Indigenous control of augmented DC voltage in D-Statcom

This paper discusses the modelling and control of custom power device, D-Statcom applied to 11kV/415 V distribution systems. This power electronics based device enhances the quality and reliability of power flow in low voltage distribution networks thus improving the quality of power supplied. Graphical modelling approach is used instead of mathematical model involving state equations and transformations. A Distribution Static Compensator (D-Statcom) is simulated in this paper using PSCAD/EMTDC with an attempt to regulate the load voltage during sudden disturbances involving load changes and faults in the distribution system. Main emphasis is given on the increase in DC voltage which rises during these conditions to compensate the sag or swell in the load voltage. The DC voltage controls itself by the inverter switching which is indirectly controlled by the controller parameters. The response is faster since the control involves the measurement of a single quantity. No transformations are used, reducing the complexity. Sinusoidal Pulse Width Modulation is employed with a six pulse VSI connected to a 415V distribution system. Comprehensive results obtained clearly shows the effectiveness of the proposed approach.