Interaction of fault ride through requirements and loss of mains protection

The strongly growing DG capacity is raising concerns related to unintentional islanding. Unintentional islanding is prohibited due to the associated safety risks, and it is therefore mandatory to equip all DG units with some kind of loss of mains (LOM) protection. However, large amounts of unnecessary tripping of DG units cannot be tolerated anymore as the share of DG has already reached a significant share of the total installed power generation in certain regions. Certain grid codes thus require DG units to be able to ride through remote faults and support the power system. It is generally known that grid codes and LOM protection objectives are of somewhat controversial. However, it appears that no papers have studied the relation of LOM protection performance and fault ride through requirements thoroughly with simulations. This paper aims to fill this gap by providing extensive simulations which show how exactly the grid code requirements affect the performance of LOM protection. The studies are performed in a unique simulation environment consisting of two different types of real time simulators and a real LOM relay.