Cable Termination Stress Control Patents: Leaders & Trends 2026
- Concentrated at the top. The five leading assignees hold 111 of 224 records in scope (49.6%), and the top ten hold 173 (77.2%) — a narrow group controls most of the filed art here.
- Filing has cooled sharply. After peaking at 16 records in 2017, filings fell from 7 in 2021 to 1 in 2024, an 86% drop over that span, though 2025-2026 counts are still filling in as publication catches up.
- Installation practice dominates the claim base. H02G (installing power and signal cables) touches 63.8% of the 224 records, well ahead of the materials-side classes — most of the contested ground is in assembly and field workmanship, not compounds.
Filing growth compares 2021 (7 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. Top-5 share is the combined record count of the five largest assignees divided by all 224 records in scope (CR5), not by the ranked leaders only.
What this field covers
Cable termination stress control governs how a high-voltage cable’s electric field is managed at the point where insulation ends and a termination or joint begins — stress cones, field grading material, and prefabricated stress control layers all exist to prevent partial discharge and breakdown at that geometric discontinuity. The 224 records in scope span the physical hardware (stress cones, cable adapters, joint bodies), the materials used to grade the field (non-linear resistive and capacitive compounds), and the installation methods that determine whether a termination performs as designed once it leaves the factory.
Because performance here depends as much on field assembly and interface pressure as on the material itself, the classification split in this dataset is unusually informative: installation-heavy claims (H02G) outnumber pure materials claims (C08K, C08L) by a wide margin, which shapes where freedom-to-operate risk actually concentrates.
Let an AI agent run this analysis on your own technology
Pick a task. Every answer cites the patents behind it.
Filing trend and technology composition
Two views of the same 224-record corpus: how filing activity has moved year over year, and which IPC subclasses carry the claim volume.
Filing trend, 2017-2026
Filings peaked at 16 records in 2017 and have declined since, reaching 7 in 2021 and 1 in 2024 — an 86% fall across that three-year window. Counts for 2025 and 2026 are not yet complete because publication typically lags filing by around 18 months, so the most recent years should not be read as a continued decline until later data arrives.
Technology composition by IPC subclass
H02G (installing power and signal cables) appears in 63.8% of the 224 records, followed by H01B (cables, conductors and insulators) at 33.9% and H01R (connectors and current collectors) at 14.7%. Materials-focused classes such as C08K and C08L sit well behind, each under 10% — a record can carry more than one class, so these figures sum to more than the total.
Shares are the percentage of the 224 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Cable Termination Stress Control with Eureka
This page is one run against one query. Ask Eureka your own question about cable termination stress control and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this corpus
HVDC Cable Accessories Based on Thermoplastic Elastomers (US20250233398A1)
There is provided an HVDC cable accessory comprising an electric stress control layer which at one position is adapted to be connected to an HVDC cable, wherein the HVDC cable accessory is prefabricated, and the electric stress control layer comprises a thermoplastic elastomer.Filed by NKT HV Cables AB, published 2025-07-17 — illustrates the shift toward prefabricated, elastomer-based stress control layers for HVDC accessories.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4252692A | Materials having non-linear electrical resistance characteristics | 111 |
| 2 | US3950604A | Heat-shrinkable articles having non-linear electrical resistance characteristics | 71 |
| 3 | WO2008076058A1 | Field grading material | 67 |
| 4 | EP0780949A1 | Universal cable adapter, cable joint using the adapter and method of making the same | 52 |
| 5 | US4831214A | High voltage cable joint and method of making same, and high voltage cable termination | 32 |
| 6 | WO1999021259A1 | Improved medium voltage branch splice and method of making the same | 29 |
| 7 | EP2375423A1 | Electrical bushing | 26 |
| 8 | EP3109958A1 | Field control element for a high-voltage cable accessory and method of optically measuring partial discharges | 21 |
| 9 | US20140065420A1 | Field grading material | 20 |
| 10 | EP0272131A2 | HV cables | 18 |
Citation counts reflect influence within the searched corpus over time and favour older filings; they are not a measure of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the numbers mean for filing strategy
Four read-outs from the concentration, trend and classification data that matter for deciding where to file or challenge.
A narrow leadership group
The five leading assignees account for 111 of the 224 records in scope. That level of concentration means a freedom-to-operate review in this field starts with a short list, not a long tail search.
Activity has cooled from its peak
Filings fell from 7 records in 2021 to 1 in 2024. Combined with the 2017 peak of 16, the pattern reads as a field that saw its main wave of claiming activity finish several years ago, with recent years still filling in.
Installation practice, not just materials
Nearly two-thirds of the 224 records touch H02G, covering installation methods for power and signal cables. Materials classes like C08K and C08L each stay under 10%, suggesting the harder-to-design-around claims sit in assembly technique and field workmanship rather than in compound chemistry alone.
Old non-linear resistance patents still anchor the field
The most-cited record in this corpus, on non-linear electrical resistance characteristics, dates back decades and still draws the heaviest citation count. That signals foundational influence on later field grading material claims, not current filing activity.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to cable termination stress control, with the prior art for and against each one.
Who holds the ground, and where it is still open
The 64 ranked assignees show a steep drop-off after the leaders, with a long tail of single- or few-filing entrants below the top ten.
A clear single leader
The top-ranked assignee holds 36 of the 224 records in scope, well ahead of fifth place at 14 and tenth place at 10 — the gap between first and the rest of the field is sharper than the gap within the top ten itself.
Most activity sits with ten firms
Ten assignees account for 173 of the 224 records. Beyond that point, the ranking runs into a long tail of smaller filers, each holding a handful of records at most.
Dense inventor clustering at the top
The strongest co-assignee pairs each recur across 12 records, all tied to the same lead inventor. That points to a small, stable inventing team behind a large share of one leader's portfolio rather than broad organisation-wide filing.
| Assignee | Recent year | YoY |
|---|---|---|
| ABB Research Ltd. | 0 | — |
| TE Connectivity Corp. | 0 | — |
| NKT HV Cables AB | 0 | -100% |
| Tyco Electronics Raychem GmbH | 0 | — |
| UNGE MIKAEL | 0 | — |
| Prysmian S.p.A. | 0 | — |
| NKT HV Cables GmbH | 0 | — |
| 3M Innovative Properties Company | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is defensive clearance or offensive filing.
Run a freedom-to-operate check against the top 10
With 77.2% of records held by ten assignees, a targeted clearance search against that group covers most of the field's active claim space before broadening further.
Explore in EurekaWatch the installation-practice classes closely
H02G's 63.8% share suggests assembly and field workmanship claims carry more weight here than materials chemistry — worth a dedicated claim chart pass.
Explore in EurekaTrack the white space in sensing and monitoring
Interface pressure and discharge inception monitoring sit well below the core classes in filing volume, making them a lower-risk area for new claims.
Explore in EurekaCommon questions on cable termination stress control patents
Stress control refers to the design features and materials that manage the electric field at the point where a high-voltage cable's insulation is interrupted, such as at a termination, joint or stress cone. Without it, the field concentrates sharply at the interruption and causes partial discharge or eventual breakdown. Field grading materials and stress cones are the two main mechanical approaches, and both appear heavily across the 224 records in this dataset, with installation-related claims (H02G) covering 63.8% of them.
The ranking covers 64 assignees, with a clear leader holding 36 of the 224 records in scope and the top five combined holding 111 records (49.6%). Coverage then drops off steadily, with the top ten holding 173 records (77.2%) and a long tail of smaller filers below that. This is a concentrated field rather than a fragmented one, so a competitive review can focus on a short list of firms.
Filing activity peaked in 2017 at 16 records and has declined since, falling from 7 records in 2021 to 1 in 2024, an 86% drop over that span. However, 2025 and 2026 figures are not yet complete because publication typically lags filing by about 18 months, so the most recent years understate true activity and should not be read as confirmation of a continuing decline on their own.
The dataset spans installation methods (H02G, 63.8% of the 224 records), cable and insulator hardware (H01B, 33.9%), connectors (H01R, 14.7%), and materials-side classes such as polymer additives (C08K) and polymer compositions (C08L), each under 10%. This spread shows that most of the contested claim space is in how terminations are assembled and installed in the field, rather than purely in the compounds used for grading.
US20250233398A1, filed by NKT HV Cables AB and published in mid-2025, describes an HVDC cable accessory with a prefabricated electric stress control layer made from a thermoplastic elastomer. It matters because it represents a recent move toward prefabricated, elastomer-based grading layers for HVDC accessories rather than field-assembled stress cones, a direction that intersects with several of the top-cited older patents on non-linear resistance materials. Anyone designing HVDC accessories with thermoplastic elastomer grading layers should check this filing's claim scope directly.
Research Cable Termination Stress Control in depth with Eureka
Go past this page: query the whole cable termination stress control corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
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.