Performance Analysis of a Three Level Twelve-pulse VSC based STATCOM under Fault Condition

Recently with the progression of distributed generation, the power system needs flexible control of power transfer, better power flow control and improvement of transient stability. Additionally for improving the reliability of power system networks, using various protection strategies, power electronic switches are widely used to include new control strategies for improvement of quality of power. Cascaded multilevel inverter based STATCOM with higher bandwidth are now thus more efficient for minimizing voltage fluctuation, flicker mitigation, better reactive power compensation as well as stability enhancement. In our paper a three level twelve-pulse VSI based STATCOM is proposed in a distribution system for analyzing its effect on voltage profile as well as reactive power compensation under three phase fault condition. The proposed method for controlling the Statcom clearly shows that by proper utilization of the Statcom in our distribution system, voltage profile across the various types of load improves effectively under three phase fault condition and thus sustainability of the overall system will also improve. The output results show that the value of THD across different load voltages, e.g, FFT analysis of output voltage across STATCOM in the branch with fault (THD = 4.26%) has been shown. Additionally, FFT analysis of output voltage across Fixed Load (THD = 5.53%), Variable Load (THD = 2.76%), and Fixed Load current (THD = 2.85%) are within the acceptable limits and thus showing its well effectiveness in our proposed control strategy.