Grid Management Services; Requirements For Grid Management Services; Dynamic Grid Support (Frt); Full And Limited Dynamic Grid Support (Frt) - SMA SUNNY CENTRAL 500CP XT User Manual

10 Function Description
10.5

Grid Management Services

10.5.1 Requirements for Grid Management Services

Due to the growing number of PV power plants feeding into the utility grid, these PV power plants increasingly have to
take on feed-in management functions. In Germany, for example, they are obliged to offer grid management services.
First and foremost, the grid operator must be able to limit the power of the PV power plant by remote control and
temporarily reduce it to zero in critical cases. The relevant control commands of the grid operator must therefore be
transmitted to the inverters quickly and reliably and implemented accordingly. The following figure shows how the
specifications of the grid operator are implemented. The specifications of the grid operator are sent to the inverters by
the Power Reducer Box or the Power Plant Controller.
Figure 41: Principle of grid integration
As an alternative to the Power Reducer Box or Power Plant Controller, there are two other ways of enabling grid
management services:
• Reception of signals via two analog inputs on the inverter
• Manual adjustment of the specifications via parameters on the inverter

10.5.2 Dynamic Grid Support (FRT)

10.5.2.1 Full and Limited Dynamic Grid Support (FRT)

With dynamic grid support (Fault Ride Through ‒ FRT), the inverter supports the utility grid during a brief grid-voltage
dip (Low Voltage Ride Through ‒ LVRT) or during a short period of overvoltage (High Voltage Ride Through ‒ HVRT).
With full dynamic grid support, grid support is ensured by feeding in reactive current.
With limited dynamic grid support, the inverter interrupts grid feed-in during a grid instability without disconnecting
from the utility grid.
Q at Night and dynamic grid support
Limited dynamic grid support is available in the operating state "Q at Night".
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