Abstract:Wind power generator is one of the core components converting wind energy to electric energy. With the rapid developed technology of wind power generation including wind power generators since the end of 70＇s last century, various topologies of wind power generator and wind power systems are developed. The technologies and features of different kinds of wind power generators worldwide are firstly overviewed. Then their control features and drive train types and their strengths and weaknesses are analyzed and compared. Finally the latest development trend and research progress of wind power generator technologies are presented, hoping to offer reference for the research and development of wind power generation in China.
Abstract:Most of Chinese low-voltage distribution systems use three-phase four-wire Y/Yno（Y/Y） connection mode.The transformer unbalanced operation state is often caused by single-phase loads.The three-phase voltage imbalance and its impact to power quality are analyzed in this paper.Distribution transformer losses and line losses caused by the imbalance are investigated in detail.Some managing and technical countermeasures for the imbalance are also proposed.