ABB REC670 Applications Manual page 578

Section 21
Remote communication
572
• 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.
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. When a merging unit according to IEC 61850-9-2 is used
instead of the TRM, this parameter shall be set to 5.
CompRange value indicates the current peak value over which truncation is made.
To set this value, knowledge of fault current levels is required. It is recommended
to set the minimum range that will cover the expected fault current value. For
example, if a 40kA fault level is expected on the network, the 0-50kA settings
range should be chosen.
2 Mbit mode specific settings
RedundantCh is used to set the channel as a redundant backup channel. The
redundant channel takes the CT group setting of the main channel, and ignores the
CT group configured in its own transmit block.
LinkForwarded is used to configure the LDCM to merge the inter-trip and block
signals from another LDCM-receiver. This is used when the analog signals for the
LDCM-transmitter is connected to the receiver of another LDCM.
1MRK 511 401-UEN A
Bay control REC670 2.2 IEC
Application manual