31
NV10P - Manual - 01 - 2015
CHARACTERISTICS
Ten minutes RMS voltage
From the values of phase voltages
U
L1
,
U
L2
,
U
L3
(versions with electronic sensors) or
U
12
,
U
23
,
U
31
(versions with inductive VTs), the RMS voltage is calculated by aggregating 10 minutes of:
The RMS voltages are acquired every 0.2 seconds;
Separately for each phase, the acquired values are aggregated to 10 minutes (600 s) performing
the square root of the arithmetic mean of the last 600/0, 2 = 3000 values squared. The aggregation
of 10 minutes is updated every 3 s.
In response to a step change of the input voltage U (with voltage initially already stabilized), the volt-
age
U
m
has a transitional trend with square-law as shown in the following fi gure.
Conventions
Phase rotation direction
The conventional rotation direction for the voltage phasors is counter-clockwise.
Cyclic phase sequence order
For three phase rotating voltages, a direct cyclic sequence is defi ned when the three phases are
L1, L2, L3 ordered, while an inverse cyclic sequence is defi ned when the three phases are L1, L3, L2
ordered.
•
•
U
m
=
3000
i=1
¥
3000
1
(
U
i
)
2
U
m
=
3000
i=1
¥
3000
1
(
U
i
)
2
Ten minutes RMS voltage (59Uavg)
200
100
100
200
300
400
500
600
U
Um
0.1
0.3
0.5
0.7
0.9
1.1
1.3
Ten minutes RMS voltage (59Uavg)
200
100
100
200
300
400
500
600
U
Um
0.1
0.3
0.5
0.7
0.9
1.1
1.3
fasori.ai
fasori.ai
fasori1.ai
U
L1
U
L3
U
L2
U
L1
U
L2
U
L3
D i r e c t s e q u e n c e c y c l i c o r d e r
I n v e r s e s e q u e n c e c y c l i c o r d e r
fasori1.ai
U
L1
U
L3
U
L2
U
L1
U
L2
U
L3
D i r e c t s e q u e n c e c y c l i c o r d e r
I n v e r s e s e q u e n c e c y c l i c o r d e r