REVCON RLD B, Руководство по эксплуатации

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Safety information
18 Operating instructions RLD
ELTROPLAN
-
REVCON

Elektrotechnische Anlagen GmbH
Length of the DC-connection:
The maximum inductivity of the DC-connection between output B6 Bridge of the frequen-
cy converter and the power feedback device must not exceed an assigned value, as this in-
ductivity inducts an additional voltage to the DC-bus of the frequency converter, when the
IGBT’s are switched off.
To avoid an overload to the components of the power feedback unit, this additional voltage
must not exceed 100V.
Resulting from this and other relevant characteristics of the power feedback unit (DC-
capacity and absolute maximum value of the grid current) the maximum inductivity can
be calculated:
The maximal valid line inductance for the power feedback unit and the coupling induct-
ance between the two conductors produce at a by the current carrying capacity-defined
cross section of the lead of the cable a maximum length of the connecting cable:
This inductivity always has to be higher or equal than the sum of the DC-bus inductivity of
the frequency inverter and the conductor inductivity of the DC connection.
The DC-bus inductivity of the frequency inverter has only to be considered, if it is placed
between the inverter B6 Bridge and the power feed-back unit. The cables, which are nor-
mally used for power applications, have an inductance per unit length of about 0,6µH/m.
If the values of the input capacitance C, the during power back feeding maximum allowed
rise of the DC-voltage
∆
U
GL
=100V, the top level of the AC-current of the device
,the inductance per unit length L´
and the inductance of the DC-bus ´choke L
ZKD
are known the maximum longitude l
max
of
the conductors can be calculated with the following equation:
( )
2
2
max ˆ
i
U C
L
GL
∆ ⋅
=
( )
25 , 0 ln ´
0
+ =
⋅ µ
r
a
l
L
π
eff
I i
× =
2
ˆ
2
eff
I i
× =
2
ˆ
2 ( )
25 , 0 ln ´
0
+ =
⋅ µ
r
a
l
L
π
L
L
L i
U C
l
ZKD GL
′
−
′
⋅
∆ ⋅
=
2
2
max
ˆ