IEEE 1547-2018 Cat III — ride-through requirements

The LVRT, HVRT, FRT envelopes a grid-scale battery must meet under IEEE 1547-2018 Cat III (US), digitized breakpoint by breakpoint and checked against the clause it came from.

By Sergey Syrvachev — Director of Product Engineering at HyperStrong

Applies to: distribution connections — DER at the distribution PCC, Category III abnormal performance. Values read from an authorised reproduction of a paywalled standard.

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.

EventDutyBreakpointsStatus
low-voltage ride-through (LVRT)ride-through0.001s → 0 pu; 1s → 0 pu; 1.001s → 0.5 pu; 10s → 0.5 pu; 10.001s → 0.7 pu; 20s → 0.7 pu; 20.001s → 0.88 puverified
high-voltage ride-through (HVRT)ride-through0.001s → 1.2 pu; 12s → 1.2 pu; 12.001s → 1.1 puverified
frequency ride-through (FRT)ride-throughHigh: 0.1s → 61.8 Hz; 299s → 61.8 Hz; 299.001s → 61.2 Hz | Low: 0.1s → 57 Hz; 299s → 57 Hz; 299.001s → 58.8 Hzverified

Where these values come from

  • LVRTIEEE 1547-2018 Table 16 / Figure H.4 ride-through capability regions, reproduced under IEEE copyright permission in EPRI's 'Crash Course: IEEE Std 1547-2018' (slide 47, 'Actual Abnormal Voltage Requirements for Category III'): momentary-cessation capability box 0.00–0.50 pu ending at 1 s; mandatory-operation capability 0.50–0.70 pu to 10 s and 0.70–0.88 pu to 20 s. Same regions in the MISO Guideline for IEEE Std 1547-2018 Implementation, Figure 4 (Category III), p.26. Independently confirmed in EPRI's reference implementation OpenDER (src/opender/operation_status/rt_crit.py, CAT_III branch): 0.7≤V<0.88 → pass at t>20 s; V<0.7 → t>10 s; V≤0.5 → t>1 s. Operating-mode bands also confirmed by the ISO-NE/Massachusetts TSRG 'Default IEEE 1547-2018 Setting Requirements' Table V (V<0.50 Momentary Cessation; 0.5≤V<0.88 Mandatory Operation; 'Identical' to 1547-2018 Cat III).
  • HVRTIEEE 1547-2018 Category III ride-through capability figure (IEEE copyright, adapted/reprinted with permission) in EPRI's 'Crash Course: IEEE Std 1547-2018', slide 47: the orange 'Momentary Cessation Capability' region spans 1.10–1.20 pu and terminates at 12 s. Same 12 s edge in MISO Guideline for IEEE Std 1547-2018 Implementation Figure 4 (Category III), p.26. Confirmed in EPRI OpenDER rt_crit.py: CAT_III high-voltage branch is a single test 'if 1.1 < v_high … if rt_time_hv <= 12: rt_pass_time_req = True' (12 s), whereas the CAT_I/CAT_II branches contain exactly the published 1.15→1 s / 1.175→0.5 s / 1.20→0.2 s ladder.
  • FRTIEEE 1547-2018 Table 19, reproduced verbatim in the ISO-NE / Massachusetts TSRG 'Default IEEE 1547-2018 Setting Requirements' Table II ('Frequency ride-through requirements for DER of abnormal operating performance-Category I, Category II, and Category III': f > 62.0 no ride-through; 61.2 < f ≤ 61.8 Mandatory Operation; 58.8 ≤ f ≤ 61.2 Continuous; 57.0 ≤ f < 58.8 Mandatory Operation; f < 57.0 no ride-through — each marked 'Identical' to 1547-2018). Duration confirmed by EPRI OpenDER rt_crit.py (299 s timers at 61.2–61.8 Hz and 57.0–58.8 Hz) and by the '299 s' annotation on the IEEE-copyright frequency figure in the EPRI 1547-2018 crash course (slide 48). Trip-side coordination: 1547-2018 defaults OF2 62.0 Hz/0.16 s, OF1 61.2 Hz/300 s, UF1 58.5 Hz/300 s, UF2 56.5 Hz/0.16 s (MISO Guideline Table 6).

Read it yourself: NERC reliability guideline on IEEE 1547-2018 (PDF) ↗

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