Ethernet Redundancy - ABB SSC600 Operation Manual

Introduction
1.1.1

Ethernet redundancy

IEC 61850 specifies a network redundancy scheme that improves the system
availability for substation communication. It is based on parallel redundancy
protocol PRP-1 defined in the IEC 62439-3:2012 standard. The protocol relies on the
duplication of all transmitted information via two Ethernet ports for one logical
network connection. Therefore, it is able to overcome the failure of a link or switch
with a zero-switchover time, thus fulfilling the stringent real-time requirements for
the substation automation horizontal communication and time synchronization.
PRP specifies that each device is connected in parallel to two local area networks.
Thus, each device incorporates a switch element that forwards frames from port to
port.
PRP
Each PRP node, called a doubly attached node with PRP (DAN), is attached to two
independent LANs operated in parallel. These parallel networks in PRP are called
LAN A and LAN B. The networks are completely separated to ensure failure
independence, and they can have different topologies. Both networks operate in
parallel, thus providing zero-time recovery and continuous checking of redundancy
to avoid communication failures. Non-PRP nodes, called single attached nodes
(SANs), are either attached to one network only (and can therefore communicate
only with DANs and SANs attached to the same network), or are attached through a
redundancy box, a device that behaves like a DAN.
Figure 2: PRP solution
10
IEC 62439-3:2012 cancels and replaces the first edition published in 2010.
These standard versions are also referred to as IEC 62439-3 Edition 1 and
IEC 62439-3 Edition 2. The IED supports IEC 62439-3:2012 and it is not
compatible with IEC 62439-3:2010.
1MRS758850 C
SSC600
Operation Manual