Event numbers 77, 7701, 7702 and 7703 indicate a problem related to the relay test.
Before connecting to the grid, the inverter checks the grid relays and monitors the grid quality. Only if all test results are positive, the relays are switched and the inverter connects to the grid.
For all 3-phase inverters (STP): Especially in new installations, (but also in existing installations, depending on the grid quality on site) the error often appears in connection with a shifted neutral point / star point. This can be caused by larger consumers on the grid, for example air conditioners, pumps, large motors and lifts or by a faulty installation.
Therefore, it is advisable to check the installation with regard to the correct connection of neutral conductor and PE (grounding), not only at the inverter connection but also in the sub-distribution and main distribution, and – depending on the plant size and system configuration – possibly also on the grid / plant transformer.
Special cases: For all Sunny Boy (SB) inverters and for the Sunny Tripower (STP) of the type STP 20000TLEE-10, STP 20000TL-30, STP 24000TLUS-10 and STP xx000TLEE-JP-10/11:
Please clarify the corrective action with the SMA Service before you check the AC installation.
Corrective measures:
If you are the system operator, please contact your installer.
| DANGER! The tasks described below may only be performed by Electrically Qualified Persons: |
- Check the complete AC installation by measurement, visual and mechanical inspection for neutral and grounding problems:
- AC-connections of the Sunny Tripower
- Sub-distribution and Main Distribution
- depending on the system configuration: if necessary also the grid / plant transformer (depending on the plant size, plant configuration and plant location (installation country))
- In many cases, it turned out that large electric consumer loads (air conditioners, pumps, large motors, lifts, …) have been the cause for shifted neutral points. If that might be the case in the affected plant, check the installation at the according time.
- Check that a suitable load disconnection unit has been installed:
Do not use screw-type fuses (e.g. DIAZED or NEOZED fuse) as load-break switches! Screw-type fuses cause damage to the inverter! Use a load-break switch or circuit breaker as a load disconnection unit.
See the inverter’s operating / installation manual and the technical information “Circuit Breaker” - Check the AC installation for loose terminals, damaged fuses, etc..
If, however, the message keeps on appearing, even though the AC installation has been checked by a skilled person, the cause and corrective action must be clarified by SMA Service.
In this case, please contact the SMA Service
with the following information:
- Device type and serial number of the Inverter
- Installation date
- Event number
- How long has the error been present for now? Is it sporadic or continuous?
- Are screw-type fuses used as load disconnection units in the installation?
- Are large electric consumer loads in or near the installation?
- After the check of the AC installation, is a faulty installation (loose cables, damaged fuses,…) ruled out as the cause?
- Grid form: TN-C grid, TT-gid, …
- Measurement results of the N-PE, L-N, L-PE, L-L voltages:
- AC-Terminal of Sunny Tripower: N – PE = _______
- AC-Terminal of Sunny Tripower: L1 – N, L2 – N, L3 – N = _______ _______ _______
- AC-Terminal of Sunny Tripower: L1 – L2, L1 – L3, L2 – L3 = _______ _______ _______
- AC-Terminal of Sunny Tripower: L1 – PE, L2 – PE, L3 – PE = _______ _______ _______
- Sub-Distribution: N – PE = _______
- Sub-Distribution: L1 – N, L2 – N, L3 – N = _______ _______ _______
- Sub-Distribution: L1 – L2, L1 – L3, L2 – L3 = _______ _______ _______
- Sub-Distribution: L1 – PE, L2 – PE, L3 – PE = _______ _______ _______
- Main Distribution: N – PE = _______
- Main Distribution: L1 – N, L2 – N, L3 – N = _______ _______ _______
- Main Distribution: L1 – L2, L1 – L3, L2 – L3 = _______ _______ _______
- Main Distribution: L1 – PE, L2 – PE, L3 – PE = _______ _______ _______
- if measured: Grid Transformer: N – PE = _______
- if measured: Grid Transformer: L1 – N, L2 – N, L3 – N = _______ _______ _______
- if measured: Grid Transformer: L1 – L2, L1 – L3, L2 – L3 = _______ _______ _______
- if measured: Grid Transformer: L1 – PE, L2 – PE, L3 – PE = _______ _______ _______