Iskra MT440 - Page 58

AppendixB:Calculations&equations
54 User’sManual
Power
()
∑
=
×⋅=
N
n
n
f
n
ff
iu
N
P
1
1
Active power by phases
N − a number of samples in a period
n − sample number (0 ≤ n ≤ N)
f − phase designation
321t
PPPP ++=
Total active power
t − total power
1, 2, 3 − phase designation
()
[]
()
[] ()
1SignQ360801
1SignQ1800
SignQ
f
f
f
−=ϕ⇒°−°∈ϕ
+=ϕ⇒°−°∈ϕ
ϕ
Reactive power sign
Q
f
− reactive power (by phases)
φ − power angle
fff
IUS ×=
Apparent power by phases
U
f
− phase voltage
I
f
− phase current
321t
SSSS ++=
Total apparent power
S
f
− apparent power by phases
()
2
f
2
fff
PSSignQQ −×= ϕ
Reactive power by phases (standard)
S
f
− apparent power by phases
P
f
− active power by phases
[]
()
∑
=
+
×⋅=
N
n
Nn
f
n
ff
iu
N
Q
1
4/
1
Reactive power by phases (delayed
current method)
N − a number of samples in a period
n − sample number (0 ≤ n ≤ N)
f − phase designation
321t
QQQQ ++=
Total reactive power
Q
f
− reactive power by phases
()
[] °°−=ϕ
=ϕ
99,179,180
Q,P2tana
s
tts
Total power angle
P
t
− total active power
S
t
− total apparent power
S
P
PF =
Distortion factor
P − total active power
S − total apparent power
f
f
f
S
P
PF =
Distortion factor
P
f
− phase active power
S
f
− phase apparent power