7.6.1
Checking the PV generator for a ground fault
DANGER
Risk of fatal injury due to electric shock!
Severe injury or death will result if the live connections are touched. When there is sunlight present on the
PV generator, there is DC voltage on the open ends of the DC cables.
›
Only touch the PV generator cables on the insulation. Do not touch the exposed ends of the cables.
›
Avoid short circuits.
›
Do not connect any strings with a ground fault to the device.
NOTE
The threshold value from which the insulation monitor reports an error can be set in the
“Parameters”
menu.
Ensure that there is no ground fault
1 Measure the DC voltage between the protective earth (PE) and the positive cable of the PV generator.
2 Measure the DC voltage between the protective earth (PE) and the negative cable of the PV generator.
ð
If stable voltages can be measured, there is a ground fault in the DC generator or its wiring. The ratio between
the measured voltages gives an indication as to the location of this fault.
3 Rectify any faults before taking further measurements.
4 Measure the electrical resistance between the protective earth (PE) and the positive cable of the PV generator.
5 Measure the electrical resistance between the protective earth (PE) and the negative cable of the PV generator.
ð
In addition, ensure that the PV generator has a total insulation resistance of more than 2.0 MOhm, since the
device will not feed in if the insulation resistance is too low.
6 Rectify any faults before connecting the DC generator.
7.6.2
Recommended standard connection
DANGER
Risk of fatal injury due to electric shock (electric arc)!
Incorrect assignment of MPP trackers will seriously damage the device. Touching the live connections will
result in severe injury or death!
›
Make sure that each MPP tracker can be disconnected from all poles.
›
Observe recommended standard connection.
The strings connected to a MPP tracker must all have the same MPP voltage. The MPP voltages of the three independ-
ently functioning MPP trackers 1, 2 and 3 may differ within the working area, however.
MPP tracker
1 2 3 4
1 2 3 4
1 2 3 4
1
2
3
DC DC+
DC DC+
DC DC+
U
MPP
U
MPP
n
1
= =
2
n
=
3
n
4
n
n
1
= =
2
n
=
3
n
4
n
n
1
= =
2
n
=
3
n
4
n
Fig. 30:
Recommended standard connection, XL variant
Powador 30.0-72.0 TL3
Page 26
EN
