Circutor computer MAX 6 - C;K PARAMETER CALCULATION; STAGES CONFIGURATION OF PF CORRECTION EQUIPMENT

21
Instruction Manual
computer MAX
IMPORTANT:
If C/K is adjusted too low the system will connect and disconnect steps with a
lower threshold and therefore the number of operations to control the average PF
will be higher.
IfC/Kisadjustedslightlyabovetherequiredvalue(10%)thesystemwillreact
with higher threshold values and therefore the number of operations to control the
average PF will be lower. Wear of PF compensation is also lower.
6�1�4�- C/K PARAMETER CALCULATION
For conditions other than those given in
Table 10 the parameter C/K can be calculated as fol-
lows.
The necessary data to perform the calculation are: The power of the smaller capacitor step,
Q and the supply voltage V. Then, the smaller step reactive current, IC, can be calculated as:
V.
Q
C
I
3
=
The current transformer ratio, K :
sec
I
prim
IK /=
where :
prim
I
istheCTprimaryratedcurrent(i.e.ina250/5CT,theprimaryratedcurrentis250
A)
sec
I
is the CT secondary rated current , usually 5 A
the C/K parameter would be:
V.K.
Q
K
I
K/C
C
3
==
Example: Assume a PF equipment at 500V where the smaller capacitor is rated to 60kvar and
the CT has a ratio 500/5. The calculation would be as follows:
K ratio:
1005/500 ==K
Smaller capacitor current :
AI
C
28,69
500.3
1000.60
==
69,0
100
28,69
/ ===
K
Ic
KC
C/K :
AI
C
28,69
500.3
1000.60
==
69,0
100
28,69
/ ===
K
Ic
KC
6�1�5�- STAGE’S CONFIGURATION OF PF CORRECTION EQUIPMENT (CONFIGURA-
TION PROGRAM)
To set-up this parameter, use the keys
until the cursor points to the option , then
push .
During the set-up of this parameter, the screen shows alternatively one of the options T1 to T6
and the cos j.
PF correction equipment is constituted by several capacitor stages, which may have different
power ratings. Taking as base the power of the smaller capacitor stage, the powers of the rest