SI4548-US-10 Manual

23 Glossary SMA America, LLC
238 SI4548_6048-US-TB_en-13 Technical description
Split-phase
A split-phase system is a three-conductor single-phase distribution system, commonly used in North
America, the UK, Australia and New Zealand for single-family residential and light commercial (up
to 100 kVA) applications. Its primary advantage is that it saves conductor material since a
single-phase system with one neutral conductor is used, while on the supply side of the distribution
system only one line conductor is necessary. Since there are two live conductors in the system, it is
sometimes incorrectly referred to as "two-phase system". To avoid confusion with split-phase
applications, it would be correct to call this power distribution system a three-conductor, single-phase,
mid-point, neutral system.
Stand-alone grid system
An energy generation system that supplies electrical energy completely independently of any external
electrical energy supply.
State of charge
Describes the current amount of charge that can be drawn from the battery, in percent of the nominal
capacity (100% = battery full, 0% = battery empty).
String
Describes a group of electrical series-connected PV modules. A PV plant usually consists of a number
of strings, which avoids excessive yield losses caused by variations in shading on different modules.
String inverter
Inverter concept in which the disadvantages of the central inverter concept are avoided. The PV is split
into individual strings, each of which is connected to the external transmission line with its own string
inverter. This greatly simplifies installation and greatly reduces the yield losses caused by
manufacturing deviations or variations in shading of the PV modules.
VRLA
Valve Regulated Lead Acid battery: Lead-acid battery with semi-solid electrolyte or valve-regulated
lead-acid battery. Examples of this type of battery are SLA batteries and AGM batteries (Absorbent
Glass Mat).