This document discusses modeling and simulation of a Dynamic Voltage Restorer (DVR) to protect sensitive loads from voltage sags and swells. The DVR uses an improved d-q-0 controller technique and PWM inverter to compensate for single line ground faults and three-phase faults. Key components of the DVR include an injection transformer, filter unit, PWM inverter, energy storage, and control system. The document evaluates the performance of the proposed DVR method through Matlab/Simulink simulations.

1. COMPENSATION OF SAGS AND
SWELLS VOLTAGE USING DYNAMIC
VOLTAGE RESTORER (DVR) DURING
SINGLE LINE TO GROUND AND
THREE-PHASE FAULTS

2. ABSTRACT
This project deals with modeling and simulation technique of a
Dynamic Voltage Restore (DVR). The DVR is a dynamic solution
to protect sensitive loads against voltage sags and swells. The DVR
can be implemented to protect a group of medium voltage or low
voltage consumers. The new configuration of DVR has been
proposed using improved d-q-0 controller technique. This study
presents compensation of sags and swells voltage during single line
to ground (SLG) fault and three-phase fault. Simulation results
carried out by Matlab/Simulink verify the performance of the
proposed method.

3. INTRODUCTION
Power Quality problems encompass a wide range of disturbances such as
voltage sags/swells, flicker, harmonics distortion, impulse transient, and
interruptions
Voltage sags/swells can occurs more frequently than other Power quality
phenomenon. These sags/swells are the most important power quality
problems in the power distribution system.
One of the most important custom power devices that has been created to
improve the performance of power quality is Dynamic Voltage Restorer
(DVR). The DVR maintains the load voltage at a nominal magnitude and
phase by compensating the voltage sag/swell, voltage unbalance and
voltage harmonics presented at the point of common coupling . These
systems are able to compensate voltage sags by increasing the appropriate
voltages in series with the supply voltage, and therefore prevent loss of
power.

4. VOLTAGE SAG
Voltage sag is a short-duration reduction in rms
voltage caused by faults on the power system
and the starting of large loads.

5. BLOCK DIAGRAM OF DVR

6. SCHEMATIC DIAGRAM OF DVR

7. PWM INVERTER
It mainly consists of
Sine wave Generator : This generator will produce sine waves
continuously and it acts as a reference signal to the comparator
Triangular Wave Generator : This generator will produce
Triangular and acts as a carrier signal to the comparator

8. DVR (DYNAMIC VOLTAGE
RESTORER)
The main function of the DVR is the protection of sensitive loads
from voltage sags/swells coming from the network. The DVR
mainly consists of the injection transformer, filter unit, PWM
inverter, and energy storage and control system that is used to
mitigate voltage sag in power distribution system.

9. PWM INVERTER
Comparator : Comparator will compare reference and carrier
signal and produce square waveform as DC input to the Inverter
Inverter : Inverter will inverts the DC input into AC output
Amplifier : Amplifier will amplifies or strengthen the DC
signal given to the Inverter

10. ENERGY STORAGE DEVICES
Energy Storage Devices such as battery to store the
electrical energy for short duration of time in the form of
chemical energy and retrieves or given back to the system
whenever the necessity occurs.
In this project, the battery is used to store the energy in the
form of dc and whenever supply fails it gives back to
inverter for continuous operation.

11. FILTER UNIT
At the output waveform of Inverter, some
ripples are present due to harmonics.
Filter such as capacitors stores the unwanted
harmonic signal in such a way it remove the
ripple content in the waveform

12. CONTROL UNIT
In this project, Control unit is used to control the
Inverter as per our requirement
It is basically used to vary the triggering angle given to
the power electronic devices used in the Inverter such
that output waveform will be controlled.

13. EXISTING SYSTEM
Distribution Static Compnesator in short form D-STATCOM.
It is a power electronic converter used to protect the
distribution bus from voltage unbalance such as sags and
swells
By using this system, due to the generation of reactive
power voltage value changes

14. PROPSED SYSTEM
In this project, DVR (Dynamic Voltage
Restorer) used to restore the voltage
and maintains at constant to protect
sensitive loads

15. APPLICATIONS
•DVR can be used to compensate the load voltage
harmonics and improves the power quality
•DVR can be used under system frequency variations to
provide the real power required by the load
•DVR can also protect the system against voltage swell and
voltage imbalances

16. THANK YOU