142

CHAPTER 7

CONCLUSION AND FUTURE SCOPE

7.1 CONCLUSION

In this research work, the design and evaluation of the robustness of

power quality solutions are carried out using the PV-UPQC system. The

installation of PV-UPQC system at the distribution system ensures the

capability of enhancing the improvement in power quality.

The proposed PV-UPQC system is simulated using

MatLab/Simulink software. Based on the analysis of the simulation results,

the conclusions of this research work are as follows.

Customized power offers the customer no interruptions, tight

voltage regulation, low harmonic voltages and tolerance to

fluctuating and non-linear loads without affecting the terminal

voltage.

It has been shown that custom power devices provide higher

performance in comparison to traditional compensation techniques.

However, the choice of the most suitable solution depends on the

characteristic of the supply at the PCC, the requirements of the load,

economic aspects and the customer value added by the installation

of power electronic based devices.

In the proposed PV-UPQC power circuit, control strategies of the

system are modeled in detail. Consequently, this model provides

efficient guidelines to deal with robust compensation techniques of

sag and swell and for obtaining steady- state waveforms.

143

Due to simple and fast response characteristics of the hysteresis

control, the proposed hysteresis method provides reactive power

compensation and the reduction of the current harmonics.

When the PV-UPQC is connected to a weak supply point, the

voltage becomes unacceptably distorted due to the switching

frequencies in the supply current. LC filters are used for interfacing

the shunt VSI with the distribution network for minimizing the

switching frequencies generated by the shunt inverter entering into

the grid.

The results are analyzed with combined operation of PV and UPQC,

which can compensate long voltage interruption and inject the active

power to the load.

The PV-UPQC system is highly suitable for compensating the power

quality problems. It can be connected to distribution systems and is capable

of generating real and reactive power at PCC. The simulation results show

that the proposed PV-UPQC compensation of the sag, swell, harmonics

and long voltage interruption is better than the other existing methods

implemented by various researchers. As compared to artificial neural

network and fuzzy logic controllers of other authors, the proposed control

system provides better voltage regulation. The PV-UPQC system approach

is found to be efficient and it provides robust power quality improvement

in power distribution systems.

144

7.2 FUTURE SCOPE

During the course of this research, the following issues have been

identified for the future work.

The research work can be extendable for the use of wind energy.

The control techniques can be enhanced to design different control

schemes.

The proposed scheme can be used with battery-based system even in

the absence of solar energy during night times and cloudy days.

145

APPENDIX

146

147

Figure A3 Load Subsystem

Figure A4 Unbalanced Distribution Creation Subsystem

148

Figure A5 Series Transformer Subsystem

Figure A6 Series Transformer Subsystem

149

Figure A7 DC link subsystem

Figure A8 DC link controller subsystem

150

Figure A9 Current controller subsystem

Figure A10 Series low pass filter subsystem

151

Figure A 11 Photovoltaic Simulation Models