asokatechnologies@gmail.com 09347143789/09949240245

Search This Blog

Monday 10 July 2017

DSTATCOM employing hybrid neural network control technique for power quality improvement

ABSTRACT
A new hybrid control technique called gradient descent back propagation (GDBP)-based i cos ϕ for a three phase two level distribution static compensator (DSTATCOM) to perform the functions such as harmonic mitigation, power factor correction under reactive loads, which further reduces the DC link voltage across the self-supported capacitor of voltage source converter (VSC). The weighted value of fundamental active and reactive components of load currents are extracted using the proposed control technique to generate the reference source currents. Furthermore, these currents are used to trigger the VSC of the DSTATCOM. The effectiveness of this control technique is demonstrated through simulation using MATLAB/SIMULINK and sim power system tool boxes. The real-time implementation of DSTATCOM is also realised by real-time digital simulator. These results reveal the robustness of the proposed DSTATCOM as it is showing outstanding harmonic compensation capabilities under the various loading conditions and keeping the total harmonics distortion of the source current well <5%, the limit imposed by IEEE-519 standard.


SOFTWARE: MATLAB/SIMULINK


BLOCK DIAGRAM:




Fig. 1 Complete layout of the proposed DSTATCOM with control algorithm
(i) Schematic diagram of the power distribution system including proposed DSTATCOM



EXPECTED SIMULATION RESULTS:


Fig. 2 MATLAB results for (i) System performance using i cos ϕ control technique-based DSTATCOM, (ii) Harmonic spectra of source current, (iii) Harmonic spectra of load current and, (iv) Waveform of a-phase source voltage and source current




Fig. 3 MATLAB results for (i)System performance using i cos ϕ control technique-based DSTATCOM under unbalanced condition, (ii) Harmonic spectra of source current, (iii) Harmonic spectra of load current and, (iv) Waveform of a-phase source voltage and source current



Fig. 4 MATLAB results for (i) System performance by GDBP controlled i cos ϕ-based DSTATCOM, (ii) Harmonic spectra of source current, (iii) Harmonic spectra of load current and (iv) Waveform of a-phase source voltage and source current




Fig. 5 MATLAB results for (i) System performance by GDBP controlled i cos ϕ-based DSTATCOM under unbalanced loading condition, (ii) Harmonic spectra of source current, (iii) Harmonic spectra of load current and, (iv) Waveform of a-phase source voltage and source current



Fig. 6 MATLAB results for (i) Comparison of vdc under balanced condition and, (ii) Comparison of vdc under unbalanced condition

CONCLUSION
The DSTATCOM using GDBP-based i cos ϕ control technique is regarded as one of the suitable challenging solution for the improvement of power quality. It has performed better for the source current harmonic reduction, power factor improvement, voltage regulation and load balancing than traditional method. Also less amount of voltage is required to store the energy across the self-supported capacitor causing decrease in rating of DSTATCOM. This proposed technique assures the corrective actions under any source voltage and load conditions. The simulation results obtained from MATLAB/ SIMULINK .

REFERENCES
[1]   Angelo, B.: ‘Handbook on power quality’ (John Wiley & Sons, NJ, USA, 2008)
[2]   Dugan, R.C., Mc Granaghan, M.F., Beaty, H.W.: ‘Electric power systems quality’ (McGraw-Hill, New York, NY, USA, 2006, 2nd edn.)
[3]   Bollen, M.H.J.: ‘Understanding power quality problems’ (IEEE press, Wiley India Edition, 2011)
[4]   Ghosh, A., Ledwich, G.: ‘Power quality enhancement using custom power devices’ (Springer International Edition, 2009)

[5]    Padiyar, K.R.: ‘FACTS controllers in power transmission and distribution’ (New Age International, New Delhi, India, 2008)