This document presents a voltage harmonic mitigation project using a DVR (Dynamic Voltage Restorer) based on MATLAB/Simulink. It was presented by 4 students under the supervision of Mr. Priyank Agarwal. The document introduces power quality issues such as voltage sags, swells and harmonics. It then discusses custom power devices for mitigating these issues including DVRs. It provides details on the DVR circuit diagram, power circuit and control strategy based on synchronous reference frame theory. The control strategy aims to restore balanced sinusoidal load voltage even during supply disturbances. MATLAB is used to model and simulate the DVR system.

1. Voltage Harmonic Mitigation
using DVR based on
MATLAB/SIMULINK
Presented by:
Aniket Naugariya(Roll no.1130921011)
Udgam Tiwari(Roll no.1130921038)
Shivam Pandey(Roll no.1130921040)
Santosh Kumar(Roll no.1130921031)
Under the supervision of:
Mr. Priyank Agarwal
Electrical & Electronics Deptt.

2. Table of contents
1. Introduction to Power Quality
2. Power Quality problems
3. Harmonics
4. Introduction of custom power devices
5. DVR(Dynamic voltage Restorers)
6. DVR Circuit diagram
7. DVR power circuit
8. About MATLAB
9. DVR control strategy (based on SRF)
10. Control Diagram
11. Advantages
12. References

3. INTRODUCTION OF POWER
QUALITY
• The IEEE defines Power Quality is defined as “Any power problem
manifested in voltage, current, and/or frequency deviations that
results in the failure and/or mal-operation of end user’s
equipment”.
PQ mainly deals with
1. Continuity of the supply.
2. “Quality” of the voltage.

4. Power Quality Problems
Voltage Sag/Dip:-
•Description: A decrease of the normal voltage level between 90% to 10% of the
nominal rms voltage at the rated power frequency, for durations of 0.5 cycle to
1 minute(IEEE).
•Causes:
1.Faults on the transmission or distribution network.
2.Connection of heavy loads and start-up of large motors.

6. Voltage Swell
• Description: It is defined as an increase in RMS voltage b/w 110%-180% at
the rated power frequency for duration ½ cycle to 1min(IEEE)
• Causes:
1.Single line to ground fault in the system
2.Abruptly increase in load
3.Switching off large capacitor bank
• Consequences:
1.Data loss.
2.Flickering of light and screen

8. Harmonics
●Harmonic waveform is a periodic distortion of the normal
Sine wave

9. Introduction of Custom power
devices
• Custom power devices are designed to improve the quality of
power at their point of installation of power distribution systems.
They are not primarily designed to improve power quality of the
entire system.
• Custom power devices are of three types:
1.DVR
2.D-STATCOM
3.UPQC

10. DVR(Dynamic voltage
restorers)
•A DVR is a voltage-source converter (VSC)-based power
electronics device.
•Connected in series between the supply and the critical
loads.
•If fault occur it provides certain amount of compensating
voltage into the distribution line.
•Restore Balanced sinusoidal load voltage even if source
voltage is unbalanced or distorted.

11. Circuit
diagram

12. DVR Power circuit
• DVR Power circuit contains three single-phase H-bridge VSCs
along with a common dc capacitor (Cdc).
• The three H-bridge VSCs is connected through a ripple
filter(Lr,Cr,Rr) and an injection transformer.
• The shunt capacitor filter Cf is used to provide a low
impedance path to higher order harmonics of load voltage
when the load is nonlinear.

13. Power circuit of DVR

14. MATLAB
MATLAB(matrix laboratory) is a fourth-generation high-level programming
language and interactive environment for numerical computation, visualization and
programming.
•MATLAB is developed by MathWorks.
•It allows matrix manipulations; plotting of functions and data; implementation of
algorithms; creation of user interfaces; interfacing with programs written in other
languages, including C, C++, Java, and Fortran; analyze data; develope algorithms;
and create models and applications.
•It has numerous built-in commands and math functions that help you in
mathematical calculations, generating plots and performing numerical methods.

15. DVR Control strategy based
on SRF
• In steady state, the phase difference between instantaneous DVR
voltages and instantaneous line currents must be 90◦.
• Generally DVR control strategy can be divided into three parts:
i. Under Balanced Sinusoidal Supply Condition with Balanced Linear
Load.
ii.Under Unbalanced and/or Distorted Supply Condition With
Unbalanced Linear Load.
iii.Fundamental Positive-Sequence Extractor

17. Advantag
es
1. Capability to adapt by itself to changes that may occur in the
power system. Such as Voltage flickers &harmonics generated
by electric arc furnace.
2. Minimizes the possible occurrence of Resonances.
3. Reduce harmonics.
4. Balance the voltage at the PCC.

18. Thank You
Office
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