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6. Electrical installation
Your PQFA is a parallel active filter: it is installed in parallel with the load(s).
Connection implies:
? ? 3 power cables
? ? 3 CT (one per phase)
? ? 6 control wires for the CT
? ? Ground/PE
6.1.
Overvoltage
The PQFA is able to withstand continuously an overvoltage (inclusive of
harmonics but not transients) of up to 110 % of the rated voltage. Higher
voltages than the rated one would imply an operation at limited power of the
filter. Since operation at the upper limits of voltage and temperature may
reduce its life expectancy, the PQFA should not be connected to systems for
which it is known that the overvoltage will be sustained indefinitely.
6.2.
Power cables and external protection
Each cubicle is fitted with its own circuit breaker (bottom cable entry) and
needs to be individually connected to the supply.
The power cable size should be rated on the basis of X times the nominal
current of the corresponding cubicle (one or two power modules) where X is a
multiplication factor which allows to take into account the skin effect.
This multiplication factor is the result of an iterative calculation and can be
determined by means of the following process:
Important remark: please note that the following process is made to take into
account the skin effect only. Other deratings due to local standards and/or
installation conditions (as e.g. cables proximity, number of cables connected
in parallel,... ) have to be taken into account by the company responsible for
the PQF cable connection.
Step 1: as initial value of this iterative process, determine the preliminary
cable section on the basis of the nominal current.
Step 2: based on the previously determined cable section, find in the table
here below the multiplication factor that must be applied.
Step 3: determine the cable section on the basis of the value of the
multiplication factor times the nominal current.
- if the cable section found is equal to the previously found cable section,
the process can be stopped.
The cable section is then determined taking into account the skin effect.
(see examples below)
Asea Brown Boveri Jumet S.A.
PQFA Instructions Manual
29
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