December 2008

Perfectly balanced

Three phase grid feed-in with maximum safety

With the series-produced Power Balancer for the Sunny Mini Central you can connect individual devices in the blink of an eye to a three-phase feed-in unit.

For larger PV systems there is really no way of avoiding three-phase design. Otherwise they would feed-in to the three-phase interconnection grid with extensive unbalanced loads. The unbalanced load, that is the asymmetric fed-in power, may however reach a maximum of 4.6 kVA - this is also valid in the event of an fault. At the latest from a nominal power of 30 kWp the utility operators set a further array of additional requirements: thus the grid voltage must be monitored three phase, combined with a section switch which completely disconnects all three phases from the grid in the event of grid failure.

Safely avoid unbalanced loads

You are optimally prepared for these requirements with the Sunny Mini Central from SMA and can simply realize three phase PV systems: via the Power Balancer function now series produced for all models three devices can be connected up as a three phase feed-in unit using a suitable connection cable. And something special: you can adapt the requirements of the customers (or the demands of the utility operator) in several stages with the integrated monitoring- and protection device. If desired the Power Balancer features even more security against unbalanced loads than the (German) VDEW guideline demands: It then not only monitors the grid, rather also the respective feed-in unit. Thus unbalanced loads are avoided if on of the individual inverters fails - a downstream grid monitoring would not register this at all.

Mit dem Einstecken des Verbindungskabels bilden jeweils drei Sunny Mini Central eine dreiphasige Einspeiseeinheit

Flexibly configurable

The Power Balancer can however also be set up so that only the feed-in power is reduced in the event of grid-or device failure: the devices not affected then feed in with a maximum power of 4.6 kVA and therefore limit the unbalanced load to the maximum allowable value. This setting minimizes the loss in yield during grid faults, however with larger systems the unbalanced load of several feed-in units are added together. A further variant equates in its function to an external, three phase voltage monitoring with section switch: in the event of drop-out of a grid phase the complete system is disconnected from the grid - monitoring of the individual inverters does not take place. However even in this case the Sunny Mini Central ensures the greatest safety: their built-in grid disconnection switch carries out an automatic self-test before every switch-on procedure.

Simply three phase

The Sunny Mini Centrals are therefore also impressive in three-phase designed PV systems: their manageable size simplifies transport and assembly, the decentral design guarantees maximum system availability with outstanding overall efficiency. With the flexibly configurable Power Balancer you achieve all demands of the utility operator, upon request also taking into consideration the economic interests of your customers. The proven Sunny Mini Central safety in the blink of an eye.

Die vier Schaltstufen des Power Balancers:

  1. Deaktiviert
  2. Power Guard
    Bei Netz- oder Gerätefehler speisen die nicht betroffenen Geräte mit reduzierter Leistung (maximal 4,6 kVA) ins Netz ein, um die Schieflast gering zu halten
  3. Phase Guard
    Wie bei einer externen Netzüberwachung wird die gesamte Anlage vom Netz getrennt, sobald eine Phase ausfällt
  4. Fault Guard
    Netzüberwachung wie "Phase Guard", zusätzlich Abschaltung der jeweiligen Einspeiseeinheit im Falle eines Gerätefehlers