P341/EN AD/F43 Update Documentation
(AD) -46
MiCOM P341
3) Breaker fail
The technique to use 52a contacts in trip circuits was described above. However, in the
event of failure of the local circuit breaker (stuck breaker), or defective auxiliary contacts
(stuck contacts), the 52a contact action is incorrect. The interrupting duty at the local
breaker then falls on the relay output contacts which may not be rated to perform this duty.
MiCOM high break contacts will avoid the risk of burnt relay contacts.
4) Initiation of teleprotection
The MiCOM high break contacts also offer fast making. This can provide faster tripping:
additionally, fast keying of teleprotection is a benefit. Fast keying bypasses the usual
contact operation time, such that permissive, blocking and intertrip commands can be routed
faster.
2.9 Ethernet board
The optional Ethernet board (ZN0049) has 3 variants which support the IEC 61850
implementation:
100 Mbits/s Fiber Optic + 10/100 Mbits/s Copper
100 Mbits/s Fiber Optic + 10/100 Mbits/s Copper + modulated IRIG-B
100 Mbits/s Fiber Optic + 10/100 Mbits/s Copper + un-modulated IRIG-B
This card is fitted into Slot A of the relay, which is the optional communications slot. Each
Ethernet card has a unique MAC address used for Ethernet communications. This is printed
on the rear of the card, alongside the Ethernet sockets.
The 100 Mbits/s Fiber Optic ports use ST® type connectors and are suitable for 1300nm
multi-mode fiber type.
Copper ports use RJ45 type connectors. When using copper Ethernet, it is important to use
Shielded Twisted Pair (STP) or Foil Twisted Pair (FTP) cables, to shield the IEC 61850
communications against electromagnetic interference. The RJ45 connector at each end of
the cable must be shielded, and the cable shield must be connected to this RJ45 connector
shield, so that the shield is grounded to the relay case. Both the cable and the RJ45
connector at each end of the cable must be Category 5 minimum, as specified by the IEC
61850 standard. It is recommended that each copper Ethernet cable is limited to a maximum
length of 3 meters and confined within one bay/cubicle.
When using IEC 61850 communications through the Ethernet card, the rear EIA(RS)485 and
front EIA(RS)232 ports are also available for simultaneous use, both using the Courier
protocol.
The physical layout of the Ethernet board is shown in Figure 5.
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