The significant development of Distributed Generation (DG) using renewable energy sources can affect power system stability, in presence of a network disturbance which can lead to switch off a large amount of power installed in DG, since traditionally these power plants are disconnected from the network when a fault occurs. However this reality has changed, so that Portuguese regulation reviewed Distribution Code Grid by introducing new requirements for DG, such as fault ride-through capability for wind farms, with the aim of promoting power system stability. This paper describes network´s protection system changes that were introduced by Portuguese Distribution System Operator, in order to fit fault ride-through capability of some DG power plants. Towards interconnection protection, it is described changes in order to fit fault ridethrough voltage characteristic. It is also described the functions needed at the Substation interconnection panel to allow auto-reclosure. An example of an incident occurred in the Portuguese distribution network involving a wind farm with fault ridethrough capability is also analysed.

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