ABB PQFS Installation, Operation And Maintenance Instructions page 135

Figure 87: Filter start-up sequence when power is applied and the start command is given
In Figure 87 it may be seen that:
· The fan starts running and the DC capacitors charge as soon as the auxiliary
circuit power is switched on.
· The start-up sequence consists of the DC capacitors voltage check, the closure
of the filter main contactor and the starting of the IGBTs
· Network identification may be done after the start-up sequence has finished. This
network identification will always be done when harmonic components were
selected and the supply to the filter was removed before or when new harmonic
components have been selected. The network identification may also be done
automatically during normal filter operation if the filter controller has noted a big
change of network impedance.
· At the end of the start up procedure, the filter will work as programmed
Remark: Filter running at 100% load while RMS current rating is not attained.
Under exceptional conditions it is possible that the active filter is showing a 100% load
indication whereas its nominal RMS current rating is not yet attained. This is because the
filter has reached an operating limit other than the RMS current limit. Possible other limits
are:
· Temperature limit due to a too high ambient temperature or a failing cooling
system
· Peak current limit due to an a-typical peak current requirement of the load
· Peak voltage limit due to an a-typical DC-link voltage requirement of the load or
due to a high network voltage
Apply power to filter
auxiliaries
Controllers
and fan(s)
running,
DC
capacitors
charging
Start filter
DC capacitors
preload check,
3, 4- wire
connectivity
check
Close MC
Start-up sequence
Start IGBTs
Network
identification
Operation as
programmed
Manual Power Quality Filter PQFS ç Operating instructions 135