Value chain · CLM-1109
In plain terms
The rulebook says the same as the guidance: nobody has to make their inverters behave like a rotating machine, but the grid needs enough plants that do, and it pays for them. If a plant offers it, it must be able to run into a dead network, feed its full rated current into a short circuit for the fault-clearing time, and be tuned within a stated damping range.
The claim as recorded
The Grid Code itself says grid forming is "not a mandatory requirement but one which will be delivered through market arrangements" while calling an appropriate volume of it "an essential requirement" for system stability, and it sets the bar CLM-0790 reported plus four things the guidance record does not carry: an equivalent Damping Factor between 0.2 and 5.0 agreed with The Company; reactive current injection of at least the Peak Current Rating when the entry-point voltage drops to zero, held for the fault clearance time, "up to 140ms" for Main Protection clearance, with no obligation to exceed the plant's rating; a submitted frequency-response characteristic for importing-capable plant; and acceptance of compliance at Power Park Unit terminals where demonstration at the entry point is impractical.
Evidence behind this: T1-the grid-forming clause read directly, confirming the guidance-derived CLM-0790 and adding what it lacks.
Scope and limits
Figure ECC.6.3.19.3 (frequency response envelope, p.267) and Figures ECC.6.3.19.5(a) (p.268) and (b) (p.269) (injection lines) are not read here; their numeric shapes are not stated. Nothing here says whether an SBSP ground converter could meet the bar. The clause is Revision 41 text; the sources row records that Revision 41 is the last to revise the ECCs, and later packs should be checked before publication.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF p.266, normalised: "it is an essential requirement that an appropriate volume of Grid Forming Plant is available and capable of providing a Grid Forming Capability"; "Grid Forming Capability is not a mandatory requirement but one which will be delivered through market arrangements, the details of which shall be published on The Company's Website"; "Each GBGF-I shall be capable of behaving at the Grid Entry Point or User System Entry Point or terminals of individual unit(s) as Internal Voltage Source behind an impedance"; raw: "maintain a Load Angle whose value can vary between 0 and 90 degrees"; normalised: "each Grid Forming Plant shall be capable of supplying Active ROCOF Response Power, Active Phase Jump Power, Active Damping Power, Active Control Based Power, Control Based Reactive Power, Voltage Jump Reactive Power and GBGF Fast Fault Current Injection". p.267: "but with a bandwidth below 5 Hz to avoid AC System resonance problems"; "equivalent Damping Factor of between 0.2 and 5.0". p.268: "operating at a minimum short circuit level of zero MVA at the Grid Entry Point or User System Entry Point"; "inject a reactive current of at least their Peak Current Rating when the voltage at the Grid Entry Point or User System Entry Point drops to zero". p.269: "for the duration of the fault clearance time which for faults on the Transmission System cleared in Main Protection operating times shall be up to 140ms". p.270: "The Company will accept compliance of the above requirements at the Power Park Unit terminals".
Basis: Grid Code ECC.6.3.19 as in force 5 June 2026
Related records
- Answers question
- QST-012 not published in this release
Cite this
energyaperture.com/c/clm-1109
CLM-1109, Energy Aperture, as of 2026-06.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-452
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