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.
Applies to: transmission connections — Generation and storage on the IESO-controlled grid.
Part of: the grid-code ride-through chart — compare this against 65 other standards in 44 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. These are the boundaries, not the behaviour: what holding one demands of the converter — reactive current injection, thermal stress, protection timing — is stepped through in the LVRT / HVRT ride-through visual.
| Event | Duty | Breakpoints | Status |
|---|---|---|---|
| frequency ride-through (FRT) | ride-through | High: 0.1s → 61.8 Hz; 8s → 61.8 Hz; ↗ 10.3s → 61.73 Hz; ↗ 13.3s → 61.659 Hz; ↗ 17.2s → 61.587 Hz; ↗ 22.2s → 61.516 Hz; ↗ 28.6s → 61.446 Hz; ↗ 36.9s → 61.375 Hz; ↗ 47.6s → 61.304 Hz; ↗ 61.3s → 61.234 Hz; ↗ 79.1s → 61.163 Hz; ↗ 102s → 61.092 Hz; ↗ 131s → 61.023 Hz; ↗ 169s → 60.952 Hz; ↗ 218s → 60.881 Hz; ↗ 281s → 60.811 Hz; ↗ 363s → 60.74 Hz; ↗ 468s → 60.669 Hz; ↗ 600s → 60.6 Hz | Low: 0.1s → 57 Hz; 3.3s → 57 Hz; ↗ 4.3s → 57.117 Hz; ↗ 5.6s → 57.235 Hz; ↗ 7.3s → 57.352 Hz; ↗ 9.5s → 57.469 Hz; ↗ 12.4s → 57.587 Hz; ↗ 16s → 57.7 Hz; ↗ 21s → 57.821 Hz; ↗ 27s → 57.932 Hz; ↗ 35s → 58.047 Hz; ↗ 46s → 58.168 Hz; ↗ 60s → 58.286 Hz; ↗ 78s → 58.403 Hz; ↗ 101s → 58.517 Hz; ↗ 132s → 58.636 Hz; ↗ 172s → 58.753 Hz; ↗ 224s → 58.87 Hz; ↗ 300s → 59 Hz | verified |
Where these values come from
- FRTIESO Renewed Market Rules, Chapter 4 'Grid Connection Requirements - Appendices', Library Record No. RUL-12, Issue 2.0, Effective December 3, 2025; Appendix 4.2, Category 1 'Off-Nominal Frequency Operation' - continuous 59.4-60.6 Hz, plus the log-linear regions bounded by (0.0 s, 57.0 Hz), (3.3 s, 57.0 Hz), (300 s, 59.0 Hz) and by (0.0 s, 61.8 Hz), (8 s, 61.8 Hz), (600 s, 60.6 Hz). Boundary is a continuous log-linear ramp; the plotted staircase is a conservative inner approximation of it.
Read it yourself: IESO Market Rules Chapter 4 ↗
Any event not in the table above is not plotted for this code. Where an absence is itself the finding — a code that defines no high-voltage envelope, or one whose curves circulate under another country's name — it is recorded in the grid codes with no ride-through curve.
Last checked against the source document on .
How Canada compares
Each event this code defines, put side by side with every other code that defines it:
- Frequency ride-through (FRT) across 45 codesWhere Ontario (IESO Market Rules App. 4.2) sits against every other published FRT envelope.
Other grid codes in North America
- California Rule 21US · FRT, HVRT, LVRT
- Canada (Alberta AESO)Canada · FRT, HVRT, LVRT
- ERCOT (NOG 2.6.2.1)US · FRT
- ERCOT (NOG 2.9.1.2 legacy)US · HVRT, LVRT
- ERCOT (NOG 2.9.1)US · HVRT, LVRT
- IEEE 1547-2018 Cat IIIUS · FRT, HVRT, LVRT
- IEEE 2800-2022US · FRT, HVRT, LVRT
- Mexico (Codigo de Red)Mexico · FRT, HVRT, LVRT
- NERC PRC-024-4 (ERCOT)US · FRT
- NERC PRC-024-4 (no-trip)US · HVRT, LVRT
- NERC PRC-024-4 (Western)US · FRT
- NERC PRC-029-1 (IBR)US · FRT, HVRT, LVRT