Manual Power Quality Filter PQFM
Electrical design and installation 45
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The input stage of the active filter is designed in such a way that it shorts the
switching frequency ripple current and prevents it flowing into the network. The
(customer provided) input cables are therefore just loaded with the harmonic
currents and therefore they are not fed with high dV/dt. As a consequence, no
special EMC requirements exist for the connection of these cables.
From the above it may be concluded that the connection of an active filter to the network
does not require special cables and special earth connection systems for the protective
earth conductor. Only the harmonic content of the current may ask for a de-rating
current wise, this implying a bigger cross section for a given RMS-current (Cf.
Section
). No special EMC measures are needed. Standard cables types are well suitable for
connecting the active filter to the supply.
6.5 Earthing guidelines
Each PQFM-cubicle two marked earth points (PE). The main earth point is situated at the
top right side of the filter plate (
for CE version and
for cULus version.)
Main earth
point (PE)
Figure 25: Identification of the main earth point in the PQFM plate (CE version)
Main earth
point (PE)
Figure 26: Identification of main earth point in the PQFM plate (cULus version)
The secondary earth point is situated at the bottom of the filter main plate (
).