94
Power Quality Analyzer Model 3945-B
1 sec RMS Values for Voltage and Current
[]
[][ ]
∑
−
=
⋅
=
1
0
2
1
Vrms
NSS
n
n
i
V
NSS
i
Single rms voltage i + 1 phase
[]
[][ ]
∑
−
=
⋅
=
1
0
2
1
Urms
NSS
n
n
i
U
NSS
i
Compound rms voltage i + 1 phase
[]
[][ ]
∑
−
=
⋅
=
1
0
2
1
Arms
NSS
n
n
i
A
NSS
i
Rms current i + 1 phase
Voltage and Current Unbalance
=
V
+
(VF[0] + a VF[1] + a
2
VF[2]) Direct voltage (complex notation a = e )
1
3
j 2
π
3
=
V
-
(VF[0] + a
2
VF[1] + a
VF[2]) Reverse voltage
1
3
Vrms
-
Vrms
+
Arms
-
Arms
+
Vunb =
, Aunb =
THD Calculation
Vthd[i] =
[
i
][
n
]
Vharm
[
i
][1]
Vharm
∑
n=2
50
2
Uthd[i] =
,
,
[
i
][
n
]
Uharm
[
i
][1]
Uharm
∑
n=2
50
2
Athd[i] =
[
i
][
n
]
Aharm
[
i
][1]
Aharm
∑
n=2
50
2
i: phase (0; 1; 2) n: range (2 to 50)