METREL MI 2893 User Manual

MI 2893 / MI 2892 / MI 2885 Measurement methods
193
 RSS value of four neighbouring frequency bins if signalling frequency differs from the power
system bin frequency (for example, a ripple control signal with frequency value of 218 Hz in a 50
Hz power system is measured based on the RMS values of 210, 215, 220 and 225 Hz bins).
Mains signalling value calculated every 10/12 cycle interval are used in alarm and recording procedures.
However, for EN50160 recording, results are aggregated additionally on 3 s intervals. Those values are
used for confronting with limits defined in standard.
5.1.10 Flicker
Standard compliance: IEC 61000-4-30 Class A (Section 5.3)
IEC 61000-4-15 Class F1
Flicker is a visual sensation caused by unsteadiness of a light. The level of the sensation depends on the
frequency and magnitude of the lighting change and on the observer. Change of a lighting flux can be
correlated to a voltage envelope on figure below.
0 0.1 0.2
0.3
0.4 0.5 0.6 0.7 0.8 0.9 1
-400
-300
-200
-100
0
100
200
300
400
time (s)
voltage(V)
Figure 158: Voltage fluctuation
Flickers are measured in accordance with standard IEC 61000-4-15. Standard defines the transform
function based on a 230 V / 60 W and 120 V / 60 W lamp-eye-brain chain response. That function is a
base for flicker meter implementation and is presented on figure below.
P
st1min
– is a short flicker estimation based on 1-minute interval. It is calculated to give quick preview of
10 minutes short term flicker.
P
st
– 10 minutes, short term flicker is calculated according to IEC 61000-4-15
P
lt
– 2 hours, long term flicker is calculated according to the following equation:
3
1
3
N
Pst
P
N
i
i
ltp



p: 1,2,3
(65)
5.1.11 Voltage and current unbalance
Standard compliance: IEC 61000-4-30 Class A (Section 5.7)

METREL MI 2893 Specifications

General

Brand	METREL
Model	MI 2893
Category	Measuring Instruments
Language	English