Integrating renewable sources into energy system for smart city as a sagacious strategy towards clean and sustainable process

The power generated by a wind turbine largely depends on the wind speed. During time periods with identical hub-height wind speeds but different shapes to the wind profile, a turbine will produce different amounts of power. This variability may be induced by atmospheric stability, which affects profiles of mean wind speed, direction and turbulence across the rotor disk. Our letter examines turbine power generation data, segregated by atmospheric stability, in order to investigate power performance dependences at a West Coast North American wind farm. The dependence of power on stability is clear, regardless of whether time periods are segregated by three-dimensional turbulence, turbulence intensity or wind shear. The power generated at a given wind speed is higher under stable conditions and lower under strongly convective conditions: average power output differences approach 15%. Wind energy resource assessment and day ahead power forecasting could benefit from increased accuracy if atmospheric stability impacts were measured and appropriately incorporated in power forecasts, e.g., through the generation of power curves based on a range of turbulence regimes.

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Atmospheric Stability Affects Wind Turbine Power Collection

Urban wind conditions and small wind turbines in the built environment: A review

Review of hydrodynamics instabilities in Francis turbine during off-design and transient operations

In this paper, a fractional order mathematical model of a hydro-turbine governing system is presented to analyze the dynamic stability of the hydro-turbine governing system in the process of operation. The fractional order hydro-turbine governing system is composed of a hydro-turbine and penstock system, a generator system and a hydraulic servo system. As a pioneering work, we proposed a universal solution about the relationship of two parameters in higher-degree equations according to the stability theorem of a fractional order system. Based on the above theorem, we presented a variable law of stable regions of the fractional-order hydro-turbine governing system and analyzed the effect of various degree of elastic water hammer on the stable regions of the parameters k d and k p with the increase of fractional order α . The nonlinear dynamic behaviors of the system are also studied in detail. Finally, all of these results supply some basic theories for the running of a hydropower plant.

Modeling and stability analysis of a fractional-order Francis hydro-turbine governing system

CFD study on prediction of vortex shedding in draft tube of Francis turbine and vortex control techniques

Transient numerical analysis of rotor–stator interaction in a Francis turbine

This paper investigates the applicability of the assumed wind fields in International Electrotechnical Commission (IEC) standard 61400 Part 2, the design standard for small wind turbines, for a turbine operating in the built environment, and the effects these wind fields have on the predicted performance of a 5 kW Aerogenesis turbine using detailed aeroelastic models developed in Fatigue Aerodynamics Structures and Turbulence (FAST). Detailed wind measurements were acquired at two built environment sites: from the rooftop of a Bunnings Ltd. warehouse at Port Kennedy (PK) (Perth, Australia) and from the small wind turbine site at the University of Newcastle at Callaghan (Newcastle, Australia). For both sites, IEC 61400-2 underestimates the turbulence intensity for the majority of the measured wind speeds. A detailed aeroelastic model was built in FAST using the assumed wind field from IEC 61400-2 and the measured wind fields from PK and Callaghan as an input to predict key turbine performance parameters. The results of this analysis show a modest increase in the predicted mean power for the higher turbulence regimes of PK and Callaghan as well as higher variation in output power. Predicted mean rotor thrust and blade flapwise loading showed a minor increase due to higher turbulence, with mean predicted torque almost identical but with increased variations due to higher turbulence. Damage equivalent loading for the blade flapwise moment was predicted to be 58% and 11% higher for a turbine operating at Callaghan and PK respectively, when compared with IEC 61400-2 wind field. Time series plots for blade flapwise moments and power spectral density plots in the frequency domain show consistently higher blade flapwise bending moments for the Callaghan site with both the sites showing a once-per-revolution response.

https://www.rees-journal.org/articles/rees/pdf/2017/01/rees170022s.pdf

Anup Kc

Papers

Urban wind conditions and small wind turbines in the built environment: A review

CFD study on prediction of vortex shedding in draft tube of Francis turbine and vortex control techniques

Transient numerical analysis of rotor–stator interaction in a Francis turbine

The suitability of the IEC 61400-2 wind model for small wind turbines operating in the built environment

An investigation of the impact of wind speed and turbulence on small wind turbine operation and fatigue loads