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Verfügbare Sprachen
Verfügbare Sprachen
Zero
P231
15
16
17 18
+
–
1
2
3
4
5
6
7
Insert U = U
if U
is not within one of the standard nomi-
N
N
nal voltage ranges.
Insert U =U
if U
is within one of the standard nominal
N min
N
voltage ranges.
Examples for three-wire, three-phase,
asymmetrically loaded schemes
Active power measuring
Example 1:
Change of input voltage from 100 V to 110 V
250 A
120 000 V
U
=
, I =
a
5 A
100 V
250 A
132 000 V
U
=
, I =
n
5 A
110 V
U
110 V
N
Ucal =
· c
=
· 1.04972
n
U
100 V
N min
Ucal = 1.1547 V new calibration voltage
Example 2:
Change of c.t. rating from 250 A to 300 A
250 A
132 000 V
U
=
, I =
a
5 A
110 V
300 A
132 000 V
U
=
, I =
n
5 A
110 V
U
110 V
N
Ucal =
· c
=
· 0.87477
U
n
100 V
N min
Ucal = 0.9622 V new calibration voltage
U
= new input voltage
n
U
= old input voltage
a
c
= new calibration factor
n
c
= old calibration factor
a
Ucal
Full-scale
–
+
P171
X174 X173
8
9
10
11
12
13
14
, 0...60 MW
c
= 1.1547
a
, 0...60 MW
c
= 1.04972
n
, 0...60 MW
c
= 1.04972
a
, 0...60 MW
c
= 0.87477
n
Example 3:
Change measuring range from
U
= 400 V, I = 5 A, 4000...0...4000 W, c
N
U
= 400 V, I = 5 A, 3000...0...3000 W, c
N
U
400 V
N
Ukal =
· c
=
· 0.866
U
380 V
n
N min
Ukal = 0.9116 V new calibration voltage
Reactive power measuring
Example 4:
Change of input voltage from 100 V to 110 V
250 A
120 000 V
U
=
, I =
a
5 A
100 V
250 A
132 000 V
U
=
, I =
n
5 A
110 V
U
c
110 V
n
N
Ucal =
·
=
100 V
U
0.7
N min
Ucal = 0.9997 V new calibration voltage
Example 5:
Change of c.t. rating from 250 A to 300 A
250 A
132 000 V
U
=
, I =
a
5 A
110 V
300 A
132 000 V
U
=
, I =
n
5 A
110 V
110 V
U
c
N
n
Ucal =
·
=
100 V
U
0.7
N min
Ucal = 0.9164 V new calibration voltage
Example 6:
Change measuring range from
U
= 400 V, I = 5 A, 2500...0...2500 Var, c
N
U
= 400 V, I = 5 A, 2000...0...2000 Var, c
N
400 V
U
c
N
n
Ucal =
·
=
380 V
U
0.7
N min
Ukal = 0.8682 V new calibration voltage
±
±
4000 W to
3000 W
= 1.15470
a
= 0.8660
n
, 0...40 MVar c
= 0.7698
a
, 0...40 MVar c
= 0.6998
n
0.6998
·
0.7
, 0...40 MVar c
= 0.6998
a
, 0...40 MVar c
= 0.58318
n
0.58318
·
0.7
±
±
2500 Var to
2000 Var
= 0.72168
a
= 0.57735
n
0.57735
·
0,7
19
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