1. Harmonics Reduction in 3-Phase, 3-Wire Distribution System with 5 level Shunt Active Filter

2. Harmonics Reduction in 3-Phase, 3-Wire Distribution System with 5 level Shunt Active Filter

3. CONTENTS Abstract Introduction
CLASSIFICATION OF SHUNT ACTIVE POWER FILTERS
Circuit Diagrams of CSC and VSC
Basic block diagram of three phase three wire shunt active power filter
Active filter controller block diagram
MULTILEVEL INVERTER
SIMULINK RESULTS
Conclusion
References

4. Abstract
This paper presents the complete examination to estimate the working of SHAF for generating the current references under steady and transient for balanced, unbalanced and non-sinusoidal conditions by using PI controller.
Harmonics are developed in transmission and distribution system with use of huge quantity of non-linear (transformer etc.,), power electronic equipments (bridge rectifier, power converters etc.,), in industrial and even house-hold electrical equipments.
In order to protect the supply system from current harmonics, we have to use the active power filters. These are used to compensate the reactive power compensation, but the performance of active power filters are based on various control strategies.

5. Introduction
Nowadays by the improvement of semiconductor and power electronic technology, the conventional use of non-linear loads is greater.
So that the quality of power deteriorates with the extensive use of non-linear loads in both transmission and distribution systems.
the non-linear loads such as transformers, arc furnaces, power converters, static VAR compensators, adjustable drives and pulse width modulated drives etc, are increases, As a result of increasing non-linear loads to produce harmonic currents or circulating currents

6. CLASSIFICATION OF SHUNT ACTIVE POWER FILTERS
the shunt active power filters are classified into two types.
(i) CSC
(ii) VSC

7. Circuit Diagrams of CSC and VSC

8. The main difference between these two topologies is energy storage element connected at DC link side.
In CSC type shunt active power filter, the converter is formed by six controllable switches in series with diodes and LfCf filter is connected in between the PWM converter and supply mains and it is used to suppress ripples in output of the converter.
In VSC type shunt active power filter, the converter is formed by six controllable switches in shunt with diodes and Lf filter is connected in between the PWM converter and supply mains and it is used to suppress ripples in output of the converter output of the converter.

9. Basic block diagram of three phase three wire shunt active power filter.

10. Active filter controller block diagram

11. CONSTRUCTION Of PI CONTROLLER

12. MULTILEVEL INVERTERS

13. SIMULINK RESULTS
Simulation results for balanced system

14. FFT analysis for source current

15. 3-phase 3-wire unbalanced source

16. FFT analysis source current

17. Simulation results for non sinusoidal source

18. FFT analysis for source current

19. Simulation results for balanced three phase with load changes

20. FFT analysis for source current

21. Simulation results for un balanced three phase with load change

22. FFT analysis for source current

23. Simulation results for non sinusoidal three phase with load changes

24. FFT analysis for source current

25. REFERENCES
1] H. Akagi, “Active Harmonic FiltNo. 12, pp , Dec. 200ters,” Proceedings of the IEEE, Vol. 93, 5.
[2] H. Akagi, Y. Kanazawa, A. Instantaneous Reactive Power inPower Electronics Conf.,Tokyo, JNabae,; “Generalize theory of the nThree-Phase Circuits”, IPEC'83 - Int. Japan,1983, pp.:
[3] IEEE Std , “IEEER ecofor Harmonic Control in Elctric Pommended Practices and Recquirements Power Systems”.
[17] H. Akagi, et al., “Instantaneou Power Conditioning”, Book IEEE us Power Theory and Applications to EPress, pp , 2007.

26. CONCLUSION
In this paper when the load may be balanced/unbalanced linear/nonlinear, the source must be sinusoidal.
Because of this we can proposed this shunt are balanced, unbalanced and non-sinusoidal under conditions the PI-controller.
This was useful to get the constant power supply and sinusoidal current waveform at point of common coupling.