SMA Sunny Island 2012 Technical Description page 207

SMA Solar Technology AG
Glossary
Invert Mode
See Inverter Operation.
Inverter operation
Operating mode of a battery inverter where it supplies the stand-alone grid from the battery energy.
In this operating mode, the battery inverter is especially responsible for the control of frequency and
voltage in the stand-alone grid.
Islanding
Islanding is the undesired formation of an island system on the generator and/or external grid
connection point. There is a danger that, if there is a public grid outage or generator failure, the
Sunny Island may deliver reverse voltages in these power supply units.
Main Cluster
The leading cluster in a multicluster system. The main cluster, for example, has the tasks of voltage
and frequency regulation, grid monitoring, generator control, load management, and control of the
Automatic Switch Box in a backup system.
Maintenance Charge
see Float Charge
Master
Configuration setting that defines a Sunny Island or backup inverter to be the master within a cluster.
This stipulates that centralized control and monitoring tasks, which in a cluster must be performed
by just one device (e.g.,frequency regulation, battery management, generator control, and control
of the Automatic Switch Box in the Sunny Backup system) are to be performed by this device. All
other inverters of the cluster must be configured so as to leave these tasks to the master, and to be
led by the master (−> Slave). The master is also the device at which the cluster's configuration,
operation, and data recording occurs in a centralized manner.
Maximum Power Point "MPP"
The working point (current/voltage characteristic curve) of a PV generator where the maximum
power can be drawn. The actual MMP changes constantly depending on, for example, the level of
solar irradiation and the ambient temperature.
MPP tracker
Regulation of the power drawn so that a PV generator is operated for as long as possible at the
MPP. This operating point varies with the solar irradiation and temperature conditions of the
modules. MPP tracking optimizes the extraction of electrical power and is a feature of inverters and
charge controllers.
MSD
See Automatic Disconnection Device.
Technical Description SI2012_2224-TEN082311 207