Dynamic influences on protection systems in distribution networks with distributed generation

This paper deals with the protection system in distribution networks with distributed generation. It describes the dynamic influences of synchronous generators on the direction determination of protection relays during network disturbances. Therefore the dynamic behaviour of the measured electrical quantities during network disturbances is derived. A relay-model is implemented to study the behaviour of protection relays. The results show that the direction determination may see reverse faults in forward direction, following unwanted tripping, during the period of acceleration of synchronous generators.