Functional Description; Gen And Dc Operating Modes; General Measuring Functions - Bender ISOMETER isoGEN423 Manual

2.3

Functional description

2.3.1

GEn and dc operating modes

The GEn mode is used in AC/DC or DC systems. In this mode, the device complies with the maximum response
time ≤ 1 s for C ≤ 1 F and R
e
The dc mode is only used in DC systems. In this mode, the device complies with the maximum response
time of ≤ 1 s for C ≤ 2 F and R
e
insulation faults, response times of ≤ 10 s for C
capacitance C is also measured in this mode.
e
The operating mode can be changed in the menu 'SEt'.
2.3.2

General measuring functions

The ISOMETER® measures the r.m.s. value of the nominal system voltage U
the residual voltages between L1/+ and earth (U
When it is connected to a DC supply system and when a minimum system voltage has been reached, the
device determines the faulty conductor L1/+ or L2/–. The fault is indicated by a '+' or '–' sign preceding the
measured value. The value range of the display is ±100 %:
Display
–100 % One-sided fault on conductor L2/–
0 % Symmetrical fault
+100 % One-sided fault on conductor L1/+
The partial resistances can be calculated from the total insulation resistance R
conductor (R %) using the following formula:
Fault on conductor L1/+ R
Fault on conductor L2/– R
When the ISOMETER® is coupled to an AC system, the faulty conductor can only be determined in a connected
DC system, and the faulty conductor is detected either on L1/+ (+100 %) or L2/– (–100 %). Calculating the fault
distribution is not possible in this case.
The detected fault can be assigned to a relay. If the values R
'AL' menu for the duration t
the alarm assignment set in the 'out' menu. In addition, the mode of operation of the relay (n.o./n.c.) can be set,
and the fault memory 'M' is activated in this menu.
If the values R or U no longer violate their respective release values (response value plus hysteresis) for the
F n
period t without interruption, the alarm relays will switch back to their initial position and the alarm LEDs
off
'AL1'/'AL2' will stop lighting. If the fault memory is activated, the alarm relays remain in alarm condition and
the LEDs light until the reset button 'R' is pressed or the supply voltage U
The device function can be tested using the test button 'T'. Parameters are assigned to the device via the LCD
and the control buttons on the front panel; this function can be password-protected. Parameterisation is also
possible via the BMS bus, e.g. by using the BMS Ethernet gateway (COM465IP) or a Modbus RTU.
≤ R /2.
F an
≤ R /2 in the event of asymmetrical insulation faults. In case of symmetrical
F an
e
Meaning
= (200 % * R ) / (100 % + R %)
L1F F
= (200 % * R ) / (100 % – R %)
L2F F
without interruption, the LEDs and relays 'K1' and 'K2' will respond according to
on
≤ 5 F and RF ≤ R /2 are complied with. The system leakage
an
) and between L2/– and earth (U
L1e
or U violate the response values activated in the
F n
isoGEN423_D00221_05_M_XXEN
ISOMETER® isoGEN423
between L1/+ and L2/– as well as
n
).
L2e
and the resistance of the faulty
F
is interrupted.
s
9