International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 04 | Apr -2017
p-ISSN: 2395-0072
www.irjet.net
POWER QUALITY IMPROVEMENT USING DYNAMIC VOLTAGE RESTORER (DVR) Mr.Jackson Prajapati 1 ,Patel Jalpa S. 2, Pradhan Mamini S. 3, Thakkar Unnati R. 4 1Assistant
professor, electrical Engg, Mahavir Swami college of Engg. & Tech, Surat, Gujarat, India
234Student, electrical Engg., Mahavir Swami college of Engg. & Tech, Surat, Gujarat, India ---------------------------------------------------------------------***--------------------------------------------------------------------1.2 Voltage swell: Abstract - Power electronics device are used to make the
life more easier using technology. Dynamic Voltage Restorer is most economical and efficient Custom power device for mitigation voltage sag/swell. The important parts of the DVR comprise of voltage source inverter (VSI), injected transformers, filter and a dc energy source. The principle of the DVR is utilized to inject the voltage in series and in synchronism with the standard voltages with a goal to compensate voltage influences. There are various control techniques used for the operation of Dynamic Voltage Restorer. This report presents the Discrete PWM technique Using PI controller, Hysteresis voltage controller, Hysteresis current controller, Fourier transform for sensing the voltage sag and generation of switching pulses of inverter of dynamic voltage restorer. The control technique based on voltage reference signals, and the proposed system is designed in MATLAB software, results shows that the how dynamic voltage restorer is useful for voltage sag/swell improvement in distribution system. Key Words: Static Series Compensator(SSC),Dynamic Voltage Restorer(DVR).
1. INTRODUCTION Recent technological advancement lead to a rapid growth in number of nonlinear load present in the power distribution system which adversely affect the quality of power supply. This nonlinear load distort the supply voltage waveform. This result in power quality disturbances[1] .Most industries are relay on the electronic drives and Programmable logic controller which are causes a problems like Voltage sag, voltage swell, harmonics, flicker, voltage transient etc. some definitions of power quality disturbances are as follow:
Voltage swell is short duration reduction in rms voltage a short duration and half of a cycle. Which can be caused by switching off a large load, energization of a capacitor bank.
2. DYNAMIC VOLTAGE From various power quality disturbances, voltage sags are the most common problem. It can be achieved by inject reactive power at point of common coupling. If a mechanical switched shunt capacitor connected at distribution transformer it can compensate the disturbances. It cannot compensate high speed transient. Some sag/swell are not compensate clearly. Other method is to use transformer taps, but this method is costly.so Custom power devices are used to overcome this problem. Most economical and efficient custom power device is Dynamic Voltage Restorer used in power system network. DVR is connected in series at point of common coupling. Custom power device that injects voltage into the system to regulate the load side voltage. DVR is installed in series between the supply and the critical load feeder at the point of common coupling (PCC).location of DVR shown in Figure 3.1. Other than voltage sags and swells compensation, DVR can also added other features like: line voltage harmonics compensation, reduction of transients in voltage and fault current limitations [2].
1.1 Voltage sags: Voltage sag is a short duration reduction in rms voltage a short duration and half of a cycle. Which can be caused by a short circuit, overload or starting of electric motors. Fig.1: Location of DVR Š 2017, IRJET
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