And C In 'Dc' Mode (Ccs); Fault Location R; System Leakage Capacitance C; System Voltages U L1E And U L2E - Bender ISOMETER isoCHA425 Manual

Function
R is the two-pole total insulation fault. It is determined up to a maximum of 2 M .
FS
The response time of the one-pole insulation fault R
R > 100 k as well as R
FU
2.3.2 R and C in 'dc' mode (CCS)
F e
The insulation fault R
F
system voltage. The maximum permissible system leakage capacitance is 5 F . The response time for R
2.3.3

Fault location R%

From U > DC 20 V the fault location R% is calculated for insulation faults R
n
Value Meaning
–100 % one-pole insulation fault at L–
0 % symmetrical insulation fault
+100 % one-pole insulation fault at L+
For values of 30 % and more, the alarm assignment of the relays distinguishes between insulation faults at L+
and L–.
From the values R% and R
• Fault at conductor DC+: R
• Fault at conductor DC–: R
2.3.4

System leakage capacitance C

The system leakage capacitance C
12 F, the message Device error 'E.07' is displayed.
For applications according to UL 2231-1/-2, the system leakage capacitance C
2.3.5 System voltages U
The system voltage U
n
overvoltage and undervoltage are available in the 'AL' menu (see 'Setting the response values (AL)'). Above
510 V, the message 'Overvoltage' is displayed regardless of the set overvoltage limit value.
The DC system voltages U
No limit value is assigned to them.
2.3.6

Functional tests of contactors in the charging station and the vehicle

If the ISOMETER® is disconnected on one pole from the monitored voltage source during a functional test of
the charging station or vehicle contactors, a false alarm may occur depending on the location of an existing
insulation fault. For insulation faults above 250 k the false alarm can be prevented by a resistor of 200 k
connected directly between the terminals L+ and L–.
10 isoCHA425_D00352_03_M_XXEN/08.2023
, the response time of R
FS
up to 2 M and the system leakage capacitance C
the partial resistances R
F
= (200 % x R ) / (100 % + R%)
F+ F
= (200 % x R ) / (100 % – R%)
F– F
is determined for insulation faults R
e
, U and U
n L1e
between terminals L+ and L– is measured as RMS value (True-RMS). Limit values for
and U are respectively measured between terminals L+ as well as L– and earth.
L1e L2e
is one second for R
FU
is ≤ 10 s.
F
and R can be calculated using the following formulas:
F+ F–
e
L2e
≤ 100 k and U
FU n
are determined independently of the
e
up to 500 k ('CHd' mode 150 k ).
F
> 10 k up to a value of 17 F. Above
F
is limited to 5 F.
e
≥ 50 V. For values
is 10 s.
F