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  1. 1. K Y Patil, D S Chavan / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue4, July-August 2012, pp.1107-1110Use of Slip Ring Induction Generator for Wind Power Generation K Y Patil, D S Chavan Department of Electrical Engineering, Bharati vidyapeeth deemed university Pune Maharashtra, IndiaAbstract applications to become more flexible and to Wind energy is now firmly established as accomplish smoother regulation.a mature technology for electricity generation.There are different types of generators that can There are different types of generators for generationbe used for wind energy generation, among which of wind energy as synchronous, asynchronous;Slip ring Induction generator proves to be more permanent magnet D.C. etc .Here experimentaladvantageous. To analyse application of Slip ring model is developed by using Slip ring inductionInduction generator for wind power generation, generator which is one of the effective generators toan experimental model is developed and results generate wind energy. By doing analysis of thisare studied. model advantages of slip ring induction generator is As power generation from natural compared to other generators.sources is the need today and variable speed windenergy is ample in amount in India, it is necessary II. PRINCIPLE OF ENERGY CONVERSIONto study more beneficial options for wind energy A Wind mills or turbines works on thegenerating techniques. From this need a model is principal of converting kinetic energy of the winddeveloped by using Slip ring Induction generator into mechanical energy.which is a type of Asynchronous generator. Power available from wind mill = ½ ρ A V³ Where, ρ=air density = 1.225 Kg. / m³ at sea level.Keywords— Wind energy, Slip Ring Induction (Changes by 10-15% due to Temperature andGenerator pressure variations) A – Area swept by windmill rotorI. INTRODUCTION V – Wind speed m/sec. Wind power generation has Air density, which linearly affects thedeveloped dramatically. Up to end of last year the power output at a given speed, is a function ofinstalled capacity was 15000 MW worldwide. The altitude, temperature and barometric perspectives for wind power seem to be quite Variation in temperature and pressure can affect airgood. A goal of 80, 0000 MW is set up to end of density up to 10 % in either direction. Warm climate2020. As a result of growth of installed capacity the reduces air density.wind power is one of the fastest expanding industries. This equation tells us that maximum powerThere is huge potential in wind power. India today available depends on rotor diameter and wind speed.has the fifth largest installed capacity of wind powerin the world and potential for on-shore capabilities III. TYPES OF GENERATORS FOR WINDof 65000MW. The increase in interest in wind ENERGYenergy is due to investment subsidies, government A generator is a device which convertsaction towards renewable energy playing a big part mechanical energy into electrical energy. Windin nation’s energy system. There is a need to Generators have traditionally been wind turbines, i.e.generate environment friendly power that not only a propeller attached to an electric generator attachedraises energy efficiency and is sustainable too. The to appropriate electronics to attach it to the electricaltime has come for moving to generation based grid.subsidies and understanding the drawbacks Types of generators used:-associated with wind power in India. However For Small rating systems - P.M.type D.C. generatorsadvances in technologies such as offshore Medium rating systems - P.M.type D.C. generatorsconstruction of wind turbines, advanced control Induction generators (Asynchronous):-methodologies, and simulation of wind energy A) Squirrel cageaffecting overall grid performance are helping wind B) Slip Ring (wound rotor)energy generation. C) Doubly fed Fortunately, many new wind power The basis of this categorization is the speed atplants are equipped with state of the art technology, which the generators are running. Synchronouswhich enables them to provide good service while Generators are running at synchronous speed (1500producing clean power for the grid. The advances in rpm for a 4 pole machine at 50Hz frequency)power electronics have allowed many power systems While asynchronous generators run at a speed more than the synchronous speed. 1107 | P a g e
  2. 2. K Y Patil, D S Chavan / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue4, July-August 2012, pp.1107-1110IV. SLIP RING INDUCTION GENERATOR Model using D.C. shunt motor coupled with The induction generator is nothing more Slip ring Induction Generator for wind energythan an induction motor driven using external prime generation at different wind speed conditions.mover above its synchronous speed by an amount Circuit diagram for the model is as shown in Fig. 2not exceeding the full load slip the unit would have To obtain variable speed conditions potential divideras a motor. method of speed control of D.C. shunt motor is used. The induction generator requires one With change in the speed, there is change in voltageadditional item before it can produce power it generated from slip induction generator. Differentrequires a source of leading VAR’s for excitation. readings were taken at different excitation voltagesThe VAR’s may be supplied by using capacitors or to rotor of slip ring induction generator. Asfrom the utility grid. excitation voltage is changed there is change in The schematic diagram for slip ring speed of rotation and change in output voltageinduction generator is shown in fig.1 generated from generator. The main advantage of three phaseinduction generators is that they are easily availableas compared to synchronous generators.Fig. 1 Schematic diagram of slip ring inductiongeneratorAdvantages of induction generator1. It is less expensive and more readily availablethan a synchronous generator.2. It does not require a DC field excitation voltage.3. It automatically synchronizes with the powersystem, so its controls are simpler and less expensive.V. DEVELOPMENT OF MODEL FOR WIND ENERGY USING SLIP RING INDUCTION GENERATOR As wind energy is mechanical type ofenergy, in development of a model, an artificialsource of mechanical energy is required Also tomodel actual wind speed conditions ,a variable speedoutput is needed .Thus D.C.shunt motor is used toprovide variable speed mechanical input togenerator .A model using D.C shunt motor coupled with slipring induction generator for wind energy generationis developed and studied at different wind speedconditions. Main components of model are 1) Slip Ring Induction generator 3 Phase ,415 volt, 1410 RPM,50 Hz, B class . Insulation, IP 22,0.5 HP, 1.4 A2) D.C. Shunt motor Fig.2. Circuit Diagram for Slip Ring Induction 220 volt, 3000RPM, 1 HP, 0.3 A, Extn type Generator Coupled with D.C. Shunt MotorShunt A) Observations with different excitation to generator 1108 | P a g e
  3. 3. K Y Patil, D S Chavan / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue4, July-August 2012, pp.1107-1110 On this model by giving different excitationvoltages the readings are taken the observations forfield excitation from 25 volt to 50 volt is given intable 1 and 2. The variation is representedgraphically as shown in fig.3B) Observations with different load types As most common load to grid in India isresistive and inductive type, it is important to carryout experiment with both resistive and inductiveload. Thus observations of generated voltage andspeed are taken for resistive load and inductive loadas shown in table 3 and 4 respectively. Table 2. Output voltage of generator for field excitation 40 and 50 volt. Table1. Output voltage of generator for field excitation 25 volt and 30 volt. Fig. 3: Graph of A.C. voltage generated 1109 | P a g e
  4. 4. K Y Patil, D S Chavan / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue4, July-August 2012, pp.1107-1110Sr. D.C. Generated Current Speed VII. CONCLUSIONNo. Excitation Voltage (In (In The model developed in this work proves to (In volts) (In Volts) Amp) RPM) be useful to study wind power generation, factors affecting amount of power generated and effect of1 70 220 0.1 1900 load on output parameters. As D.C. shunt motor is used it is possible to2 45 50 0.25 1100 obtain easy speed variation so as to create natural wind speed conditions as slow speed, medium speed3 40 20 0.5 1300 and high wind speeds. By considering all these parameters its impact on wind power generation is Table 3. When resistive load is applied observed. Sr. D.C. Generated Current Speed REFERENCES No. Excitation Voltage (In (In [1] 2005 IEEE/PES Transmission and (In Volts) (In volts) Amp) RPM) Distribution Conference paper. [2] PhD Thesis on power quality of wind turbine by AKE LARSSON 1 40 400 0.5 1700 [3] IEEE Canadian Review – Spring [4] Wind farm models and control strategies by Table 4. When resistive load is applied Poul Sørensen, Anca D. Hansen, Florin Iov, Frede Blaabjerg VI. ADVANTAGES OF SLIP RING INDUCTION [5] Wind book on Wind Power in Power GENERATOR FOR WIND POWER Systems by Thomas Ackermann GENERATION [6] Conceptual survey of Generators and Power Electronics for Wind Turbines; The main advantage of three phase 2001 induction generators is that they are easily available [7] IEEE power & energy magazine 1540 as compared to synchronous generators. Other 7977/03/$17.00©2003 IEEEE important advantages are, [8] Emerging Practices in developing wind 1. It is less expensive and more readily available power for the clean Development than synchronous generator. Management by jyoti painuly 2. It automatically synchronizes with the power [9] Design and economics of reactive power system, so its controls are simpler and less control in distribution substation by Khin expensive. Trar Trar Soe A) Advantages of developed model [10] Paper on Wind Power generation technology As induction generators are used it is possible it is [11] Paper on Effects on major power quality possible to operate at low speed as well as high issue due to incoming induction generators speed range. in power system (APRN journal of 1. The construction (stator and rotor) is simple. Engineering and science) 2. Less maintenance 0 3. As D.C. shunt motor is used easy and smooth speed control is possible. . 1110 | P a g e