Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546
(OP) 5-115
OP
For three relays to work together as a protection system, their addresses must be in the
same group and they should be assigned separately with addresses A, B and C.
They must also have a fixed connection configuration, as shown in Figure 75, in which
cha
nnel 1 of one relay is connected to channel 2 of another relay.
For example, if the group 1 address is used, addresses 1-A, 1-B and 1-C should be assigned
to relays A, B and C respectively. Relay A will only accept messages with address 1-A and
will send messages carrying addresses 1-B and 1-C to channel 1 and channel 2
respectively. Relay B will only accept messages with address 1-B and will send messages
carrying addresses 1-C and 1-A to channel 1 and to channel 2 respectively. Similarly relay
C will only accept messages with address 1-C and will send messages carrying addresses
1-A and 1-B to channel 1 and to channel 2 respectively.
Channel 1
Channel 1
Channel 1
Channel 2
Channel 2
Channel 2
Relay A
Relay B
Relay C
P1033ENa
P1033ENa
Figure 75 3-terminal system connection
2.1.17 Reconfiguration of three-ended system
This functio
n only applies to relays which are set-up for 3 Terminal operation. The operation
depends on the status of the communication channels, the relays in the scheme and various
time periods. There are two general areas of operation, these being the change in
configuration by a user and that generated by an energization of a relay. The various
considerations applying to each of these cases are given below.
Four settings are provided as follows:
Three Ended
Two Ended Local and Remote 1 (L & R1)
Two Ended Local and Remote 2 (L & R2)
Two Ended Remote 1 and Remote 2 (R1 & R2)
Remote 1 and Remote 2 relate to protection signaling channel 1 and 2 respectively.
The operation of the reconfiguration is described in 2.1.18 and 2.1.19.
2.1.18
User reconfiguration
This covers t
he normal set-up of the relays into a 2-ended or 3-ended scheme depending on
the state of the protected line and the relays. The facilities provided allow the user to initially
use two relays to protect a two ended line and later to upgrade the scheme to three ended
using a further relay. It also allows one end of a three ended scheme to be isolated and the
other two ends to operate as a two ended scheme. This allows tests to be performed on the
end that has been isolated and also allows for that relay to be removed altogether.
The change in configuration is enabled by two external interlocks and by the current state of
the relay and its communications. If the scheme is changed from 3-ended to 2-ended, it is
considered to be a reconfigure command. If the scheme is changed from 2-ended to
3-ended, it is considered to be a restore command. The checks performed for a
reconfiguration are slightly different to those for a restore.
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