Comparison between class A And meter PQM

Table 5
THD THD THD
Time
phase L 1 phase L 2 phase L 3
18:47 9,8 10,0 9,9
Figures 2, a) ... d) present screen captures and values
measured with PQ Analyzer FLUKE 435 for current
waveforms.
Fig. 2, d) Current THD and individual harmonics values
Fig. 2, a) Current RMS values and phasors for voltage and current
Fig. 2, b) Three phase current waveforms
Fig. 2, c) Harmonics spectrum
Test performed on 20.11.2011 during the time interval
18:23 to 18:50.
Current THD values per phase recorded with Energy
static meter A1RLQ+, with SN: 2748989, are presented
in Table 6.
Table 6
THD THD THD
Ora
phase L 1 phase L 2 phase L 3
18:47 49,8 48,8 48,9
Residual voltage measurement uncertainty for voltage
sags detected by Energy static meter A1RLQ+ was estimated
using information from technical specification,
[13], and formula (2):
2,3
U = = 1, 02 V
2,248
where:
• 2,3 V represents the limit value L = ± 1% from
voltage reference value U ref = 230 V, as in IEC
62053-22:2003, [14];
• 2,248 is the value of normal inverse cumulative
−1
distribution function Φ (.)
, for 95% probability,
assigned for limit L.
We can state that voltage sags detected by Energy static
meter A1RLQ+ have a measurement uncertainty of 1V
with a 95% probability.
The residual voltage measurement uncertainty for voltage
sags detected measured with PQ Analyzer Fluke 435
was estimated using recommendations included in Guide
ISO/IEC 98-3, [9], with formula:
U = k ⋅u
n
2
c
= k ⋅ ∑u i
i=
1
(3)
where:
• k multiplier of the combined uncertainty; k = 2
when the real value falls within ± U interval with
95% probability;
• u c composed standard uncertainty;
• u i components of standard uncertainty allocated to
different error types.