Operating instructions

Protect PV.600/800 OD Series - Operating Instructions
8000041160 BAL Page 37 of 100
I
f the DC voltage continues to increase due to the sun's rays get-
ting stronger and the mains voltage and mains frequency are with-
in acceptable limits, a start-up attempt is made. During a start-up
attempt, the inverter stack is switched on, thereby drawing power
from the DC voltage that is present. INV output contactor K7 is
open during a start-up attempt. If the load on the DC voltage caus-
es it to collapse too dramatically during this start-up attempt, the
inverter stack is switched off again and there is a delay until the
next start-up attempt is made. If the DC voltage does not dip too
significantly, the INV output contactor K7 closes and power is fed
into the mains. The inverter is now in the "Operation" status.
Day
During the course of the day, the inverter will remain in the "Opera-
tion" status if the sun's rays are strong enough and no faults occur.
Power is fed into the mains and the INV output contactor K7 is
closed.
Evening
As the sun goes down, the power fed into the mains decreases. If
this power falls below a certain value for a certain time, the operat-
ing conditions are no longer met. The INV stack is switched off, the
INV output contactor K7 opens and the equipment switches to the
"Waiting" status.
Once the "Waiting" status delay has elapsed, the equipment
switches back to the "Waiting for feed conditions" status. Although
the sun's rays are not as strong, the DC voltage might still be high
enough for a successful start-up attempt. However, because the
sun's rays are not as strong, it is unlikely that the operating condi-
tions will still be met in the "Operation" status. As a result, the
equipment will switch back to the "Waiting" status once a delay
has elapsed.
When the equipment switches back to the "Waiting" status, the de-
lay is extended until the equipment switches to the "Waiting for
feed conditions" status.
The cyclic change of the "Operation"  "Waiting"  "Waiting for
feed conditions"  "Operation" statuses can take place several
times depending on insolation, the time of year, location and other
conditions (e.g. snow on the PV cells).
So that INV output contactor K7 is not overloaded by this, the
"Waiting" status delay is extended with each cycle of changes.
This behaviour has very little effect on the energy fed in, because
the low levels of insolation mean that hardly any energy is being
generated.
Later in the evening
The level of insolation drops; as a result, the DC voltage generated
also drops again. If the DC voltage drops below a certain value for
a certain time, no more start-up attempts are made. If the DC volt-
age continues to drop, the equipment switches to the "Night" sta-
tus.