FUNCTION CHARACTERISTICS
173
NVA100X-D - Manual - 02 - 2016
Minimum power factor - 55
Preface
Two independent time adjustable thresholds with lag, lead or lag/lead programmable power factor.
For each elements can a consensus for start / trip operation may be set only if the circuit breaker is
closed and after an adjustable enabling time, the closure (tARM-cosphi<) .
Operation and settings
The power factor is computed:
± cos
ϕ
=
± P
/
S
where:
P
is the total active power:
± P
=
U
L1
·
I
L1
·
cos
ϕ
L1
+
U
L2
·
I
L2
·
cos
ϕ
L2
+
U
L3
·
I
L3
·
cos
ϕ
L3
S is the total apparent power:
S
= √
P
2
+
Q
2
The lag power factor (
cos
ϕ
=
P
/S with
Q
≥ 0) and the lead power factor are compared with the setting
value (
cos
ϕ
lag
<,
cos
ϕ
lead
<).
—
•
•
-Q
G
lag
Q
/ 2
Q
Q
/ 2
Q
cos
G
G
lead
CPhi1<def
CPhi1<def
NO TRIP
NO TRIP
TRIP
TRIP
+Q
+P
-P
TRIP
CPhi1<def
CPhi1<def
TRIP
TRIP
TRIP
NO TRIP
NO TRIP
Tripping direction setting: CosPhi Lag/Lead
General operation characteristic for the out of step element - 55
-Q
G
lag
Q
/ 2
Q
Q
/ 2
Q
cos
G
G
lead
CPhi1<def
NO TRIP
TRIP
+Q
+P
-P
TRIP
CPhi1<def
TRIP
NO TRIP
NO TRIP
NO TRIP
Tripping direction setting: CosPhi Lag
General operation characteristic for the out of step element - 55
-Q
G
lag
Q
/ 2
Q
Q
/ 2
Q
cos
G
G
lead
CPhi1<def
NO TRIP
TRIP
+Q
+P
-P
CPhi1<def
TRIP
TRIP
NO TRIP
NO TRIP
NO TRIP
Tripping direction setting: CosPhi Lead
General operation characteristic for the out of step element - 55