Power Limitation (Power Derating); Power Reduction Due To Environmental Conditions - ABB UNO-DM-TL-PLUS-US Product Manual

P
ower limitation (Power Derating)
P
ower reduction due to environmental conditions
In order to allow inverter operation in safe thermal and electrical condi-
tions, the unit automatically reduces the value of the power fed into the
grid.
Power limiting may occur due to:
• Adverse environmental conditions (thermal derating)
• Percentage of output power (value set by the user)
• Grid voltage over frequency (mode set by user)
• Grid overvoltage U>10min Der. (enabling carried out by user)
• Anti-islanding
• High input voltage values
• High input current values.
The power reduction value and the inverter temperature at which it oc-
curs depend on the ambient temperature and on many operating para-
meters. Example: input voltage, grid voltage and power available from
the photovoltaic field.
The inverter can therefore reduce the power during certain periods of the
day according to the value of these parameters.
In any case, the inverter guarantees the maximum output power even at
high temperatures, provided the sun is not shining directly on it.
Pout Vs Tamb @ Vnom
100%(Pacr)
90%
80%
70%
60%
50%
40%
UNO-DM-3.3-TL-PLUS
30% UNO-DM-3.8-TL-PLUS
UNO-DM-4.6-TL-PLUS
20%
UNO-DM-5.0-TL-PLUS
10%
0
- 26 -
Ambient temperature (°C)
2 - Characteristics