ABB PQFS Installation, Operation And Maintenance Instructions page 160

Fault message
Overcurrent RMS
Overcurrent peak (SW)
Overvoltage RMS
Preload problem
Unbalanced supply
160 Troubleshooting guide ç Manual Power Quality Filter PQFS
Cause
The system has detected
RMS overcurrent in the
filter.
The software peak current
protection has been
triggered.
The RMS value of the
supply voltage measured
with the AC voltage
measurement board is
higher than the acceptable
maximum value.
The DC capacitors could
not be preloaded at startup.
The voltage increase on the
DC capacitors during the
preload phase is not high
enough.
The supply network
imbalance is out of range.
What to do
– Verify that the filter CTs are
properly installed and are not
shorted.
– Verify that the unit current ratings
and order programmed at the
commissioning stage corresponds
to the rating and order physically
present.
– Verify the filter cooling system and
check the IGBT temperature using
the PQF-Manager.
– Deactivate harmonic and reactive
power requirements and see if the
problem persists.
– Verify that the filter CTs are
properly installed and are not
shorted.
– Verify that the unit current ratings
and order programmed at the
commissioning stage corresponds
to the rating and order physically
present.
– Verify the filter cooling system and
check the IGBT temperature using
the PQF-Manager.
– Deactivate harmonic and reactive
power requirements and see if the
problem persists.
– Measure the three line voltages
and check if they are within limits.
– Measure the line voltages (e.g.
voltmeter) and compare them with
the line voltages given by the filter
(PQF-Manager or PQF-Link).
– Ensure that the AC voltage is
properly measured.
– Measure the three line voltages
and check if they are within limits.
– Verify the preload circuit and its
resistor R06.
– Inspect the DC-bus for traces of
damage that may have caused a
short circuit on the DC side of the
IGBT module or on the DC voltage
measurement board.
– Measure the three line voltages
and check if they are within limits
including the imbalance limit.
– Measure the line voltages (e.g.
voltmeter) and compare them with
the line voltages given by the filter
(PQF-Manager or PQF-Link).
– Ensure that the AC voltage is
properly measured. Do the checks
discussed for the 'Loss of phase'
fault.
– Check the earth of the unit.