Ontario (IESO Market Rules App. 4.2) — ride-through requirements

The FRT envelope a grid-scale battery must meet under Ontario (IESO Market Rules App. 4.2) (Canada), digitized breakpoint by breakpoint and checked against the clause it came from.

By Sergey Syrvachev — Director of Product Engineering, grid-scale BESS · 10+ GWh delivered

Part of: the grid-code ride-through chart — compare this against 63 other standards in 42 countries.

What this is, and is not. A reading aid compiled from the clause cited below — not a compliance document. The primary text governs. Every value here was read from a current primary source.

Breakpoints

Times are seconds from the start of the disturbance. Voltage is per-unit of nominal; frequency in hertz. An LVRT curve is a lower boundary (stay connected while voltage is on or above it), an HVRT curve an upper boundary, and FRT gives the band between its High and Low boundaries.

Event Duty Breakpoints Status
frequency ride-through (FRT) ride-through High: 0.1s → 61.8 Hz; 23.5s → 61.8 Hz; 23.501s → 61.5 Hz; 69s → 61.5 Hz; 69.001s → 61.2 Hz; 204s → 61.2 Hz; 204.001s → 60.9 Hz; 600s → 60.9 Hz; 600.001s → 60.6 Hz | Low: 0.1s → 57 Hz; 10.2s → 57 Hz; 10.201s → 57.5 Hz; 31.5s → 57.5 Hz; 31.501s → 58 Hz; 97s → 58 Hz; 97.001s → 58.5 Hz; 300s → 58.5 Hz; 300.001s → 59.4 Hz verified

Where these values come from

  • FRT IESO Renewed Market Rules, Chapter 4 'Grid Connection Requirements - Appendices', Library Record No. RUL-12, Issue 2.0, Effective December 3, 2025; Appendix 4.2 'Requirements for Generation and Electricity Storage Facilities Connected to the IESO-Controlled Grid', Category 1 'Off-Nominal Frequency Operation'. Verified from the IESO-hosted PDF (ieso-mr-chapter0-4-appx.pdf), text extracted directly.

Last checked against the source document on .

Other grid codes in North America