SMA SC 500CP XT - Manual (Page 94)

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.
10.2.4 Low-Temperature Option
With the "low-temperature option", the operating temperature range is extended to the following range:
−40°C to +62°C. The inverter is in feed-in operation until the switch-off threshold is exceeded. The temperature of the
switch-off threshold is: −25°C.
If the ambient temperature falls below the switch-off threshold, the inverter goes into the operating state "Stop" and the
supplementary heating element is activated. As soon as the temperature exceeds the switch-on threshold again, the
inverter resumes feed-in operation. The temperature of the switch-on threshold is: −20°C.
10.3 Power Control
10.3.1 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 22: Power behavior of the inverter when the frequency limit P-HzStr is exceeded
10 Function Description SMA Solar Technology AG
User Manual SCCPXT-BA-E4-en-54 94