ERCOT (NOG 2.9.1) — ride-through requirements

The LVRT, HVRT envelopes a grid-scale battery must meet under ERCOT (NOG 2.9.1) (US), 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
low-voltage ride-through (LVRT) ride-through 0.001s → 0 pu; 0.32s → 0 pu; 0.321s → 0.096 pu; 0.4s → 0.141 pu; 0.48s → 0.186 pu; 0.56s → 0.231 pu; 0.594s → 0.25 pu; 1.2s → 0.25 pu; 1.201s → 0.5 pu; 3s → 0.5 pu; 3.001s → 0.7 pu; 6s → 0.7 pu; 6.001s → 0.9 pu verified
high-voltage ride-through (HVRT) ride-through 0.001s → 1.2 pu; 1s → 1.2 pu; 1.001s → 1.1 pu verified

Where these values come from

  • LVRT ERCOT Nodal Operating Guides, Section 2.9.1.1 'Preferred Voltage Ride-Through Requirements for Transmission-Connected Inverter-Based Resources (IBRs)', paragraph (1), Table B: Applicable to PhotoVoltaic Generation Resources (PVGRs) and ESR IBRs, plus the following paragraph defining the sub-0.25 pu straight-line function ('0.15 seconds at zero voltage and 1.75 seconds at 0.9 p.u. voltage'). Source: February 1, 2026 ERCOT Nodal Operating Guide PDF (body dated DECEMBER 5, 2025), sheet pp. 52-54.
  • HVRT ERCOT Nodal Operating Guides Section 2.9.1(1)(a)/(b) (applicability by SGIA date, no MW threshold); Section 2.9.1.1(1) Tables A and B high-voltage rows (1.10<V<=1.20 -> 1.0 s; V>1.20 may ride-through or trip); Section 2.9.1.2(1) Table A (1.175<V<=1.2 -> 0.2 s; 1.15<V<=1.175 -> 0.5 s; 1.10<V<=1.15 -> 1.0 s). sheets pp. 50-55.

Last checked against the source document on .

Other grid codes in North America