AbstractA Static Var Generator (SVG) based on a self‐commutated inverter using GTO thyristors has been newly developed. The size of the SVG used for improving power system stability will be as large as approximately 100 MVA. The technical subjects to be solved for developing such a large SVG are summarized as follows:compact design;harmonic elimination by means of multiple transformers; andlarge inverter with series connection of GTO thyristors.This paper describes the solutions to these subjects, especially the application of a large number of multipulse connection and series connection of GTO thyristors, including the analysis of the basic performance of SVG and the multiple transformer. The test results of a 12‐pulse partial model (8 MVA) and a 48‐pulse miniaturized model prove the solutions proposed in this paper to be effective and reaso