WIND POWER SMOOTHING CONTROL USING SUPER

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ST. VINCENT PALLOTI COLLEGE OF ENGINEERING & TECHNOLOGY WIND POWER SMOOTHING CONTROL USING SUPER CAPACITOR PRESENTED BY : NIRUL MASURKAR SAGAR LANJEWAR KAVITA AJICK PRIYA DUGGAL Guided by Prof N.K.DHOTE

CONTENTS : 

CONTENTS INTRODUCTION WHY NONCONVENTIONAL TYPES OF NONCONVENTIONAL WHY WIND GENERATION PROBLEMS FACED IN WIND ENERGY STORAGE DEVICE VOLTAGE EQUALIZATION TECHNIQUE PROPOSED WORK

INTRODUCTION : 

INTRODUCTION Initiated by Government of India in mid-80’s Private sector investments started in early ’90s Resource potential of 65,000 MW + Installation >5,200 MW by March, 2006 Fourth in the world 1700 MW + in the FY 2006 High growth in the past 5 years

Gross and Technical potential : 

Gross and Technical potential

Role of India in global wind generation : 

Role of India in global wind generation

Year wise wind generation : 

Year wise wind generation

State wise wind generation : 

State wise wind generation

WHY NON CONVENTIONAL? : 

WHY NON CONVENTIONAL? 1.Energy i) World is running out of fossil fuel 2.Enviromental problems I) CO2 emission ii) Ozone depletion iii) Global warming 3.It is free of cost 4.Pollution free

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5.Readily available 6.In exhaustible 7.renewable 8.Sustainable development (energy+ecology+economy)

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Emission reduction obligation of developed world and moral obligation of all nation for mitigation of human climate crisis that is fast approaching as environment of calamities and well being of future generation and planet has to take us in direction of sustainable renewable energy way

Types of non conventional energy : 

Types of non conventional energy 1.Wind energy 2.Geothermal energy 3.Solar energy (Solar thermal,Solar cell) 4.Tidal waves 5.Biogas plant 6.H2O 7.Microgeneration (PV ,micro-HP)

Why wind generation ? : 

Why wind generation ? 1.No adverse effect on global environment 2.Fuel cost is zero 3.Construction time is less 4.A permanent shield against ever increasing power price 5.Wind form size can be 0.25MW to 200MW to suit industry size 6.A favorable policy exist in India 7.Solar energy inactive at night 8.Biogass plant content a waste material called sludge 9.Geothermal content some poisonous gas

Favorable nature of wind generation in India : 

Favorable nature of wind generation in India 1.Indian coastline stretches about 5700km on the mainland 2.7500km include the two island territories 3.Geomorphological features of coast 4.Wind availability is abundant inexhaustive ,everlasting ,pollution free

Wind resources in India : 

Wind resources in India 1.Identified wind potential-65000MW 2.Today wind generation is 7845MW 3.The known potential of Tamil Nadu is 5900MW 4.3845MW of wind projects through 8500 wind mills have been installed

Problems faced in wind generation on transmission network : 

Problems faced in wind generation on transmission network 1. Power flow 2. Short circuit 3. Transient stability 4. Electromagnetic transients 5. Protection 6. Power leveling and energy balancing 7. Power Quality

Power flow : 

Power flow Ensure that the interconnecting transmission or distribution lines will not be over- dutied. This type of analysis is needed to ensure that the introduction of additional generation will not overload the lines and the introduction of additional generation will not overload the lines and other electrical equipment. Both active and reactive power requirements other electrical equipment. Both active and reactive power requirements should be investigated. Reactive power should be generated not only at the interconnection point partial private circuit (PCC), but also throughout the network, and should be compensated locally.

Short circuit : 

Short circuit Determine the impact of additional generation sources to the short circuit current ratings of existing electrical equipment on the network

Transient stability : 

Transient stability Dynamic behavior of the system during contingencies, sudden load changes and disturbances. Voltage and angular stability during these system disturbances are important. In most cases, fast acting reactive-power compensation equipment, including SVCs and STATCOMs, are included for improving the transient stability of the network.

Electromagnetic transients : 

Electromagnetic transients Ensure these fast operational switching transients have a detailed representation of the connected equipment, wind turbines, their controls and protections, the converters, and DC links

Protection : 

Protection Investigate how unintentional islanding and reverse power flow may have a large impact on existing protection schemes, philosophy, and settings.

Power leveling and energy balancing : 

Power leveling and energy balancing Due to the fluctuating and uncontrollable nature of wind power as well as the uncorrelated generation from wind and load, wind power generation has to be balanced with other fast controllable generation sources. These include gas, hydro, or renewable power generating sources, as well as short and long-term energy storage, to smooth out fluctuating power from wind generators and increase the overall reliability and efficiency of the system. The costs associated with capital, operations, maintenance and generator stop-start cycles have to be taken into account as well.

Power Quality : 

Power Quality Fluctuations in the wind power and the associated power transport (AC or DC), have direct consequences to the power quality. As a result, large voltage fluctuations may result in voltage variations out side the regulation limits, as well as violations on flicker and other power quality standards.

Main draw back of wind generation : 

Main draw back of wind generation The main drawback of utilization of the wind energy sources is that wind power systems generally experience high fluctuation in power supply from the wind turbine generators due to the turbulent (variation) nature of the wind The wind speed often changes in the time frame of seconds and these result in fluctuating power from the wind turbine. Because the power captured by a wind turbine is proportional to the cube of the wind speed, small variations in wind velocity produce relatively large changes in the captured power. These are directly reflected in the electrical output of the wind energy conversion system (WECS) unless smoothing is applied Where p=power v=velocity

Energy storage device : 

Energy storage device To eliminate the problem energy storage is used Energy storage can improve the efficiency and reliability of the electric system by reducing the requirements for spinning reserves to meet peak power utility demands, making better use of efficient base load generation, and allowing greater use of intermittent renewable energy technologies. A number of energy storage technologies have been developed or are under development for electric power applications, including :

examples : 

examples • Large storage batteries • Compressed air energy storage (CAES) • Pumped hydropower • Superconducting magnetic energy storage (SMES) • Flywheels energy storage • Supercapacitors

Supercapacitor : 

Supercapacitor Supercapacitor stores energy electrostatically by polarizing an electrolytic solution. 2.Though it is an electrochemical device there are no chemical reactions involved in its energy storage mechanism 3. This mechanism is highly reversible, allowing the supercapacitor to be charged and discharged hundreds of thousands of times.

Comparison of supercapacitor ,capacitor and battery : 

Comparison of supercapacitor ,capacitor and battery

Applications of supercapacitor : 

Applications of supercapacitor Applications Supercapacitors are excellent solutions in a number of system configurations when used alone, or combined with other energy sources. Examples of applications include: 1. Quick-charge applications which can be charged in seconds and then discharged over a few minutes. (Power tools and toys are two examples) 2. Short-term support for un-interruptible power systems, where the supercapacitor provides the power for short outages, or as a bridge to a 3. generator set or other continuous backup power supply. 4. Load-leveling an energy-rich, power-poor energy source such as a solar array.

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5. Supporting power buses when they are switched from one source to another . 6. Low-current, long duration requirements such as computer memory backup 7. low-power devices for the purpose of memory data backup. 8. load leveling in hybrid electric vehicles 9. high power application is in telecommunications, 10.Short high power pulses are required and power smoothing in elevators

The structure of a Supercapacitor : 

The structure of a Supercapacitor

Elements used in supercapacitor : 

Elements used in supercapacitor 1.Electrode 2.Carbon 3. Metal oxides 4. Polymers 5. Electrolyte 6. Organic 7. Aqueous 8.Separator

1.Electrode : 

1.Electrode The design of the electrodes is very important for Electrochemical double-layer capacitance (EDLC) performance. The electrode not only determines the capacitance but also contributes significantly to the overall equivalent series resistance (ESR). It can be attributed that the electric capacitance stored in the layer is proportional to the surface area of the electrode and reverse proportional to thickness of double layer. The high-rate charge/discharge characteristics can be improved by optimizing the pore-size distribution of the electrodes . With respect to electrode materials, there are three main categories: carbon based, metal oxides and polymeric materials.

2.Carbon : 

2.Carbon Many studies have been undertaken on carbon material as electrode .Carbon is frequently used as a electrode material due to low cost, high surface area and easy availability. Carbon is available with a specific surface area up to 2500sqm/g as powders, woven cloths, or fibers. However it can be observe that both stability and conductivity of the activated high carbon area decrease with increasing surface area. Moreover activated carbons with larger pores are found to be more suitable for high power applications. The accessible time to pores of various sizes was correlated with the pore size distribution of the materials

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Conducting metal oxides such as RuO 2 or IrO 2 are the favored electrode materials. The high specific capacitance in combination with low resistance resulted in very high specific powers. However these capacitors have turned out to be too expensive. In addition, metal oxides are only suitable for aqueous electrolytes, thus limiting the nominal cell voltage to 1 V. 3. Metal oxides

4. Polymers : 

4. Polymers Polymeric materials, such as P AND N dopable poly, have been suggested as electrodes. It is not usually used due to swelling and shrinking of Electro active polymers, thus it may lead to degradation during cycling.

5. Electrolyte : 

5. Electrolyte A simple capacitor is perceived as being capable of discharge (or recharge) at high rates, limited only by a small equivalent series resistance. However, in the case of super capacitor, based on high specific area porous electrode materials, power limitations arise due to the complex-distribution of electrolyte internal resistance

6. Organic : 

6. Organic The advantage of an organic electrolyte is the higher achievable voltage. However organic electrolytes have a significantly higher specific resistance. The higher electrolyte resistance reduces the maximum power, some of this reduction in power, however, is compensated by the higher cell voltage achievable with an organic electrolyte. Most of the presently available capacitors use an organic electrolyte.

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7. Aqueous The advantage of aqueous electrolyte is the higher conductance and cost is usually much lower than organic electrolytes. However aqueous electrolytes limit the unit cell voltage to typically 1 V.

8.Separator : 

8.Separator In the first instance, the impedance of the separator in electrolyte is proportional to its thickness and inversely proportional to its porosity. Therefore the key characteristics for a membrane separator are high porosity, high strength and ultra thin manufacture. There are a number of very good polymeric separators now available, and although expensive, provide low impedance and high strength with a thickness of 20~40μm . It is interestingly noted that thickness and porosity alone are not sufficient to determine the ESR contribution, but that other characteristics such as tortuosity and wet ability also need to be taken into account

Principle of energy storage : 

Principle of energy storage Electrochemical capacitors store the electric energy in an electrochemical double layer formed at a solid/electrolyte interface. Positive and negative ionic charges within the electrolyte accumulate at the surface of the solid electrode and compensate for the electronic charge at the electrode surface. 2 E =1/2 CV E is the energy in joules [J] V is the rated, or operating voltage of the supercapacitor C is capacitance [F]

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Another measure of supercapacitor performance is the ability to store and release the energy rapidly. This is the power, P, of a supercapacitor and is given by Where, R is the internal resistance of the supercapacitor

Difficulty in supercapacitor : 

Difficulty in supercapacitor 1.The main difficulty with the supercapacitors is their low operation voltage. The maximum voltage that can be applied to a supercapacitor is low, near 2.5 volts but most powerful applications require considerably higher voltages. To reach the required application voltage the supercapacitors are connected in series to form a system 2. However the series supercapacitor stacks lead to unequal voltage distributions because each capacitance of supercapacitors is not exactly same. Its capacitance is also varying with different dc bias voltage [7-1]. Voltage distribution in a series stack of supercapacitors is initially a function of capacitance. After the stack has been held at voltage for a period of time, voltage distribution then becomes a function of internal parallel resistance (leakage current).

Voltage equalization techniques : 

Voltage equalization techniques 1.Using resistors in parallel to the capacitors 2.Zener diodes

Using resistors in parallel to the capacitors : 

Using resistors in parallel to the capacitors In order to prevent the adverse effects of unequalized charging of supercapacitors, individual supercapacitor needs to be maintained at an equalized charge level. This can be achieved by regulating the voltage of individual cells. A simple approach to equalize the supercapacitor stacks is to use bypass resistor in parallel

WORKING : 

WORKING When the voltage starts grow slowly from zero to maximum voltage, the charging current is flowing through C1. As soon as the capacitor C1 reaches its maximum voltage, the current is flowing to resistance R1. Next when the capacitor C2 is charged, its current starts flowing to resistance R2. This process will be continued to end of the capacitor. Therefore the process of charging is quite slow which is roughly 400 second to charge the supercapacitors and also obviously power is dissipated on each resistor highly. If all the parallel resistances are the same, the cells with higher voltages should discharge through the parallel resistance at a higher rate than the cells with lower voltages. This will help to distribute the total stack voltage evenly across the entire series of capacitors.

Zener diodes : 

Zener diodes A zener diode is a specially processed single PN junction that provides relatively constant voltage across two terminals despite changes in zener current. Because of this unique characteristic, it is used as a voltage regulator when placed in parallel across a load to be regulated

WORKING : 

WORKING When the zener is positively biased, it behaviors as a regular diode. When it is reverse biased, if the cathode-anode voltage VKA is less than the breakdown voltage VB, it will block the conduction. Otherwise, the voltage VKA will be clamped to VB. As soon as a capacitor C1 reaches its maximum voltage, the diode Z1starts conducting the charging current. And also when the C2 is fully charged, the diode Z2 is conducted. In this scheme, the amount of lost energy is minimized since the shunt circuitry is only active when the cell voltage exceeds the preset level. However this approach also leads to increased losses and, furthermore, suffers from the temperature dependency of the Zener diodes

over Work : 

over Work Modeling of wind generation by using MATLAB,SIM POWER ,STOOL-BOX,STIMULATOR Analysis of the performance of wind generator with and without connecting supercapacitor [power ,frequency &voltage vs. time] Analysis of voltage equalization technique using RESISTOR

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WIND POWER SYSTEM MODELING FORSIMULATION

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Wind farm

Simple capacitor reactive power : 

Simple capacitor reactive power

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supercapacitor reactive power and simulation

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ANY ?? Wind farm

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Thank You