Method to Estimate Complete Curves of Hydraulic Pumps through the Polymorphism of Existing Curves

Lima, Gustavo Meirelles; Luvizotto, Edevar

doi:10.1061/(asce)hy.1943-7900.0001301

Cited by 8 publications

(5 citation statements)

References 18 publications

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“…In [22], the authors developed a method for predicting complete pump curves using only normal operation data, along with curves from other machines with similar specific speeds. To model the complete curves, the authors used a trigonometric series and conducted particle swarm optimization (PSO) for fitting of the coefficients.…”

Section: Literature Reviewmentioning

confidence: 99%

Universal Form of Radial Hydraulic Machinery Four-Quadrant Equations for Calculation of Transient Processes

Giljen,

Nedeljković

2023

Energies

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Suter curves for the Wh and Wm characteristics and four-quadrant (4Q) diagrams of 11 radial pump–turbine models with different specific speeds (nq = 24.34, 24.8, 27, 28.6, 38, 41.6, 41.9, 43.83, 50, 56, and 64.04) are presented for the first time in this paper, as well as Suter curves for two pump models (nq = 25 and 41.8) previously published in the literature. All of these curves were analyzed to establish a certain universal law of behavior, depending on the specific speed. To determine such a law, a fitting procedure using regression and spline methods was carried out. This paper provides details of a research plan and structures (including data collection for four-quadrant diagrams for pump–turbine and pump models under different specific speeds nq), a procedure for re-calculating four-quadrant diagrams of the models as Suter curves for the Wh and Wm characteristics, definitions of the optimal points for pump and turbine operating modes in pump–turbine models under different specific speeds, and the development of numerical models in MATLAB to obtain a universal equation for the Wh and Wm characteristics. The scientific contribution of this paper is that it is the first to publish original mathematical curves using universal equations for the Wh and Wm characteristics of radial pumps and pump–turbines. The applicability of the equations is demonstrated by considering a pumping station in which two radial pumps were installed, for which the calculation of transient processes was performed using a numerical model developed in MATLAB by the authors. The transition process results are compared for two cases: first, when input data in the numerical model are used with the values of the Suter curves for the Wh and Wm characteristics obtained by re-calculating the four-quadrant operating characteristics (Q11, n11, M11) at a given specific speed, and second, when the values of the Suter curves for the Wh and Wm characteristics are obtained from the universal equations.

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Section: Literature Reviewmentioning

confidence: 99%

Universal Form of Radial Hydraulic Machinery Four-Quadrant Equations for Calculation of Transient Processes

Giljen,

Nedeljković

2023

Energies

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“…To evaluate the overspeed effect in a turbogenerator, the relative overpressure values shown in Figure 5 To evaluate the overspeed effect in a turbogenerator, the relative overpressure values shown in Figure 5 as a function of the specific turbine speed 𝑛 𝑠 and the relations 𝑇𝑤/𝑇𝑚 and 𝑇 𝑐 /𝑇𝐸 are estimated. The start-up time of rotating masses, Tm (s), is defined based on Equation (22):…”

Section: Overspeed Effect Due To Full-load Rejectionmentioning

confidence: 99%

“…Pérez-Sánchez et al (2018) [21], for instance, studied unsteady flows in systems containing small-inertia PATs using the EWCA, which was validated using experimental measurements. Pump characteristic curves (PCCs) are crucial input data in typical numerical formulations related to WDN design, real-time WDN operation, hydropower generation with PATs, leakage reduction using PATs, and the general assessment of transient flow scenarios [22]. However, PCCs, provided by the manufacturer, frequently do not include the turbine regime.…”

Section: Introductionmentioning

confidence: 99%

“…However, PCCs, provided by the manufacturer, frequently do not include the turbine regime. The utilization of the PCC of a similar pump, instead of the real behavior, may result in errors in unsteady flow simulations [22]. Usual methods for predicting PAT behavior are restricted by the limited sample size of complete curves of PATs that could be utilized for PCC calibration [10].…”

Section: Introductionmentioning

confidence: 99%

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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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“…As a crucial part of PSU, an accurate pump turbine model is the key to the accurate modeling and simulation of PTGS [10]. In the current research work, the modeling of a pump turbine is mainly based on complete characteristic curves where different operational conditions of this model can be described [11][12][13]. The complete curves of pump turbine include the flow characteristic curve and the moment characteristic curve.…”

Section: Introductionmentioning

confidence: 99%

An Improved Autoencoder and Partial Least Squares Regression-Based Extreme Learning Machine Model for Pump Turbine Characteristics

et al. 2019

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Complete characteristic curves of a pump turbine are fundamental for improving the modeling accuracy of the pump turbine in a pump turbine governing system. In view of the difficulty in modeling the "S" characteristic region of the complete characteristic curves in the pump turbine, a novel Autoencoder and partial least squares regression based extreme learning machine model (AE-PLS-ELM) was proposed to describe the pump turbine characteristics. First, a mathematical model was formulated to describe the flow and moment characteristic curves. The improved Suter transformation was employed to transfer the original curves into WH and WM curves. Second, the ELM-Autoencoder technique and the partial least squares regression (PLSR) method were introduced to the architecture of the original ELM network. The ELM-Autoencoder technique was employed to obtain the initial weights of the Autoencoder based extreme learning machine (AE-ELM) model. The PLS method was exploited to avoid the multicollinearity problem of the Moore-Penrose generalized inverse. Lastly, the effectiveness of the proposed AE-PLS-ELM model has been verified using real data from a pumped storage unit in China. The results demonstrated that the AE-PLS-ELM model can obtain better modeling accuracy and generalization performance than the traditional models and, thus, can be exploited as an effective and sufficient approach for the modeling of pump turbine characteristics.

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Method to Estimate Complete Curves of Hydraulic Pumps through the Polymorphism of Existing Curves

Cited by 8 publications

References 18 publications

Universal Form of Radial Hydraulic Machinery Four-Quadrant Equations for Calculation of Transient Processes

Universal Form of Radial Hydraulic Machinery Four-Quadrant Equations for Calculation of Transient Processes

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

An Improved Autoencoder and Partial Least Squares Regression-Based Extreme Learning Machine Model for Pump Turbine Characteristics

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