Chroma 66203 - Page 37

Operation
4-11
Crest Factor
CFi
rms
pkpk
I
IIofimum ),(max
−+
THD & Harmonic value
v
THD
%100
.......
1
22
5
2
4
2
3
2
2
×
++++
V
VVVVV
n
2
n
I the subscript n indicates the range of
harmonic which is 2.3.4….100.
i
THD
%100
.......
1
22
5
2
4
2
3
2
2
×
++++
I
IIIII
n
2
n
V the subscript n indicates the range of
harmonic which is 2.3.4….100.
Integration
Energy (Wh or Joule)
∫
T
dttitv
T
0
)()(
1
T is a setting integration time by user.
Integration(W)
∫
T
dttitv
0
)()(
T is a setting integration time by user.
Frequency
F Zero crossing detection
Σ Measurement Parameter
The Σ function contains the wiring systems of 1P3W, 3P3W and 3P4W. Following table lists
the calculation formula defined by IEEE for active power, reactive power, apparent power
and power factor. The apparent power uses the Vector apparent power for calculation.
Wiring System
Measurement
parameter
Single-phase,
Three-wire (1P3W)
Three-phase,
Three-wire (1P3W).
Two wattmeter
method
Three-phase,
Four-wire (3P4W).
Three wattmeter
method
)(PWΣ
21
WW
+
321
WWW ++
)(QVARΣ
21
VARVAR
+
321
VARVARVAR ++
)(SVAΣ
22
)()( VARW Σ+Σ
P
F
Σ
VA
W
Σ
Σ