Operation Manual

Protect PV.250 Operating Instructions
Page 16 of 51 80000027023 BAL, en
4.2.2 Fan Control Parameters
Stack temperature limit value for switching on the fan:
If the IGBT stack temperature rises above this limit value, the fans
which were switched off are switched to the fast fan stage.
Stack temperature limit value for switching off the fan:
If the IGBT stack temperature falls below this limit value, the fans
which were running in the slow fan stage are switched off.
Stack temperature limit value for switching to the fast fan
stage:
If the IGBT stack temperature rises above this limit value, the fans
which were running in the slow fan stage are switched to the fast
fan stage.
Stack temperature limit value for switching to the slow fan
stage:
Minimum time in the fast fan stage:
If the IGBT stack temperature falls below this limit value, the fans
which were running in the fast fan stage are switched to the slow
fan stage if the minimum time in the fast fan stage has elapsed.
4.3 Insulation Monitoring and Earthing of PV Cells
4.3.1 General
Insulation measurements and tests are carried out with a "Bender
A-ISOMETER IRDH275B". This device detects and checks the in-
sulation resistance.
The insulation resistance detected is compared with two limit val-
ues stored in the isometer. If the insulation resistance is below one
of the limit values, the device generates a signal. If the limit value
is below the other limit value, the device generates a second sig-
nal. The limit values can be displayed and even modified on the
isometer.
The insulation resistance detected and the two signals are sent to
the Protect PV.250 control. The insulation resistance is displayed
as a measured value. Signalling faults are generated from the two
isometer signals, see Chapter 5.
Sequence control behaviour differs depending on which solar cells
are connected.
The solar cells do not need to be earthed for operation with
monocrystalline or polycrystalline solar cells. Insulation measure-
ment is always active.
In the case of operation with thin-film solar cells, the solar cells
have to be earthed. Insulation measurement is not active during
earthing.
Insulation measurement sequence control features a "Mainte-
nance mode". This mode can only be activated for thin-film solar
cells. Activating this mode removes earthing. This can be useful
when mowing areas where solar panels are installed, for example.