This paper deals with dynamic impedance compensation and control schemes for changes in load as well as change in line reactance in transmission lines. Static Synchronous Series Compensator (SSSC) designed to compensate the reactive power to the transmission line. Here SSSC uses Neutral Point Clamped (NPC) Voltage Source Converter (VSC) to generate three phase voltage waveforms. It can provide dynamic response by quickly changing the equivalent reactance (capacitive) to desired level of compensation. The paper discusses the performance characteristics of SSSC with the Direct and Indirect controllers. Modeling and simulation of the transmission line with NPC VSC based SSSC and its performance is evaluated. © 2015 Praise Worthy Prize S.r.l. - All rights reserved.