The dataset's leading-assignee ranking includes established grid-equipment manufacturers such as ABB and Siemens, transmission utilities such as Scottish Hydro Electric Transmission, and state grid operators including State Grid Corporation of China and General Electric's grid technology arm. None of these assignees shows filings in the latest tracked year, which is consistent with an overall filing plateau rather than any single company stepping back. A practical read is that the field is held by a small group of long-standing industrial and utility filers rather than a wave of new entrants.

Not clearly. Filings rose from 3 in 2017 to a peak of 11 in 2021, then eased to 8 by the 2022 midpoint, and the trend does not show renewed acceleration afterward. Because publication lags filing by roughly 18 months, the final one to two years in any such trend will always look lower than the eventual total, so a flat or declining recent tail should not be read as certain decline. Taken together, the pattern looks like a maturing rather than expanding claim space.

Most records sit in H02J, the class covering power supply and grid systems, which accounts for 143 of the 151 families in this dataset. H02M, power conversion, covers 43 records, and H02H, protective circuit arrangements, covers 28; smaller counts appear in digital data processing (G06F), switches and relays (H01H), and electric measurement (G01R). The heavy overlap between H02J and the smaller classes indicates most inventions claim grid-level control logic layered on existing conversion and protection hardware rather than new hardware architectures on their own.

WO2025083383A1, filed by Scottish Hydro Electric Transmission and published in April 2025, describes methods for stabilising multi-terminal HVDC systems by characterising and optimising the dynamic performance of the transfer network. The core mechanism configures each transfer branch and each HVDC converter to be bounded-input-bounded-output stable, specifically to avoid instability arising from interactions between multiple converters operating on the same DC grid. Anyone designing multi-terminal control schemes with more than two converters should check this filing directly, since converter-interaction stability is a narrower and more specific claim area than general HVDC control.

The technology composition data shows lighter representation outside the core H02J/H02M/H02H cluster, in areas such as digital-twin or data-processing overlays on grid-support control (G06F, only 6 records), and DC fault ride-through coordination logic that sits between protection and control claims. These branches are not unclaimed, but they carry meaningfully less IPC density than core multi-terminal control, so a targeted freedom-to-operate search there is more likely to surface open claim space than a search in the crowded H02J core. Marine and offshore DC collection (B63H overlap, 1 record) is another visibly thin branch worth checking if the application involves offshore wind HVDC collection grids.