The advanced static VAR compensator (ASVC) device is now recognized as one of the most important Flexible Alternating Current Transmission Systems (FACTS) devices. It has been proven that the mid-point of a transmission line is the optimal location for some FACTS devices or reactive power support, and the proof is based on the linear load, which is not valid practically. The validity of the optimal location of Pulse Width Modulation (PWM) based ASVC device is investigated when the non-linear load model is considered. In this paper, the ASVC applied to a non-linear load is modeled and analyzed. It was found that the optimum installation position for this device is at the sending end bus, where the wide range of receiver terminal line voltage and active power can be controlled. It was found that a wider range of reactive power could be controlled when the device is installed close to the receiving end bus. (c) 2005 Elsevier Ltd. All rights reserved.