Singapore (EMA Transmission Code App. F6) ride-through requirements
Frequency ride-through for Singapore. 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.
What is the frequency ride-through envelope for Singapore (EMA Transmission Code App. F6)?
The plant must ride through between the upper and lower bands. The upper (over-frequency) band holds 52 Hz from t = 0, plotted to 60 min. The lower (under-frequency) band holds 47 Hz from t = 0 to 20 s; then 47.5 Hz from 20 s onward — the last band the envelope defines, with no stated end time. Correction: one band here stops at the published chart’s window while the clause quoted below states continuous operation across the same range — where the two disagree, the clause governs.
Covers only the part of the envelope the source defines. The last band has no stated end time. The clause below states a continuous region — highlighted; check which band it covers, because it is not always the last one. The upper band stops where the published chart stops; the code states no end time.
Applies to Generating units and ESS on the SG transmission system
Upper limit
| From | To | Frequency | Between the points |
|---|---|---|---|
| 0 | plotted to 60 min | 52 Hz | Held flat |
Lower limit
| From | To | Frequency | Between the points |
|---|---|---|---|
| 0 | 20 s | 47 Hz | Held flat |
| 20 s | no stated end | 47.5 Hz | Held flat |
The clause this came from
Energy Market Authority of Singapore, Transmission Code, 26 September 2024, Appendix F, section F6.1–F6.2 'Frequency Range of Generating Unit' (p.79): F6.1 normal 49.5–50.5 Hz, exceptional rise to 52 Hz / fall to 47 Hz; F6.2 table — '52 Hz – 47.5 Hz: Continuous operation is required'; '47.5 Hz – 47 Hz: Generating unit is required to remain in operation for at least 20 seconds each time frequency falls below 47.5Hz'. ESS definition in section 1.3; Appendix L3.
This row stops at the chart window, and the clause does not. One band here stops at a fixed time, while the clause above speaks of continuous operation across the same range — and the other band of the same row has no stated end. Where the chart and the clause disagree, the clause governs.
Operating requirements beyond the envelopes.
The envelopes above are what Singapore (EMA Transmission Code App. F6) demands during a disturbance. The rows below are the same regime’s operating and fault-response requirements — reactive capability, frequency response, continuous operating range and ramp rate — each researched from the document its own row cites, separately from the plotted corpus. Every row carries its clause and a verbatim quote, so you can check it the same way.
| Requirement | What the code states | Clause |
|---|---|---|
| Generating-unit power factor range 0.95 leading – 0.85 lagging Reactive capability | Each generating unit: capability of operating at power factor from 0.95 leading to 0.85 lagging, measured at the generating-unit terminals prior to the step-up transformer; grid-connected solar PV inverters: 0.9 leading to 0.9 lagging Binds the Generation Licensee for each generating unit connected to the transmission system — a generation-scoped rule, not storage-explicit. ESS is defined in Section 1.3 as 'a generating facility' (a generation facility is one or more generating units), so the generation chain plausibly reaches ESS, but the code never states expressly that Section 6.6.1's power-factor band applies to ESS; for ESS, Appendix L instead requires submission of the plant's own Reactive Power Capability Curve (see separate claim). Basis: power factor at unit terminals (pre step-up transformer), not Q/Pmax at the connection point. | Section 6.6.1 (Reactive Power Requirements) + Section 1.3, definition of "Energy Storage System" |
The clauses this row citesSection 6.6.1 (Reactive Power Requirements) — “ The Generation Licensee responsible for each generating unit connected to the transmission system shall ensure that each generating unit has the capability of operating at a power factor from 0.95 leading to 0.85 lagging as measured at the terminals of the generating unit prior to the step-up transformer. For grid-connected solar photovoltaic generating unit(s), the connected person shall ensure that the inverter(s) has the capability of operating at a power factor from 0.9 leading to 0.9 lagging. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) Section 1.3, definition of "Energy Storage System" — “ "Energy Storage System" or "ESS" means a generating facility that has the ability to consume electricity from the transmission system, store the energy consumed, and later release the energy by supplying electricity to the transmission system; ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
| ESS reactive capability: project-specific curve submission + commissioning tests Reactive capability | No numeric Q or power-factor envelope for ESS is prescribed in Appendix L — the requirement is project-specific: the ESS Licensee must submit the ESS's Reactive Power Capability Curve (with factory/field test reports) in the Appendix L data schedule, and a commissioning test schedule including Reactive Power Capability Tests. Binds storage explicitly. L1 requires every Licensee responsible for an ESS seeking connection to the transmission system to provide the L1.1–L1.3 information, which includes the capability curve under L1.2(g); L2 requires each Licensee responsible for a centrally dispatchable ESS to provide commissioning test schedules under L2.1–L2.3, including L2.3(d) Reactive Power Capability Tests. The accepted capability curve — not a code-prescribed envelope — defines the plant's reactive obligation. | Appendix L, L1.2(g) + Appendix L, L2.3(d) (item under 'Commissioning Test Schedules') |
The clauses this row citesAppendix L, L1.2(g) — “ (g) Capability Curve: • Reactive Power Capability Curve • Factory test reports and field test result if any ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) Appendix L, L2.3(d) (item under 'Commissioning Test Schedules') — “ (d) Reactive Power Capability Tests ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
| Primary reserve with 2-second response: deadband, droop, sustain Frequency response | Deadband ±0.20 Hz around nominal frequency (no quick response 49.80–50.20 Hz); frequency-response droop of 1% or lower, giving full ESS output for a 0.50 Hz deviation (49.30 Hz system frequency); response to full output measured at 2 seconds; sustained for 9 minutes and 58 seconds Binds storage explicitly: Appendix L3 applies to all ESSs registered with the Energy Market Company as generation registered facility, which shall be centrally dispatched and designed with these capabilities except where the Licensee declares with technical justification that a capability is technically not possible, for PSO consideration. Droop basis: 1% droop is defined by full output at a 0.50 Hz deviation (1% of 50 Hz nominal). The droop response shall stay enabled as long as the ESS is connected to the transmission system. Sustain and response verified through test per the System Operation Manual. | Appendix L, L3(c)(i)–(ii) + Appendix L, L3(c)(iii) |
The clauses this row citesAppendix L, L3(c)(i)–(ii) — “ i. A deadband of ±0.20 Hz around nominal system frequency shall be used to prevent the centrally dispatchable ESS from providing quick response from 49.80 Hz to 50.20 Hz. ii. A frequency response droop of 1% or lower shall be set to ensure full centrally dispatchable ESS's output for a frequency deviation of 0.50 Hz (49.30 Hz system frequency). The droop response shall be enabled as long as the centrally dispatchable ESS is still connected to the transmission system. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) Appendix L, L3(c)(iii) — “ iii. The state-of-charge shall be managed locally to be capable of providing primary reserve with response to full output measured at 2 seconds and to be sustained for the period of 9 minutes and 58 seconds, and must be verified through test stipulated in the System Operation Manual. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
| Over-frequency MW reduction (LFSM-O equivalent) Frequency response | Start reducing MW output when system frequency exceeds 50.20 Hz, with droop of 1% or lower Binds storage explicitly (centrally dispatchable ESS, Appendix L3 scope: all ESSs registered with EMC as generation registered facility; technically-not-possible exceptions subject to PSO consideration). This is the over-frequency counterpart to the L3(c) primary-reserve deadband, which already suppresses quick response between 49.80 and 50.20 Hz. | Appendix L, L3(e) |
The clause this row citesAppendix L, L3(e) — “ The centrally dispatchable ESS shall start to reduce its MW output when system frequency is greater than 50.20Hz with droop of 1% or lower. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
| Contingency reserve: rated MW within 10 minutes Frequency response | Contingency reserve up to Rated MW Capacity within 10 minutes, verified by test per the System Operation Manual Binds storage explicitly (centrally dispatchable ESS, Appendix L3 scope: all ESSs registered with EMC as generation registered facility; technically-not-possible exceptions subject to PSO consideration). Basis is the ESS's Rated MW Capacity. Commissioning test schedule for Contingency Reserve Tests is required under L2.3(b). | Appendix L, L3(d)(i) |
The clause this row citesAppendix L, L3(d)(i) — “ The centrally dispatchable ESS must be capable of providing contingency reserve up to its Rated MW Capacity within 10 minutes and shall be verified through test stipulated in the System Operation Manual. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
| Frequency operating range: 49.5–50.5 Hz normal; 47.5–52 Hz continuous; 47–47.5 Hz for 20 s Continuous operating range | Normal system control band 49.5–50.5 Hz; exceptional excursions to 52 Hz / 47 Hz; continuous operation required 52–47.5 Hz; between 47.5 and 47 Hz the unit must remain in operation for at least 20 seconds each time frequency falls below 47.5 Hz Binds the 'generating unit' — a generation-scoped rule, not storage-explicit. ESS is defined in Section 1.3 as a generating facility (one or more generating units), and Appendix L contains no separate frequency operating range for ESS, so F6 is the general provision that would reach ESS via that definition chain; express confirmation is not stated. Bands are in absolute Hz (50 Hz nominal system). | Appendix F, F6.1–F6.2 (Frequency Range of Generating Unit) + Appendix F, F6.2 (table) |
The clauses this row citesAppendix F, F6.1–F6.2 (Frequency Range of Generating Unit) — “ The generating unit shall be capable of sustained operation within the system frequency range which is normally controlled within the limits of 49.5Hz – 50.5Hz and, in exceptional circumstances, it could rise to 52Hz or fall to 47Hz. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) Appendix F, F6.2 (table) — “ The generating unit shall operate within the frequencies range of 52 Hz to 47 Hz in accordance to the following: Frequency Range Requirement • 52 Hz – 47.5 Hz Continuous operation is required • 47.5 Hz – 47 Hz Generating unit is required to remain in operation for at least 20 seconds each time frequency falls below 47.5Hz ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
| Capacity Limited Ramp Rate near SoC limits: max 20% rated MW per minute Ramp rate | Per-minute Capacity Limited Ramp Rate shall not exceed 20% of the rated MW capacity of the ESS, applying to active power (charging and discharging) as the ESS approaches its state-of-charge limits Binds storage explicitly (centrally dispatchable ESS, Appendix L3 scope). This is a capacity-limited (SoC-boundary) ramp constraint, not a normal-operation ramp limit — the code states no general MW/min ramp limit for ESS elsewhere (L1.2(f) only asks the Licensee to declare 'Maximum Rate of MW Change Capability' in MW/sec for each direction as a data item). Basis: rated MW capacity of the ESS; applies to both charge and discharge ('charging/discharging'). | Appendix L, L3(f) |
The clause this row citesAppendix L, L3(f) — “ Capacity Limited Ramp Rate describes the manner in which the centrally dispatchable ESS shall control its active power (charging/discharging) as it approaches the limits of its energy capacity (State-of-Charge). The per minute Capacity Limited Ramp Rate shall be not exceed [sic] 20% of the rated MW capacity of the ESS. ” (Transmission Code, Energy Market Authority of Singapore, 15 June 2026, accessed 2026-08-08) | ||
Who does Singapore (EMA Transmission Code App. F6) bind, and since when?
Generating units and ESS on the SG 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.
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 Singapore (EMA Transmission Code App. F6)
- Does Singapore (EMA Transmission Code App. F6) 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 Singapore (EMA Transmission Code App. F6) 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 Singapore (EMA Transmission Code App. F6) 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 Singapore (EMA Transmission Code App. F6)?
- Singapore (EMA Transmission Code App. F6) is charted here with 1 envelope — frequency ride-through (FRT). No low-voltage or high-voltage envelope is charted here — check Singapore (EMA Transmission Code App. F6) 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.
Elsewhere in Asia-Pacific: Taiwan (TPC), Vietnam BESS (Circular 05/2025/TT-BCT Art. 44), Australia (NER / AEMO), China (GB/T 36547-2024), India (CEA Connectivity Regs), Malaysia (Grid Code Additional Code 2025), and 9 more