Configuration And Calculation - Siemens Sivacon S8 Planning Information

7.1

Configuration and calculation

When cubicles with direct connection to the main busbar
are configured, the selection of capacitor modules depends
Tab. 7/3: Configuration of capacitor modules
Cubicle Compensation
height power per cubicle
Reactive power per cubicle: 600 kvar / 400 V / 50 Hz at 35 °C ambient temperature
2,200 mm 600 kvar
Cubicle power: up to 500 kvar / 400 V, 525 V, 690 V / 50 Hz at 35 °C ambient temperature
50 kvar
100 kvar
150 kvar
200 kvar
2,000 mm,
2,200 mm
250 kvar
300 kvar
350 kvar
400 kvar
400 kvar
2,200 mm 450 kvar
500 kvar
1) 14 % choked only possible for 400 V
2)
Can only be implemented with degree of protection IP30 / IP31
Legend:
+ possible
- not possible
When calculating the required compensation power, you
can proceed as follows:
1. The electricity bill of the power supplier shows the
consumption of active energy in kWh and reactive energy
in kvarh. The distribution system operator (DSO) usually
requires a cos φ between 0.90 and 0.95. To avoid costs, the
value should be compensated to a cos φ near 1. Where
tan φ = reactive energy / active energy
2. From Tab. 7/4 the conversion factor F must be deter-
mined by compensation in dependency of the original
value for tan φ (row) and the desired cos φ
1
3. The compensation power required is the product of the
conversion factor F and the mean active power consump-
tion P
m
Compensation power P
68 SIVACON S8 Planning Principles – Reactive power compensation
Type
Non-choked
Number of
modules
Without switch-
disconnector
12 x 50 kvar
2 x 25 kvar
4 x 25 kvar
6 x 25 kvar
4 x 50 kvar
5 x 50 kvar
6 x 50 kvar
7 x 50 kvar
8 x 50 kvar
8 x 50 kvar
9 x 50 kvar
10 x 50 kvar
(column).
2
= F x P
comp m
on the total power in this cubicle and the number of mod-
ules, as it becomes apparent in Tab. 7/3.
With switch-
disconnector
+ -
+ +
+ +
+ +
+ +
+ +
+ +
+ -
+ -
+ +
+ -
+ -
Example:
Reactive energy W
= 61.600 kvarh per month
b
Active energy W = 54.000 kWh per month
w
tan φ = W / W = 1.14 (cos φ
1 b w
Mean power consumption P
P = active energy / working time
m
= 54,000 kWh / 720 h
= 75 kW
Desired power factor cos φ
Conversion factor F (tan φ
F = 0.81
Compensation power P
P = 60 kvar
comp
1)
Choked 5.67 %, 7 %, 14 %
Rear busbar Top busbar
position position
- -
+ +
+ +
+ +
+ +
+ +
+ +
+ +
+ +
+ +
2)
+ -
2)
+ -
= 0.66)
1
m
= 0.95
2
= 1.14; cos φ = 0.95)
1 2
= F x P = 0.81 x 75 kW
comp m
2)
2)