NOVAR 300 Operation & Maintenance Manual
NOVAR_CM
Page 19 of 29
Example 3
A multi-stage unit controls a six stage capacitor bank. Each stage is rated at 100 kvar. The
VT is 3.3 kV/110 V and the CT ratio is 500/5.
C = 100,000 vars, V = 3 300 V, I = 500 A
C / k
100,000 5
3 3,300 500
0.17
=
×
×
×
=
As above, this value can be directly entered into the unit.
NB: The NOVAR 300 calculation has been formulated in such a way that it will work for any
value of secondary amps and volts which can be used with the unit. However, if the nominal
secondary amps used is other than 5 amps, the value represented by the scalings on the
c/k potentiometer will no longer be the actual capacitor starting current in amps. This makes
no difference to the operation of the unit.The NOVAR 300 ratings must match the
secondary rating of any CT and VT used.
3.5 SETTING OF TARGET COS PHI
This is set using the potentiometer, labelled “cos
ϕ
“, located on the front panel.
To make use of the expanded display mode, the lower push-button should be pressed once
more .The display will now indicate the potentiometer setting and a large C in the fourth digit
of the display.
kW
C/k
Minimum
(Deadband)
0.03
Lead
Lag
kvar
C/k
Maximum
(Deadband)
1.0
Range of C/k adjustment for cos
ϕ
= 1.0
kW
kvar
Range of cos
ϕ
for a given C/k
C/k
C/k
ϕ
1
ϕ
2
Lead
Lag
cos
ϕ
adjustment
0.80 lag to
0.95 lead
FIGURE 6 - Ranges for C/k and cos
ϕ
settings
