METREL Energy Master MI 2883, Instruction Manual

Page: 138 / 172

MI 2883 Energy Master Theory and internal operation
138
U nominal
Swell limit
Dip
duration
U
dip
U
swell
half cycle period
(10 ms @ 50 Hz)
U
t
Dip limit
Interruption
limit
U
rms(1/2)
[n] U
rms(1/2)
[n+1]
U
int
Interrupt
duration
Swell
duration
E
v
e
n
t
h
y
s
te
re
s
is
In
te
rr
u
p
t
h
y
s
te
re
s
is
S
w
e
ll
h
y
s
te
re
s
is
Figure 5.10 Voltage events definition
Voltage dip
Standard compliance: IEC 61000-4-30 Class S (Sections 5.4.1 and 5.4.2)
The
Dip Threshold is a percentage of Nominal voltage defined in CONNECTION
menu. The Dip Threshold and Hysteresis can be set by the user according to the use.
Dip Hysteresis is difference in magnitude between the Dip start and Dip end
thresholds. Instrument event evaluation in Event table screen depends on Connection
type:

On single-phase system (Connection type: 1W), a voltage dip begins when the
U
Rms(1/2)
voltage falls below the dip threshold, and ends when the U
Rms(1/2)
voltage
is equal to or above the dip threshold plus the hysteresis voltage ( see Figure
5.10 and Figure 5.9),.

On poly-phase systems (Connection type: 2W, 3W, 4W, Open Delta) two
different views can be used for evaluation simultaneously:
o
Group view with selected
ALL
INT
view (in compliance with IEC 61000-
4-30 Class S): a dip begins when the U
Rms(1/2)
voltage of one or more
channels is below the dip threshold and ends when the U
Rms(1/2)
voltage on
all measured channels is equal to or above the dip threshold plus the
hysteresis voltage.
o
Phase view Ph. (for troubleshooting): a voltage dip begins when the
U
Rms(1/2)
voltage of one channel falls below the dip threshold, and ends
when the U
Rms(1/2)
voltage is equal to or above the dip threshold plus the
hysteresis voltage, on the same phase.