: Centralized protection is required for systems over 30 kVA to prevent islanding. Voltage Quality
: You can find official English versions of various application rules, guidelines, and info papers on the VDE FNN English Documents page . vde-ar-n 4105 english pdf
| Voltage at PCC | Required response time | Disconnection time | | :--- | :--- | :--- | | U < 195 V (0.85 p.u.) | Disconnect within 0.2 seconds | – | | 195 V ≤ U < 207 V (0.85–0.90 p.u.) | 10 seconds (limited power) | 10 seconds | | 207 V ≤ U ≤ 253 V (0.90–1.10 p.u.) | Normal operation | No disconnection | | 253 V < U ≤ 259.9 V (1.10–1.13 p.u.) | Reduce active power linearly | 0.2 seconds to disconnect | | U ≥ 264.5 V (1.15 p.u.) | Immediate disconnect | 0.1 seconds | : Centralized protection is required for systems over
While the full official standard is a paid document, several English translations and summaries are available for reference. Large systems may be required to remain connected
Large systems may be required to remain connected during brief voltage dips (Fault Ride Through) to prevent a cascading grid failure.