This paper presents the comparison of power captured by vertical and horizontal axis wind turbine (VAWT and HAWT). According to Betz, the limit of maximum coefficient power (CP) is 0.59. In this case CP is important parameter that determines the power extracted by a wind turbine we made. This paper investigates the impact of wind speed variation of wind turbine to extract the power. For VAWT we used H-darrieus type whose swept area is 3.14 m2 and so is HAWT. The wind turbines have 3 blades for each type. The air foil of both wind turbines are NACA 4412. We tested the model of wind turbine with various wind velocity which affects the performance. We have found that CP of HAWT is 0.54 with captured maximum power is 1363.6 Watt while the CP of VAWT is 0.34 with captured maximum power is 505.69 Watt. The power extracted of both wind turbines seems that HAWT power is much better than VAWT power.

Performance comparison of vertical axis and horizontal axis wind turbines to get optimum power output

This paper aims at summarizing various methods used for representing and estimating the power coefficient in wind turbines, such as exponential, sinusoidal and polynomial models, as well as mathematical tools known as state observers. We present an exhaustive bibliographic review of the models used to calculate the power coefficient, given that this type of studies are scarce nowadays. In addition, we propose models that can be satisfactorily used for various analyzes of wind energy conversion systems, such as the representation by a polynomial function of fourth degree and the models based on the stochastic probability function. The relevance of this work is supported by the advantages and disadvantages of the various models and estimators of the power coefficient, which are presented at the end of the article in a comparative table with the purpose of offering to the reader a general summary. Ultimately, this review aims at helping researchers, students, university professors and those who wish to venture into this field, even though they do not have much experience, to establish a quick synthesized understanding of the different models and representations of the power coefficient.

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Representation and estimation of the power coefficient in wind energy conversion systems

Different types of renewable resources are need of the hour as fossil fuels are on The verge of extinction but electricity demand is increasing exponentially. In reality renewable energy is available in such a huge amount that it can provide 3078 times the present global energy need. Wind energy is one of these sources and having potential to generate 200 times energy than require globally. It is the oldest source of energy on the earth and from 1887 only it started to use for electricity generation. The efficiency of wind turbine, gear and generator decides the overall efficiency among this wind turbine is having scope of improvement. The wind turbine will generate maximum power if wind variation is less but it is not in someone's hand. Thus an MPPT technique comes into picture and maximizes power output. Various MPPT techniques are present till date, but in this paper we proposed perturb and observe, Incremental Conductance and Fuzzy logic control algorithms along with mechanical MPPT i.e. pitch control. These MPPT algorithms track the maximum power for varying wind conditions. Pitch control comes handy when speed increases more than rated speed, it will change pitch angle in such a way that it will rotate and constant speed to generate maximum power.

A Review on Various MPPT Techniques for Wind Energy Conversion System

The environment and the economy are negatively impacted by conventional energy sources, such as coal, gasoline, and other fossil fuels. Pakistan’s reliance on these resources has resulted in a catastrophic energy crisis. This has driven the government to make critical decisions such as early retail closures, power outages for the industrial sector, and an increase to two days a week vacations. Wind energy, accessible and affordable, will become a viable option for meeting Pakistan’s present and future energy demands. Approximately 3% of Pakistan’s land can produce nearly 132 GW of power with an installed capacity of 5 MW per km2. In this study, four zones (Karachi, Thatta, Badin, and Jamshoro) in Sindh province are assessed for the feasibility of wind energy generation. The installed capacity, generator types, and detailed specifications are provided for each zone. Moreover, the wind mapping of Pakistan is presented considering the four potential zones. The zones are analyzed using annual wind speed and power output considering wind data measured at 50 m height over one year. The higher mean speed is recorded at Jamshoro compared to other zones. The analysis indicates that all four sites are suitable for large-scale wind power generation due to their energy potential.

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Wind Energy Potential in Pakistan: A Feasibility Study in Sindh Province

This paper presents the most important factors that influence the energy output of the wind system. Also, a mathematical model is presented for wind power & investigates the influence of such parameters on the electrical power generated by the wind turbine. The considered factors are wind speed, turbine swept area, air density, weather temperature, and height of tower. Power coefficient as a function of pitch angle and blade tip speed is also studied. This study can be used in the selection of wind turbine with optimal parameters, which yield the highest amount of energy can be captured from wind. Simulation MATLAB program is implemented for this study and wind turbine sample parameters have been used in this simulation.

Evaluation of factors affecting wind turbine output power

Due to rapid changes in wind velocity the power captured by a wind turbine varies continuously. Such operations are highly undesirable and needs controllers. Therefore in order to achieve the best performance of wind turbine under variable speed operation, there is a need to modify the design of wind turbine. Power coefficient, Cp is an important parameter that determines the power extracted by a wind turbine and also effect its performance. It is limited by Betz's limit to 0.593 and will vary with wind speed. It's variation under same operating condition may effect the performance of different machines in different manner. In this paper an attempt has been made to analyze such effect using fifteen wind turbines. Simulation results using MATLAB coding are found to be effective to propose few recommendations for the selection of wind turbines for variable wind speed zones.

Effect of change in power coefficient on the performance of wind turbines with different dimensions

For proper utilization of wind energy it is necessary to drive the wind turbine at maximum power points at all wind speeds. Speed control of rotor is done within the operating range of wind turbines for maximum power point tracking(MPPT). Controllers are used depending upon the range within which the control of rotor angular velocity is required and this range varies for various turbines. Smaller range for rotor speed control supports the economy of controllers. So, for a particular wind energy location, selection of wind turbine should be done in such a manner that it requires minimum speed control to track maximum power during wind variations. In this paper an attempt has been made to analyze the performance of wind turbines for MPPT. Simulation results using MATLAB coding are found to be effective to propose few recommendations for the selection of wind turbines suitable for MPPT.

Selection of wind turbine for MPPT

The energy extracting efficiency of a wind energy conversion system (WECS) depends on the suitability between wind turbine and wind energy conversion site. Capacity factor is a parameter widely used for matching wind turbines with a windy site with its high value desired. A high capacity factor ensures low cost of wind energy conversion system. In addition to this availability factor is another parameter of performance index of a wind turbine. A High value of availability factor indicates that wind turbine is operational most of the time. Availability factor is important because the decision of licensing agencies may depend on it in order to support the operational planning of the utility in the area. For a wind energy site these factors depends on speed ratings of the wind turbine i.e. cut-in speed, rated speed and cut-out speed. But these parameters have different effects on capacity factor and availability factor under different conditions. In this paper an attempt has been made to analyze such effect using fifteen wind turbines. Simulation results using MATLAB coding are found to be effective to propose few recommendations for the selection of wind turbines for variable wind speed zones.

Himani Kala

Papers

Effect of change in power coefficient on the performance of wind turbines with different dimensions

Selection of wind turbine for MPPT

Performance analysis of wind turbines with different ratings for site matching