Nigeria (TCN Grid Code) ride-through requirements

Low-voltage ride-through, High-voltage ride-through, Frequency ride-through for Nigeria. Every breakpoint below is read from the code itself, and where a point was taken off a published figure rather than stated in the clause, the section under that chart says so — an envelope that stops where its published chart stops or an envelope the source only partly defines.

3Envelopes
LVRT · HVRT · FRTEvents
Transmission Connection level
LVRT

What is the low-voltage ride-through envelope for Nigeria (TCN Grid Code)?

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 0.85 pu at 2 s; then 0.85 pu from 2 s, plotted to 20 s.

The clause states this boundary as a line; intermediate points are interpolated between its stated vertices. The envelope stops where the published chart stops; the code states no end time.

Applies to Power Park Modules on the TCN transmission system

Nigeria (TCN Grid Code) — low-voltage ride-through envelopeNigeria (TCN Grid Code) low-voltage ride-through envelope. The plant must ride through for any voltage that stays on or above the line; below it, the envelope no longer applies. Logarithmic time axis from 0.01 s to 30 s; linear voltage axis in per-unit. The first band applies from the instant of the event (t = 0). The envelope holds 0 pu from t = 0 to 150 ms; then ramps linearly from 0 pu at 150 ms to 0.85 pu at 2 s; then 0.85 pu from 2 s, plotted to 20 s. Stops where the published chart stops — the code states no end time.Nigeria (TCN Grid Code) — low-voltage ride-through envelopeStops where the published chart stops — the code states no end timenominal 1.00 pu0.010.11100.000.200.400.600.801.001.20Time from event start (s, log scale) · first band applies from t = 0Voltage (pu)0.85 puplotted to 20 sMUST RIDE THROUGHmust ride through on or above the lineends at the plotted window, not a stated limit
Low-voltage ride-through envelope for Nigeria (TCN Grid Code). Time runs on a logarithmic axis, so the ramp — a straight line in real time — only looks curved here. Scroll the chart sideways for the rest of the time axis →
Low-voltage ride-through breakpoints for Nigeria (TCN Grid Code)
From To Voltage Between the points
0 150 ms 0 pu Held flat
150 ms 2 s 0 → 0.85 pu Ramps linearly
2 s plotted to 20 s 0.85 pu Held flat
The clause this came from

The Grid Code for the Nigeria Electricity Transmission System, NERC, published 01-08-2018 (cover 'Version 03', page footers 'Version 02'), clause 12.6.9(a)-(c) and Figure 1 'Voltage Fault Ride Through requirement for Power Park Modules' (p.63); Vmin from Table 1, subsection 10.1.5 (p.47).

HVRT

What is the high-voltage ride-through envelope for Nigeria (TCN Grid Code)?

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 2 s; then 1.1 pu from 2 s onward — the last band the envelope defines, with no stated end time.

Covers only the part of the envelope the source defines.

Applies to Power Park Modules on the TCN transmission system

Nigeria (TCN Grid Code) — high-voltage ride-through envelopeNigeria (TCN Grid Code) high-voltage ride-through envelope. The plant must ride through for any voltage that stays on or below the line; above it, the envelope no longer applies. Logarithmic time axis from 0.1 s to 10 s; linear voltage axis in per-unit. The first band applies from the instant of the event (t = 0). The envelope holds 1.2 pu from t = 0 to 2 s; then 1.1 pu from 2 s onward — the last band the envelope defines, with no stated end time (drawn as an open dashed tail). The source defines only part of this envelope.Nigeria (TCN Grid Code) — high-voltage ride-through envelopeThe source defines only part of this envelopenominal 1.00 pu0.11100.20.5250.951.001.051.101.151.201.25Time from event start (s, log scale) · first band applies from t = 0Voltage (pu)1.1 puMUST RIDE THROUGHmust ride through on or below the lineopen — no stated end time
High-voltage ride-through envelope for Nigeria (TCN Grid Code). Time runs on a logarithmic axis. Scroll the chart sideways for the rest of the time axis →
High-voltage ride-through breakpoints for Nigeria (TCN Grid Code)
From To Voltage Between the points
0 2 s 1.2 pu Held flat
2 s no stated end 1.1 pu Held flat
The clause this came from

Nigeria Grid Code (NERC, 01-08-2018), clause 12.6.9(d) and Figure 1 HVRT limb; Vmax from Table 1, subsection 10.1.5.

FRT

What is the frequency ride-through envelope for Nigeria (TCN Grid Code)?

The plant must ride through between the upper and lower bands. The upper (over-frequency) band holds 51.75 Hz from t = 0 to 15 s; then 51.5 Hz from 15 s onward — the last band the envelope defines, with no stated end time. The lower (under-frequency) band holds 47.5 Hz from t = 0, plotted to 15 s.

The lower band stops where the published chart stops; the code states no end time.

Applies to Power Park Modules on the TCN transmission system

Nigeria (TCN Grid Code) — frequency ride-through envelopeNigeria (TCN Grid Code) frequency ride-through envelope. The plant must ride through for any frequency that stays between the lower and upper bands. Logarithmic time axis from 1 s to 50 s; linear frequency axis in hertz. The first band applies from the instant of the event (t = 0). upper (over-frequency) band: holds 51.75 Hz from t = 0 to 15 s; then 51.5 Hz from 15 s onward — the last band the envelope defines, with no stated end time (drawn as an open dashed tail). lower (under-frequency) band: holds 47.5 Hz from t = 0, plotted to 15 s. The lower band stops where the published chart stops — the code states no end time.Nigeria (TCN Grid Code) — frequency ride-through envelopeThe lower band stops where the published chart stops — the code states no end timenominal 50 Hz110252047484950515253Time from event start (s, log scale) · first band applies from t = 0Frequency (Hz)51.5 Hz47.5 Hzplotted to 15 sMUST RIDE THROUGHUpper band (over-frequency)Lower band (under-frequency)must ride through between the bandsopen — no stated end timeends at the plotted window, not a stated limit
Frequency ride-through envelope for Nigeria (TCN Grid Code). Time runs on a logarithmic axis. The shading stops where the shorter band’s data ends; the other band continues, as the table shows. Scroll the chart sideways for the rest of the time axis →

Upper limit

Frequency ride-through breakpoints for Nigeria (TCN Grid Code) — Upper limit
From To Frequency Between the points
0 15 s 51.75 Hz Held flat
15 s no stated end 51.5 Hz Held flat

Lower limit

Frequency ride-through breakpoints for Nigeria (TCN Grid Code) — Lower limit
From To Frequency Between the points
0 plotted to 15 s 47.5 Hz Held flat
The clause this came from

Nigeria Grid Code (NERC, 01-08-2018), clause 12.6.5 (corroborated by clause 10.1.4).

Scope

Who does Nigeria (TCN Grid Code) bind, and since when?

Power Park Modules on the TCN transmission system. No date of effect is published here — grid codes are reissued, so check the current issue before relying on it.

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 Nigeria (TCN Grid Code). That is a gap on this site, not a statement that Nigeria (TCN Grid Code) 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

Questions this page answers about Nigeria (TCN Grid Code)

Does Nigeria (TCN Grid Code) 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 Nigeria (TCN Grid Code) 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 Nigeria (TCN Grid Code) itself?
Every breakpoint is read from the code, and where a point was taken off a published figure rather than stated in the clause, the section under that chart says so — on this page that includes an envelope that stops where its published chart stops or an envelope the source only partly defines. The clause each curve came from is quoted under it.
Which events are charted for Nigeria (TCN Grid Code)?
Nigeria (TCN Grid Code) is charted here with 3 envelopes — low-voltage ride-through, high-voltage ride-through, frequency ride-through (LVRT, HVRT, FRT).
Related

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.

Elsewhere in Africa: Kenya (KNTGC VRPP), Morocco (CRENT), South Africa (NRS 097 / RPP)

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