Network interface for transmitting protection data of a power network

The invention relates to a network interface for redundant coupling of a substation communication network and a packet-switched WAN of a power network. The interface device comprises: a first redundancy module comprising: two LAN ports connectable with the Substation communication network, and a first interface port; a second redundancy module comprising: two WAN ports connectable with the WAN, and a second interface port; and a first interworking module connecting the first with the second redundancy module via the first and the second interface port, and adapted to forward protection data between the first and the second redundancy module.