ABB RED650, Applications Manual

Page: 403 / 454

ComFailAlrmDel defines the time delay for communication failure alarm. In
communication systems, route switching can sometimes cause interruptions with a
duration of up to 50 ms. Too short a time delay can thus cause nuisance alarms.
ComFailResDel defines the time delay for communication failure alarm reset.
RedChSwTime defines the time delay before switching over to a redundant channel
in case of primary channel failure.
RedChRturnTime defines the time delay before switching back to the primary
channel after channel failure.
AsymDelay denotes asymmetry which is defined as transmission delay minus
receive delay. If fixed asymmetry is known, Echo synchronization method can be
used, provided that AsymDelay is properly set. From the definition follows that
asymmetry is always positive at one end and negative at the other end.
AnalogLatency specifies the time delay (number of samples) between actual
sampling and the time the sample reaches LDCM. The value is set to 2 when
transmitting analog data..
MaxTransmDelay indicates maximum transmission delay. Data for maximum 40
ms transmission delay can be buffered up. Delay times in the range of some ms are
common. If data arrive in wrong order, the oldest data is disregarded.
MaxtDiffLevel indicates the maximum time difference allowed between internal
clocks in respective line ends.
TransmCurr is used to select among the following:
• one of the two possible local currents is transmitted
• sum of the two local currents is transmitted
• channel is used as a redundant backup channel
1½ breaker arrangement has two local currents, and the Current Transformer (CT)
earthing for those can differ.
CT-SUM transmits the sum of the two CT groups. CT-
DIFF1 transmits CT group 1 minus CT group 2 and CT-DIFF2 transmits CT group
2 minus CT group 1.
CT-GRP1 and CT-GRP2 transmit the respective CT groups, and setting
RedundantChannel determines that the channel is used as a redundant backup
channel. The redundant channel takes the CT group setting of the main channel.
RemAinLatency corresponds to LocAinLatency set in the remote IED.
CompRange value indicates the current peak value over which truncation is made.
To set this value, knowledge of fault current levels is required. However, the setting
is not very critical as it considers very high current values in which correct
operation can usually still be achieved.
1MRK 505 393-UEN B
Section 19
Remote communication
Line differential protection RED650 2.2 IEC 397
Application manual