V dc , if the electrical power is increased, then a step change S in voltage with the same sign takes place.…”

“…Then, the generated power P is calculated and used as an input to the MPPT stage. At the MPPT stage, a reference value for the voltage V dc * is chosen according to (20). The difference between the measured and the reference value of the voltage V dc is fed to a PI controller.…”

“…It is relevant to mention that references [18][19][20][21][22][23][24] exploit the knowledge behind MPPT algorithms reported for wind applications. However, when such an approach is adopted the performance of the algorithms needs to be further investigated under the presence of restricted and turbulent water flows.…”

The Benefits of Variable Speed Operation in Hydropower Plants Driven by Francis Turbines

“…While the Francis runner is known to allow a wide variation in its operating flow, changes in the head result in an extreme reduction of efficiency. Figures 6 and 7 present the normalized efficiency curves of Francis runners for four different specific speeds as a function of the normalized flow and for the normalized head at constant rotational speed and head [59][60][61]. Thus, once designed for a specific rated condition, the Francis runner must work within very narrow application limits.…”

“…Figure 6and 7 present the normalized efficiency curves of Francis runners for four different specific speeds as a function of the normalized flow and for the normalized head at constant rotational speed and head[59][60][61].…”