Channel Monitor - GE L90 Instruction Manual
Ur series line current differential system
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Also See for L90:
- Instruction manual (900 pages) ,
- Communications manual (532 pages) ,
- Instruction manual (700 pages)
Table of Contents
2.2 PILOT CHANNEL RELAYING
The master L90 relay performs the following functions:
•
Performs all functions of a slave L90.
•
Receives current phasor information from all relays.
•
Performs the current differential algorithm.
•
Sends a current differential DTT signal to all L90 relays on the protected line.
2
In the peer-to-peer mode, all L90 relays act as masters.
The L90 has logic to detect that the communications channel is deteriorating or has failed completely. This can provide an
alarm indication and disable the current differential protection. Note that a failure of the communications from the master to
a slave does not prevent the master from performing the current differential algorithm; failure of the communications from a
slave to the master will prevent the master from performing the correct current differential logic. Channel propagation delay
is being continuously measured and adjusted according to changes in the communications path. Every relay on the protec-
tion system can assigned an unique ID to prevent advertent loopbacks at multiplexed channels.
2-12
Tx
Rx
IED-1
Tx
Optional redundant channel
Rx
Typical two-terminal application
Tx
Rx
IED-1
Tx
Rx
Typical three-terminal application
Figure 2–2: COMMUNICATIONS PATHS
L90 Line Current Differential System
2 PRODUCT DESCRIPTION
Rx
Tx
Rx
Tx
Rx
Tx
Rx
Tx
Tx
Rx
Tx
Rx
CHn
CHn
IED-3
2.2.2 CHANNEL MONITOR
IED-2
IED-2
831009A5.CDR
GE Multilin
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