EN
34
3.7 Power derating
In order to allow inverter operation in safe thermal and electrical conditions, the unit automatically reduces the value of the power fed into
the grid.
Power derating 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
• Grid under voltage
• Input voltage values too high.
• High input current values.
3.7.1 Power derating due to environmental conditions
The power reduction value and the inverter temperature at which it occurs depend on the ambient temperature and on many operating
parameters. 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. The graph
shown below the power reduction in relation to the ambient temperature at the nominal input voltage.
0
10
20
30
40
50
60
70
80
90
100
92
91
93
94
95
96
97
98
99
100
480 Vdc
620 Vdc
Rated Output Power (%)
Efficiency (%)
800 Vdc
3.7.2 Power derating due to the input voltage
The power reduction occurred for too high or too low DC input voltage values is adjusted automatically.
NOTE –
D
Power reduction behaviour is guaranteed only in case of balanced input channels.
Input voltage (Vdc)
Output power (kW)
PVS-33-TL
PVS-30-TL
PVS-20-TL
0
10
20
30
40
350
450
550
650
750
850
950
