14-10-2016, 10:59 AM
Power Quality Improvement in Wind Grid Energy System using STATCOM With BESS - Control Scheme
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INTRODUCTION
Power Quality Improvement in Wind Grid Energy System using STATCOM With BESS - Control Scheme is simulated by using MATLAB.
The effects of connecting wind turbine in grid system covers power quality areas are the active power, reactive power, and variation of voltage, harmonics and electrical behaviour of switching operations.
This paper demonstrates the power quality problem due to installation of wind turbine with the grid.
In this proposed scheme Static Synchronous Compensator (STATCOM) is connected at a point of common coupling with a battery energy storage system (BESS) to improve the power quality of the grid.
CONTD..
At low power demand hours the generated power can be stored in the batteries.
The combination of battery storage with wind energy generation system will stabilize the grid system by absorbing or injecting reactive power and enable the real power flow required by the load.
This relives the main supply source from the reactive power demand of the load and the induction generator in this proposed scheme.
POWER QUALITY ?
Power quality is simply the interaction of electrical power with electrical equipment.
If electrical equipment operates correctly and reliably without being damaged or stressed, we would say that the electrical power is of good quality.
On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, we would say that the electrical power quality is poor.
Power quality determines the fitness of electric power to consumers devices.
Power quality is defined as the electrical network's or the grid's ability to supply a clean and stable power supply.
DESCRIPTION
The grid connected system shown in Fig. It mainly consists of battery energy storage system (BESS) with STATCOM, turbine, induction generator, interfacing transformer, and rectifier to get dc bus voltage.
The grid connected system is implemented for power quality improvement at point of common coupling (PCC).
The induction generator does not require any separate field circuit, and can be connected with constant and variable loads.
STATCOM
The STATCOM or (Static Synchronous compensator) is a solid state switching converter device which is capable of generating or absorbing the real and reactive power at its output terminals when it is fed from an energy source at its input terminals.
When system voltage is low, the STATCOM generates reactive power (STATCOM capacitive).
When system voltage is high, it absorbs real power (STATCOM inductive).
Basically, the STATCOM considered as a voltage-source converter because produces a set of 3-phase ac-output voltages.
It is a voltage regulating device used on AC transmission networks.
BATTERY ENERGY STORAGE SYSTEM(BESS)
For the voltage regulation in STATCOM, the battery energy storage system (BESS) is used as an energy storage element.
It controls the power fluctuations occurs in transmission and distribution system with very fast response by charging and discharging of DC link capacitor.
The battery is connected in parallel to the dc capacitor of STATCOM ..
POWER QUALITY ISSUES
Grid side power quality issues
Voltage variations
Frequency variations
Voltage unbalance
Generation of current harmonics
Injection of fluctuating power
IMPLICATION OF POWER QUALITY
Increased current & losses in the system
low energy efficiency
Blocked capacity
Failure of equipments
Poor operational efficiency
Poor quality of products manufactured
APPLICATIONS
Power system voltage control applications.
Large electric arc furnace installations.
Reactive power compensation applications.
Railway or underground systems with huge load variations
CONCLUSION
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 in the wind grid system.