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Inverters for commercial plants

Inverters for commercial plants

The correct selection of inverters for larger installations or projects is often difficult because the purchase costs, the installation effort and the follow-up costs have to be weighed up. However, it can certainly be said that the use of large inverters makes economic sense compared to many small devices.

We give a small overview of the most important players:

 

 

SolarEdge 55k / 82.8k

SolarEdge 55k-82.8k

This large inverter is available in 2 versions and always consists of a primary unit and a secondary unit (model 55k) or two secondary units (model 82.8k). SolarEdge focuses on the low installation effort, as the PV field is connected exclusively centrally to the DC junction box.

  • Output power: 55 kVA or 82.8 kVA
  • Central connection box for DC and AC connection including DC circuit breaker
  • Overvoltage protection TYPE II(optional)
  • DC fuses 30A (optional)
  • Free, integrated monitoring
  • Low installation effort due to long strings, savings on DC cable sections
  • 2 connection variants available: MC4 plug or 4-10mm² terminals
  • System status indicated by LEDs on the primary unit immediately
  • Low follow-up costs due to monitoring on module levels

ABB PVS 100/120

FIG PVS 100/120

ABB's power package guarantees a cost-effective solution for open spaces or commercial facilities. The integrated connection box and compact design enable quick installation.

  • Output power: 100 kVA at 400 Vac, 120kVA at 480 Vac
  • DC connection: 6 MPPT with 4 strings each
  • With FULL version: string fuses, string current monitoring, DC switch, AC switch, overvoltage protection type II
  • High flexibility due to 6 MPPT
  • Free, integrated monitoring

SMA Highpower Peak1

SMA SHP75

True to the motto "The best of two worlds", the Sunny Highpower PEAK1 combines the advantages of central inverters with those of a decentralised system layout: High efficiency, flexible system design, simple installation and low maintenance costs. A selection of connection boxes enables a tailored solution for your system

  • Output power: 75 kVA
  • Connection boxes optionally with:
  • 16-18 string inputs
  • string fuses
  • DC circuit breaker
  • Overvoltage protection type II

 

  • Inverter Manager as central monitoring and control unit
  • Free, integrated monitoring

SMA Core 1

SMA Core 1

With the Core 1, SMA focuses on simple installation in rooftop and ground-mounted systems. As the world's first freestanding inverter, complex installation is no longer necessary. The high number of MPPTs and integrated communication round off the overall package.

  • Output power: 50kVA
  • DC connection: 6 MPPT with 2 strings each
  • Free-standing inverter
  • DC and AC overvoltage protection (optional)
  • DC disconnectors
  • Integrated, free monitoring
  • Up to 150% oversizing possible

 

Delta M88H

Delta M88H

The M88H inverter is an economically attractive solution for commercial installations and is available in two versions, with standard MC4 plug connections or screw terminals. The output power can also be increased by connecting the 480V mains.

  1. Output power: 73 kVA at 400 Vac, 88kVA at 480 Vac
  2. M88H CF model:
    1. 18 x MC4 strings on 2 MPPT
    2. string fuses
    3. DC disconnectors
    4. Overvoltage protection type II
  3. M88H ST model:
    1. screw terminals 35-150mm
    2. Overvoltage protection type II
  4. External monitoring, e.g. solar log

Costs per kVA inverter power

Large inverters benefit from economies of scale and thus lower costs per kVA inverter output. Compared to smaller devices, these can even be halved in individual cases. Below is a rough size comparison of the large inverters from SMA, ABB and Delta as well as a standard 15kW inverter.

Comparison of acquisition costs:

 

Saving of NA-protective dome switches

For installations above 30kVA, the energy supplier in Germany requires a central, external NA protection. This must have two redundant, series-connected tie breakers, which disconnect the inverters from the grid in the event of a fault. These switches must be able to switch high power and are accordingly expensive (usual cost range approx. 1.000€) .
To keep these additional costs under control, SolarEdge, Delta and ABB inverters mentioned above can control the internal AC relays in the inverter by the NA protection measuring device so that they are triggered in the event of a fault. Therefore, only the relatively inexpensive measuring device is necessary.
Please note: The release must be given by the energy supplier. In individual cases, however, external tie breakers may be required.


Other factors

Apart from price, other factors often play an important role in ensuring a good long-term return on investment.
Additional costs arise, for example, during installation and assembly, during regular maintenance and as consequential costs in the event of system defects. It is therefore imperative that an overall picture of the costs is taken into account. Installation effort can be kept within limits by simple assembly, maintenance effort by good monitoring and follow-up costs by good support and warranty period. Below is a rough overview of the manufacturers:

Conclusion

The choice of the right device should be decided in each individual case on the basis of the existing conditions.
If price-sensitive projects, in which monitoring and maintenance play a rather minor role, Delta inverters offer themselves due to their low purchase costs.
SolarEdge is an interesting system if you want to minimize the follow-up costs for maintenance and troubleshooting, receive a 12-year warranty, and guarantee the maximum energy yield or return on investment.
SMA and ABB offer a good average between acquisition costs and monitoring/follow-up costs and differ mainly in the performance class.

Would you like to get more information about inverters for commercial plants? In the blog post inverters for commercial photovoltaic projects, we give you an insight into Krannich's newest portfolio of inverters.

 

03.07.2018 14:57
by Maik Wünsche

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