Configuring Limitation of Active Power Feed-In
The active power feed-in can be limited to fixed settings or controlled via external components. A Moxa device allows the grid operator, for example, to control the feed-in power of PV systems via a ripple control receiver.
Prerequisite:
The parameter Operating mode active power setting must be set to Active power limitation P via system control or to External specification for the inverters.
When using a Moxa device with ripple control receiver, in the Modbus configuration, the profile MOXA..._PLimit must be selected.
NOTICE
Responsibility of the system operator for limitation of active power feed-in
The system operator is responsible for the accuracy of the information on limiting the active power feed-in and the nominal system power.
- Ask your grid operator beforehand whether you are permitted to use the Sunny Home Manager to limit active power feed-in (Manufacturer's Declaration "Feed-In Management in Accordance with the Renewable Energy Sources Act (EEG) 2012 with Sunny Home Manager (SHM) from SMA" available at www.SMA-Solar.com).
- Set the limitation of active power feed-in required by the grid operator. If you are not sure about this, contact your grid operator.
- Ensure you have correct information on the nominal PV system power. If you extend the system, adjust the value for the nominal PV system power accordingly.
If your grid operator only allows a certain active power feed-in into the utility grid, the Sunny Home Manager can monitor and fulfill this requirement by reducing the PV generation of the inverters when the specified limit is exceeded.
This takes into account that in times when your PV system generates a lot of PV power, which is also used directly by loads - household appliances or a battery that is being charged - a PV power higher than the feed-in limitation is allowed regardless (dynamic active power limitation).
In addition to the dynamic limitation of PV generation, the Sunny Home Manager can also use intelligent energy management to ensure that loads in the household are switched on at precisely those times when so much PV energy is available that the feed-in limit will be reached. If switching on a load means that more power is consumed directly in the household, the PV generation must not be reduced by as much or must not be reduced at all.
| Limitation of the active power feed-in to 70% of the nominal PV system power |
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Due to high levels of solar irradiation, the system (system size: 10 kWp / feed-in limit: 7 kW) can currently produce 90% of the nominal PV system power.
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A Limiting of the active power feed-in can be entered as follows:
Limitation to a fixed value of the nominal system power in kW (setting range: 0 kW to 0.99 x nominal system power kW)
If there is also a limit due to external setpoints in addition to this setting, the limit is set to the smallest value.Limitation to a percentage of the nominal system power (setting range: 0% to 99%)
If there is also a limit due to external setpoints in addition to this setting, the limit is set to the smallest value.Zero export – blocks grid feed-in into the utility grid (setting: 0% or 0.000 kW of the nominal system power). Due to control cycle times, an inevitable remaining quantity of energy might nevertheless be fed into the utility grid.
External setpoints - the active power feed-in is only limited when this is required by external setpoints. Such limitations can come from various external sources, such as grid management services via Ethernet-based communication or a connected Moxa device.
This option can be activated in addition to a previously entered limiting value (in % or kW of the system power).
As a general rule, if there are several external specifications, the smallest value is used.
If a battery or hybrid inverter is part of your system, after a defined limit of the nominal system power (< 10 % of or the corresponding kW value of the system power) is set, you can include the battery or hybrid inverter in the energy management and use the surplus PV energy to charge the battery-storage system.
You can use a function test to check the limitation of the active power feed-in:
In the Limitation of active power feed-in section, click on the option button max. xx kW and enter the value 0. Thus, the Sunny Home Manager immediately limits the active power when the inverters starts feeding into the utility grid.
Supported inverters for the limitation of the active power feed-in to 0%
The limitation of the active power feed-in to 0% is only supported by inverters that support the fallback function. In the event of a communication failure between the Sunny Home Manager and the inverter, the inverter reverts to an output power of 0 watts. For more information see the inverter manual at www.SMA-Solar.com.
Procedure:
- In the area Limiting of the active power feed-in, select the applicable option:
- If limitation of active power feed-in is not required for your system, select no limiting of the active power feed-in (default setting).
- If limitation of active power feed-in is required for your system, you can fulfill this requirement as follows:
- If the grid operator requires limitation to a percentage of the nominal PV system power, select the option Max. xx % of the nominal PV system power and enter the required percentage.
- If the grid operator requires limitation to a maximum active power in kW, select the option max. xx kW and enter the maximum permitted active power in kW.
- If the grid operator requires limitation of the active power feed-in to 0% or 0 kW ("zero export"), enter the value 0 in the relevant option.
- If the active power feed-in is only to be limited when this becomes necessary due to external specifications, activate Only implement external specifications.
- If your system has a battery or hybrid inverter and you have set the nominal system power to a correspondingly low value, you can use the surplus PV energy to charge the battery-storage system. To do this, enable the option button Including the battery inverter.
- Click on [Save].
- The data is being transferred. This process can take up to 5 minutes. In the page and menu selection Energy balance > Day, the specified limitation of active power feed-in is displayed as a dotted red line in the diagram Generation.
- In the page and menu selection Energy balance > Day, the specified limitation of active power feed-in is displayed as a dotted red line in the diagram Generation.