The development of semiconductors and microcomputers have led to progress in the production, transmission and distribution of electrical energy. The power transmission in HVDC (High Voltage Direct Current) based on converters of type VSC (Voltage Source Converter) to win the challenge the power transfer of large values. The complexity of controller loop settings is a necessity to achieve the desired results. The control techniques used prove the effectiveness of the results with better performance in terms of stability, speed and reliability with the respect of the tolerance interval of overrun. The main contribution of this paper is the best control management of a bidirectional transfer of power experimentally between two infinite bus grids using HVDC system. The simulation results obtained in MATLAB-Simulink environment and through test bench model justify an improvement of voltage rate in the electric grid and flexibility of active and reactive power control through HVDC transmission systems. Besides, these results were obtained following the adoption of new additive performances based on a better estimation of the variation margins of the controlled variable.

Wind farms will need to continue to provide voltage and frequency stability to the grid even during periods of disturbance or faults. Particular attention has been paid to the maintenance of production under disturbed conditions (fault ride-through capability LVRT) and grid support capability. The maintenance of the production in disturbed regime is possible by the design and the dimensioning of controllers able to maintain the connection to the grid and that in the presence of network defects. Control of reactive energy in the grid using flexible alternative current transmission systems (FACTs) can improve the transient and permanent stability of the later. This paper deals with the behavior of a double-fed induction generator (DFIG) under asymmetric voltage faults. A static compensator (STATCOM) is connected to the common coupling point (PCC) and serves as a reactive support to regulate the mains voltage and keep the DFIG connected. The different converters used in this paper are controlled by the oriented voltage control strategy (VOC) decomposed in positive and negative sequences. Simulation results under MATLAB/SIMULINK environment are introduced to show the validity and efficiency of the control strategy.