Fault Location & Service Restoration Patents: Leaders & Trends 2026
- Concentrated at the top. The top 5 assignees together hold 51.3% of all 189 records in scope, with a single leader at 43 filings.
- Filing has cooled from its 2020 peak. Activity peaked at 21 records in 2020; the last complete comparison window shows filings down 25% from 2021 to 2024.
- Communications classes outweigh grid hardware classes. H04L (digital information transmission) appears in 29.6% of records, ahead of H02H protective circuits at 21.2% and H02J power supply/grid systems at 18.0%.
Filing growth compares 2021 (4 records) with 2024 (3) — 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 189 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Fault location, isolation and service restoration (FLISR) sits at the intersection of protective relaying, switch/recloser automation and communications middleware. The 189 records in scope span filings from 2015 through the current partial year, drawn from a search string that pairs distribution-automation terms — self-healing feeders, automatic reconfiguration — with the specific mechanics of restoration: switch coordination logic, centralized versus distributed decision making, and false-operation rate.
Because the search string ties electrical-grid restoration language to communications and coordination terms, the resulting corpus pulls in a meaningful share of telecom-network restoration patents alongside grid-specific ones — a reminder that fault isolation and restoration logic first matured in optical and telecom networks before being adapted to distribution feeders.
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Filing trend and technology composition
Two views of the same 189 records: when the filings happened, and which IPC subclasses they carry. Both are read against the same denominator, so shares are directly comparable.
Filing trend: rise, peak, plateau
Recorded filings run from 8 in 2017 up to a peak of 21 in 2020, then ease off. The 2021-to-2024 window — the last stretch that publication lag has fully caught up with — shows a decline from 4 to 3 filings, a 25% drop. Counts for 2025 and 2026 are still incomplete because publication typically lags filing by around 18 months, so those years should not yet be read as a continued fall.
Technology composition: communications classes lead
H04L (digital information transmission) touches 29.6% of the 189 records, more than any single grid-hardware class. H02H protective circuit arrangements (21.2%) and H02J power supply and grid systems (18.0%) follow, with H04B transmission, H04J multiplex communication and H04Q switching rounding out a strong communications-and-switching signature. G01R measurement and G06F data processing appear in a smaller but still notable share, at 9.0% and 7.4% respectively. Because records can carry multiple IPC classes, these percentages overlap rather than sum to 100%.
Shares are the percentage of the 189 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Fault Location Isolation and Service Restoration with Eureka
This page is one run against one query. Ask Eureka your own question about fault location isolation and service restoration and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20130063273A1 — Fault isolation and service restoration in an electric grid
Fault isolation and service restoration in an electrical grid are provided. An approach for receiving a notification message including a state of an electrical component on an electrical grid, and determining, by a computing system, a command message including at least one action to take in response to the state of the electrical component, is described. The approach further includes sending the command message to at least one of the electrical component and other electrical components on the electrical grid.Filed by Crosslayer Communications LLC, this claim sits squarely on the centralized-decision branch of FLISR: a computing system reads component state and issues a command message, rather than leaving reconfiguration to distributed relay logic.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5986783A | Method and apparatus for operation, protection, and restoration of heterogeneous optical communication networ… | 171 |
| 2 | US6046833A | Method and apparatus for operation, protection, and restoration of heterogeneous optical communication networ… | 113 |
| 3 | US6202071B1 | Method and system for improved database disaster recovery | 93 |
| 4 | US6331906B1 | Method and apparatus for operation, protection and restoration of heterogeneous optical communication networks | 90 |
| 5 | US5627889A | Service restoration technique for telecommunications facilities having a single degree of freedom | 71 |
| 6 | US5982517A | Method and system for service restoration in optical fiber communication networks | 60 |
| 7 | US20090285106A1 | IPTV fault integration and fault location isolation | 42 |
| 8 | US20090290275A1 | Fault Protection System and Method for an Electrical Power Distribution System | 41 |
| 9 | US9906294B2 | Systems and methods improving optical restoration time in networks | 40 |
| 10 | US8872667B2 | Fault isolation and service restoration in an electric grid | 39 |
Citation counts reward older filings that have had more time to accumulate citations within the searched corpus — treat them as a measure of influence on later filers, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once the ranking, the trend and the IPC composition are read together.
A narrow leadership group, not a fragmented field
The leader alone accounts for 43 records, and the fifth-ranked assignee still holds 6. That gap between first and fifth means new entrants are filing into a space where core restoration-command architectures are already staked out by a small group.
Filing has passed its peak, not disappeared
Activity built steadily to 2020 then eased; the 2021-to-2024 comparison shows a 25% decline. That is consistent with a technology whose foundational architectures (centralized command, recloser coordination) are largely claimed, pushing new filings toward narrower refinements.
Communications logic, not just switchgear, is the contested layer
H04L's lead over H02H and H02J indicates that a large share of the claim activity is about how state and command messages move between grid components, not only about the protective circuitry itself. Filers focused purely on hardware protection risk missing where the messaging-layer claims already sit.
Filing geography is US-anchored with a real China and EPO presence
United States filings lead at 65, with Europe at 24 and China at 16; WIPO PCT and India each carry a smaller but non-trivial share. A freedom-to-operate check limited to one jurisdiction would miss meaningful activity in at least two others.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to fault location isolation and service restoration, with the prior art for and against each one.
Who holds the ground, and where it's still open
The ranked list covers 73 companies scored by family count in this dataset. Momentum in the most recent complete year is flat across the named leaders, which is more informative than it first looks.
One assignee anchors the top of the ranking
At 43 records the leader holds close to a quarter of the entire 189-record corpus on its own, well ahead of the rest of the top 5 combined total of 97.
A sharp drop after the leader, then a longer tail
Fifth place holds 6 records and tenth place holds 4 — a much gentler slope than the gap between first and second, suggesting the mid-table is where smaller specialists and telecom-heritage filers compete.
No leader shows fresh activity in the newest recorded year
Every one of the assignees tracked for recent-year momentum shows zero filings in the latest year captured. Given the roughly 18-month publication lag, this likely reflects incomplete data rather than an actual stop in filing, but it does mean the ranking's top slots were built on filings from earlier years.
| Assignee | Recent year | YoY |
|---|---|---|
| S&C Electric Co | 0 | — |
| ZTE Corp | 0 | — |
| Huawei Technologies Co Ltd | 0 | — |
| Ciena Corp | 0 | — |
| Optical Networks Inc | 0 | — |
| AIP Research Ltd | 0 | — |
| International Business Machines Corp (IBM) | 0 | — |
| Lucent Technologies Inc | 0 | — |
Where to take this
The landscape points to a field with claimed core architecture and softer claim density in the coordination-logic and data-processing layers.
Map the messaging-layer claims in detail
With H04L present in 29.6% of records, a deeper read of exactly which command-message formats and state-notification structures are already claimed would clarify where a new filing on distributed decision-making could actually sit.
Explore in EurekaCheck freedom-to-operate across US, EPO and China
With 65 US, 24 EPO and 16 China filings, a jurisdiction-by-jurisdiction claim comparison is worth doing before committing R&D to any one restoration architecture.
Run a claim comparison in EurekaCommon questions about this landscape
In this dataset, a FLISR patent is one whose claims cover detecting a fault on an electrical distribution grid, isolating the affected section, and automatically restoring service to unaffected customers, typically through switch or recloser reconfiguration. The search also captures the communications and decision-making layer that carries fault state and restoration commands between grid components, which is why classes like H04L and H04Q appear alongside grid-specific classes like H02H and H02J. Records that only cover general protective relaying without an isolation-and-restoration action are generally excluded.
The ranking covers 73 companies, with a single leader holding 43 of the 189 records in scope and the top 5 combined holding 51.3%. The gap between the leader and the rest of the top 5 is large, while the drop from fifth to tenth place is comparatively gentle, indicating a concentrated top tier followed by a longer, more even tail of specialist and telecom-heritage filers. Company-level names and exact positions are shown in the ranked table rather than repeated here.
Filing activity rose to a peak of 21 records in 2020 and has since eased; the most recent fully comparable window, 2021 to 2024, shows a 25% decline in filings. Figures for 2025 and 2026 are still incomplete because patent publication typically lags the original filing date by around 18 months, so the true recent trend is understated rather than necessarily falling. Read the 2020 peak as the high point of a filing wave built around core centralized-restoration architecture, not as evidence the technology has stalled.
Centralized approaches, like the representative filing US20130063273A1, rely on a computing system that receives component state notifications and issues command messages back to grid equipment. Distributed decision-making pushes that logic out to the switches and reclosers themselves, letting them coordinate restoration without a central controller. The evidence in this dataset shows centralized-style claim language well represented, while distributed decision-making appears as a comparatively thinner, more open sub-area based on the current IPC and claim mix.
The United States leads with 65 filings in this dataset, followed by the European Patent Office at 24 and China at 16. WIPO PCT filings account for 14 and India for 11, with Canada at 10. Anyone assessing freedom to operate should treat the US, EPO and China as the three jurisdictions carrying the bulk of relevant claim activity, rather than clearing only one.
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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.