Power Quality Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled since its 2025 peak. 232 families published in 2025 against 194 in 2017, but the 2026 count of 76 is a partial year, not a collapse.
- China dominates the filing office mix. 1,709 of the tracked records originate from China, more than five times the next-largest office, the United States at 198.
- State Grid affiliates file together, not alone. The strongest co-assignee pair links State Grid's national entity with its Jiangsu unit at 14 shared filings, a pattern of provincial-national co-filing repeated across the ranking.
Filing growth compares 2021 (116 records) with 2024 (162) — 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 2,606 records in scope (CR5), not by the ranked leaders only.
What this patent set covers
This landscape tracks 2,606 patent families filed against power quality and harmonic mitigation claims: active power filters, compensation schemes for voltage sag and flicker, and grid code compliance methods, searched across H02J, H02M and G01R classifications. The core technical mass sits in H02J (power supply and grid systems), with H02M power conversion and G01R measurement forming the next-largest clusters.
A smaller but present share of filings pulls in G06F, G06N and G06Q classifications, signalling that data processing and AI-assisted diagnostics are being layered onto what was historically a purely electrical engineering problem. Publication lags filing by roughly 18 months, so the 2026 figures in this dataset are necessarily incomplete and should not be read as a downturn on their own.
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Trend, geography and classification mix
Three cuts of the same 2,606-family dataset: the year-by-year filing trend, where applicants filed, and how the technology splits across IPC subclasses.
A decade of filings, front-loaded then flattening
Filings ran at 194 in 2017, sat near the midpoint at 115 in 2022, then climbed back to a peak of 232 in 2025. The apparent drop to 76 in 2026 reflects a partial year under an 18-month publication lag rather than a genuine slowdown; the underlying trend across the decade reads as flat-to-declining once the peak year is set aside.
Classification mix: grid systems dominate, compute is a growing minority
H02J accounts for 2,413 of the tracked records, essentially the whole dataset given the 2,606 total, confirming this is fundamentally a grid and power-supply category. H02M (468) and G01R (242) are the next-largest technical clusters, covering conversion hardware and measurement respectively, while G06F, G06N and G06Q together point to a smaller but non-trivial software and analytics layer building on top of the electrical core.
Shares are the percentage of the 2,606 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Power Quality and Harmonic Mitigation with Eureka
This page is one run against one query. Ask Eureka your own question about power quality and harmonic mitigation and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
Electric power quality control method and device for oil production platform, and storage medium (US20240322567A1)
Filed by Cangzhou Power Supply Company and State Grid Hebei Electric Power Co., Ltd., this application discloses a method that pulls test data from electrical loads across an oil production platform's power distribution rooms, derives power quality index data for each room, flags rooms with a quality problem against a preset index range, and configures a compensation scheme specific to the detected problem.Filed 2024-09-26. Note the domain-specific framing: oil production platform distribution rooms, not a generic grid node.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6738692B2 | Modular, integrated power conversion and energy management system | 314 |
| 2 | US20040084965A1 | Hybrid variable speed generator/uninterruptible power supply power converter | 260 |
| 3 | US5751138A | Active power conditioner for reactive and harmonic compensation having PWM and stepped-wave inverters | 169 |
| 4 | US6503649B1 | Variable fuel cell power system for generating electrical power | 158 |
| 5 | CN2891438Y | 电力有源滤波装置 | 151 |
| 6 | CN101807799A | 超级电容储能型电能质量补偿器 | 133 |
| 7 | US20020149953A1 | Unified constant-frequency integration control of three-phase power factor corrected rectifiers, active power… | 97 |
| 8 | CN101924370A | 一种混合型电能质量治理装置 | 91 |
| 9 | US6545887B2 | Unified constant-frequency integration control of three-phase power factor corrected rectifiers, active power… | 89 |
| 10 | US6459559B1 | Thyristor controlled dynamic voltage suppressor for electric power systems | 82 |
Citation counts favour older filings simply because they have had longer to accumulate references; treat them as a measure of influence within this corpus, not as a signal of current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Reading the filing trend, the office split and the citation table together points to a category that is large, geographically concentrated, and increasingly layered with software.
Growth has flattened, not accelerated
Filings moved from 194 in 2017 to a midpoint of 115 in 2022 before climbing back to 232 in 2025. That U-shape, rather than steady growth, suggests renewed regulatory or grid-modernisation pressure rather than a continuously expanding field.
China's receiving office dominates by a wide margin
China accounts for 1,709 records against 310 for India and 198 for the United States. A filing strategy built only around US or EPO coverage would miss the bulk of the activity in this category.
Grid-systems claims dominate; conversion and measurement trail
H02J covers nearly the entire dataset, meaning most claims are framed at the grid or power-supply system level rather than at the component level. H02M (conversion hardware) and G01R (measurement) are meaningful but secondary clusters.
State Grid's national and provincial units file together
Of 10 identified co-assignee pairs, the strongest links State Grid's national entity with its Jiangsu provincial unit at 14 shared filings, with Fujian (13) and the China Electric Power Research Institute (12) close behind.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to power quality and harmonic mitigation, with the prior art for and against each one.
Who is filing, and where the field is thin
Assignee activity is concentrated among Chinese state-grid entities and universities, with several previously active filers showing sharp year-on-year drops in the latest tracked year.
National entity activity has dropped to zero in the latest year
State Grid's national assignee shows 0 filings in the latest tracked year, a -100% year-on-year change, even as provincial affiliates and research institutes continue to co-file. This looks like a reporting-lag artefact as much as a genuine pullback given the 18-month publication delay.
Academic filers are small but persistent
Hunan University and Zhejiang University each show only 1 filing in the latest year, with Hunan down 80% year-on-year and Zhejiang flat. These are long-tail contributors rather than volume filers, but their presence across years suggests sustained research interest rather than one-off filings.
Non-Chinese vendor activity has thinned out
Schneider Electric's US entity shows 0 filings in the latest year against a -100% year-on-year drop, consistent with the broader geographic skew of this dataset toward Chinese receiving offices and assignees.
| Assignee | Recent year | YoY |
|---|---|---|
| Hunan University | 1 | -80% |
| Zhejiang University | 1 | 0% |
| State Grid Corporation of China | 0 | -100% |
| Schneider Electric USA, Inc. | 0 | -100% |
| Hohai University, Changzhou Campus | 0 | — |
| Yijie Electronics Co., Ltd. | 0 | — |
| Southeast University | 0 | — |
| North China Electric Power University | 0 | — |
Where to take this analysis
The trends and rankings here are a starting point for freedom-to-operate and whitespace work, not a substitute for claim-level review.
Run a freedom-to-operate check on specific claim language
Filing density in H02J does not tell you which specific claims block a given design; a claim-level search against the assignees active in your target geography is the next step.
Explore Patsnap EurekaTrack the under-claimed branches as they mature
AI-assisted diagnostics and EV-load flicker compensation show thin filing density now, but that can shift quickly once one assignee stakes out foundational claims.
Explore Patsnap EurekaCommon questions about power quality patents
This dataset tracks 2,606 patent families published between 2015 and mid-2026, searched against active power filter, harmonic mitigation and power quality terms combined with IPC classes H02J, H02M and G01R. The figure counts distinct families rather than raw document counts, which is the fairer unit because it neutralises duplicate filings across jurisdictions and continuation applications. Coverage runs through a data cut-off of 2026-07-31, so the most recent year is understated due to the roughly 18-month lag between filing and publication.
State Grid's national entity and its provincial affiliates, including Jiangsu, Fujian, Shandong, Tianjin and Beijing units, along with the China Electric Power Research Institute, form the most active filing cluster in this dataset, frequently co-filing with each other. Universities such as Hunan University and Zhejiang University also appear but at much lower volumes, typically single-digit filings per year. Non-Chinese vendors such as Schneider Electric's US entity are present in the historical data but show no filings in the most recent tracked year.
The apparent drop to 76 filings in 2026, down from a peak of 232 in 2025, is very likely a publication-lag artefact rather than a real decline in filing activity. Patent applications typically take about 18 months from filing to publication, so a large share of 2026 filings simply have not been published yet at this dataset's 2026-07-31 cut-off. The more reliable read is the multi-year pattern: filings ran at 194 in 2017, dipped toward a midpoint of 115 in 2022, then recovered to the 2025 peak.
China's receiving office accounts for 1,709 of the 2,606 tracked records, by far the largest share, followed by India at 310 and the United States at 198. Europe (EPO), South Korea and the WIPO/PCT route each contribute smaller but notable shares, in the range of 70 to 110 records. A filing or freedom-to-operate strategy focused only on US or European coverage would miss the majority of documented activity in this field.
US20240322567A1, assigned to Cangzhou Power Supply Company and State Grid Hebei Electric Power Co., Ltd., discloses a method for detecting power quality problems in an oil production platform's distribution rooms and configuring a matched compensation scheme. Its claim scope is tied to that specific application context and detection-then-compensation workflow, so it does not broadly block general active power filter or harmonic compensation designs outside that framing. Anyone filing in adjacent industrial power quality applications should still check its specific claim language, since detection-and-response method claims can be drafted more broadly than the abstract implies.
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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.