NERC PRC-029-1 (Table 1: AC-connected wind IBR /…) — ride-through requirements

The LVRT envelope a grid-scale battery must meet under NERC PRC-029-1 (Table 1: AC-connected wind IBR /…) (US), digitized breakpoint by breakpoint and checked against the clause it came from.

By Sergey Syrvachev — Director of Product Engineering at HyperStrong

Applies to: transmission connections — AC-connected wind IBR on the BES (per Attachment 1 note 1).

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. Enforceable from 1 Oct 2026 (FERC Order No. 909).

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.

EventDutyBreakpointsStatus
low-voltage ride-through (LVRT)ride-through0.001s → 0 pu; 0.16s → 0 pu; 0.161s → 0.25 pu; 1.2s → 0.25 pu; 1.201s → 0.5 pu; 2.5s → 0.5 pu; 2.501s → 0.7 pu; 3s → 0.7 pu; 3.001s → 0.9 puverified

Where these values come from

  • LVRTNERC Reliability Standard PRC-029-1, Attachment 1, Table 1 ("Voltage Ride-through Requirements for AC-Connected Wind IBR"), p.12; applicability per Attachment 1 note 1. FERC Order No. 909, RM25-3-000; effective 1 Oct 2026.

Read it yourself: NERC PRC-029-1 (PDF) ↗

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 US compares

Each event this code defines, put side by side with every other code that defines it:

Other grid codes in North America