Disturbance assessment in the grid integration of power electronic devices and other non-linear loads

Two main grid access contracts have been set up in France between utilities and customers. These grid connection contracts not only fix power quality commitments for grid operators but also customer disturbance emission limits. The practice of these contracts shows that a good overall power quality can only be achieved by respecting commitments and doing effort from both of grid and customer sides. Since the beginning of the 1990´s, a substantial growth of power electronic application has been noticed in electric power systems. More and more power electronic devices have been used in grid and facilities such as low voltage electronic devices (compact fluorescent lamp, switching-mode power supply), adjustable speed drive (ASD), high voltage direct current link (HVDC), etc. The application of power electronic devices in facilities has brought both advantages (energy saving) and side-effects (disturbances). The second part of this paper deals with disturbance load modelling and grid disturbance assessment. For grid disturbance assessment, it is suggested to use multi-phase harmonic injection method with fundamental power flow. This method can give an acceptable results with very short computing time for non linear load modelling. The key point of proposed frequency domain method is that each harmonic source is individually considered as both disturbance source and disturbance receiver in order to take into account interactions between sources. A plug&play HVDC component has been developed and used in one of two case studies in the end of this article.