PERFORMANCE INVESTIGATIONS OF STATIC COMPENSATOR USING MULTI LEVEL INVERTER

Abstract

Reactive power compensation is necessary in order to increase the power utilization and transmission capability of the power system. This also increases the power quality. Due to the advances in power electronics, the conventional compensators are replaced by static compensators such as STATCOM, TCS, TCR, DVR etc. The trend to minimize harmonics in conventional 2-level voltage source inverter (VSI) is to use various PWM techniques. However, this has some problems, like generating a common mode voltage, increase of switching frequency and increase of the switching losses which becomes significant at high power levels. Multilevel power converters have gained much attention in recent years due to the significant problems that are shown above. The general structure of the multilevel inverter is such as to synthesize a sinusoidal voltage from several levels of DC voltage. Increasing the number of levels produce a fine staircase waveform approaching close to a sinusoidal wave with minimum harmonic distortion. In this thesis, simulation of 3-Level inverter is carried and the performance of the inverter is investigated for two different PWM techniques. The performance of STATCOM using 3-level neutral point clamed GTO inverter is done for different loading conditions. The system is analyzed using MATLAB through a set of- simulations, to determine the effect of the DC-link capacitors. The control of the system is carried out using the implementation of a PI regulator. And the system performance is compared with different regulators like fuzzy and fuzzy pre compensated PI regulators.