SMA SC 500CP-US-10 600V - Manual (Page 52)

7 Active Power Limitation SMA America, LLC
52 SCCP-US-BE-US_en-52 Operating Manual
7 Active Power Limitation
The inverter can limit its active power if requested by the grid operator. The limitation of the active power can be
performed both dependent on the power frequency and independent of the frequency.
The frequency-dependent active power limitation is regulated in accordance with the specifications of IEEE 1547 and
cannot be changed. This Section describes the function and parameterization of both types of active power limitation.
7.1 Power Frequency-Dependent Active Power Limitation
In addition to the procedures for active power limitation that can be chosen using the P-WMod parameter, active power
can be limited dependent on the power frequency.
During active power limitation via the power frequency, the inverter constantly checks the connected power frequency.If
the active power is to be limited by a hysteresis, the parameter WCtlHzMod must be set to CurveHys.
Figure 21: Inverter behavior when exceeding the P-HzStr frequency limit
If the power frequency exceeds a limiting value defined in the parameter P-HzStr, shown here under point A,
the inverter will save the current feed-in power P
cur
. The reduced feed-in power is calculated based on this saved value.
The reduction of the feed-in power is defined via the P-WGra parameter. This parameter indicates the percentage of the
saved power P
cur
by which the power per Hz will be reduced if the power frequency continues to rise.
If the power frequency decreases again as shown here under point B, the last feed-in power reached will remain valid.
Only if the power falls below the limiting value defined in the parameter P-HzStop, shown here in point C, can the
amount of power fed in be increased again. The saved value P
cur
will be rendered invalid. In addition, a minimum
threshold for power frequency shortfall can be defined with the parameter P-HzStopMin, shown here at point D.
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Operation failure of the inverter due to incorrectly set parameters
If the parameter settings for grid management services are incorrect, the inverter may not be able to meet the grid
management requirements. This may lead to yield losses and disconnection of the inverter by the grid operator.
• When setting the mode of grid management services, ensure that the control procedures are parameterized as
agreed with the grid operator.
•