ERCOT (NOG 2.9.1.2 legacy) — ride-through requirements

The LVRT, HVRT envelopes a grid-scale battery must meet under ERCOT (NOG 2.9.1.2 legacy) (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; 0.15s → 0 pu; 0.35s → 0.1125 pu; 0.55s → 0.225 pu; 0.75s → 0.3375 pu; 0.95s → 0.45 pu; 1.15s → 0.5625 pu; 1.35s → 0.675 pu; 1.55s → 0.7875 pu; 1.75s → 0.9 pu verified
high-voltage ride-through (HVRT) ride-through 0.001s → 1.2 pu; 0.2s → 1.2 pu; 0.201s → 1.175 pu; 0.5s → 1.175 pu; 0.501s → 1.15 pu; 1s → 1.15 pu; 1.001s → 1.1 pu verified

Where these values come from

  • LVRT ERCOT Nodal Operating Guides Section 2.9.1.2 (applies where the SGIA was executed before 1 Aug 2024): V=0 to 0.15 s then the defined ramp V(t)=0.5625t-0.084375 reaching 0.90 pu at 1.75 s.
  • HVRT ERCOT Nodal Operating Guides Section 2.9.1.2 high-voltage table: 1.20 pu / 0.2 s, 1.175 pu / 0.5 s, 1.15 pu / 1.0 s, then 1.10 pu.

Last checked against the source document on .

Other grid codes in North America