Value chain · CLM-0790
In plain terms
Great Britain does not oblige an inverter-based generator to behave like a synchronous machine; it pays for that behaviour through a market. Plants that do offer it face a demanding specification, including being able to keep operating when the grid at its connection point has a short-circuit level of zero.
The claim as recorded
In Great Britain the provision of a grid-forming service is explicitly not a mandatory Grid Code requirement but is delivered through market arrangements, and where a plant does provide it, a GB Grid Forming Inverter (GBGF-I) must be capable of operating at a minimum short circuit level of zero MVA at the Grid Entry Point or User System Entry Point, of operating as a voltage source behind an impedance, of remaining in synchronism with the Total System while maintaining a load angle between 0 and 90 degrees, 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, and of doing so with an Active Control Based Power bandwidth below 5 Hz to avoid AC system resonance problems.
Scope and limits
This is interim system operator guidance, not the Grid Code text, and ECC.6.3.19 itself was not obtained when this record was written; it is read directly in CLM-1109 (2026-09-19), which confirms the quotations above as the code's sentences and adds the damping factor band, the Peak Current Rating injection at zero volts, the 140 ms injection duration and the unit-terminal compliance concession. It establishes that grid-forming is a market service in GB and what its technical bar is. It establishes nothing about whether any SBSP ground converter could meet that bar, and nothing about grid-forming obligations outside Great Britain.
What it assumes
That the guidance note reflects the Grid Code ECC.6.3.19 text as in force. The note describes itself as interim, so the position may move.
Where it comes from
Non-mandatory status, verbatim: "The provision of a Grid Forming Service 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 . Grid Forming Capability can be implemented by any technology including Electronic Power Converters with a GBGF-I ability, rotating Synchronous Generating Units or a combination of the two." Load angle and services, verbatim: "...each Grid Forming Plant is required to remain in synchronism with the Total System and maintain a Load Angle whose value can vary between 0 and 90 degrees... When subject to a fault or disturbance, or System Frequency change, 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." Zero short circuit level, verbatim, listed as a capability each GBGF shall have: "Operating at a minimum short circuit level of zero MVA at the Grid Entry Point or User System Entry Point." GBGF-I specifics, verbatim: "Operating as a voltage source behind an impedance". Bandwidth, verbatim: "Include an Active Control Based Power part of the control system that can respond to changes in the Grid Forming Plant or external signals from the Total System available at the Grid Entry Point or User System Entry Point but with a bandwidth below 5 Hz to avoid AC System resonance problems." Interim status, verbatim: "This guidance document can therefore be treated as the interim document before further updates are developed to the Grid Code."
Basis: GB Grid Code ECC.6.3.19 grid-forming provisions as described by the system operator's interim guidance; requirement measured at the Grid Entry Point or User System Entry Point
Related records
- Answers question
- QST-012 not published in this release
Cite this
energyaperture.com/c/clm-0790
CLM-0790, Energy Aperture, as of 2026.