Communication - ABB Relion SMU615 Product Manual

Substation Merging Unit
SMU615
Product version: 1.0

3. Communication

The IEC 61850 protocol is a core part of the SMU615 merging
unit. Both Edition 1 and Edition 2 versions of the standard are
supported.
The IEC 61850 communication implementation supports
monitoring and control functions. Additionally, parameter
settings and disturbance recordings can be accessed using the
IEC 61850 protocol. Disturbance recordings are available to
any Ethernet-based application in the standard COMTRADE file
format. The merging unit supports simultaneous event
reporting to five different clients on the station bus and can
exchange data with other devices using the IEC 61850
protocol.
SMU615 supports IEC 61850 process bus by sending sampled
values of analog currents and voltages. The measured values
are transferred as sampled values using the IEC 61850-9-2 LE
protocol. Merging units with process bus based applications
use IEEE 1588 for high accuracy time synchronization.
The merging unit can send and receive signals from other
devices using the IEC 61850-8-1 GOOSE (Generic Object
Oriented Substation Event) profile. Binary GOOSE messaging
can, for example, be employed for interacting with the
switchgear primary equipment when utilizing the merging unit's
physical interface. The merging unit meets the GOOSE
performance requirements for tripping applications in
distribution substations as defined by the IEC 61850 standard
(<10 ms data exchange between the devices).
For redundant Ethernet communication, the merging unit offers
either two optical or two galvanic Ethernet network interfaces. A
third port with galvanic Ethernet network interface is also
available. The third Ethernet interface provides connectivity for
any other Ethernet device to an IEC 61850 station bus inside a
switchgear bay, for example, a connection to a Remote I/O.
Ethernet network redundancy can be achieved using the high-
availability seamless redundancy (HSR) protocol or the parallel
redundancy protocol (PRP).
The IEC 61850 standard specifies network redundancy which
improves the system availability for substation communication.
The network redundancy is based on two complementary
protocols defined in the IEC 62439-3 standard: PRP and HSR.
Both the protocols are able to overcome a failure of a link or
switch with a zero switch-over time. In both the protocols, each
network node has two identical Ethernet ports dedicated for
one network connection. The protocols rely on the duplication
ABB
of all transmitted information and provide a zero switch-over
time if the links or switches fail, thus fulfilling all the stringent
real-time requirements of substation automation.
In PRP each network node is attached to two independent
networks operated in parallel. The networks are completely
separated to ensure failure independence and can have
different topologies. The parallel network operation provides
zero-time recovery and continuous checking of redundancy to
avoid failures.
HSR applies the PRP principle of parallel operation to a single
ring. For each message sent, the node sends two frames, one
through each port. Both the frames circulate in opposite
directions over the ring. Every node forwards the frames it
receives from one port to another to reach the next node. When
the originating sender node receives the frame it sent, it
discards the frame to avoid loops. The HSR ring with SMU615
merging units supports the connection of up to 30 devices. If
more than 30 devices are to be connected, it is recommended
to split the network into several rings to guarantee the
performance for real-time applications.
All communication connectors, except for the front port
connector, are placed on integrated communication modules.
The merging unit can be connected to Ethernet-based
communication systems via the RJ-45 connector (100Base-TX)
or the fiber-optic LC connector (100Base-FX).
The merging unit supports the following high accuracy time
synchronization method with a time-stamping resolution of 4 μs
required in process bus applications and is included in all
variants.
• PTP (IEEE 1588) v2 with Power Profile
IEEE 1588 v2 features
• Ordinary Clock with Best Master Clock algorithm
• One-step Transparent Clock for Ethernet ring topology
• 1588 v2 Power Profile
• Receive (slave): 1-step/2-step
• Transmit (master): 1-step
• Layer 2 mapping
• Peer to peer delay calculation
• Multicast operation
The required accuracy of the grandmaster clock is +/-1 μs. The
merging unit can work as a master clock per BMC algorithm if
the external grandmaster clock is not available for short term.
1MRS758420 B
5