050 Sungrow — CEI 0-21 Interface Protection
At a glance
- Severity
- FAULT STOP
- Domain
- MONITORING_COMM
- Reference standard
- CEI 0-21 (Ed. 2019) / Allegato A70
- Product / context
- Grid Protection Parameter Error
What it means
Verification and maintenance of interface protections according to the CEI 0-21 standard for LV-connected systems. Checking the protection relay trip thresholds (59.S1, 27.S1, 81>.S1, 81<.S1) and trip times.
Probable causes
- Protection thresholds accidentally modified during a maintenance intervention.
- Protection relay not updated to the latest CEI 0-21 requirements.
- Missed periodic protection verification (mandatory every 5 years per CEI 0-21).
- Relay firmware incompatible with the parameters required by the distribution operator.
Where to start
Access the interface protection relay (SPI) and read the currently set thresholds. Compare the values with the CEI 0-21 table (59.S1 = 1.10 Vn, 27.S1 = 0.85 Vn, 81>.S1 = 50.3 Hz, 81<.S1 = 49.7 Hz). Are the values compliant?
Full guided diagnosis in the app
The diagnostic tree for this fault has 7 guided steps with measurements, checks and resolutions. You'll find it in ElectraIQ, one of the four IndexOS apps: free, works offline.
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