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
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