SMA SB 700U, SB 3000US, SB 3800-US-10, SB 4000US, SB 5000US Technical Information

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Technical Information

PV Inverters

Use of PV Inverters in Off-Grid and Backup Systems in North and South America

Content

Both in off-grid systems and in the event of grid failures in backup systems, grid fluctuations in the stand-alone grid are possible. This may cause severe deviations in nominal voltage and nominal frequency. Despite such fluctuations, all of the components in these systems must function without problems.

This technical information will inform you about the following topics:

• Which PV inverters you can use in off-grid systems and backup systems

• Which parameters you need to set in the PV inverter

• What type of communication you need to install in backup systems

• Which values the parameters of PV inverters will take in stand-alone mode

• How the output power of the PV inverter can be limited by the Frequency-Shift Power Control (FSPC) function of the Sunny Island

SB-OffGrid-TI-US-en-18 | Version 1.8 AMERICAN ENGLISH

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1 Applicability of PV inverters (date: February 2016) SMA Solar Technology America LLC

1 Applicability of PV inverters (date: February 2016)

PV Inverters Off-grid system Backup system Available?

Sunny Boy (SB)

SB 700U ✓ ✖ No

SB 3000US ✓ ✓ No

SB 3800-US-10 ✓ ✓ No

SB 4000US ✓ ✓ No

SB 5000US ✓ ✓ No

SB 6000US ✓ ✓ No

SB 7000US ✓ ✓ No

SB 8000US ✓ ✓ No

SB 2000HFUS-30 ✖ ✖ No

SB 2500HFUS-30 ✖ ✖ No

SB 3000HFUS-30 ✖ ✖ No

SB 3000TL-US-22 ✖

SB 3800TL-US-22 ✖

SB 4000TL-US-22 ✖

SB 5000TL-US-22 ✖

SB 6000TL-US-22 ✖

SB 7000TL-US-22 ✖

SB 7700TL-US-22 ✖

✓Yes

SB5.0-1-SP-US-40 ✓ ✖ Yes

SB6.0-1-SP-US-40 ✓ ✖ Yes

SB 5000TLUS-12 ✓ ✓ No

SB 6000TLUS-12 ✓ ✓ No

SB 7000TLUS-12 ✓ ✓ No

SB 8000TLUS-12 ✓ ✓ No

SB 9000TLUS-12 ✓ ✓ Yes

SB 10000TLUS-12 ✓ ✓ Yes

SB 11000TLUS-12 ✓ ✓ Yes

Since 2016, no longer supported.

✓ Compatible ✖ Not compatible

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SMA Solar Technology America LLC 2 Configuration of PV Inverters in Off-Grid Systems

PV Inverters Off-grid system Backup system Available?

Sunny Tripower (STP)

STP 12000TL-US-10 ✖ ✖ Yes

STP 15000TL-US-10 ✖ ✖ Yes

STP 20000TL-US-10 ✖ ✖ Yes

STP 24000TL-US-10 ✖ ✖ Yes

STP 30000TL-US-10 ✖ ✖ Yes

✓ Compatible ✖ Not compatible

System failures due to excessive power output of AC sources in the stand-alone grid

If the power of the AC sources (e.g. PV inverters) in off-grid systems or backup systems is too high, it may cause system failures.

• Design the total nominal AC power of the PV inverters to be no more than twice as high as the nominal AC power of the Sunny Island.

• If wind power inverters feed into the stand-alone grid, design the total nominal power of the AC sources in the stand-alone grid to be no larger than the nominal AC power of the Sunny Island.

• Allow at least 100 Ah of battery capacity per 1,000 W of nominal AC power from the AC sources in the stand-alone grid.

2 Configuration of PV Inverters in Off-Grid Systems

The country data set must be set to stand-alone mode in off-grid systems.

You can order PV inverters configured for stand-alone mode or you can configure existing PV inverters for stand-alone mode (see Section4 "Communication Products for Configuring PV Inverters", page5). During the first ten operating hours you can adjust the country data set for many PV inverters by means of rotary switches (see the manual of the PV inverter).

Setting the Country Data Set via RS485 (e.g. with Sunny WebBox)

The following table shows how the country data set must be set during configuration of the PV inverter via RS485. The parameter name and the configurable value depend on the PV inverter being used.

Parameter name Value

Either Default

CntrySet

Either Off-Grid

depending on power frequency, OFF-Grid50 for 50 Hz power frequency or Off-Grid60 for 60 Hz power frequency

Technical Information SB-OffGrid-TI-US-en-18 3

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3 Configuration of PV Inverters in Backup Systems SMA Solar Technology America LLC

Setting the Country Data set via Speedwire or BLUETOOTH* (e.g. with Sunny Explorer)

The following table shows how the country data set must be set during configuration of the PV inverters via Speedwire or BLUETOOTH. The country data set value depends on the PV inverter being used.

Parameter name Value

Set country standard Either Island mode

depending on power frequency, Island mode 50 for 50 Hz power frequency or

Island mode 60 for 60 Hz power frequency

3 Configuration of PV Inverters in Backup Systems

In a backup system, the Sunny Island is connected to the utility grid and communicates with the PV inverters via RS485. This is why the Sunny Island and each PV inverter must be equipped with an RS485 Piggy-Back or an RS485 data module. In a cluster, only the master of the Sunny Island inverters may be equipped with an RS485 Piggy-Back. In a backup system, all PV inverters must be configured for backup operation (see Section4 "Communication Products for Configuring PV Inverters", page5).

Setting Backup Operation via RS485 (e.g. with Sunny WebBox)

The following table shows how backup operation must be set during configuration of the PV inverter via RS485. The parameter name and the configurable value depend on the PV inverter being used.

Parameter name Value

Either Backup Mode

Op.BckOpMod

In backup systems you operate the PV inverters with the locally typical country data set for grid-connected PV systems as per UL1741. If the parameter is set to On all or OnAllPhs, the system meets the requirements as per UL1741.

PV inverters without backup mode

For PV inverters without backup mode, the country data set must be set to the locally typical value for grid-tie PV systems as per UL1741. The PV inverter is then configured for operation on the utility grid. In the event of a utility grid failure, the Sunny Island is unable to derate the PV inverters by means of Frequency-Shift Power Control (FSPC). If there is an excessive supply of energy, the PV inverters will switch off.

Either On all

OnAllPhs

* The BLUETOOTH® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of these marks by

SMA America, LLC is under license.

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SMA Solar Technology America LLC 4 Communication Products for Configuring PV Inverters

4 Communication Products for Configuring PV Inverters

SMA Grid Guard code required to change grid-relevant parameters

To change grid-relevant parameters in the PV inverter after ten operating hours, you will need the SMA Grid Guard code.

• Select a communication product corresponding to the type of communication and the PV inverter used.

• Apply for an SMA Grid Guard code to change grid-relevant parameters (for an application for the SMA Grid Guard code, see the certificate "Application for SMA Grid Guard Code" at www.SMA-Solar.com).

PV Inverters with RS485

You can configure PV inverters with RS485 using the following communication products:

• Sunny WebBox

• Sunny Boy Control

• Computer with Sunny Data/Sunny Data Control software

For PV inverters without RS485 Piggy-Back or RS485 data module, you will also need a service cable for data transmission (USB Service Interface, SMA order number: USBPBS).

PV Inverters with Speedwire

You can configure PV inverters with Speedwire using the following communication products:

• Sunny Explorer

• SMA Cluster Controller

PV Inverters with BLUETOOTH

You can configure PV inverters with BLUETOOTH using the following communication products:

• Sunny Explorer

• Sunny WebBox mit BLUETOOTH Wireless Technology

Technical Information SB-OffGrid-TI-US-en-18 5

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5 Parameter Values in Stand-Alone Mode SMA Solar Technology America LLC

5 Parameter Values in Stand-Alone Mode

The OFF Grid setting for the Default parameter affects the following parameters of the PV inverter. The given values are examples and have no general validity.

Parameters Unit Value

Test current mA Off (MSD=0)

Vac.Min V ‒50% V

Vac.Max V +20% V

Fac-delta‒

Lower range in which the Sunny Boy is active relative to f

Fac-max+

Upper range, where the Sunny Boy is active, based on f

dFac-Max

Hz -4.5

(starting from base frequency f

Hz +4.5

(starting from base frequency f

Hz 5

Max. rate of change

Fac-start delta

Frequency increase in relation to f

, at which point the

Hz 1

(starting from base frequency f

power adjustment via frequency begins

Fac-Limit delta

Frequency increase based on f

, where the power

Hz 2

(starting from base frequency f

control via frequency ends. The power of the Sunny Boy at this point is 0 W.

= 208 V/240 V/277 V

AC Nom

AC Nom*

)

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SMA Solar Technology America LLC 6 Frequency Shift Power Control (FSPC)

6 Frequency Shift Power Control (FSPC)

If PV inverters are connected on the AC side in off-grid operation or back-up operation, the Sunny Island must be able to limit their output power. This situation can occur, for example, when the battery of the Sunny Island is fully charged and the PV power available from the PV array exceeds the power required by the connected loads.

To prevent the excess energy from overcharging the battery, the Sunny Island recognizes this situation and changes the frequency at the AC output. This frequency change is monitored by the PV inverter. As soon as the power frequency

increases beyond the value specified by Fac-Start delta, the PV inverter limits its power accordingly.

Figure1: Operating principle of FSPC

The terms used have the following meanings:

• f

refers to the base frequency of the stand-alone grid (here 60 Hz).

Delta- and fAC Delta+ are the maximum ranges relative to fAC in which the PV inverter is active.

• f

•fAC Start Delta is the frequency increase relative to fAC at which frequency-based power control begins.

• f

Limit Delta is the frequency increase relative to fAC at which frequency-based power control ends. The power

of the PV inverter at this point is 0 W.

If the limits f

Delta- or fAC Delta+ are exceeded, the PV inverters disconnect from the utility grid.

When an external energy source, (e.g. a diesel generator) is operating in the stand- a lone grid, this external energy source determines the frequency and the PV inverters set to off-grid operation react to certain frequency changes brought about by the external energy source.

When diesel generators are used as external energy sources, the output voltage frequency under load is 60 Hz. For this reason, in most cases the PV inverters will deliver their entire power to the stand-alone grid, even when the diesel generator is in operation.

If the current battery voltage is greater than the battery voltage setpoint and the stand-alone grid is also to be synchronized with an external energy source, the Sunny Island temporarily increases the frequency and the PV inverters disconnect via frequency shutdown (overfrequency). Afterwards, the Sunny Island synchronizes with the external energy source.

Technical Information SB-OffGrid-TI-US-en-18 7