SMA SC 200 - Manual (Page 57)

SMA Solar Technology AG Active Power Limitation
User Manual SC-BEN100262 57
10.2 Active Power Limitation via Grid Frequency
The downward regulation of active power via the grid frequency is based on the available power at
the start time of the downward regulation. If the grid frequency exceeds a certain threshold defined
by you (P-HzStr), for example 50.2 Hz, the Sunny Central saves the feed-in power value at that
moment in time. Depending on grid frequency, the saved value defines the power limit. The gradient
of the limit can be set via the P-WGra parameter (standard = 40 %). Should the grid frequency drop,
the last power limit reached remains in effect. Increasing the feed-in power is only permissible when
grid frequency drops below, for example, 50.05 Hz (P-HzStop).
Example:
A Sunny Central with 500 kW capacity is currently feeding 350 kW (P
mom
) into the public grid. The
frequency rises to 51.2 Hz. From the difference between the current grid frequency and P-HzStr
(51.2 Hz - 50.2 Hz) multiplied by the gradient P-WGra (40 %) we arrive at a reduction of active
power by 40 % of the last available power P
mom
(350 kW). This results in a power limitation of
140 kW and a maximum active power of 210 kW.
Formula: P
Grenz
= P
mom
– ( ( (f
Netz
– P-HzStr) / Hz) * P-WGra * P
mom
)
P
Grenz
= limit power
P
mom
= current power
Calculation for this example:
210 kW = 350 kW – ( (51.2 – 50.2) * 40 % * 350 kW )
Deactivating active power limitation via grid frequency
If you wish to deactivate the active power limitation via grid frequency, please contact
Sunny Central Service.
P-HzStop
Frq
Pac
P-WGra
P-HzStr
Hz
%
Δ