This document introduces UPQC-S, a new concept for unified power quality conditioning that provides simultaneous voltage sag/swell compensation and reactive power compensation using the series inverter of UPQC. It begins with introductions of power quality, problems like voltage sag/swell, the basic UPQC diagram and operation. It describes types of UPQC including UPQC-P, UPQC-Q and the new UPQC-S. UPQC-S optimally utilizes the series inverter to reduce the burden on the shunt inverter allowing it to use a minimum KVA rating. In conclusion, UPQC-S provides optimal control of apparent power flow through coordinated control of the series inverter.

1. UPQC-S: A Novel Concept of
Simultaneous Voltage Sag/Swell and
Load Reactive Power Compensations
Utilizing Series Inverter of UPQC

2. CONTENTS :
 Introduction
 Power quality
 Power quality problems
 Upqc block diagram
 Operation of Upqc
 Types of Upqc
 Advantages
 Conclusion

3. INTRODUCTION:
This project introduces a new
concept of optimum unified power
quality conditioner.
 Here the series inverter of Upqc
plays vital role in this Upqc-s
 Due to this series inverter operation
Upqc-p is turned into Upqc-s.

4. . POWER QUALITY:
Power quality means variation of
voltage ,current and frequency in permissible
limits.

6. POWER QUALITY PROBLEMS:
 VOLTAGE SAG
 VOLTAGE SWELL
 TRANSIENTS
 FLICKERS
 NOTCHES
 VOLTAGE UNBALANCE
 VOLTAGE INTERRUPTION
 POOR POWER FACTOR

8. VOLTAGE SOURCE CONVERTER:
 Generally we use the voltage source inverters in all facts
devices.
 In VSI input voltage maintained constant and the
amplitude of output voltage does not depend on the load.
 How ever the waveform of the current as well as its
magnitude depends upon the nature of a load.

9. BLOCK DIAGRAM OF UPQC :

10. EQUIVALENT CIRCUIT FOR A UPQC

11. TYPES OF UPQC:
Depending upon the series inverter operation operation
the UPQC is to be classified in to three types .
They are
 UPQC-P
 UPQC-Q
 UPQC-S

12. OPERATION OF UPQC-P:

13. CONT….

16. CASE V:
series inverter injects the voltage harmonics
to source voltage to neutralize the voltage
harmonics in the source side.
CASE Vl:
shunt inverter injects the current harmonics
to the load current to neutralize the harmonics in the
load current.

17. CONCEPT OF PAC OF UPQC-S :

18. QshQsr
OPERATION OF UPQC-S:
Apparent power flow during under voltage sag condition
Case 1:

19. Qsr
Qsh
Apparent power flow during under voltage swell condition
Case2 :

20. Qsr
Qsh
Reactive power flow under normal condition
Case 3:

21. ADVANTAGES:
ADVANTAGES OF UPQC-P OVER UPQC-Q:
 In UPQC-P minimum injected voltage magnitude
required to get the nominal voltage compared to
UPQC-Q .
 UPQC-P rectify the both voltage sag and voltage swell
but UPQC-Q rectifies voltage swell only.

22. ADVANTAGES OF UPQC-S OVER UPQC-P:
 UPQC-S is a optimum utilization of UPQC-P .
 In UPQC-S the series inverter reduces the burden
to shunt inverter .
In UPQC-S we use minimum KVA rating of shunt
inverter.

23. CONCLUSION:
It is not a separate upqc but by using power angle
control ,we can use the upqc optimally.
In this, a concept of controlling of apparent power
through a series inverter is implemented.