Internal Earth Fault Protection Of The Acs800-17/37; Parameter Settings; Earth Fault Monitoring In It (Ungrounded) Systems - ABB ACS800 Series Hardware Manual

Internal earth fault protection of the ACS800-17/37

The drive is equipped with a similar earth fault protection against earth faults in the
motor cable or motor as in the ACS800-07. In addition, the drive is equipped with an
earth fault protection against earth faults in the input cable and line-side converter
based on input current sum measurement.

Parameter settings

The following IGBT Supply Control Program parameter settings define how the line-
side converter reacts when an earth fault is detected:
Parameter 30.02 EARTH FAULT
WARNING
FAULT
Parameter 30.03 EARTH FAULT is fixed to 3.

Earth fault monitoring in IT (ungrounded) systems

The internal current sum measurement-based earth fault monitoring of the drive
detects earth faults in some cases in IT (ungrounded) systems. However, often the
earth fault leakage current does not exceed the trip level and the drive goes on
running.
According to EN 60204-1 protection against indirect contact by automatic
disconnection of supply (6.3.3) requires the use of earth fault detection or residual
current detection to initiate automatic disconnection of IT systems. If earth fault
detection is used, it is permissible for the first fault to initiate only an alarm signal
instead of automatic disconnection. For this type of protection, the requirements of
413.1 of IEC 60364-4-41 shall apply:
• In cases where an IT system is used for reasons of continuity of supply, an
insulation monitoring device shall be provided to indicate the occurrence of a first
fault from a live part to exposed-conductive-parts or to earth. This device shall
initiate an audible and/or visual signal.
• If there are both audible and visible signals, it is permissible for the audible signal
to be cancelled, but the visual alarm shall continue as long as the fault persists.
• Note: It is recommended that a first fault be eliminated with the shortest
practicable delay.
The drive can be equipped with insulation monitoring device option +Q954 for the
above described protection, or the IT system must be monitored otherwise with a
monitoring device suitable for use with variable speed drives. Because of the
leakage currents of drives, many earth fault monitoring devices do not work properly
with drives.
The converter generates a warning.
Default (with parallel-connected converter modules fixed)
The converter trips on EARTH FAULT (non-parallel-connected converter
modules) or CUR UNBAL xx (parallel-connected converter modules).
Earth fault monitoring in IT (ungrounded) systems (+Q954)
85