SMA SC 500CP XT - Manual (Page 62)

6.5 Changing the Insulation Monitoring
6.5.1 Insulation Monitoring with GFDI and Insulation Monitoring Device
6.5.1.1 Safety during Insulation Monitoring of the PV Power Plant with GFDI and
Insulation Monitoring Device
Danger to life from electric shock due to live voltage
High voltages are present in the conductive components of the inverter. Touching live components results in death or
serious injury due to electric shock.
• After switching off the inverter, wait at least 15 minutes before opening it to allow the capacitors to discharge
completely.
• Wear suitable personal protective equipment for all work on the product.
• All work must be carried out in accordance with this document. All safety information must be observed.
• Do not touch any live components of the inverter or the medium-voltage grid. Comply with all applicable safety
regulations for handling medium-voltage grids.
Ground-fault monitoring with GFDI does not provide protection from personal injury.
The order option "GFDI and insulation monitoring device" allows you to manually switch the PV power plant from
grounded operation to insulated operation. To ensure that there is no insulation error on the grounded terminal, an
insulation measurement is carried out. After switching to insulated operation, the insulation monitoring device checks all
poles of the PV power plant for potential insulation errors. Switching to insulated operation is useful for performing
maintenance or service work on or near the PV power plant (e.g. cutting the grass) or for checking the status of the
insulation at regular intervals. After completion of the maintenance work, the PV power plant must be switched back to
grounded operation.
6.5.1.2 Switching to Insulated Operation
1. Turn the key switch to Stop.
2. Wait 15 minutes before opening the inverter. This will ensure that the capacitors are discharged.
3. Disconnect the circuit breaker of the GFDI manually.
4. Close the inverter.
5. Turn the key switch to Start.
☑ The insulation monitoring device starts collecting data. If the parameter IsoErrIgn is set to On, the error
3504 ‒ Insulation failure ignored is displayed.
✖ After 15 minutes, the displayed error 3504 does not disappear?
The insulation is defective.
• Have the insulation checked and, if necessary, repaired by a qualified person.
• Acknowledge the error.
6. Log into the user interface (see Section 9.4.1, page 81).
7. Wait a few minutes and then call up the instantaneous value Riso on the user interface.
☑ The insulation resistance is greater than 45 kΩ. It is safe to enter the PV system.
✖ The insulation resistance is less than 45 kΩ?
There is an insulation error and you must not enter the PV system.
• Have the insulation checked and, if necessary, repaired by a qualified person.
6 Operation SMA Solar Technology AG
User Manual SCCPXT-BA-E4-en-54 62