Special reports and papers for high voltage direct current(HVDC) transmission and power electronic technology in the study committee(SC) B4 of CIGRE 2012 are introduced. The main issues of reports and papers include the development of HVDC technology, especially the recent progress of 1 000 MW voltage source converter based HVDC projects, the research, development and application of new flexible AC transmission system(FACTS) equipment, and the application of power electronic technology to renewable energy integration.