Chapter 10—C445 Ground Fault Monitoring and Protection
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
www.eaton.com
209
Zero-sequence Ground Fault Monitoring and
Protection
The zero sequence sense current transformer (also called
core balance current transformer, window current
transformer, or toroidal current transformer) is the basis for
sensitive ground fault protection of motors.
When Ground Fault Module (GFM) is recognized, the C445
system no longer uses current information from the
C445M… measurement module for ground fault current
calculations. The measurement module is still used for
current, voltage, and power information including overload
protection that is provided to the C445B… base module.
Table 67. Zero-sequence Ground Fault Parameterization
Zero-sequence Ground Fault monitoring requires the use of
an external zero-sequence CT that is connected to a
C445XG-MOD adapter module (GFM) coupled to a
zero-sequence CT. Current sense range for the Ground Fault
Module (GFM) is 0.03 – 10.0 Amps which encompasses all
four (4) C445XG-CT… current transformers.
Table 68. C445 Zero-sequence Current Transformers
The C445XG-MOD GFM may be either DIN rail mounted or
directly mounted with screws by utilizing the optional
mounting tabs. The GFM has two (2) RJ12 terminals to
enable easy connection to the C445 system with
D77E-QPIP… cabling used on the base and measurement
modules. Connection to the CT is made via a screw terminal
connector on the GFM and screw terminals on the CT.
Note:
If the C445 has been powered up and configured prior
to connecting the GFM and/or the D77E-QPIP…
cables have been moved to different RJ12 terminals, a
Repair
action may be necessary to reconfigure the
C445 system.
Parameter Value
Debounce (Milliseconds)
Fault
Code
Action
Modbus Units
Frame
Min.
Max.
Default
Min.
Max.
Default
Modbus
4
Fault Trip
1060
Amps
C445XG-CT…
0.03
10.0
4
0
60,000
1,000
1063
Fault Trip Indication Only
1087
Amps
C445XG-CT…
0.03
10.0
4
0
60,000
1,000
1063
Shunt trip
1089
Amps
C445XG-CT…
0.03
10.0
4
0
60,000
1,000
1063
Fault Warning
1061
Amps
C445XG-CT…
0.03
10.0
3.4
200
5,000
2,000
1079
Fault Trip Delay
At Powerup
0s
5s
0s
1062
Fault Trip Inhibit
1064
Disable
Enable
Disable
Catalog Number
Current (A)
Aperture
C445XG-CT2
45
28mm round
C445XG-CT3
90
52mm round
C445XG-CT4
135
63mm round
C445XG-CT7
800
175mm(w) x 80mm (h)