Operation Manual

Protect PV.250 Operating Instructions
Page 13 of 51 80000027023 BAL, en
If the DC voltage continues to increase due to the sun's rays get-
ting stronger and the mains voltage and mains frequency are
within 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. The inverter output con-
tactor is open during a start-up attempt. If the load on the DC volt-
age causes it to collapse too dramatically during this start-up at-
tempt, the 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 inverter output contactor 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 inverter 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 inverter stack is switched off,
the inverter output contactor K7 opens and the unit switches to the
"Waiting" status.
Once the "Waiting" status delay has elapsed, the unit switches
back to "Waiting for feed conditions". Although the sun's rays are
not as strong, the DC voltage might still be high enough for a suc-
cessful start-up attempt with the inverter stack and the inverter
output contactor K7 being switched on again. However, because
the sun's rays are not as strong, it is unlikely that the operating
conditions will still be met in the "Operation" status. As a result, the
unit will switch back to the "Waiting" status once a delay has
elapsed. When the unit switches back to this status, the delay is
extended until the unit switches back to the "Waiting for feed con-
ditions" status.
The cyclic changes of status "Operation" -> "Waiting" -> "Waiting
for feed conditions" -> "Operation" can take place several times
depending on insolation, the time of year, location and other condi-
tions (e.g. snow on the PV cells). So that the inverter output con-
tactor K7 is not overloaded by this cycle of changes, the delay in
the "Waiting" status is extended every time the unit switches to this
status.
This has very little effect on the energy fed in, because the low
levels of insolation mean that hardly any energy is being gener-
ated.
Later in the evening:
Levels of insolation continue to fall. As a result, the DC voltage
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 unit switches to the "Night" status.
Night:
The Protect PV.250 shuts down all possible loads so that as little
energy as possible is being consumed. The inverter remains in the
"Night" status until the following morning.