VAr Compensation is the control of reactive power in order to improve the performance of ac power system. This book presents simple and popular VAr compensation technologies that have replaced the traditional method of fixed or mechanically switched capacitors used for power factor correction. Dynamic var compensation techniques described in this book use combinations of variable inductive and capacitive elements with solid-state devices, such as thyristors, GTOs, and IGBTs for switching to achieve faster, smooth and accurate response to changes in ac system conditions.A control system determines the gating instants and issues the gating pulses to the solid-state switches in response to some ac system changes.With these devices, known as Static VAr Compensators (SVC),it is possible to achieve unity power factor, minimize losses, enhance active power transfer capability,stabilize voltage and damp power oscillations.The book will be of immense value to practicing engineers, teachers and students.