This landscape identifies 19 patent families that combine HVDC transmission terminology with explicit safety-compliance language such as DC protection compliance, insulation coordination or grid code compliance, filtered to relevant power-systems IPC classes. That is a small, specific corpus rather than a general HVDC patent count, since it excludes filings that mention HVDC without making a compliance-related claim. Anyone using this figure for competitive analysis should treat it as the compliance-specific subset, not the full HVDC transmission patent universe.

The dataset shows a fragmented ownership picture with no assignee showing filing activity in the most recent year, including larger names such as Hitachi Energy, ABB and LS Electric. Hitachi Energy specifically recorded a -100% year-on-year change, meaning it had filings previously but none most recently. With only 19 families across the whole field, ownership is spread thin enough that no single company holds a dominant blocking position right now.

Filing activity rose to a peak of 5 families in 2020, then dropped to zero by the 2022 midpoint. This pattern is more consistent with a short cluster of related development work, possibly tied to a specific regulatory update or project deployment, than with sustained R&D investment. Readers should also account for publication lag: filings from the last one to two years are undercounted in any dataset with a mid-2026 cutoff, so the apparent decline may soften once later filings publish.

Relative to the 19-of-19 concentration in H02J power-grid classifications, areas like DC fault-current limiting circuits, PV-to-HVDC direct pole coupling, insulation coordination specific to converter stations, and multi-terminal HVDC compliance testing show comparatively thin representation. These sit adjacent to the core grid-system claims but are not the primary focus of most filings in this corpus. A first claim in one of these branches would need to tie a specific protection or coordination mechanism to a named HVDC configuration rather than claiming the grid system generally.

WO2013115915A1, covering control and protection of a DC power grid, is the most-cited record in this corpus at 17 citations, well ahead of the next tier which clusters around 2 to 6 citations. Records describing safe and resilient energy distribution for microgrids also recur across multiple jurisdictions (US, WO and EP filings of essentially the same invention), indicating that family is actively being pursued for broad geographic coverage. Any new DC protection or grid-safety claim should be checked against both of these before drafting.