ASCO 5010 Remote Display Unit
47
9
THD
Total Harmonic Distortion. The contribution of all harmonic frequency currents to the delta between
the fundamental harmonic- a pure sine wave- and the actual wave form.
THD=
√
(
Σ
n(h
n
2
)); where n is the order of the harmonic and h is the value of the measured parameter.
10
Line or phase Voltage, Current
V
Li
, I
Li
The voltage between a phase and GND or Neutral.
The current flowing from the phase to Neutral in a Y configuration. A phase is marked as
Li
i=1,2,3,N
11
Line-to-Line Voltage, Current
V
Li,j
I
Li,j
The voltage between two phases.
The current flowing from one phase to another.
12
Crest factor
Ratio of peak to peak waveform value to its RMS nominal value. Signifies the quality of a sine
waveform.
13 K
factor
The weighting of the harmonic load currents according to their effects on transformer heating. A K-
factor of 1.0 indicates a linear load (no harmonics). The higher the K-factor, the greater the harmonic
heating effects.
25
1
2
25
1
2
)
(
h
h
i
h
i
K
15
Active power - P
The amount of power consumed as usable energy. Sometimes referred to as Real power.
ASCO calculates the Active power accurately by taking all harmonics up to the 40
th
into account
using the following formula:
P =
2
1
i
j
i
Cos
j
Ii
j
Vi
,
,
,
[Watt]
Where i is the harmonic an j is the phase.
16
Reactive power- Q
The amount of power consumed as un-usable energy.
ASCO calculates reactive power using the following forumula:
Q = -Pq = -
Sin
I
V
=-
I
V
=
0
0
ˆ
ˆ
ˆ
Iy
Ix
Vy
Vx
k
j
i
=
)
(
IxVy
VxIy
k
[VAr]
ASCO calculates the sign of Q using the following formula:
Sign of Q = sign of (
Ixi
Vyi
Iyi
Vxi
i
(
)
17
Aparent power- S
The total power supplied to the load, a vector addition of the Active and Reactive power.
ASCO uses formula: S = V
RMS
* I
RMS
[VA]
18
10/12 or Long measurements
The EN50160 and IEC61000-4-30 standards require that certain parameters be sampled and
averaged over 10/12 cycles (50/60Hz). ASCO displays these terms on the ASCO 5400 Series as
10/12 or Long or IEC 61000-4-30.
19
Cycle-by-cycle
ASCO displays RMS parameters down to a resolution of one cycle. These measurements are
referred to as cycle-by-cycle values.
