Power electronics blends the main area of Electrical engineering, power electronics and control. As a result of technological evaluation many more semiconductor devices and their combinations are available. Flexible AC Systems (FACTS) is a controller and it is a technology pioneered by N.G.Hingorani and L.Gyugyi. The FACTS controller is one aspect of the power electronics revolution that is taking place in all area of electric energy. This book is the modification of the reference given and some approach has been accepted to develop the thinking process of the students in reaching a sound understanding of a broad range of topics in the FACTS controllers and application to the field of Power Systems. In general FACTS is the subject matter of this book and relatively the modification and clear understanding of the principal role to enhance controllability and power transfer capability in the ac systems. The FACTS involves conversion and/or switching power electronics in the range of a few tens to a few hundred megawatts. The book contains eight chapters. ukryj opis