ABB PQFS Installation, Operation And Maintenance Instructions page 164

Symptom
The filter is working at
100% of its nominal
capacity because the load
requirement is asking this.
The filter is working at
100% of its nominal
capacity while the load is
only at a fraction of the
filter rating.
The filter is running but it
is unstable (oscillating
behavior)
164 Troubleshooting guide ç Manual Power Quality Filter PQFS
Table 59: Other filter indications and behavior with corresponding troubleshooting tips
Cause / State
The harmonic stress on the
network is still too high.
The harmonic stress on the
network is sufficiently low.
The load requirement is only
a fraction of the filter size.
There is a problem in the CT
connections or a hardware
problem.
There is a software problem.
The filter has been asked to
generate static reactive
power.
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.
Two master units are fed from
the same CTs. The setup
guidelines for this installation
setup have not been
implemented.
What to do
Install additional filter units to reduce
the stress further.
The filter can be kept running in this
condition.
– 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 PQF-Link).
Stop the filter, switch off the power of
the auxiliaries and switch it on again.
Restart the filter and see if the problem
is solved.
If the problem persists, contact your
ABB service provider.
Verify the reactive power settings of the
filter.
– 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 PQF-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.
– Interconnect the units with an RJ-
45 cable. If this is not possible:
– Select different harmonics on
both filters.
– If not possible, ensure that one
filter is operating in Mode 1 and
the other filter is operating in
Mode 3.