Model validation and stochastic stability of a hydro-turbine governing system under hydraulic excitations

Xu, Beibei; Chen, Diyi; Tolo, Silvia; Patelli, Edoardo; Jiang, Yanlong

doi:10.1016/j.ijepes.2017.08.008

Cited by 56 publications

(22 citation statements)

References 26 publications

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“…Defining the right items of Equations (15) and (16) as f 0 (x) and f i (x) respectively, they can be rewritten as follows:…”

Section: Stochastic Mathematical Model Of Hydraulic Vibrationmentioning

confidence: 99%

“…On the basis of the random vibration theory, the response spectrum method and advanced testing technology were used in the testing and calculation of large hydroelectric generating sets [15]. The dynamic characteristics of the stochastic hydro-turbine governing system were obtained from numerical experiments based on the simplified stochastic hydro-turbine governing model [16]. The dynamic interaction between the unsteady flow occurrence and the resulting vibration of the pipe was analyzed based on experiments and numerical models, and the importance of integrated analysis of fluid-structure interaction was then emphasized [17].…”

Section: Introductionmentioning

confidence: 99%

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Discussion on Stochastic Analysis of Hydraulic Vibration in Pressurized Water Diversion and Hydropower Systems

Zhou

Chen

2018

Water

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Hydraulic vibration exists in various water conveyance projects and has resulted in different operating problems, but its obvious effects on system's pressure head and stable operation have not been definitively addressed in the issued codes for engineering design, especially considering the uncertainties of hydraulic vibration. After detailed analysis of the randomness in hydraulic vibration and the commonly used stochastic approaches, in the basic equations for hydraulic vibration analysis, the random parameters and the formed stochastic equations were discussed for further probabilistic characteristic analysis of the random variables. Furthermore, preliminary investigation of the stochastic analysis of hydraulic vibration in pressurized pipelines and possible self-excited vibration in pumped-storage systems was presented for further consideration. The detailed discussion indicates that it is necessary to conduct further and systematic stochastic analysis of hydraulic vibration. Further, with the obtained frequencies and amplitudes in the form of a probability statement, the stochastic characteristics of various hydraulic vibrations can be investigated in detail and these solutions will be more reasonable for practical applications. Eventually, the stochastic analysis of hydraulic vibration will provide a basic premise to introduce its effect into the engineering design of water diversion and hydropower systems.

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“…Defining the right items of Equations (15) and (16) as f 0 (x) and f i (x) respectively, they can be rewritten as follows:…”

Section: Stochastic Mathematical Model Of Hydraulic Vibrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Discussion on Stochastic Analysis of Hydraulic Vibration in Pressurized Water Diversion and Hydropower Systems

Zhou

Chen

2018

Water

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“…The governor is the core component of the hydro-turbine governing system and contains the dead zone nonlinearity and saturation nonlinearity [38]. For the subsystem of hydraulics, the hydraulic nonlinearity becomes more significant with the increase of the length of the pipeline [39,40]. For instance, the nonlinearity of the head loss for the hydropower station with a long headrace tunnel would cause a nonlinear hydraulic gradient.…”

Section: Introductionmentioning

confidence: 99%

A Review of the Transient Process and Control for a Hydropower Station with a Super Long Headrace Tunnel

Guo

Zhu

2018

Energies

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The hydropower station with a super long headrace tunnel is a significant development type for hydropower energy. By constructing a super long headrace tunnel, the huge natural water fall head can be utilized to generate more electricity. With the development of hydropower energy, a hydropower station with a super long headrace tunnel becomes more and more competitive. Compared with a hydropower station with a short headrace tunnel, the transient process and control for a hydropower station with a super long headrace tunnel is much more complicated and becomes an intractable challenge. It is well known that the transient process and control is the basis of the design and operation of a hydropower station. To overcome the challenge of the transient process and control, much research has been carried out. This paper provides a systematic review on the latest research progress of the transient process and control for hydropower stations with a super long headrace tunnel. Firstly, two key issues for the transient process and control, i.e., hydraulic design optimization of the surge tank and operation control of unit, are illuminated. Secondly, for both single surge tanks and surge tanks with special types or combinations, the hydraulic design optimization methods are described. The most disadvantageous design and advantageous operation of surge tanks under combined operating conditions are discussed. Thirdly, the stability and regulation quality of the hydro-turbine governing system under isolated and grid-connected operation conditions are presented. Finally, some trends and recommendations for future research directions are made. A research thought for establishing the complete theory and application system of the transient process and control for hydropower stations with a super long headrace tunnel from the perspective of multi-slice and multi-scale is proposed.

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“…By the end of 2015, the combined installed hydropower station capacity reached 320.03 GW [4,5]. However, some challenges are also found in the operation of the hydro-turbine generator units [6][7][8][9][10], such as water hammer in the penstock, the self-oscillation of the machinery, the unbalanced magnetic pull, and so on. At the same time, with the rapid development of wind energy and the photovoltaic power generation in recent years, these unstable resources need to be balanced utilizing hydropower stations [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Modeling and Dynamic Analyses of the Hydro–Turbine Governing System in the Load Shedding Transient Regime

2018

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Load shedding processes are widespread in hydropower stations, which has great influence on the safe and stable operation of the hydro-turbine governing system. In order to study the dynamic characteristics of the hydro-turbine governing system during the load shedding process, a novel nonlinear mathematical model of the hydro-turbine governing system is established considering the hydro-turbine system, the generator system and the governor system. In particular, a novel nonlinear mathematical model of the six hydro-turbine transfer coefficients is presented based on the definitions and hydro-turbine internal characteristics. After that, from the viewpoint of nonlinear dynamics and the practical engineering, the dynamic characteristics of the hydro-turbine governing system are investigated utilizing bifurcation diagrams, time series, Poincare maps, power spectrums and phase planes. Some meaningful results are found. The advantages of the novel nonlinear mathematical model are illustrated and commented in detail in comparison with the previous model. Finally, these models and analysis results will provide some theoretical references for the operation of hydropower stations in the load shedding transient.Energies 2018, 11, 1244 2 of 17 to optimizing the control of the HTGS. Based on the polynomial robust H ∞ optimization method, Eker [16] presented a robust single-input multi-output design approach for governors for speed control of hydro-turbines. Khodabakhshian and Hooshmand [17] put forward a new robust proportionalintegral-derivative (PID) controller for automatic generation control of hydro-turbine power systems, which is designed mainly based on a maximum peak resonance specification. Ren et al. [18] proposed an improved cascade control strategy for hydro-turbine speed governors, which can effectively decrease fluctuations of the rotational speed under non-Gaussian disturbance conditions in practical hydropower plants. Chen et al. [19] focused on designing the fractional-order PID controller using a chaotic non-dominated sorting genetic algorithm II for the HTGS, which has a better performance than traditional integer PID controllers. Zhang et al.[20] created a brand new non-linear predictive control method using the Takagi-Sugeno (T-S) fuzzy method and the generalized predictive control, which can govern a non-linear system more effectively. Chen et al.[21] established a new nonlinear mathematical model of the HTGS with a surge tank, and then, the nonlinear dynamical behaviors of the system in small fluctuation process were studied in detail. Guo et al. [22] studied the stability of the HTGS of the hydropower station with sloping ceiling tailrace tunnel utilizing the Hopf bifurcation theory, and also got the algebraic criterion of the occurrence of Hopf bifurcation. Xu et al. [23] built the Hamiltonian mathematical model of the multi-hydro-turbine governing system with a sharing common penstock under the excitation of stochastic and shock load, and then, discussed the stability of the system by comparing ...

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Model validation and stochastic stability of a hydro-turbine governing system under hydraulic excitations

Cited by 56 publications

References 26 publications

Discussion on Stochastic Analysis of Hydraulic Vibration in Pressurized Water Diversion and Hydropower Systems

Discussion on Stochastic Analysis of Hydraulic Vibration in Pressurized Water Diversion and Hydropower Systems

A Review of the Transient Process and Control for a Hydropower Station with a Super Long Headrace Tunnel

Nonlinear Modeling and Dynamic Analyses of the Hydro–Turbine Governing System in the Load Shedding Transient Regime

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