International Journal of Industrial Electronics and Electrical Engineering, ISSN: 2347-6982 Volume-4, Issue-4, Apr.-2016
1
RASHMI RANJAN PRADHAN,
2
SRINIBAS SWAIN,
3
DEVARCHETTI SAI VENKATESH,
4
RATI RANJAN SABAT
4
Associate Professor
1,2,3,4
Deptt. EEE-Dept. Gandhi Institute of Engineering and Technology, GUNUPUR
Abstract- Wind energy conversion system have been attracting wide attention as renewable energy source though copious technology varies continually. Wind power provides ecofriendly power generation and helps to encounter the national energy requirements, when there is a diminishing trend in terms of non-renewable assets. This paper moderates the modeling and simulation of Wind Energy Conversion Systems (WECS), and a functional structure of a wind energy conversion system. In addition, the modeling & dynamic behavior of a variable wind turbine is explained in detail & the turbine performance curves are simulated in the MATLAB/Simulink. The main objective of the paper is make WES systems more coherent and cost effective for developing an economically feasible solution to increasing environmental issues through proper transmission of wind generated power.
1. INTRODUCTION
One way of addressing the arising energy demands and growing environmental concerns, is to tackle green sources of power. Among these, tapping wind energy with wind turbines appears to be the most optimistic source of renewable energy. Wind energy conversion systems are used to catch the energy available in the wind to convert into electrical energy.
Renewable energy including solar, wind, tidal, small hydro geothermal, refused obtained fuel and fuel cell energies is sustainable, reusable and environmentally friendly and clean. With the growing scarcity in fossil fuels, and pollution problems renewable energy has become a salient energy source. Among the other renewable energy sources wind energy has evinced to be one of the most economical one. Ultimately
Constant speed WECS were initiated to generate constant frequency voltages from the variable wind.
However, irregular speed WECS operations can be contemplated advantageous, because additional energy can be collected as the wind speed increases.
A dynamic steady state simulation of wind energy conversion system is essential to understand the behavior of wind energy conversion. This paper traverses steady-state characteristics of a typical variable-speed wind energy conversion that uses doubly fed induction generators using MATLAB. A
Simulation scrutiny is performed and a variety of double fed induction generator characteristics, including real and reactive-power over speed characteristics are analyzed.
II. FUNCTIONALITY OF A WIND TURBINE
A wind energy conversion system is a complex system in which grasp from a wide array of fields embracing of aerodynamics, mechanical, civil and electrical engineering come together. The principle components of a contemporary wind turbine are the tower, the rotor and the creel, which holds the transmission mechanisms and the generator. The wind turbine seizes the wind’s kinetic energy in the rotor consisting of two or more blades mechanically coupled to an electrical generator. The foremost component of the mechanical assembly is the gearbox, which modifies the slower rotational paces of the wind turbine to higher rotational speeds on the electrical generator side. The rotation of the electrical generator’s shaft handled by the wind turbine generates electricity, whose output is preserved as per specifications, by employing suitable control and directing techniques. Besides recording the output, these control systems also include protection systems to secure the overall system. In this paper the dynamic model of a wind turbine is developed and simulated in the MATLAB/Simulink, hinge on the turbine performance curves.
III. WIND TURBINE MODELLING
The modeling of wind turbine is to control the high power wind turbine’s performance and various parameter characteristics to meet a required operational characteristic. In this paper A 1.5 MW wind farm consisting of a 1.5 MW wind turbine coupled to a 25-kV distribution system transports power to a 120-kV grid through a 30-km, 25-kV feeder. A plant existing of a motor load (induction motor at 0.93 PF) and a resistive load is fastened on the same feeder at bus B25. Both the wind turbine and the motor load have a secure system monitoring voltage, current and machine speed. The DC link voltage of the DFIG is also observed.
Modeling And Simulation Of High Power Wind Energy Conversion System Connected To Long Transmission Line
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International Journal of Industrial Electronics and Electrical Engineering, ISSN: 2347-6982 Volume-4, Issue-4, Apr.-2016
Fig-1 Block Diagram of a wind turbine connected to a grid
3.1 Inputs and Outputs of a Wind Turbine P is the Mechanical Power extracted by the rotor in
The inputs and output variables of wind turbine can be shattered into the following:
1.
The independent input quantity wind speed, watts.
V is the wind velocity at the commencement of the rotor blades in m/s.
2.
determines the energy input to the wind turbine.
Turbine speed, rotor blade slope, and rotor blade pitch angle, arising from the transmission system of the wind energy conversion system.
3.
Turbine output quantities, namely Power or
Drive torque, which may be controlled by altering the above three input amounts.
3.3. Tip Speed Ratio
The tip speed ratio λ , described as the ratio of the linear speed at the tip of the blade to the free stream wind speed and is given by the following proclamation.
TSR = λ= ω R /V
3.2. Power Extraction from the Air Stream
With the recognition of the wind turbine’s input and output variables, now it is possible to derive an expression relating these two values. The link between the power and wind speed is acquired as follows
The kinetic energy in air of mass m moving with speed V is given by the backing:
Kinetic energy =½·m.V2 Joules
The power in moving air flow is the drift rate of kinetic energy per second.
Power =½ · (mass flow rate per second).V2
Where:
IV. SIMULATION RESULTS
Where:
R is the rotor blade radius in meters ω is the rotor angular speed in rad/sec.
TSR is associated to the wind turbine employing point for extracting maximum power. The maximum rotor efficiency is attained at a particular tip speed ratio
TSR, which is distinct to the aerodynamic outline of a given turbine. The rotor must turn at high-speed at high wind, and at low-speed at low wind, to keep tip speed ratio TSR persistent at the optimum level at all times. The larger the tip speed ratio TSR, the quicker is the rotation of the wind turbine rotor at an exact wind speed. High (rotational) speed turbines are proposed for efficient electricity generation.
Fig-2 Wind Speed (m/s)
Fig-3 Pitch Angle (Deg)
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International Journal of Industrial Electronics and Electrical Engineering, ISSN: 2347-6982 Volume-4, Issue-4, Apr.-2016
Fig-4 Rotor Speed (Pu)
Fig-5 DC Voltage (V)
Fig-6 Generated Power P (MW)
Fig-7 Generated Power Q (MW)
The below figure shows the Torque-Speed characteristics of the turbine used in the windmill.
Fig-8 Turbine Power Characteristics
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International Journal of Industrial Electronics and Electrical Engineering, ISSN: 2347-6982 Volume-4, Issue-4, Apr.-2016
From the graph it is noticed that with the change in wind speed from 8m/s to 14m/s the other parameters also changed to an extent that yields a change in the output power of the windmill. The pitch angle changes from 0 degree to 0.8 degree and the rotor speed changes from 0.8pu to 1.2pu. The DC voltage remain almost constant. The active power generated increased from 0.3MW to 1.5MW.
CONCLUSION
In this paper a variable speed wind energy conversion system has been presented. Prominence has been laid on the wind turbine part of the total system. A variable speed wind turbine replica was simulated based on the power coefficient curves. The acknowledgement of the simulated model was observed with dynamic load and changing wind states.
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