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IMPROVING GRID POWER QUALITY WITH FACTS DEVICE

By:-S.ShivaprasadN.SwathireddyT.RamuRanjankumar1ABSTRACT:- Injection of the wind power into an electric grid affects the power quality.

The influence of the wind turbine in the grid system concerning the power quality measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operation and these are measured according to national/international guidelines

The performance of the wind turbine and thereby power quality are determined on the basis of the measurements and the norms followed according to the guidelines specified. in International Electro-technical Commission standard, IEC-61400In this proposedscheme STATCOM( Static Synchronous Compensator) at a point of common coupling with a battery energy storage system to mitigate the power quality issues.

A proper control scheme in wind energy generation system is required under normal operating condition to allow the proper control over the active power production. In the event of increasing grid disturbance, a battery energy storage system for wind energy generating system is generally required to compensate the fluctuation generated by wind turbineity, power quality problems.

The integration of wind energy into existing power system presents a technical challenges and that requires consideration of voltage regulation , stability, power quality problemsCONTENTSIntroductionWind Energy SystemPower QualityFACTS DevicesRenewable Energy SourceINTRODUCTIONThe modern power system has to confront some major operating problems, such as voltage regulation, power flow control, transient stability, and damping of power oscillations, etc. FACTS devices can be a solution to these problems.

They are able to provide rapid active and reactive power compensations to power systems, and therefore can be used to provide voltage support and power flow control, increase transient stability and improve power oscillation damping.BLOCK DIAGRAMWind Energy System:-Wind is the natural movement of air across the land or sea.

WT convert wind energy in to electric energy which are fed in to electricity supply systems.

The three main components for energy conversion in WT are rotor, gear box and generator. The rotor converts the fluctuating wind energy into mechanical energy and is thus the driving component in the conversion system.SIMULINK MODEL OF WIND FARMWT convert wind energy into electrical energyMain components for energy conversion in WT are1.Rotor2. Gear Box3. GeneratorRotor converts the fluctuating wind energy into Mechanical energy.

The generator and possibly electronic inverter absorbs the mechanical power while converting it in to electrical energy, fed in to supply GridThe generator and possibly an electronic inverter absorb the mechanical power while converting it into electrical energy, fed into a supply grid. The gear box adapts rotor to generator speed.

At the point of common coupling (PCC) between the single WT or the wind farm and the grid a circuit breaker for the disconnection of the whole wind farm or of the WT must existPower QualityA Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or a mal- operation of end user equipmentsPower Quality Issue & its Consequences:Voltage variationHarmonicsWind turbine Location in Power SystemSelf Excitation of wind turbine generating SystemOne of the most common power qualityproblems today is voltage dipsA voltage dip is caused by a fault in the utility system, a fault within the customers facility or a large increase of the load current, like starting a motor or transformer energizing.

Faults due to lightning, is one of the most common causes to voltage dips on overhead lines.FACTS DEVICESFlexible AC Transmission Systems are represented by agroup of power electronic devices.FACTS devices can be divided into two generations.Older generation was based on the thyristor valve, wherenewer uses Voltage Source Converters (VSC).Among the FACTS family, the shunt FACTS devices such as the STATCOM has been widely used to provide smooth and rapid steady state and transient voltage control at points in the network.The proposed STATCOM control scheme for grid connected wind energy generation for power quality improvement has following objectivesReactive power support only from STATCOM to wind Generator and Load.Simple bang-bang controller for STATCOM to achieve fast dynamic response.Unity power factor at the source side.STATIC COMPENSATOR (STATCOM)STATCOM system is a static synchronous generator operated as a static compensator connected in parallel whose output current (inductive or capacitive) can be controlled independently of the AC system voltage.These controllers are possible by the high switching frequency of the IGBT, GTO, IGCT or IEGT transistors of the power converter. The system connects to the grid via a transformer.The AC/DC power converter is controlled by PWM techniques.If V=Vs (pu values), no current flows through Rtr and Ltr.If V> (or )