Fluke 1745, User Manual

Page: 55 / 72

Power Quality Logger
Measurement Theory
41
Active power of the
fundamental per phase
per interval
∑
=
⋅ =
M
j
j
bas bas
Ph
M
Ph
1
1
1
1
Total active power of the
fundamental for three
phases
∑
=
⋅ =
3
1
1 1
k
k total
Ph Ph
Apparent power of the
fundamental per phase.
Basic value for 200 ms.
1 1
. 1 I V Sh
bas
=
Apparent power of the
fundamental per phase
per interval
∑
=
⋅ =
M
j
j
bas
Sh
M
Sh
1
1
1
1
Power factor of the
fundamental per phase
1
1
1
1
cos
1
Qh
Qh
Sh
Ph
total ⋅ =
ϕ
Total power factor on all
three phases
total
total
total
total
Qh
Qh
Sh Sh Sh
Ph
1
1
1 1 1
1
cos
3 2 1
1
⋅
+ +
=
ϕ
Active energy per phase
and total Active power accumulated on each logging
interval
Sign of PF, tan φ , cos φ :
Sign “+” : Q positive (“inductive”)
Sign “-“ : Q negative (“capacitive”) independent of the sign of active power P