DC Cable and Overhead Line Patents: Leaders & White Space 2026
- 78.4% of records sit in H01B (cables, conductors & insulators) confirming that insulation and conductor design, not grid-system integration, is where the claim density actually lives.
- Filings peaked in 2017 at 8 and have since cooled with the tracked span from 2021 to 2024 showing a -50% change — a genuine three-year comparison, not a read on the still-incomplete 2025–2026 data.
- The ranked leader holds 14 records against a fifth-place count of 5 so the field has one clear front-runner ahead of a long tail of single- and double-digit filers among the 26 ranked companies.
Filing growth compares 2021 (2 records) with 2024 (1) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field.
What this landscape covers
This review covers 51 published records matching HVDC cable, extruded DC cable and space-charge accumulation terms crossed against insulation resistivity, polarity reversal, prequalification testing, cable joint design, thermal aging and nanocomposite insulation. The scope is narrow by design: it isolates the material and construction science of DC cable insulation rather than the broader HVDC converter or grid-control literature. Patent families, not raw document counts, anchor the assignee ranking, which neutralises continuation filings and multi-jurisdiction duplicates.
Coverage runs from 2015 through the 2026-07-31 cut-off. Because publication trails filing by roughly 18 months, the most recent one to two years in any trend chart will always understate actual filing activity — a structural lag, not a sign the field has gone quiet.
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Filing trend and technology composition
Two views of the same 51-record set: activity over time, and where the claims actually sit across IPC subclasses.
Filing activity, 2017-2026
Filings peaked at 8 in 2017. The tracked comparison window, 2021 (2 filings) to 2024 (1 filing), shows a -50% change over three years — the most recent complete-year comparison available. Years after 2024 are still filling in under the publication lag and should not be read as a continued decline.
IPC subclass composition
H01B (cables, conductors & insulators) covers 78.4% of the 51 records, with C08L (polymer compositions) at 45.1% close behind — together they confirm that insulation material formulation is the dominant claim territory. Smaller shares in C08K (additives, 13.7%), H02J (grid systems, 9.8%) and measurement-related G01R (5.9%) mark adjacent but thinner filing activity. Because records can carry multiple IPC codes, these shares sum to more than 100% of the record total.
Shares are the percentage of the 51 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on DC Cable and Overhead Line Technology with Eureka
This page is one run against one query. Ask Eureka your own question about dc cable and overhead line technology and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited and representative filings
HVDC Cable With Improved Electric Field Distribution
A high voltage direct current (HVDC) cable is provided. The cable includes a conductor and an insulation layer disposed inside outer layers. The insulation layer includes ethylene-propylene rubber, talc, and montmorillonite.Filed by General Electric Company, 2016-04-13 (EP3007177A1).
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20160322129A1 | Electrical HV Transmission Power Cable | 15 |
| 2 | WO2015090643A1 | An electrical HV transmission power cable | 13 |
| 3 | US20030149176A1 | Electrically insulating resin composition and electric wire or cable both coated therewith | 13 |
| 4 | US7196267B2 | Electrically insulating resin composition and a DC electric wire or cable both coated therewith | 12 |
| 5 | US20210165030A1 | Method for measuring trap parameters in XLPE cable based on polarization-depolarzation current test | 9 |
| 6 | US20190180889A1 | Semi-conductive composition for power cable | 6 |
| 7 | JP1983152303A | DC electrically insulating resin composition | 5 |
| 8 | WO2001073795A1 | An insulated electric direct current cable | 3 |
| 9 | EP1283527A1 | Electrically insulating resin composition and electric wire or cable both coated therewith | 3 |
| 10 | EP3611739A1 | Direct current power cable | 2 |
Citation counts inside this searched corpus favour older filings and should be read as a signal of influence within the set, not as a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three read-throughs from the composition and citation data that matter for anyone deciding where to file next.
Insulation and conductor design is the crowded zone
With H01B and C08L together covering the large majority of records, new filings on base cable construction and polymer insulation formulation face dense prior art. Differentiated claims need to sit on specific additive chemistry, layer geometry or measurement method rather than the cable structure itself.
Activity has cooled from its 2017 peak
The peak year, 2017, produced 8 filings; the last complete comparison window, 2021 to 2024, records a -50% change. That is a real three-year decline, not an artefact of the reporting lag, since both endpoints are far enough back to be considered stable.
Older US and WO filings still anchor the citation graph
The most-cited records in this set date to the mid-2010s and concern electric field distribution and resin insulation composition for HV cables. Their citation counts reflect years of accumulated influence inside a searched corpus, not that the underlying claims are still the frontier.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to dc cable and overhead line technology, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranking covers 26 companies across the 51 records in scope — the whole list the dataset returns, not a top-50 or top-100 cut.
One assignee well ahead of the field
The top-ranked company holds 14 records, more than double the fifth-place count of 5. That gap points to sustained, deliberate portfolio-building around DC cable insulation rather than opportunistic single filings.
A cluster of state-grid and utility filers
Several Chinese state-grid entities and research institutes appear together in co-assignee pairs, most strongly at a count of 5, suggesting coordinated filing programmes across parent and subsidiary research units rather than independent competition.
A long tail of light filers
By tenth place the count has dropped to 2 records, and most of the 26 ranked companies sit at or below that level. This is a field where a handful of programmes carry the bulk of activity against many single- or double-filing entrants.
| Assignee | Recent year | YoY |
|---|---|---|
| Sumitomo Electric Industries, Ltd. | 0 | — |
| State Grid Liaoning Electric Power Co., Ltd. | 0 | — |
| LS CABLE & SYST LTD | 0 | — |
| General Electric Company | 0 | — |
| State Grid Liaoning Economic Technology Research Institute | 0 | — |
| Global Energy Interconnection Research Institute Co., Ltd. | 0 | — |
| State Grid Corporation of China | 0 | — |
| ABB TECHNOLOGY LTD | 0 | — |
Where to take this analysis
The dataset points to a mature core and a thinner periphery. Two directions make sense from here.
Stress-test a specific insulation claim
Run a candidate formulation or layer geometry against the H01B and C08L prior art directly, rather than relying on subclass-level shares, to see which specific claims it would need to design around.
Explore in EurekaTrack the state-grid filing cluster
The co-assignee pairs among state-grid entities suggest a coordinated programme worth monitoring on its own trajectory, separate from the single-company leader.
Set up monitoring in EurekaCommon questions on DC cable patenting
One assignee leads the ranked field with 14 records, well ahead of the fifth-ranked company at 5. The ranking covers 26 companies in total across the 51 records in scope, and the gap between first and fifth place suggests a sustained portfolio strategy rather than a single breakthrough filing. Beyond the top few positions the counts thin out quickly into a long tail of light filers.
Filings peaked at 8 in 2017, and the most recent reliable comparison, 2021 (2 filings) to 2024 (1 filing), shows a -50% change over three years. Data for 2025 and 2026 is still incomplete because publication typically lags filing by around 18 months, so those later years should not yet be read as continuing the decline. Overall the trend points to a cooling from an earlier peak rather than an actively expanding field.
H01B, covering cables, conductors and insulators, appears in 78.4% of the 51 records in scope, and C08L, polymer compositions, appears in 45.1%. Together these confirm that the bulk of patenting activity concerns the physical cable construction and its polymer insulation formulation rather than grid integration or measurement systems. Smaller shares in additive chemistry (C08K) and grid systems (H02J) mark thinner but present adjacent activity.
The most-cited record in this set is US20160322129A1, an electrical HV transmission power cable filing cited 15 times, followed closely by related US and WO filings on similar cable and resin-composition subject matter. High citation counts inside a searched corpus tend to favour older filings simply because they have had more time to accumulate references, so treat these figures as a measure of historical influence rather than current commercial importance.
The thinner IPC shares point to specific under-claimed branches: cable joint prequalification methodology, space-charge trap parameter measurement, nanocomposite additive dispersion control, and polarity-reversal thermal cycling protocols all sit well below the dominant H01B and C08L shares. These are narrower technical routes rather than wide-open fields, so a workable first claim would need to be specific to a test method, additive system or measurement technique rather than a general cable structure.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.