ABB PQFM Instruction Manual page 220

Symptom
The filter is working at
100% load indication
while its nominal RMS
current rating is not
attained.
The filter is running
but it is unstable
(oscillating behavior).
220 Troubleshooting guide ç Manual Power Quality Filter PQFM
Cause / State
Other limit than the RMS
current limit has been
attained.
Temperature limit due to
a too high ambient
temperature or a failing
cooling system.
Other limit than the RMS
current limit has been
attained.
Peak voltage limit due to
an a-typical DC-link
voltage requirement, due
to a high network voltage,
or due to a high demand
of high frequency
harmonics.
Other limit than the RMS
current limit has been
attained.
Peak current limit due to
an a-typical peak current
requirement of the load.
There is a problem in the
CT connections or a
hardware problem.
Presence of (detuned)
power capacitor banks or
plain capacitors (LV or
MV).
The filter is installed on a
very weak network.
What to do
- Check the ambient temperature
and ensure that it complies with
the filter specifications.
- Check the filter cooling system.
- Check the DC voltage level
measurement on the PQF Manager
when the filter is switched off. If
the value reduces to 0, then the
filter is functioning normally.
- Check the network voltage level for
excessive values. If the network
voltage is not excessive than the
limitation is due to a combination
of load requirement with network
voltage requirement. Resources
may be freed by setting curve
values (for high frequency
components).
Verify the filter current waveforms
reported by the filter with external
monitoring equipment. If the
waveform is similar then the filter is
functioning normally. Else, the filter
internal measurement system may be
faulty. Contact your ABB service
provider.
- Check the CT installation (CT
location, CT shorts ...).
- Check the connection between the
CT terminal block X21 and the main
controller terminals P5-1..P5-6.
- Measure the line currents (e.g.
ammeter) and compare them with
the line currents given by the filter
(PQF-Manager or PQ-Link).
Refer to Section 8.10 for precautions
to take when plain capacitors are
present in the network.
- Make sure that the filter is
operating in Mode 3.
- If the problem persists, contact
your ABB representative.