Flexible fault current contribution with inverter interfaced distributed generation

This paper describes a control scheme to flexibly control the positive and negative sequence fault current contribution of inverter interfaced distributed generation (IIDG). This flexible control can be beneficial to limit the impact of distributed generation (DG) on existing grids. This way, a large scale integration of DG becomes possible in existing grids. A double synchronous reference frame (DSRF) control strategy is chosen. The phase locked loop (PLL) and current controller are based on available techniques and are described briefly. The performance of the control system is illustrated in a PSCAD simulation environment. Both symmetrical and asymmetrical faults are applied on a generic European medium voltage grid. Only the setpoints during faults have to be changed to obtain a specific fault response, creating the required flexibility.