Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780 Available online @ www.ijntse.com 40 Design and Simulation of Turbine Design for Improving the Performance of Hydro Electric Power Plant Dr.Vimalakeerthy Devadoss 1 , Dr.M.Sivakumar 2 ,Humaid Abdullah Fadhil Al-Hinai3 2 , Hamood Salim Mohamed Al-Bimani 4 Lecturer, Nizwa College of Technology, Sultanate of Oman 1 , Lecturer, Nizwa College of Technology, Sultanate of Oman 2 , Student Nizwa College of Technology 3 , Nizwa College of Technology 4 , Sultanate of Oman Abstract: Hydro Electric power plant is both an renewable and reliable form of clean source of renewable energy. It has be an eminent method of harnessing renewable energy from small rivers and streams. This power plant is designed to be a run -of-river type, because it requires a reservoir in order to power the turbine. The working medium is water and it is mainly dependent on the nature of the seasons and secondly it rarely meets peak load demands. In this paper a detailed study of turbines is made and a simple new design of turbine is presented. The presented design if efficient in terms of the simplicity of construction, cost and efficiency. Mechanical software Solid Works is used to design the turbine. Construction of turbine is made using the design. A mode hydro electric power plant is simulated using presented turbine design MATLAB/SIMULINK and the results are presented for verification. Keywords: Hydro Electric Power plant, Turbine Design. I. INTRODUCTION Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy. Hydro plants range in size from "micro-hydros" that power only a few homes to giant dams like Hoover Dam that provide electricity for millions of people. Fig 1 shows the components of hydro electric power plant. Parts of a Hydroelectric Plant include: (i) Dam: Raises the water level of the river to create falling water. Also controls the flow of water. The reservoir that is formed is, in effect, stored energy. (ii)Turbine: The force of falling water pushing against the turbine's blades causes the turbine to spin. A water turbine is much like a windmill, except the energy is provided by falling water instead of wind. The turbine converts the kinetic energy of falling water into mechanical energy. (iii)Generator: Connected to the turbine by shafts and possibly gears so when the turbine spins it causes the generator to spin also. Converts the mechanical energy from the turbine into electric energy. (iv) Transmission lines. Conduct electricity from the hydropower plant to homes and business. To maintain the generator voltage frequency constant, the turbine must spin the generator at a constant speed given by P f n 120 (1) where f is the generated voltage frequency and p is the number of poles of the generator. Elaborate control schemes are used to regulate the flow of water in order to keep the turbine speed constant.
Transcript
Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780
Available online @ www.ijntse.com 40
Design and Simulation of Turbine Design for Improving the Performance of Hydro Electric
Lecturer, Nizwa College of Technology, Sultanate of Oman 1, Lecturer, Nizwa College of Technology, Sultanate of Oman 2, Student Nizwa College of Technology 3,
Nizwa College of Technology 4, Sultanate of Oman
Abstract: Hydro Electric power plant is both an renewable and reliable form of clean source of renewable energy. It has be an eminent method of harnessing renewable energy from small rivers and streams. This power plant is designed to be a run -of-river type, because it requires a reservoir in order to power the turbine. The working medium is water and it is mainly dependent on the nature of the seasons and secondly it rarely meets peak load demands. In this paper a detailed study of turbines is made and a simple new design of turbine is presented. The presented design if efficient in terms of the simplicity of construction, cost and efficiency. Mechanical software Solid Works is used to design the turbine. Construction of turbine is made using the design. A mode hydro electric power plant is simulated using presented turbine design MATLAB/SIMULINK and the results are presented for verification.
Keywords: Hydro Electric Power plant, Turbine Design.
I. INTRODUCTION Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the
kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy. Hydro plants range in size from "micro-hydros" that power only a few homes to giant dams like Hoover Dam that provide electricity for millions of people. Fig 1 shows the components of hydro electric power plant. Parts of a Hydroelectric Plant include:
(i) Dam: Raises the water level of the river to create falling water. Also controls the flow of water. The reservoir that is formed is, in effect, stored energy.
(ii)Turbine: The force of falling water pushing against the turbine's blades causes the turbine to spin. A water turbine is much like a windmill, except the energy is provided by falling water instead of wind.
The turbine converts the kinetic energy of falling water into mechanical energy. (iii)Generator: Connected to the turbine by shafts and possibly gears so when the turbine spins it
causes the generator to spin also. Converts the mechanical energy from the turbine into electric energy. (iv) Transmission lines. Conduct electricity from the hydropower plant to homes and business. To maintain the generator voltage frequency constant, the turbine must spin the generator at a constant speed given by
Pfn 120
(1)
where f is the generated voltage frequency and p is the number of poles of the generator. Elaborate control schemes are used to regulate the flow of water in order to keep the turbine speed constant.
Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780
Available online @ www.ijntse.com 41
Fig 1. Hydro Electric Power Plant
The potential energy of the water in the reservoir is proportional to the mass of water and the
difference in height between the water impoundment and the water outflow [1]. This height difference is called the head or effective head. That is
mghPE (2)
The mass of water is its volume times its density. Therefore, P.E. = volume × ρgh and the available hydro power becomes
ghqPw W (3) Where
q = rate of flow of water in m3/s h = effective head of water in m ρ = density of water ≈ 1000 kg/m3 g = acceleration of gravity = 9.81 m/s2
II TYPES OF TURBINE Water for a hydroelectric power station’s turbines can come from a specially constructed dam, set
high up in a mountain range, or simply from a river close to ground level. As water sources vary, water turbines have been designed to suit different locations [2][4]. The design used is determined largely by the head and quantity of water available at the particular site.
The three main types are: 1. Pelton wheels, 2. Kaplan or propeller type turbines (named after their inventors) and 3. Francis turbines
Fig 2 shows different types of turbine blades.
A. Pelton Wheel Turbine Pelton wheel is high head, horizontal shaft, peripheral flow, impulse turbine. It needs moderately less
Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780
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amount of water. It is especially intended buckets are consistently spaced with fixed around the edge of runner. Runner is hold on a horizontal shaft with is housed in a casing. Nozzle is fixed at end of penstock. It is give by a spear rod. Hand wheel is fixed to spear rod so as to respond it to get a preferred size jet of water. Water is conveying to turbine during penstock with nozzle to type a free jet of water.
Nozzle is reserved very close to bucket to minimize the losses due to windage. Moreover jet is so familiar that it is peripheral to pitch circle of runner. Jet of water at elevated velocity impinges the bucket. It might be noted that just a only some buckets will be strike by jet at a time. While a result the runner turn, supplying power to shaft.
After performing work on buckets water release freely in to tail race. Brake nozzle is use to hold up speed of runner rapidly to rest, by help of a direct water jet above back of buckets. In arrange to derive additional power, larger size runners by multiple nozzles are use. The amount of nozzles is depending on definite speed. Two nozzles by a horizontal shaft four or six nozzles by a vertical shaft are admired designs.
Fig 2. Turbine blade types
B. Kaplan Turbine A Kaplan turbine is basically a propeller with adjustable blades inside a tube. It is an axial-flow turbine,
which means that the flow direction does not change as it crosses the rotor. The inlet guide-vanes can be opened and closed to regulate the amount of flow that can pass through the turbine. When fully closed they will stop the water completely and bring the turbine to rest.
Depending on the position of the inlet guide-vanes they introduce differing amounts of ‘swirl’ to the flow, and ensure that the water hits the rotor at the most efficient angle for the highest efficiency. The Kaplan or propeller type turbines can be mounted at almost any angle, but this is usually vertical or horizontal.
C. Francis Turbine Francis turbine now a number of direct vanes are set about the circumference of runner. It is encircled
by a couple of upper with lower stay rings have continue vanes in among them. Every guide vane is prepared to turn on its pivot centre by help of individual link with lever. Runner is hold by a regulating shaft. Guide vanes function like to engine valves, allow simply necessary amount of water. Runner is enclosed in a spiral casing and scroll casing. Go out end of runner is attached to small end of draft tube. Big end of draft tube is inundated cavernous in tail race. Therefore whole water way right as of head race up to tail race is completely enclosed.
Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780
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III. DESIGN OF TURBINE SOLIDWORKS has been used for designing the turbine which is a 3D mechanical CAD
(computer-aided design) program that runs on Microsoft Windows and is being devel-oped by Dassault Systèmes SolidWorks Corp. It helps companies define, organize, and publish 3D Product Manufacturing Information (PMI) including 3D model data in indus-try standard file 3D PDF.
(a) (b) (c) (d)
Fig 3.(a),(b),(c) and (d). Mechanical design of new turbine
Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780
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The micro model turbine was constructed with the following dimensions. • Diameter of the inner wheel = 20cm • Wheel thickness =15mm • Blade thickness = 8 mm • Number of blades = 6 • Blade angle = 35 • Shaft Length = 30cm • Shaft diameter = 15 mm • Bearings = 15 mm • Mounting height= 80cm from ground levels
IV. MODELING OF ELECTRO HYDRO SERVO SYSTEM The equations related to the transient performance of the hydraulic turbines are based on the following
assumption [3]. • The blade of the hydraulic turbine`s blade is considered as smooth • The presence of water hammer on penstock is neglected. • The fluid in this micro model is assumed to be incompressible. • In the penstock the velocity of water varies directly with gate opening. • The output power developed by the turbine is proportional to the product of head and velocity of
flow. Equation 4 and 5 represents the flow rate and the developed mechanical power at the shaft
respectively in terms gate opening of the system and the net head [5]. HGQ
(4) Where Q is Flow rate in m3/sec, G is gate opening in rad,H is net head in meter. The developed power, Pm in turbine can be written as )( 1ntm QQHAP (5) Where, At is the turbine gain, and Qn1 is the no load flow rate Velocity of water in Penstock “U” is given by
HGKU u (6) Ku is proportional constant. Once the velocity of the water in penstock is determined, the relation of flow rate, head
GUQ (7) The mechanical power output is given by
im PPP (8) Where is the fixed power loss in turbine due to friction.
HUP NLi (9) Where UNL stands for no load speed.
The hydraulic characteristics and mechanical power output of the turbine is modeled here. The nonlinear characteristics of hydraulic turbine are neglected in this model.
Dr.Vimalakeerthy Devadoss. / International Journal of New Technologies in Science and Engineering Vol. 2, Issue. 6, 2015, ISSN 2349-0780
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V. MATLAB/SIMULINK MODEL OF MICRO HYDRO POWER PLANT The individual sub-models like hydro turbine governor, synchronous generator, excitation system and
3-phase RLC load are now connected together to form the com-plete block diagram of micro hydro power plant (Figure 4).
Fig 4. MATLAB/Simulink Model of a Hydro Power Plant
VI SIMULATION RESULTS OF MICRO HYDRO POWER PLANT MODEL The following figures show the simulation results of normal operation mode, where Fig.5 shows
excitation voltage, while Fig.6 shows rotation speed and Fig 7 shows output mechanical power of the turbine. All quantities are per unit, and the horizontal axis is always the time in second. In all the cases, the simulation time step is 100μs, the excitation field is activated at 0 s, and the total simulation time is 125 s. They demonstrate that the proposed turbine model can be considered to be acceptable for future turbine designs. More accurate simulations can be obtained by using more accurate values of the inertia and speed damping constants of the turbine.
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VI. CONCLUSION
A detailed study of hydro electric power plant along with the types of turbine has been done. A new model of the turbine is introduced which combines the future of pelton when and Kaplan turbine. This turbine can be used for both vertical as well as horizontal heads of water flow. Solid works has been used as the mechanical design tool for designing the turbine. Also simulation work of hydro electric power plant using the newly designed turbine was done. The simulation results shows that with proper choice of turbine design for micro hydro power plant leads to constant voltage output and constant speed with variation of load values. This leads to an economical operation of the system.
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