Design of STATCOM using CHB and its Comparison with other RPC Devices

Background/Objectives: Due to the immense development in distributed generation, the entire power system network requires flexible control of power flow and increased stability.  Methods/Statistical analysis: In order to achieve this as well as to improve the reliability of the network, power electronics switches are incorporated at several locations as the control of these switches are comparatively easy and accurate.  Cascaded multilevel inverter based static synchronous compensator is one such device that provides better reactive power compensation, improves voltage profile as well as enhances the power factor of the system. Findings: This paper is intended to design and analyze static synchronous compensator (STATCOM) utilizing cascaded H-bridge (CHB) multilevel inverter. The designed STATCOM has been used for the Reactive Power Compensation (RPC) and power factor improvement for the single end fed power system network modeled in Simulink.  Seven levels CHB multilevel inverter has been designed for STATCOM using sine pulse width modulation (SPWM). The output of the inverter is then filtered using the pi filter to obtain nearly sinusoidal voltage profile. Single end fed power system network has been modeled in Simulink. STATCOM majorly provides reactive power and improve the power factor of the system without any further loading on it.  For confirming the effectiveness of the proposed STATCOM compensation, the system has also been analyzed with shunt compensation by fixed capacitor and thyristor switched capacitor (TSC) individually and the same study has been carried out to compare them. Applications/Improvements: It has been found that with the STATCOM implemented, the voltage profile of all the bus has increased nearly to 1 pu and the power factor has improved to 0.97 when compared to the other compensating devices.