ABB RELION RET670, Commissioning Manual, Page: 318 / 328

CB Circuit breaker
CBM Combined backplane module
CCITT Consultative Committee for International Telegraph and
Telephony. A United Nations-sponsored standards body within
the International Telecommunications Union.
CCM CAN carrier module
CCVT Capacitive Coupled Voltage Transformer
Class C Protection Current Transformer class as per IEEE/ ANSI
CMPPS Combined megapulses per second
CMT Communication Management tool in PCM600
CO cycle Close-open cycle
Codirectional Way of transmitting G.703 over a balanced line. Involves two
twisted pairs making it possible to transmit information in both
directions
COM Command
COMTRADE Standard Common Format for Transient Data Exchange format
for Disturbance recorder according to IEEE/ANSI C37.111,
1999 / IEC 60255-24
Contra-directional Way of transmitting G.703 over a balanced line. Involves four
twisted pairs, two of which are used for transmitting data in both
directions and two for transmitting clock signals
COT Cause of transmission
CPU Central processing unit
CR Carrier receive
CRC Cyclic redundancy check
CROB Control relay output block
CS Carrier send
CT Current transformer
CU Communication unit
CVT or CCVT Capacitive voltage transformer
DAR Delayed autoreclosing
DARPA Defense Advanced Research Projects Agency (The US
developer of the TCP/IP protocol etc.)
DBDL Dead bus dead line
Section 16
1MRK 504 165-UUS -
Glossary
312 Transformer protection RET670 2.2 ANSI
Commissioning manual