Abstract— Dynamic stability analysisof hybrid system comprising hydro power and solar power generation, integratedinto a distribution power grid.A Super Capacitor (SC) is utilized to smooth thegenerated power delivered to the distribution power gridKeywords—Hydroturbine;Hydro generator;Solar panel;Boost Converter;Supercapacitor;Utility grid;Power grid I.
Introduction Renewable energy is collected from variable resources. It often provides energy in electricitygeneration. Solar and hydro energy play a major role in renewable energysources. Solar energy has the greatest potential of all the sources of renewableenergy.
Solar energy is radiant light and heat from the sun that is harnessedusing a range of ever-evolving technologies such as solar heating, photovoltaics,solar pumping, etc.., Water is the main soures of hydro powergeneration. The kinetic energy of the flowing water strick the blades or vanes, it starts turns inside thehydraulic turbine, then, it converted into mechanical energy. In the hybridsystem of hydro and solar energy, to achieve the maximum power. When combiningboth hydro and solar, power fluctuation will be occured. By using the supercapacitor power fluctuation will be reducedused to reduce kinetic energy.
To balancing a two energy sources that will beproduce a unstable condition by using of supercapacitor to reduce this problem. HYDRO ENERGYHydro power plant is a conventional renewable energy source. It has basically its two main sections, firstly the mechanical partof the plant which includes hydraulic turbine, penstock, controller, hydraulicservo motor, control valve etc. Fig.
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1.Hydro Turbine modelSecond partof the plant is electrical section which mainly consists of generator and load.To analysis a generator part transmutemechanical energy to electrical power. HYDRO TURBINEGOVERNOR is combination of hydraulic turbine and controller.Modelling of hydroturbine describing variation in flow and developed mechanical powerwith respect to the turbine speed, gate opening and runner blade movement ofhydro turbine. Synchronous generators or alternators aresynchronous machines used to convert mechanical power to ac electric power.Synchronous machines are used widely as generators of electrical power. Largemachines generating electrical power in hydro, nuclear or thermal powerstations are the synchronous generators.
They can generate active and reactivepower and has an important role in voltage control technic.SOLAR ENERGYSolar energyhas the especially potential of all the sources of renewable energy and if only a minimum levelof energy could be used , it will be one of the most important supplies ofenergy especially when other sources in the country have depleted. Energy comesto the earth depending on the sun radiation level. Thesolar panel can be used as a device of a larger photovoltaic system to generateand supply electricity in commercial and suburban applications. Each panel israted by its DC output power. Solar panels useto take a light energy (photons)from the sun to generate electricity through the photovoltaic effect.
Themajority of modules use wafer based crystalline silicon cells or thin-filmcells based on cadmium telluride or silicon. The structural (load carrying)member of a module can either be the upper layer or the back layer. Cells must also be protected from mechanical damage and moisture. SUPERCAPACITORSupercapacitor is a trendy energy storing device, storing very high valueof electric capacitance in a very flatten structure. They are rated in farads,and offers thousands of times higher storing capacity than the electrolyticcapacitor. They are also known as Ultra capacitors and Double layer capacitors.Differs with the convention energy deposit methods of capacitors, that they are not madeup of dielectric material. They store energy in plates filled with double layerof same substance.
This allows for separating the charge without the need for adielectric, the plates are fill up witha much larger surface area resulting in high capacitance .The supercapacitor isfaultless for energy storage that undergoes frequent charge and dischargecycles at high current and short duration. Supercapacitors have much longer life than that that Lithiumbatteries, normally of 10 to 20 years.Thay have very high charging rate, can becharged within seconds. Supercapacitors can be easily installed and offers easyinterface with other devices with adaptable mountings.
Super capacitors havevery fast transient response as compared to the commonly available lithium ionbatteries.SC used to maintain a stable operation of connecting two energysources.DISTRIBUTION POWER GRID An electricalgrid is a combination network of network delivering electricity to consumers. Itconsists of Generating stations,Transmission and Distribution. Generationconsist of hydro and solar power combination.To transmit a power generation todistribution to maintain stable condition with help of super capacitor.
DC-linkconnected to the converter circuit that output passing through the inverter.That inverter output is connected to the transformer(step up) power deliver tothe Transmission line. Two-way ?ows of electricity and information couldimprove the delivery network is called an utility grid. The protection systemof a utility grid provides grid reliability analysis, failure protection, andsecurity and privacy protection services. While the additional communicationinfrastructure of a smart grid provides additional protective and securitymechanisms, it also presents a risk of external attack and internal failures.
An important problem in unmanageablegeneration sources such as photovoltaic and hydro is their power fluctuation Generation variability can be moderated throughthe comprehensive of various systems.This method is limited in small grids, isolated systems or grids with highpenetration of renewable energy sources so for this purpose can limit thepercentage of renewable energy sources in the grid.BLOCKDIAGRAMFig.2The hydro power vs solarpower generation connected to the distribution power grid.
The PV system isconnected to a common dc link through a dc-dc boost converter. The hydro poweris connected to a dc link through an inverter circuit because of output voltage of AC will be converted to DCwith help of the inverter circuit. ASuper Capacitor (SC) is act as a major role of smooth the generated powerdelivered to the distribution power grid. To achievethe maximum power extractions from PV array and hydro power generation systemANALYSIS OF HYDRO AND SOLARHydro: A Francis turbine is considered in thispaper. It is referred to a fixed head and a constant water flow. It is assumedthat water flow variations are very slow compared to the drive dynamics. Theturbine model is a basic one, i.
e. it includes neither blade pitch control norupstream guide vane one. According to these assumptions, hydro power turbinebehavior may be taken into account by means of simplified static mechanicalcharacteristics represented in Fig.2 for a fixed rate of flow. The modelling of micro hydro power plant is donein this thesis by using MAT LAB/Simulation. Introduction of micro hydro powerplant reduces a lot of burden without any adverse effect on environment whilemeeting the localized power requirement. The simulation results shows that withproper choice of governing system for micro hydro power plant leads to properload sharing, constant voltage output and constant speed with variation of loadvalues.
This leads to an economical operation of the system. The main motive of thisproposed work is an efficient design of solar panel for constantCurrent-Voltage (V-I) characteristics of a Photovoltaic array of variousenvironmental conditions like different radiance and temperature. To nominate anew model uses constant environmental condition in combination with actualsolar radiation and ambient temperature.
The new model is developed on Matlab-Simulink platform for calculating and analyzing the power output from a PVpanel by taking the values of current and voltage with constantly varying solarradiation at any geographical location and different day The output power ofsolar panel is directly given to dc/dc controller in order to reduce circuitcomplexity. MAT LAB SIMULATION In order to compensate the powerfluctuations from the HPGS and the PV array, the SC will continuously exchangewith the dc link a power grid. The difference between the power generated byboth the renewable sources and the power fed to distribution power grid. Itshould be noticed that when performing the sizing of the SC, the power profilesof the HPGS and the PV array must be given in advance and the sum of theiraverage is taken as the power fed to the distribution power grid. MATLAB is apowerful electrical engineering software tool that allows engineering to buildelectrical models in Simulink environment and change their operatingconditions. Fig3.
SIMULATION MODEL OF HYBRID SYSTEM PV pannel simulation model PV array was operating very close to thepeak points under the varying solar condition.The PV array is composed ofseveral PV cells interconnected in series.If required voltage level that cellarrangement will be varry.Depending on the cell connected in series/parallalconnection required current and voltage collected from the PV cell. Boostconverter simulation model:The DC-DC boost converter was use to convert thevariable DC input to a fixed DC output voltage at a required voltage level.Theoutput of the PV pannel is varriable DC voltage that will be converted to fixedDC voltage with help of boost converter.Hydro power plant: The simulation model can be build individualsub-model like hydro power plant combination of turbine, governor, synchronousgenerator, excitation system and RLC loads are connected together.
The output ofgenerating electrical power depending on the rotating speed of turbine.So thespeed and electromagnetic torque will be measuredThat output of hydro power plant is pure form of AC voltage thatwill be connected to supply through a DC link so that output power converteredinto Dcwith help of convertercircuit.The combination of converter circuit design by IGBT power electronicdevice because of various kind of application like a transistors have low ONresistance,high voltage capacity, fast switchinf action and various high levelof voltage applications like PWM,SMPS, variable speed control,AC to DCconverter power by renewable energy sources. Super capacitor simulation model:The super capacitor is combinationwith the control scheme to improve the performance of hydro and pv systems.Ifany disturbance will be occur in the hybrid system it will be produce a fluctuationin systems.
At the time of period that system may go on to unstable condition.To prevent this fluctuation condition with help of super capacitor is placed.The variable-speed hydro power plant together with SCESD allowscompensating and smoothing the fluctuating wind power, when connected to thegrid. The discharge strategy attempts to maintain the SC at their lowestoperational voltage (half rated voltage) to make available the SC energycapacity for absorbing power peaks. Once the generator power exceeds a predeterminedvalue(dependent on the sea state), the SC prevent any excess power ?owing tothe grid and absorb the difference. Once the input power drops below thisvalue, the SC maintain this power to the grid until the minimum voltageis achieved.Grid simulation model: Power fluctuations occur in themain grid under unbalances condition utility grid maintain a stable condition.
Advanced electricity generation,delivery, and consumption of electric power with help of utility grid.Solar Simulation:The PV array was operating very closeto the peak points under the varying solar condition.The PV array is composedof several PV cells interconnected in series. The DC-DC boost converter areused to convert the unregulated DC input to a controlled DC output at a desiredvoltage level. Fig 4.
VOLTAGE AND CURRENT OF PV PANELHydro: The simulationmodel can be build individual sub-models like hydro turbine governor,synchronous generator, excitation system and 3-phase RLC load are now connectedtogether to form the complete block diagram of hydro power plant. Fig 5:ELECTROMAGNETIC TORQUE OF HTThe output power of generator depending on the turbinespeed so the speed and electromagnetic torque will be measured.Fig6:Stator Three Phase CurrentCharacteristics at Steady State (iny-Axis Current in pu and in x-Axis Time in Sec)The speed governing system ofturbine adjusts the generator speed based on the feedback signals of thedeviations of both system frequency and power with respect to their referencesettings. This ensures power generation at synchronous frequency Fig 7: VOLTAGE OFHYDRO GENERATORThe simulation results shows thatwith proper choice of governing system for micro hydro power plant leads toproper load sharing, constant voltage output and constant speed with variationof load values. This leads to an economical operation of the system.Introduction of micro hydro power plant reduces a lot of burden without anyadverse effect on environment while meeting the localized power requirement. Fig 7. STATE OF CHARGEThe physical phenomena associated with supercapacitor chargingcreate unobservable internal states of charge(SOC) Fig 8:OUTPUT VOLTAGE ACROSS SCFor filtering purpose connected a thyristor circuit give the gatepulse signal.
Then the output fed to the super capacitor.output wave formdisplayed by using of scope.super capacitor paves the way for smoothing powerfluctuation of hybrid system Fig 9: BEFORE SUPER CAPACITOR Fig 10:AFTER SUPER CAPACITOR Power fluctuations occur in the main grid underunbalances condition utility grid maintain a stable condition Fig 11: GRID VOLTAGE CONCLUSION The dynamic stability analysisresults of a hybrid hydro and PV system integrated into a distribution powergrid have been presented. An SC-based energy-storage system has been employedto support for smoothing out the power fluctuations. A control scheme has beenproposed aiming to suppress the power fluctuations from feeding to thedistribution power grid and maintain stable operation of the studied systemwhile achieving the maximum power extractions from the PV array and the hydropower-generation system. Both modal analysis and MATLAB simulations of thestudied system have been performed to examine the dynamic performance of thestudied system under the operating conditions.
It can be concluded from the simulation results that the proposedcontrol scheme has the ability to maintain stable operation of the studiedsystem under various operating conditions while extracting the maximum powerfrom both the renewable-energy sources. It can also be concluded from thesimulation results that the SC combined with the proposed control scheme caneffectively smooth out the power fluctuations of the studied hybrid hydro andPV system. For future scope to a floating of solar array or floatingof solar panel refers to an array of photovoltaicpanels on astructure that floats on a body of water. In order that the renewableenergy generatedis not wasted, and does not become negatively disruptive to the overall energysystem, battery storage should be installed between the point of generation andthe grid system. . .
