Chapter 10—C445 Ground Fault Monitoring and Protection
208
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
www.eaton.com
Chapter 10—C445 Ground Fault Monitoring and Protection
Ground Fault Monitoring Methods
●
Residual Ground Fault Protection
●
Zero-sequence (Core Balance) Fault Protection with
Ground Fault Module
●
Pulse Detection Protection – Low Voltage High Resistance
Ground Fault Pulsing Systems (LVHRGPS)
The C445 Motor Management Relay provides three (3)
ground fault monitoring and protection methods for use in
industrial applications. These applications may encompass
solid ground, low resistance ground, high resistance ground,
or high resistance ground systems pulsed ground detection.
Only one (1) protection configuration (Residual or
Zero-sequence) can be active in a system. The C445 can
monitor and respond to an application that has been
configured with a pulsing system. The C445 does not
generate the pulse waveforms required for such systems.
All methods may incorporate Fault Trip, Fault trip Indication
Only, and Fault Warning responses to events that trigger the
C445 protection protocols. Additionally, delay times may be
set for selected parameters to optimize system
performance.
Residual Ground Fault Monitoring and Protection
Residual Ground Fault protection monitors the ground
current of the motor and will react with a Fault action if the
ground current exceeds the set threshold. The Ground Fault
protection is always active. Ground Fault protection may be
set to Fault Trip, Fault Warning, of Fault Trip Indication Only
status.
The vector sum of the 3-phase currents is calculated from
each phase current transformer (CT) in the C445M…
Measurement Module and is transmitted to the C445B…
Base Module for signal processing. At such time the signal
exceeds a user settable threshold, the C445 will react with a
Fault action in accordance with programmed parameters. At
such time the signal returns to the allowable operating range
programmed into the C445, the Fault action will extinguish.
Fault reset requirements such as Manual Reset or
Auto-Reset will occur in accordance with programmed
parameters.
Table 66. Residual Ground Fault Parameterization
Parameter Value
Debounce (Milliseconds)
Fault
Code
Action
Modbus Units
Frame
Min.
Max.
Default
Min.
Max.
Default
Modbus
4
Fault Trip
1060
Amps
C445MA2P4…
0.12
2.4
1
0
60,000
1,000
1063
C445MA005…
0.25
5
3
0
60,000
1,000
1063
C445MA032…
1
9.6
3
0
60,000
1,000
1063
C445MA045
1
13.5
3
0
60,000
1,000
1063
C445MB072…
3
21.6
3
0
60,000
1,000
1063
C445MC090
3
27.0
3
0
60,000
1,000
1063
C445MC136…
34
40.8
34
0
60,000
1,000
1063
C445M…EXT
30% of
CT Primary
50% of
CT Primary
50% of
CT Primary
0
60,000
1,000
1063
Fault Trip Indication Only
1087
0
60,000
1,000
1063
Shunt trip
1089
0
60,000
1,000
1063
Fault Warning
1061
200
5,000
2,000
1079
Fault Trip Delay
—
At Powerup
0s
5s
0s
1062
Fault Trip Inhibit
1064
Disable
Enable
Disable
Fault Trip Inhibit - Run
1065
%
25
100
50
