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Appendix A - Glossary
• Inverter mode: Operating mode of a inverter where it supplies the stand-alone grid from
the PV array and/or battery pack energy. In this operating mode, the inverter is especially
responsible for the control of frequency and voltage in the stand-alone grid.
• Lithium-ion (Li-ion) Battery: Type of rechargeable battery where lithium ions flow from
the negative electrode to the positive electrode when the battery is being discharged
and back when the battery is recharging.
• Local utility company: A local utility company is a company under which the installation
belongs to.
• Maximum Power Point: The operating point (current/voltage characteristic curve) of a PV
array where the maximum power can be drawn. The actual MPP changes constantly
depending e.g. on the level of solar irradiation and the temperature.
• MPPT: Maximum Power Point Tracking.
• MPPT Channel: Regulation of the power drawn so that a PV field remains as close as
possible to the MPP. Multiple strings of same type could be connected on the same MPPT
channel.
• NEC: The National Electrical Code (NEC), or NFPA 70, is a United States standard for the
safe installation of electrical wiring and equipment.
• Nominal Energy Throughput of the Battery: A nominal energy throughput is the
calculated result of one full charge and discharge of the battery.
• Nominal power: Nominal power is the maximum permissible continuous power output
indicated on name plate ratings.
• Nominal current: Nominal current is the max. continuous current. Typically, if the device
is supplied with the nominal voltage and yields its nominal power.
• Overload / Surge Capacity: The overload capacity of an inverter describes its ability to
supply short-term (seconds) that loads can significantly draw higher than the nominal
power at start-up. The overload capacity is necessary in order to be able to also start
electronic machines that have a nominal power similar to the nominal power of the
inverter in the stand-alone grid, since these machines typically need 2-6x times more
current during start than in steady-state.
• Standalone: This happens when the utility grid is lost. Also called Off-grid.
• Photovoltaic (PV): The conversion of PV energy into electrical energy. The name is
composed of the component parts: Photos: the Greek word for light - and Volta - after
Alessandro Volta, a pioneer in electrical research.
• Power dissipation: Power dissipation is designated as the difference between absorbed
power and power of a device or process yielded. Power dissipation is released mainly as
heat.
• PV Array: Technical device for the conversion of solar energy into electrical energy. All
electrically connected (in series and in parallel) PV modules of a PV system are referred to
as the PV array.
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