SMA MEDIUM VOLTAGE POWER STATION 500SC-JP - Power Control

Insulation monitoring should be performed in the operating state "MPP load operation". This will ensure that all parts of
the system are included in the insulation measurement.
Insulation monitoring
To disable the grounding of the PV array, the parameter RemMntSvc must be set to On. This will open the
RemoteGFDI by means of a motor drive.
If the Remote GFDI has been opened by a motor drive via the parameter RemMntSvc, the insulation monitoring
device will start measuring after the waiting time defined in parameter IsoMeasDly has elapsed. This allows the
insulation monitoring device to determine the insulation resistance without interrupting feed-in operation. If an insulation
error is present, this will only be taken into account at the end of the waiting time.
Once the insulation monitoring process is complete, the parameter RemMntSvc should be set to Off, thus switching
the PV array into grounded operation.
If after approximately five minutes one of the errors 3501 ‒ Insulation Failure, 3504 ‒ Insulation failure ignored
or 3601 ‒ Warning insulation failure is displayed, the insulation is defective. In this case, a qualified person will
need to check and, if necessary, repair the insulation and then acknowledge the error.
Type of insulation monitoring device used
The insulation monitoring device used is the A-ISOMETERiso-PV1685 device supplied by BenderGmbH&Co.KG.
13.3 Power Control
13.3.1 Frequency-Dependent Active Power Limitation
With frequency-dependent active power limitation, 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 67: Power behavior of the inverter when the frequency limit P-HzStr is exceeded
If the power frequency exceeds a threshold defined in the parameter P‑HzStr, shown here at pointA, the inverter will
store 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 parameter P-WGra. 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 in point B, the last feed-in power value reached will remain valid. Only when the power
frequency falls below the threshold defined in the parameter P-HzStop, as shown here at pointC, can the feed-in
13 Function Description
SMA Solar Technology AG
System ManualMVPS22JP-SH-en-11190