The use of VSC HVDC (voltage source converter for high voltage direct current link) to transmit the power over long distance has lot of technical advantages compared to AC transmission as eradicating of interactions problem that can happen when the AC systems are coupled directly. To achieve wanted objectives from the use of HVDC system, it is necessary to develop the performance of the control system and this passes by selecting good parameters of Proportional – Integral PI regulators used for the control these systems. In this paper simplex optimization method is one of direct methods that can be used for tuning process of the designed PI regulators which consequently ameliorate the control system behavior. The benefit from the use of this method is to get new optimized PI gains with perfect accuracy and in typical speed. PSCAD/ EMTDC simulations are presented to show the performance of the proposed method during response steps and under serious perturbation.

VSC HVDC; optimization, simplex method, PI regulators