Stochastic Analysis of Water Hammer and Applications in Reliability-Based Structural Design for Hydro Turbine Penstocks

Zhang, Qinfen Katherine; Karney, Bryan W.; Li-sheng, Suo; Colombo, Andrew F.

doi:10.1061/(asce)hy.1943-7900.0000414

Cited by 24 publications

(15 citation statements)

References 56 publications

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“…Also the probability of overtopping of the dam remains quite low for both the time scenarios considered, as shown in Table 1, while the probability of load rejection results quite signficant. This value is coherent with the historical average frequency of load rejection calculated on the basis of eight hydroelectric stations in China [21]. The overall results can be interpreted as proof of the robustness of the facility to rapid transients: even if a sudden rejection of the load is required the structural safety of the penstock is guaranteed.…”

Section: Resultssupporting

confidence: 81%

“…The network provides the modelling of the reservoir in order to evaluate the probaility of overtopping of the dam, as described in Section 3.2 under the different climate scenarios described in Section 3.1. The overtopping of the dam is assumed to potentially result in the load rejection, which can also be caused by the failure of the external power grid, on-site trasformer malfunction, human action or mechanical accidents in turbine units [21]. The section of the network modelling these failure mechanisms (Section 3.3) considers also the eventual occurrence of water hammer in the penstock of the station due to load rejection.…”

Section: Proposed Modelmentioning

confidence: 99%

“…This phenomenon, generally known as water hammer, threatens the structural safety of the station penstock and can trigger more critical accident scenarios jeopardizing the safety of the entire facility. In order to take into account the occurrence of the water hammer in the model, a stochastic approach was adopted on the basis of former studies [21]. Structural damages are assumed to occur when the combination loads acting on the penstock results higher than the yielding strength of the pipe material.…”

Section: Penstock Structural Reliability and Turbine Operationmentioning

confidence: 99%

See 2 more Smart Citations

Vulnerability of Hydropower Installations to Climate Change: Preliminary Study

Tolo

Patelli

Chen

2017

Proceedings of the 2nd International Conference on Uncertainty Quantification in Computational Sciences and Engineering (UNCECO

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Abstract. The climate trends observed worldwide over the past few decades appear to corroborate the concerns of the scientific community about the many threats posed by global warming. Future changes of the current climate are expected to occur on different scales all around the globe, hence modifying the environmental background on the basis of which technological installations have been designed and operated. This can potentially threat the safety of the installations as well as their. The development of suitable tools aiming to predict the impact of climate change on technological installations is then essential in the wider context of climate change mitigation. Hydropower installations play often a crucial role not only as a long-term renewable resource of energy but also for flood control and water supply in the case of droughts. All these aspects highlight the increasing importance of such installations as well as their growing vulnerability to natural hazards. It is hence essential to enlarge the current understanding of the interaction mechanisms between such installations and the changing surrounding environment in order to take adequate measures for climate change adaptation and ensure the future safety and productivity of hydropower production. The current study aims to provide a novel model for the evaluation of the impact of climate change on the safety of hydropower stations. The approach adopted allows to include in the model the uncertainty inevitably associated with the input variables and to propagate such uncertainty within the analysis. The model proposed is finally applied to a realistic case-study in order to highlight its potential and limitations.

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Section: Resultssupporting

confidence: 81%

Section: Proposed Modelmentioning

confidence: 99%

Section: Penstock Structural Reliability and Turbine Operationmentioning

confidence: 99%

See 1 more Smart Citation

Vulnerability of Hydropower Installations to Climate Change: Preliminary Study

Tolo

Patelli

Chen

2017

Proceedings of the 2nd International Conference on Uncertainty Quantification in Computational Sciences and Engineering (UNCECO

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“…Based on the established stochastic model of the water level in a surge tank, in which pipe roughness and original load were random variables, probability density functions of the head loss and maximum relative surge were deduced and further case analysis showed better agreement with results from the Monte Carlo method [25]. Finally, Zhang et al [26] provided a preliminary exploration of a stochastic design for water hammer loading explicitly by considering various random parameters and conditions to advance the undertaking of reliability-based structural design.…”

Section: Introductionmentioning

confidence: 97%

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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“…Probabilistic solutions of the WHE can be obtained with Monte Carlo simulations (MCS Duan, ; Zhang et al, ). This method is robust and easy to implement but suffers from slow convergence and correspondingly high computational cost.…”

Section: Introductionmentioning

confidence: 99%

Method of Distributions for Water Hammer Equations With Uncertain Parameters

Alawadhi

Boso

Tartakovsky

2018

Water Resources Research

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Water hammer equations (WHE) are routinely used to interpret leak detection tests in pipe networks. Assimilation of pressure data into model predictions is typically done within the probabilistic framework, which treats uncertain model parameters (e.g., initial and boundary conditions, location, and intensity of a leak) as random variables so that solutions of the WHE are given in terms of probability density functions (PDFs) of fluid pressure and velocity. These are usually estimated with computationally expensive Monte Carlo simulations. We use the method of distributions to derive a deterministic equation for the (joint) PDFs of the pressure and flow rate governed by the WHE. This PDF equation employs a closure approximation that ensures the self‐consistency in terms of the mean and variance of the state variables. Our numerical experiments demonstrate the agreement between solutions of the PDF equation and Monte Carlo simulations, and the computational efficiency of the former relative to the latter.

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Stochastic Analysis of Water Hammer and Applications in Reliability-Based Structural Design for Hydro Turbine Penstocks

Cited by 24 publications

References 56 publications

Vulnerability of Hydropower Installations to Climate Change: Preliminary Study

Vulnerability of Hydropower Installations to Climate Change: Preliminary Study

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

Method of Distributions for Water Hammer Equations With Uncertain Parameters

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