Development of 20 MVA static synchronous compensator

Static synchronous compensator (STATCOM) has been proved to have a number of advantages over other techniques available at present in stabilizing power transmission systems. To improve the stability of the power transmission system of China's Henan province, the Henan Electric Power Company and Tsinghua University have jointly investigated and developed a 20 MVA STATCOM employing GTO inverters. The STATCOM consists of four six-pulse voltage source inverters (VSIs) unit rated 5 MVA which use 48 GTOs rated 4500 V, 4000 A. The STATCOM has been installed in a 220 kV substation and has been put into operation successfully since April 1999. The field tests have been carried out to verify the performance and the long-term reliability of the installation. The outline, technical features and field test results of the 20 MVA STATCOM are given in this paper.