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COMBI521
EN - 75
6.8. LOZ: LINE/LOOP IMPEDANCE WITH HIGH RESOLUTION
This Line/loop impedance measurements with high resolution (0.1m
) is performed by
using the optional accessory
IMP57
connected to the Master unit through the optical
cable/RS-232 C2001 supplied with same accessory. The IMP57 must be directly powered
by the mains on which measurements are performed. For detailed information, please
refer to the user manual of the accessory IMP57.
Please find below the procedure for the measurement of
STD L-L impedance in TN
systems
. The same procedures can be applied to any other case considering what is
reported in previous § 6.7.
1. Press the
MENU
key, move the cursor to
LoZ
in the main
menu by means of the arrow keys (
,
) and confirm
with
ENTER
. Subsequently the instrument displays a
screen similar to the one reported here to the side.
The “
IMP57 not detected
” message indicates that the
IMP57 accessory is not connected to the instrument or
not powered directly by the mains
L o Z
15/10 – 18:04
TN
Ipsc
ZL-L
=
=
- - -
- - -
A
m
R = - - - m
X = - - - m
FREQ. = - - -Hz
VL-L= - - -V
IMP57 not detected
L-L STD
FUNC
MODE
2. Connect the IMP57 to the instrument via the cable C2001
and to the powered system via the input terminals
C1
,
C2
and
P1
,
P2
placed on it (see the IMP57 user manual).
The following screen appears on the display
L o Z
15/10 – 18:04
TN
Ipsc
ZL-L
=
=
- - -
- - -
A
m
R = - - - m
X = - - - m
FREQ. = 50.0Hz
VL-L= 384V
L-L STD
FUNC
MODE
3. Press the
GO/STOP
key on the instrument to start the
test. The following screen is shown on the display (in
case of L-L measurement in STD mode).
The standard (STD) prospective short-circuit current is
shown on the display.The L-L Loop impedance values, in
addition to its resistive and reactive components, are
shown in the central part of the display, expressed in
m
L o Z
15/10 – 18:04
TN
Ipsc
ZL-L
=
=
15.3
15.0
kA
m
R = 13.2 m
X = 7.5 m
FREQ. = 50.0Hz
VL-L= 384V
L-L STD
FUNC
MODE
4. Press the
SAVE
key to store the test result in the instrument’s memory (see § 7.1) or
the
ESC/MENU
key to exit the screen without saving and go back to the main
measuring screen
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