Special reports and papers for high voltage direct current(HVDC) transmission and power electronic technology in the study committee(SC) B4 of CIGRE'2010 are introduced. The main issues of reports and papers include the development of HVDC technology, especially the recent progress of±800 kV ultra high voltage direct current(UHVDC) and voltage source converter(VSC) HVDC projects, the flexible AC transmission system(FACTS) operation experience and its new planning scheme, the application of power electronic devices in renewable energy, and typical issues about HVDC and FACTS projects, etc.