ABB RELION REX640, Техническое руководство, Страница: 80 / 1960

The LHMI has two RJ-45 connectors. One is for connecting the LHMI to the
protection relay main unit and the second is a service port which is used for
connecting the LHMI and a computer. This computer can be, for example, a laptop
with the PCM600 engineering tool or a browser for WHMI.
An optional serial interface is available for RS-485 communication.
3.2.1 Ethernet addresses for HMI
There is a DHCP server available at X0 port that can provide an IP address and a
netmask for one client. The service port on the LHMI has a DHCP server that can
also serve one client. To use WHMI or PCM600, a PC can be connected either directly
to X0 port or to the LHMI's service port. In both cases, the PC can use the DHCP
client to receive the IP address automatically.
If the LHMI is connected to the relay through the station network, the service port
still offers the DHCP server even if the LHMI's main unit port uses a static address.
The LHMI device functions as a router between the PC and the protection relay.
Main unit's X0 port IP address can also be changed to avoid conflicts with other
network addresses. Parameter is located under Configuration/Communication/
Ethernet/HMI address. Subnet mask for X0 IP address is always 255.255.255.0 and
cannot be changed.
3.2.2 Self-healing Ethernet ring
The protection relay supports a self-healing ring solution for small installations. For
the correct operation of self-healing ring topology, the network topology must be
a ring. 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 ring
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/linkdown events can cause temporary breaks in communication. For a better
performance of the self-healing ring, 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 ring.
The end links of the protection relay loop can be attached to the same external
switch or to two adjacent external switches. If two adjacent external switches are
connected to the relay loop, the point-to-point Ethernet link connecting these two
switches should be prioritized by setting higher RSTP priority (lower setting value
for port priority). This ensures that most of the network traffic that is not meant for
the relays flows between the Ethernet switches.
The self-healing ring solution supports the connection of up to 30
protection relays. However, the HSR or PRP network is recommended to
ensure redundant and proper functionality.
Self-healing is not recommended for time-critical applications using IEC
61850-9-2 and PTP due to longer recovery time. Instead, HSR/PRP is
recommended to ensure reliable performance.
Basic functions 1MRS759142 F
80 REX640
Technical Manual