MI 2893 / MI 2892 / MI 2885
Measurement methods
181
5.1.4
Frequency measurement
Standard compliance: IEC 61000-4-30 Class A (Section 5.1)
During RECORDING with aggregation time Interval:
≥
10 sec frequency reading is obtained every 10 s.
The fundamental frequency output is the ratio of the number of integral cycles counted during the 10 s
time clock interval, divided by the cumulative duration of the integer cycles. Harmonics and
interharmonics are attenuated with digital filter in order to minimize the effects of multiple zero
crossings.
The measurement time intervals are non-overlapping. Individual cycles that overlap the 10 s time clock
are discarded. Each 10 s interval begin on an absolute 10 s time clock, with uncertainty as specified in
section 6.2.20.
For RECORDING with aggregation time Interval:
<
10 sec and on-line measurements, frequency reading
is obtained from 10/12 cycles frequency. The frequency is ratio of 10/12 cycles, divided by the duration
of the integer cycles.
Frequency measurement is performed on chosen Synchronization channel, in CONNECTION SETUP
menu.
5.1.5
Modern Power measurement
Standard compliance: IEEE 1459-2010
See section 3.23.6 how to select Modern Power measurement method. Please note that instrument
record all measurement (Classic and Modern), regardless of selected method. Data presentation could
be changed on the instrument LCD or inside the PowerView3.0.
Instrument fully complies with power measurement defined in the latest IEEE 1459 standard. The old
definitions for active, reactive, and apparent powers are valid as long as the current and voltage
waveforms remained nearly sinusoidal. This is not the case today, where we have various power
electronics equipment, such as Adjustable Speed Drives, Controlled Rectifiers, Cyclo-converters,
Electronically Ballasted Lamps. Those represent major nonlinear and parametric loads proliferating
among industrial and commercial customers. New Power theory splits power to fundamental and
nonfundamental components, as shown on figure below.
S
(apparent power)
S
fund
(fundamental apparent power)
S
N
(non fundamental apparent power)
P
fund
(fundamental active power)
Q
fund
(fundamental reactive power)
D
I
(
current distortion power)
D
V
(voltage distortion power)
S
H
(
harmonic apparent power)
P
H
(active harmonic power)
D
H
(harmonic distortion power)
Figure 150: IEEE 1459 phase power measurement organisation (phase)
