Application Notes P54x/EN AP/La4
MiCOM P543, P544, P545 & P546
(AP) 6-47
AP
2.16.2 Clock source setting
The Clock Source should be set to “Internal” at all system ends, where they are connected
by direct optical fiber, as the P54x at each end has to supply the clock.
The Clock Source should be set to External at all system ends, where the ends are
connected by multiplexer equipment which is receiving a master clock signal from the
multiplexer network. It is important that there is a single master clock source on the
multiplexer network and that the multiplexer equipment at each end is synchronized to this
clock.
Note: This setting is not applicable if IEEE C37.94 mode selected.
2.16.3 Data rate
The
data rate for signaling between the two or three ends may be set to either 64 kbit/sec or
56 kbit/sec as appropriate.
If there is a direct fiber connection between the ends, the data rate would usually be set to
64 kbit/sec, as this gives a slightly faster trip time.
If there is a multiplexer network between the ends, then this will determine the data rate to
be used by the P54x system. The electrical interface to the multiplexer
(G.703 co-directional, V.35, or X.21) will be provided on either a 64 kbit/sec or 56 kbit/sec
channel, and the P54x at each end must be set to match this data rate.
Generally, North American multiplexer networks are based on 56 kbit/sec (and multiples
thereof) channels, whereas multiplexer networks in the rest of the world are based on
64 kbit/sec (and multiples thereof) channels.
This setting is not applicable if IEEE C37.94 mode selected.
2.17 InterMiCOM
64
(“Fiber InterMiCOM”)
The protection signaling channels of the P54x primarily intended to provide the capability for
implementing current differential protection are also capable of supporting InterMiCOM
64
teleprotection. If the P54x is configured to provide differential protection, then the
InterMiCOM
64
commands (IMx command) are transmitted together with the current
differential signals. If the differential protection of the P54x is not being employed, then the
communications messages are restructured to provide InterMiCOM
64
signaling of the type
supported by the MiCOMho P446, P443 and P445 relays. In either case, the fundamental
operation of the InterMiCOM
64
commands is the same.
2.17.1 IMx command type
Due to the fa
st data rate, there is not so much difference in real performance between the
three generic modes of teleprotection (Direct Intertrip, Permissive and Blocking), so only two
are implemented for InterMiCOM
64
. Direct Intertripping is available, with the second mode a
combined mode for Permissive/Blocking (the latter is named as ‘Permissive’ in the menu).
To increase the security for Intertripping (Direct transfer tripping), the InterMiCOM
64
Direct
command is issued only when 2 valid consecutive messages are received. The
recommended setting is:
For Blocking schemes set ‘Permissive’
For Permissive scheme set ‘Permissive’
For Transfer (inter)tripping set ‘Direct’
The setting files provide independent setting for each of the first 8 commands. Due to the
fast data rate, there will be minimal speed difference between the two mode options. Both
will give a typical operating time (PSL trigger at the send relay, to PSL state change at the
receive relay) as shown below:
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