Dynamic modeling and dynamical analysis of pump-turbines in S-shaped regions during runaway operation

Zhang, Hao; Chen, Diyi; Wu, Changzhi; Wang, Xiangyu; Lee, Jae-Myung; Jung, Kwang-Hyo

doi:10.1016/j.enconman.2017.01.053

Cited by 84 publications

(24 citation statements)

References 23 publications

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“…Moreover, the chaoticity of this model has been numerically examined by calculating the maximal Lyapunov exponents using the Wolf's algorithm. The calculations show that chaos exists in this system when the fractional parameter lies in the intervals (0, 1) and (1,2).…”

Section: Complexitymentioning

confidence: 93%

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Dynamics, Chaos Control, and Synchronization in a Fractional‐Order Samardzija‐Greller Population System with Order Lying in (0, 2)

et al. 2018

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This paper demonstrates dynamics, chaos control, and synchronization in Samardzija-Greller population model with fractional order between zero and two. The fractional-order case is shown to exhibit rich variety of nonlinear dynamics. Lyapunov exponents are calculated to confirm the existence of wide range of chaotic dynamics in this system. Chaos control in this model is achieved via a novel linear control technique with the fractional order lying in (1, 2). Moreover, a linear feedback control method is used to control the fractional-order model to its steady states when 0<α<2. In addition, the obtained results illustrate the role of fractional parameter on controlling chaos in this model. Furthermore, nonlinear feedback synchronization scheme is also employed to illustrate that the fractional parameter has a stabilizing role on the synchronization process in this system. The analytical results are confirmed by numerical simulations.

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Section: Complexitymentioning

confidence: 93%

“…Dynamic analysis of engineering and biological models has become an important issue for research [1][2][3][4][5][6][7][8][9][10]. One of the most fascinating dynamical phenomena is the existence of chaotic attractors.…”

Section: Introductionmentioning

confidence: 99%

Dynamics, Chaos Control, and Synchronization in a Fractional‐Order Samardzija‐Greller Population System with Order Lying in (0, 2)

et al. 2018

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“…This is not consistent with the actual water head of PSU, which may lead to unstable and discontinuous simulation in the start-up condition and running condition conversion. Therefore, the improved method is as in Equation (13), which takes into account when the guide vane opening is very small or zero. Hence, it guarantees the consistency between the calculation and the actual operation of the pump-turbine.…”

Section: Modeling Of Pump-turbinementioning

confidence: 99%

A Real-Time Accurate Model and Its Predictive Fuzzy PID Controller for Pumped Storage Unit via Error Compensation

et al. 2017

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Model simulation and control of pumped storage unit (PSU) are essential to improve the dynamic quality of power station. Only under the premise of the PSU models reflecting the actual transient process, the novel control method can be properly applied in the engineering. The contributions of this paper are that (1) a real-time accurate equivalent circuit model (RAECM) of PSU via error compensation is proposed to reconcile the conflict between real-time online simulation and accuracy under various operating conditions, and (2) an adaptive predicted fuzzy PID controller (APFPID) based on RAECM is put forward to overcome the instability of conventional control under no-load conditions with low water head. Respectively, all hydraulic factors in pipeline system are fully considered based on equivalent lumped-circuits theorem. The pretreatment, which consists of improved Suter-transformation and BP neural network, and online simulation method featured by two iterative loops are synthetically proposed to improve the solving accuracy of the pump-turbine. Moreover, the modified formulas for compensating error are derived with variable-spatial discretization to improve the accuracy of the real-time simulation further. The implicit RadauIIA method is verified to be more suitable for PSUGS owing to wider stable domain. Then, APFPID controller is constructed based on the integration of fuzzy PID and the model predictive control. Rolling prediction by RAECM is proposed to replace rolling optimization with its computational speed guaranteed. Finally, the simulation and on-site measurements are compared to prove trustworthy of RAECM under various running conditions. Comparative experiments also indicate that APFPID controller outperforms other controllers in most cases, especially low water head conditions. Satisfying results of RAECM have been achieved in engineering and it provides a novel model reference for PSUGS.

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“…The change in load, together with frequent starts and stops, represents one of the most important characteristics of a pump-turbine: it allows one to counter the increased need for leveling the peak demand of electrical energy and to better balance the system. For these reasons, pump-turbines' working conditions are particularly suitable to be investigated using unsteady analyses [4,5].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Internal Flow Field of a Reversible Turbine during Continuous Guide Vane Closing

et al. 2017

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The unsteady flow field in a reversible pump-turbine is investigated during the continuous load rejection using a 3D computational fluid dynamic analysis. Numerical calculations are carried out using the detached eddy simulation (DES) turbulence model and a new approach involving automatic mesh motion. In this way, the instability of the flow field is analyzed by continuously changing the guide vane openings from the best efficiency point (BEP). Unsteady flow characteristics are described by post-processing signals for several monitoring points including mass flow, torque, head and pressure in the frequency and time-frequency domains. The formation of vortices of different scales is observed from the origin to further enlargement and stabilization; the effect of the rotating structures on the flow passage is analyzed, and the influence of unsteady flow development on the performance of the turbine is investigated. Finally, the evolution during the period of load rejection is characterized in order to determine the hydrodynamic conditions causing the vibrations in the machine.

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Dynamic modeling and dynamical analysis of pump-turbines in S-shaped regions during runaway operation

Cited by 84 publications

References 23 publications

Dynamics, Chaos Control, and Synchronization in a Fractional‐Order Samardzija‐Greller Population System with Order Lying in (0, 2)

Dynamics, Chaos Control, and Synchronization in a Fractional‐Order Samardzija‐Greller Population System with Order Lying in (0, 2)

A Real-Time Accurate Model and Its Predictive Fuzzy PID Controller for Pumped Storage Unit via Error Compensation

Numerical Study on the Internal Flow Field of a Reversible Turbine during Continuous Guide Vane Closing

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