Catalog LV 70 2011 - Low & Medium Voltage - Siemens

BD2 System — 160 ... 1250 A
© Siemens AG 2011
Configuration information
Temperature characteristic of BD2 systems
0,19
NSV0_00193a
Rated current (%)
120
115
110
105
100
95
90
85
80
75
70
65
–5 5 15 25 35 45 55 65
NSV0_00186a
U (V/m)
0,17
0,15
0,13
0,11
BD2C-.-250
BD2C-.-400
BD2C-.-800
Ambient temperature °C
(24h average)
0,09
BD2C-.-1000
BD2C-.-630
BD2C-.-160
BD2C-.-1250
Voltage drop
Voltage drop at rated current
The following diagrams show the voltage drop of the
BD2A/BD2C systems
• Taking into account the heat resistors (according to
IEC/EN 60439-2)
• With a load distribution factor a = 1
• Under loading with the rated current. (With a different load distribution
factor, the curve value must be multiplied by the corresponding
distribution factor.)
0,07
0,4 0,5 0,6 0,7
0,8 0,9 1,0
cos
Voltage drop BD2C
Calculation of the voltage drop
For long busbar lines, it may be necessary to calculate the
voltage drop.
ΔU = a × √3 × I x l × (R × cos ϕ + X × sin ϕ) × 10 -3
(V)
0,18
NSV0_00192a
ΔU = Voltage drop (V)
U (V/m)
0,16
BD2A-.-630
BD2A-.-250
BD2A-.-160
I = Load current (A)
l = Length (m)
a = Load distribution factor
5
0,14
0,12
BD2A-.-400
BD2A-.-800
BD2A-.-1000
R = Ohmic resistance R 1 (mΩ/m)
X = Inductive resistor X 1 (mΩ/m)
cos ϕ = Power factor (p.f.)
Factor a used in the equation for calculating the voltage drop is
dependent on the load distribution.
Load distribution
Load distribution
Factor a
0,10
A
A
B
C
D
B
E
Infeed at A,
one outgoing feeder at B 1
Infeed at A,
outgoing feeders at B, C, D, E 0.5
0,08
0,4 0,5 0,6 0,7
Voltage drop BD2A
0,8 0,9 1,0
cos
B
B
D
A
A
E
C
C
Infeed at A,
outgoing feeders at B, C 0.25
Infeed at A,
outgoing feeders at B, C, D, E 0.125
A
C
D
E
F
B
Infeed at A, B,
outgoing feeders at C, D, E, F 0.25
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