Distortion Factor Calculation (Df); K Factor; Different Power Levels 1 Sec - AEMC PowerPad 3945 User Manual

8.1.9 Distortion Factor Calculation (DF)

Two global values giving the relative quantity of harmonics are computed: the THD
in proportion to the fundamental and the DF in proportion to the RMS value.
50
∑
Vharm
[]
=
=
n 2
Vthd i
Vharm
50
1
∑
Vharm
2
[]
=
=
n 2
Vdf i
Vrms
Multiplying the voltage harmonic factor with the current harmonics factor gives the
power harmonic factor. Differentiating voltage harmonic phase angle with current
harmonic phase angle gives power harmonic phase angle.
VAharm[3][51] , VAph[3][51]

8.1.10 K Factor

[]
Akf i

8.1.11 Different Power Levels 1 sec

1
[]
=
W
i
NSS
VA[i] = Vrms[i] Arms[i] Apparent power i + 1 phase
1
VAR[i] =
NSS
ou VAR[i] = VA[i] – W[i] if computation method is with harmonics
Power Quality Analyzer Model 3945
[][ ]
2
i n
[]
, Uthd i
[][ ]
1
i
[][ ]
2
i n
[]
, Udf i
[]
i
n=50
∑
n 2 Aharm
=
=
n 1
n=50
[][ ]
∑
Aharm
=
n 1
NSS-1
[][ ] [][ ]
∑
.
V i n A i
=
n 0
.
NSS-1
[][
∑
.
n - NSS / 4
VF i
=
n 0
2 2
50
[][ ]
∑
Uharm i n
=
=
n 2
[][ ]
1
Uharm i
50
1
[][ ]
∑
Uharm i
2
=
=
n 2
[]
Urms i
[][ ]
2
i n
K factor for the i + 1 phase
2
i n
n Active power i + 1 phase
] [][ ]
.
AF i
50
∑
2
Aharm
[]
=
=
n 2
, Athd i
Aharm
1
∑
2
n
2
[]
=
, Adf i
n Reactive power i + 1 phase
[][ ]
2
i n
[][ ]
1
i
50
[][ ]
2
Aharm i n
=
n 2
[]
Arms i
83