Frequency ride-through (FRT) compared across 45 grid codes

Every FRT envelope in the dataset

Frequency band is the full span between the low and high boundaries of the published envelope. It is read off the breakpoints in the same row, not quoted from the code, so treat it as a way to sort the table rather than as a value to put in a specification — the breakpoints are the published figure. Times are seconds from the start of the disturbance.

Last checked against the source documents on 25 July 2026.

Countries with no FRT envelope here

8 countries appear in this dataset for another event but carry no FRT row. Those are two different situations, and conflating them would turn a research backlog into a claim — so they are separated.

Not established either way

No FRT row here, and no finding that the code lacks one. The honest statement is that we have not established it — go to the code itself rather than reading this list as evidence of absence.

Chile · Colombia · France · Ireland · Italy · Netherlands · Poland · Spain

The reasoning for every checked absence, code by code, is on the grid codes with no ride-through curve.

The other two obligations

LVRT, HVRT and FRT are three separate duties. A code can define one and not the others, and meeting one says nothing about the other two.

• Low-voltage ride-through (LVRT)52 envelopes in the dataset, plotted against per-unit voltage.
• High-voltage ride-through (HVRT)33 envelopes in the dataset, plotted against per-unit voltage.