power quality issues ppt

STATCOM CONTROL SCHEME FOR GRID-CONNECTED WIND ENERY SYSTEM FOR POWER QUALITY IMPROVEMENT

UNDER THE GUIDENCE OF Mrs. M. KIRAN JYOTHI

BY

B.BALA KRISHNA

P.VARSHINI

P.N.S.V.MADHAV

P.SRINIVAS

Injection of the wind power into an electric grid affects the power quality. The performance of the wind turbine and thereby power quality are determined on the basis of measurements and the norms followed according to the guideline specified in International Electro-technical Commission standard,IEC-61400. The influence of the wind turbine in the grid system concerning the power quality measurements are measured according to national/international guidelines.

In this proposed scheme Static Compensator (STATCOM) is connected at a point of common coupling with a battery energy storage system (BESS) to mitigate the power quality issues. The battery energy storage is integrated to sustain the real power source under fluctuating wind power.

ABSTRACT

Injecting Wind Power into Grid & Improve the Power

Quality.

OBJECTIVE OF THE PROJECT

BLOCK DIAGRAM

FACTS

STATCOM

BESS.

WIND ENERGY GENERATING SYSTEM

COMPONENTS USED IN THE SCHEME

It is a system composed of static equipment.

Used to enhance controllability and increase power transfer capability."

FACTS

It is a regulating device used on AC transmission networks.

It is based on a voltage-source converter.

It acts in either capacitive or inductive mode

STATCOM

WIND ENERGY GENERATING SYSTEM

Load

kinetic Energy

Mechanical Energy

Electrical Energy

TYPES OF WIND TURBINES

VAWT

HAWT have the main rotor shaft and generator at the top of a tower and must be pointed into the wind.

VAWT have the main rotor shaft arranged vertically .The generator and gear box placed near the ground.

It is used for the purpose of voltage regulation.

It can be used to level the power fluctuation by charging and discharging operation.

It rapidly injects or absorbed reactive power to stabilize the grid system.

BATTERY ENERGY STORAGE SYSTEM

Without the proper power, an electrical device may malfunction, not operate at all.

Power quality determines the fitness of electrical power to consumer devices.

Synchronization of the voltage frequency and phase allows electrical systems to function properly.

POWER QUALITY

Voltage variation

Harmonics

Reactive power

Wind turbine location in power system.

POWER QUALITY ISSUES

SIMULATION DIAGRAM

It is based on injecting the currents into the grid using “bang-bang controller.”

The controller uses a hysteresis current controlled technique.

The controller keeps the control system variable between boundaries of hysteresis area.

It gives correct switching signals for STATCOM operation.

CONTROL SCHEME

SIMULATION RESULTS

Switching signal within a control hysteresis bando The three phase injected current into the grid from STATCOM will cancel out

the distortion caused by the nonlinear load and wind generator.

o The generation of switching signals from reference current is simulated within hysteresis band of 0.08..

CONTINUE..

The performance of the system is measured by switching the STATCOM at time 0.7s in the system and how the STATCOM responds to the step change command for increase in additional load at 1.0 s is shown in the simulation.

Performance of STATCOM under load variations

CONT.....

Three phase injected inverter Current

The compensated current for the nonlinear load and demanded reactive power is provided by the inverter.

The real power transfer from the batteries is also supported by the controller of this inverter.

CONT.....

Supply Voltage and Current at PCC.

The source current with and without STATCOM operation is shown in Fig.

The unity power factor is maintained for the source power when the STATCOM is in operation.

CONT…..

(a) DC link voltage. (b) Current through Capacitor.

The DC link voltage regulates the source current in the grid System.

The DC link voltage is maintained constant across thecapacitor as shown in Fig.

CONT…..

It is observed that the source current on the grid is affected due to the effects of nonlinear load and wind generator.

Thus purity of waveform may be lost on both sides in the system.

The power quality issues and its consequences are presented.

STATCOM has a capability to cancel out the harmonic parts of the load current.

STATCOM maintains the source voltage and current in-

phase and support the reactive power demand for the wind generator and load at PCC.

Thus the proposed scheme fulfills the power quality norms as per the IEC standard 61400-21.

CONCLUSION

Power system voltage control applications.

Large electric arc furnace installations.

Reactive power compensation applications.

Railway or underground systems with huge load variations

APPLICATIONS

STATCOM can be replaced with UPQC for better power control.

Replacing the induction generator with doubly fed induction generator is preferred for better results.

In future the off-shore wind turbines will be implemented due to its advantages of producing high power.

FUTURE SCOPE