ERCOT (NOG 2.9.1.2 legacy) ride-through requirements
Low-voltage ride-through, High-voltage ride-through for the United States. Every breakpoint below is read from the code itself, and carries the clause it came from — so you can check it, not just cite it.
What is the low-voltage ride-through envelope for ERCOT (NOG 2.9.1.2 legacy)?
The plant must ride through for any voltage that stays on or above this envelope. The envelope holds 0 pu from t = 0 to 150 ms; then ramps linearly from 0 pu at 150 ms to 0.9 pu at 1.75 s; then 0.9 pu from 1.75 s onward — the last band the envelope defines, with no stated end time.
The clause states this boundary as a line; intermediate points are interpolated between its stated vertices.
Applies to Transmission IBR with SGIA executed before 1 Aug 2024
| From | To | Voltage | Between the points |
|---|---|---|---|
| 0 | 150 ms | 0 pu | Held flat |
| 150 ms | 1.75 s | 0 → 0.9 pu | Ramps linearly |
| 1.75 s | no stated end | 0.9 pu | Held flat |
The clause this came from
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. The code defines a linear recovery ramp; the vertices are read from the clause and the chart draws the segment between them.
What is the high-voltage ride-through envelope for ERCOT (NOG 2.9.1.2 legacy)?
The plant must ride through for any voltage that stays on or below this envelope. The envelope holds 1.2 pu from t = 0 to 200 ms; then 1.175 pu from 200 ms to 500 ms; then 1.15 pu from 500 ms to 1 s; then 1.1 pu from 1 s onward — the last band the envelope defines, with no stated end time.
Every breakpoint is stated in the clause cited below.
Applies to Transmission IBR with SGIA executed before 1 Aug 2024
| From | To | Voltage | Between the points |
|---|---|---|---|
| 0 | 200 ms | 1.2 pu | Held flat |
| 200 ms | 500 ms | 1.175 pu | Held flat |
| 500 ms | 1 s | 1.15 pu | Held flat |
| 1 s | no stated end | 1.1 pu | Held flat |
The clause this came from
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.
Who does ERCOT (NOG 2.9.1.2 legacy) bind, and since when?
Transmission IBR with SGIA executed before 1 Aug 2024. Binds resources whose SGIA was executed before 1 Aug 2024.
These figures are a reading aid, not legal advice. Grid codes are reissued: verify against the current edition before you design to them.
Digitised operating parameters beyond ride-through — droop, reactive capability, operating ranges — are published for 36 of the 66 codes in this atlas, not yet for ERCOT (NOG 2.9.1.2 legacy). That is a gap on this site, not a statement that ERCOT (NOG 2.9.1.2 legacy) sets none — the atlas hub marks the codes that carry them.
Curve data last checked against the code on — 66 standards, 130 envelopes, published by bess.engineer under CC BY 4.0.
Questions this page answers about ERCOT (NOG 2.9.1.2 legacy)
- Does ERCOT (NOG 2.9.1.2 legacy) require ride-through, or only that the plant does not trip?
- Ride-through. Every envelope on this page is a performance duty the plant must meet, not a protection-setting no-trip boundary — they are different obligations. That is what these curves are; they are not everything ERCOT (NOG 2.9.1.2 legacy) contains. The requirement sentence under each chart says which side of the curve is the compliant one.
- Are the numbers on this page taken from ERCOT (NOG 2.9.1.2 legacy) itself?
- Yes. Every breakpoint is read from the code, and each envelope carries the clause it came from, quoted in full under its chart — so you can check the figure against the standard rather than cite it from this page.
- Which events are charted for ERCOT (NOG 2.9.1.2 legacy)?
- ERCOT (NOG 2.9.1.2 legacy) is charted here with 2 envelopes — low-voltage ride-through, high-voltage ride-through (LVRT, HVRT). No frequency envelope is charted here — check ERCOT (NOG 2.9.1.2 legacy) itself before concluding it sets none.
Ride-through, in context.
An envelope is a compliance boundary; understanding why it exists is a different question. The ride-through and grid-forming entries cover the engineering, and the Engineering Foundations course builds it from the physics up.
Also for the United States: ERCOT (NOG 2.6.2.1), IEEE 1547-2018 Cat III, IEEE 2800-2022, NERC PRC-024-4 (ERCOT), NERC PRC-024-4 (no-trip), NERC PRC-024-4 (Western), and 5 more