Dynamic Safety Assessment in Nonlinear Hydropower Generation Systems

Li, Shuang; Yang, Yong; Xia, Qing

doi:10.1155/2018/5369253

Cited by 2 publications

(2 citation statements)

References 30 publications

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“…The pressure pulsation characteristics with different typical guide-vane closures were analyzed during the load-reduction process. In [33], stability problems in a hydropower station were analyzed using a nonlinear hydropower generation system for the load rejection transient process, where the authors carried out a dynamic safety assessment of the evolution behavior in the transient process. Thus, the framework of dynamic safety assessment aiming at transient processes should not only provide the guidance for safe operation, but also supply the design standard for hydropower stations.…”

Section: Dynamic Effects In Hydropower Systemsmentioning

confidence: 99%

Mathematic Modelling of a Reversible Hydropower System: Dynamic Effects in Turbine Mode

Ramos

Coronado-Hernández

Morgado

et al. 2023

Water

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Over the past few years, there has been significant interest in the importance of reversible hydro-pumping systems due to their favorable flexibility and economic and environmental characteristics. When designing reversible lines, it is crucial to consider dynamic effects and corresponding extreme pressures that may occur during normal and emergency operating scenarios. This research describes essentially the turbine operation, although various boundary elements are mathematically formulated and presented to provide an understanding of the system complexity. Different numerical approaches are presented, based on the 1D method of characteristics (MOC) for the long hydraulic circuit, the dynamic turbine runner simulation technique for the behavior of the power station in turbine mode and the interaction with the fluid in the penstock, and a CFD model (2D and 3D) to analyze the flow behavior crossing the runner through the velocity fields and pressure contours. Additionally, the simulation results have been validated by experimental tests on different setups characterized by long conveyance systems, consisting of a small scale of pumps as turbines (at IST laboratory) and classical reaction turbines (at LNEC laboratory). Mathematical models, together with an intensive campaign of experiments, allow for the estimation of dynamic effects related to the extreme transient pressures, the fluid-structure interaction with rotational speed variation, and the change in the flow. In some cases, the runaway conditions can cause an overspeed of 2–2.5 of the rated rotational speed (NR) and an overpressure of 40–65% of the rated head (HR), showing significant impacts on the pressure wave propagation along the entire hydraulic circuit. Sensitivity analyses based on systematic numerical simulations of PATs (radial and axial types) and reaction turbines (Francis and Kaplan types) and comparisons with experiments are discussed. These evaluations demonstrate that the full-load rejection scenario can be dangerous for turbomachinery with low specific-speed (ns) values, in particular when associated with long penstocks and fast guide vane (or control valve) closing maneuver.

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Section: Dynamic Effects In Hydropower Systemsmentioning

confidence: 99%

Mathematic Modelling of a Reversible Hydropower System: Dynamic Effects in Turbine Mode

Ramos

Coronado-Hernández

Morgado

et al. 2023

Water

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“…Li, Yang, and Xia [17] have published a study that focused on the stability problems in a hydropower station, where a nonlinear hydropower generation system for the load rejection transient process was considered. They identified four critical variables of the system.…”

Section: Introductionmentioning

confidence: 99%

Evaluating Fractional PID Control in a Nonlinear MIMO Model of a Hydroelectric Power Station

et al. 2019

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In this paper a Fractional PID Control is presented. This control was designed for a hydropower plant with six generation units working in an alternation scheme. The parameters and other features of such a set of hydrogeneration units have been used to perform the respective tuning up. In order to assess the behavior of this controlled system, a model of such nonlinear plant is regulated through a classical PID by classical linearization of its set points, and then a pseudo-derivative part is substituted into a Fractional PID. Both groups of signals contain variations of voltage suggesting some abrupt changes in the supply of electricity fed to the network. Both sets of resulting signals are compared; the simulations show that the Fractional PID has a faster response with respect to those plots obtained from the classical PID used.

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Dynamic Safety Assessment in Nonlinear Hydropower Generation Systems

Cited by 2 publications

References 30 publications

Mathematic Modelling of a Reversible Hydropower System: Dynamic Effects in Turbine Mode

Mathematic Modelling of a Reversible Hydropower System: Dynamic Effects in Turbine Mode

Evaluating Fractional PID Control in a Nonlinear MIMO Model of a Hydroelectric Power Station

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