SMA SC 400HE - Manual (Page 47)

SMA Solar Technology AG 4 Sunny Central Control
Operating Manual SC4-63HE-BE-BEN103280 47
Calculating the power limit:
Formula: P
lim
= P
cur
– ( (f
power
– P-HzStr) * P-WGra * P
cur
)
4.7.9 Displaying the Status of the Active Power Limitation
The "P-WModStt" spot value displays the status of the active power limitation.
Displaying the Spot Value "P-WModStt"
• Select Spot Values > Red.effect.pow. > P-WModStt.
P
lim
Power limit P
cur
Current power
f
power
Power frequency P-HzStr Selected frequency limit which will
lead to reduction of feed-in power
P-WGra Gradient for reducing active
power
Example:
A Sunny Central with 500 kW is feeding 350 kW (P
cur
) into the power distribution grid. The
frequency will reach up to 51.2 Hz.
The difference between the current power frequency and P-HzStr (51.2 Hz - 50.2 Hz) multiplied by
the gradient "P-WGra" (40%/Hz) results in an active power reduction of 40% in the last available
power P
cur
(350 kW). This results in a power limitation of 140 kW and a maximum active power
of 210 kW.
Calculation:
210 kW = 350 kW – ( (51.2 Hz – 50.2 Hz) * 40%/Hz * 350 kW )
Used parameters P-HzStr
P-HzStop
P-WGra
Display Description
Off No procedure for limiting active power has been chosen.
WMax Active power is limited by the specified maximum limit. This limit is based on Pmax.
Hz Active power is limited by a frequency increase.
Tmp Active power is limited due to temperature derating.
AmpPv Active power is limited via PV power limitation.