Fault ride through concept in low voltage distributed photovoltaic generators for various dispersion and penetration scenarios

The Distributed Generation expansion and its smooth integration in distribution networks have gained much interest over the last years. Particularly, the photovoltaic systems connected to the low voltage distribution networks, present noteworthy benefits for the energy markets and customers. Meanwhile, aiming to high penetration level, many issues emerge regarding their behavior under grid disturbances. In this paper, the concept of Fault Ride Through Capability (FRTC) is applied to low voltage distributed photovoltaic generators (DG-PV), aiming mostly to the coordinated design and control of their interfacing inverters, so as to successfully address the FRTC requirements. These design alterations are examined in combination with an appropriate control concept that improves the FRT behavior of the DG-PV units. In order to apply the proposed control, an energy storage system is deemed indispensable. Through load flow analysis, the impact of the DG-PV interfaced reactance value XDG is thoroughly investigated for various dispersion and penetration levels scenarios. Therefore, by applying the above control concept, a suitable selection of XDG can be reached, achieving so compliance with FRT limits without leading to extremely inverter overloading (during faults). Finally, it is shown that the wider dispersion of DG-PV units enhances their FRT compatibility.