Most of the
parameters of this sheet are only informative, some of them (bold)
denote special features
| Multi-MPPT
|
Some inverters involve several
MPPT inputs, which allow to connect PV arrays of different sizes,
module types or orientations. |
|
|
Normally each MPPT input may be
considered as half an inverter (for a 2 MPPT); these are completely
independent and have half the nominal power, they don't share the
Power capacity of the full inverter. This is a limitation of the
PVsyst simulation possibilities with respect to the manufacturer's
specifications. |
| Unbalanced MPPT
|
When clicking this checkbox you
have the opportunity of defining 2 different MPPT inputs (as
available with some recent inverters on the market like the
Tripower series of SMA). PVsyst defines the Main and
Secondary MPPT inputs. See
Inverter model: Multi-MPPT |
| Max ISC current
|
When defining unbalanced MPPT,
the manufacturers use to
specify the different inputs by their maximum ISC current, not the
Power limitations.
|
|
|
Therefore, after sizing, PVsyst will allocate a
Nominal power to each input, according to the ratio of the nominal
PV power of each sub-array.
|
| Number of DC inputs
|
Indicative for the acceptable number of strings
(connectors), not used by PVsyst. Not to be confused with the
number of MPPT inputs !
|
| String inverter
|
some manufacturers propose inverters which may
directly receive the string terminals without intermediary
circuitry. The device includes all securities normally mounted in a
junction box on the roof (fuses, non-return diodes, overvoltage
protections). The number of "String" inputs should of
course correspond to the effective number of strings.
|
| Transformer
|
May
be transformerless (the best efficiencies), Low Frequency
or High Frequency transformers.
|
|
|
The
transformer is required for some applications like arrays of
Amorphous modules (degradation of the TiO2 electrode) or some
old back-contact modules (which should be polarized with respect to
the ground voltage)..
|
| Master/Slave
|
some inverters may operate in the "Master/Slave"
mode, one of them ensuring the MPP tracking, and transmitting this
information to the other one(s). This allows to turn ON the
required number of devices, improving the efficiency at lower
powers. In this configuration the full array should be connected to
all devices at a time, in parallel. For the Master/slave operation,
you should define the Power threshold from which the second device
will be turned ON. See
Inverter model: Multi-MPPT |
| Internal Master/Slave
|
Many big inverters are announced as
"master/slave" devices. These are assemblies of standard units of a
defined power, which operate internally in Master/slave mode. This
operation mode results in a very good efficiency curve (of the
whole device) with a sharp elbow at low powers. These should not be
treated as "Master/Slave" in the simulation process as this
behavior is already taken into account in the efficiency.
|
| Auxiliaries consumption
|
Fans or other accessory device consumption, to be
deduced from the inverter output available energy. For the
simulation, the auxiliaries consumption is not automatic, even if
defined here: it should be explicitly specified in the
"Detailed
Losses" part.
|
| Night consumption
|
Usually negligible. If less than 0.05%, will not
appear on the loss diagram.
|
| Other specifications
|
give additional information about
the configuration, features and securities of the device, not used
in the simulation. |
| Isolation Monitoring
|
is a continuous check of the
isolation of the PV array with respect to ground. |
| DC Swich
|
indicates if the device includes
it, otherwise it should be foreseen externally on all DC
inputs. |
| AC Swich
|
indicates if the device includes
it, otherwise it should be foreseen externally. |
AC Disconnect adjust: the inverter
should cut the AC connection immediately when the grid voltage goes
out of a given AC voltage range (in Europe, 230 V or 400V + 6% and
- 10%). This feature allows to adjust these limits.
| ENS
|
indicates that the shut-down
security in case of grid defection works on the basis of the grid's
impedance measurement. This system is mandatory in Germany. |
