Merlin Gerin Varlogic NR12, User Manual

Page: 26 / 32

26
USER´S MANUAL
6.2 Manual calculation of response value
Normally the response value, more generally known as the C/K value, is set automatically as
a part of the Auto Setup sequence, but there are cases when these values must be entered
manually. The correct value can be calculated using an equation requiring the 1st step size
(in vars), line-to-line voltage of the network used (in volts) and the CT ratio as follows
where Q
1st
= size of 1
st
step in vars
U
LL
= line-to-line voltage in volts
I
1
/5A = CT ratio
Alternatively, the C/K value can be taken from the table below (valid for 400 V networks)
Table 1: C/K-values for 400 V network
By successive connections (or disconnections) of steps we adjust the reactive power between
two symmetrical limits corresponding to response value
n1/n2 Smallest step (kvar)
12,5 20 25 30 40 50 60 100
100/5 0,91 1,44
150/5 0,60 0,96 1,20 1,44
200/5 0,45 0,72 0,90 1,08 1,44
250/5 0,36 0,58 0,72 0,87 1,16 1,44
300/5 0,30 0,48 0,60 0,72 0,96 1,20 1,44
400/5 0,36 0,45 0,54 0,72 0,90 1,08
500/5 0,29 0,36 0,43 0,58 0,72 0,87 1,44
600/5 0,30 0,36 0,4 0,60 0,72 1,20
800/5 0,27 0,36 0,45 0,54 0,90
1000/5 0,29 0,36 0,43 0,72
1500/5 0,24 0,29 0,48
2000/5 0,22 0,36
2500/5 0,29
3000/5 0,24
3 5
/
1
1
× ×
=
LL
st
U A I
Q
K C