Germany (VDE-AR-N 4120, draft summary) ride-through requirements

FNN/VDE 'Summary of the draft VDE-AR-N 4120:2017-05' (Forum Netztechnik/Netzbetrieb im VDE, May 2017). READ THIS BEFORE USING THE NUMBERS: it is a summary of a DRAFT (E VDE-AR-N 4120), it states on its own first page that it 'does not cover all parts of the VDE-AR-N 4120 and is therefore not exhaustive' and is 'purely informative', and it has since been superseded twice — by VDE-AR-N 4120:2018-11 and amendment A1:2024-04. Values may have changed on publication. Slide 19 (Type 1 modules, upper limit curve) read together with slide 21, whose prose states the surge requirement is 'unchanged compared to AR-N-4120-2015 (after 60s to U=1.15)'. The 1.25 pu level is corroborated a third time by the protection table on slide 48, where the generating-unit setting is U>> 1.25 UNS at 0.1 s. Published because three statements in the document agree, not because the chart alone was legible. Low-voltage ride-through is deliberately not included for this code. The LVRT curves exist only as chart images here, and two earlier candidate readings were wrong in ways worth naming: 4110 and 4120 LVRT curves that were byte-identical across different voltage levels, which no real code does, and a 'high-voltage' curve that was really a VDN-2004 voltage-relay setting. That second substitution is visible in this very document, which prints the relay table beside the curves — the tables are crisp and the curves are images, so the legible thing gets digitised. Protection settings say when a plant MAY disconnect; a ride-through envelope says when it MUST NOT. Plotting LVRT needs VDE-AR-N 4120:2018-11 itself, ideally with A1:2024-04.

FNN/VDE 'Summary of the draft VDE-AR-N 4120:2017-05' (Forum Netztechnik/Netzbetrieb im VDE, May 2017). READ THIS BEFORE USING THE NUMBERS: it is a summary of a DRAFT (E VDE-AR-N 4120), it states on its own first page that it 'does not cover all parts of the VDE-AR-N 4120 and is therefore not exhaustive' and is 'purely informative', and it has since been superseded twice — by VDE-AR-N 4120:2018-11 and amendment A1:2024-04. Values may have changed on publication. Slide 51, tabular: for VDE-AR-N 4120 (new), at or below 47.5 Hz isolation from the grid, between 47.5 and 51.5 Hz 'isolation not permitted', between 51.5 and 52.5 Hz isolation PERMITTED, and at 52.5 Hz isolation from the grid. Plotted here is the firm obligation only — the 47.5 to 51.5 Hz band, which carries no time limit. The 51.5 to 52.5 Hz shoulder is discretionary and is deliberately not drawn as a requirement. The matching generating-unit protection settings on the same slide are f< 47.5 Hz at 0.1 s, f> 51.5 Hz at up to 5 s, and f>> 52.5 Hz at 0.1 s. Low-voltage ride-through is deliberately not included for this code. The LVRT curves exist only as chart images here, and two earlier candidate readings were wrong in ways worth naming: 4110 and 4120 LVRT curves that were byte-identical across different voltage levels, which no real code does, and a 'high-voltage' curve that was really a VDN-2004 voltage-relay setting. That second substitution is visible in this very document, which prints the relay table beside the curves — the tables are crisp and the curves are images, so the legible thing gets digitised. Protection settings say when a plant MAY disconnect; a ride-through envelope says when it MUST NOT. Plotting LVRT needs VDE-AR-N 4120:2018-11 itself, ideally with A1:2024-04.

This row stops at the chart window, and the clause does not. One band here stops at a fixed time, while the clause above speaks of continuous operation across the same range — and the other band of the same row has no stated end. Where the chart and the clause disagree, the clause governs.