Self-Healing Ethernet Ring; Ethernet Redundancy - ABB RELION 620 Series Technical Manual

1MRS757644 H
connected to Ethernet-based communication systems via the RJ-45 connector
(100Base-FX) or the fiber-optic LC connector (100Base-FX).
2.5.1

Self-healing Ethernet ring

For the correct operation of self-healing loop topology, it is essential that the
external switches in the network support the RSTP protocol and that it is enabled
in the switches. Otherwise, connecting the loop topology can cause problems to the
network. The protection relay itself does not support link-down detection or RSTP.
The ring recovery process is based on the aging of the MAC addresses, and the link-
up/link-down events can cause temporary breaks in communication. For a better
performance of the self-healing loop, it is recommended that the external switch
furthest from the protection relay loop is assigned as the root switch (bridge
priority = 0) and the bridge priority increases towards the protection relay loop.
The end links of the protection relay loop can be attached to the same external
switch or to two adjacent external switches. A self-healing Ethernet ring requires
a communication module with at least two Ethernet interfaces for all protection
relays.
Figure 7: Self-healing Ethernet ring solution
2.5.2

Ethernet redundancy

IEC 61850 specifies a network redundancy scheme that improves the system
availability for substation communication. It is based on two complementary
620 series
Technical Manual
Client A
Managed Ethernet switch
with RSTP support
The Ethernet ring solution supports the connection of up to 30
protection relays. If more than 30 protection relays are to be connected,
it is recommended that the network is split into several rings with
no more than 30 protection relays per ring. Each protection relay
has a 50-μs store-and-forward delay, and to fulfil the performance
requirements for fast horizontal communication, the ring size is limited
to 30 protection relays.
620 series overview
Client B
Network A
Network B
Managed Ethernet switch
with RSTP support
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