Operation Manual

Protect PV.250 Operating Instructions
Page 18 of 51 80000027023 BAL, en
The insulation test can only be started manually if an insulation
test is not already running at the time.
4.3.4 Insulation Monitoring in Partner Operation
In partner operation (see Chapter 4.5), both inverters are fitted with
the isometer.
Insulation measurement in single operation
In single operation, the two inverters behave like two single units.
Insulation measurement is active in both inverters.
Insulation measurement in linked operation
In linked operation, the inverters are connected on the DC voltage
side. If both inverter isometers were to be active in this operating
mode, this would distort the measurement of the insulation resis-
tance. Therefore, in linked operation, the isometer of the inverter
which is not active is switched off and its sensors are disconnected
from the DC voltage. Now only one isometer is active and the
measurement of the insulation resistance is correct.
4.3.5 Insulation Monitoring Parameters
All parameters are only relevant for operation with thin-film solar
cells.
Insulation test time:
The analogue and digital signals from the isometer are evaluated
during this time.
Delay for insulation test following shutdown of K21:
Once the earthing has been disconnected, this time must elapse
before insulation measurement can start.
Delay for shutdown of K21 in night operation:
Once sequence control has switched to the "Night" status (see
Chapter 4.1.6), this time must elapse before earthing is removed
with contactor K21.
Minimum time in maintenance mode:
If maintenance mode has been activated, the earthing is discon-
nected and remains so for at least this time.
4.4 MPP Tracker
In the "Operation" status (see Chapter 4.1.3), the inverter detects
the maximum power point (MPP) of the PV cells.
The MPP tracker detects the point at which the solar cells give off
maximum power.
This enables the system to achieve optimum efficiency.