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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/three-phase-power-distribution-systems-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Patent Landscape · Power Electronics & GridThree-Phase Power Distribution Patents: who holds the ground on unbalanced-load and voltage-regulation claims
- Filing has cooled since its 2024 peak. 28 families published in 2024 against 18 in 2017 and just 5 so far in 2026 — the field grew, then flattened rather than continuing to accelerate.
- China dominates the filing venue by a wide margin. 165 of 281 records were filed at China's receiving office, versus 25 in the United States and 23 at the EPO, concentrating both prior art and competitive risk in one jurisdiction.
- The most-cited prior art predates the current filing wave by decades. The top-cited record, US5883796A on dynamic series voltage restoration, carries 165 citations — a signal of foundational influence, not of where today's claims are being written.
281
Published Records
29%
Top-5 Share of All Records
+211%
Filing Growth 2021→2024
CN
Leading Jurisdiction
Filing growth compares 2021 (9 records) with 2024 (28) — 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 281 records in scope (CR5), not by the ranked leaders only.
Published byPatsnap Research··7 min readSourced from Patsnap Eureka
Overview
What this landscape covers
Three-phase power distribution patenting spans the hardware that moves power — transformers, switchgear, protection relays — and the control logic that keeps it balanced: neutral-current compensation, phase-rotation correction and voltage regulation under uneven load. This dataset pulls 281 patent families published between 2015 and mid-2026 under IPC classes covering power supply and grid systems, switchboards and substations, and power conversion, filtered to records that explicitly discuss unbalanced load, neutral current, protection coordination, switchgear or voltage regulation.
Because publication lags filing by roughly 18 months, the 2025 and 2026 counts in any trend line are undercounts of actual filing activity, not a real drop-off. The composition below reads better as a map of where claim density already sits than as a forecast of where it is heading.
Filing activity, 2017-2026
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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The data
Filing trends and technology composition
Two views of the same 281 families: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
A flat-to-declining filing curve after 2024
Filings rose from 18 in 2017 to a peak of 28 in 2024, with 2022 sitting at the 18-family midpoint — the growth phase has already happened, and the curve has not extended past its 2024 high even before adjusting for publication lag.
H02J dominates; secondary classes are thin
H02J (power supply and grid systems) accounts for 238 of the records that also appear in adjacent classes, dwarfing H02B switchgear (52) and the digital-processing, protection and measurement classes that each sit in the high teens — evidence that most claim activity is grid-control logic rather than switchgear hardware or standalone measurement instrumentation.
Shares are the percentage of the 281 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Source: Patsnap Eureka. Filing trend and technology composition. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
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The prior art anchoring this space
Newest published family
WO2026040184A1 — voltage regulation for high-PV-penetration distribution areas
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID
The application defines a reinforcement-learning agent's states, actions and rewards to build a solving framework for voltage regulation in distribution areas with a high share of photovoltaic generation. The agent trains a policy network against a simulated environment, then applies that trained policy to live grid-state input to output a regulation strategy. The stated aim is to hold every node's voltage within its allowed range while simultaneously minimising three-phase voltage imbalance, even when the area's topology parameters and PV output forecasts are both uncertain.Filed by Electric Power Research Institute, China Southern Power Grid; published 2026-02-26.
Most-cited records in the corpus
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5883796A | Dynamic series voltage restoration for sensitive loads in unbalanced power systems | 165 |
| 2 | US10439432B2 | Highly flexible, electrical distribution grid edge energy manager and router | 66 |
| 3 | CN105207237A | 配网三相负荷不平衡调整控制系统 | 48 |
| 4 | US5648894A | Active filter control | 48 |
| 5 | JP2004056931A | Distribution line voltage regulation device | 39 |
| 6 | WO2010083164A2 | Distribution system analysis using meter data | 32 |
| 7 | CN207938972U | 一种应用于箱式变电站的智能监控系统 | 28 |
| 8 | CN109888800A | 一种基于负荷预测和换相策略的配电台区三相不平衡负荷调整方法 | 26 |
| 9 | CN201708445U | 应急多功能配电电源抢修车 | 26 |
| 10 | US20220244076A1 | Distributed control of energy storage device charging and grid stability | 25 |
Citation counts are drawn from within this searched corpus and favour older filings; treat them as markers of foundational influence rather than current competitive 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.
Source: Patsnap Eureka. Citation counts and representative records. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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What the numbers imply for filing strategy
Three read-outs from the trend and citation data that matter more than the raw family count.
Filing momentum
28 → 5
peak (2024) vs. latest partial year
The growth phase is behind, not ahead
Filings climbed from 18 in 2017 to a peak of 28 in 2024 before easing. Even allowing for the 18-month publication lag understating 2025-2026, the curve had already flattened by its peak year rather than still accelerating into it.
Source: filing trend, 2017-2026
Venue concentration
165 / 281
records filed in China
One jurisdiction carries most of the risk and the prior art
China's receiving office accounts for 165 of the 281 families, more than six times the US total of 25. Freedom-to-operate work that skips a China-specific search is working from an incomplete picture of this field.
Source: receiving-office breakdown
Claim density by class
238 records
in H02J, power supply & grid systems
Control logic, not hardware, is the crowded layer
H02J outnumbers H02B switchgear by more than 4:1 and dwarfs the protection, measurement and control classes that each sit around 15-19 records. New hardware-side filings face thinner prior art than new control-algorithm claims.
Source: IPC composition
Citation anchor age
165 citations
on US5883796A, filed pre-corpus
The most-cited art is foundational, not current
The top-cited record on dynamic series voltage restoration predates this filing window and its citation count reflects decades of accumulated reference, not present-day relevance to active claim drafting.
Source: most-cited records table
Eureka AI Agent
Looking for what nobody has claimed yet?
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to three-phase power distribution systems, with the prior art for and against each one.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Players
Who is filing, and where the field is thinning
Co-assignee activity clusters around a small number of Chinese state-grid and utility-research pairings, while momentum across the recent-year leaders has gone flat or negative across the board.
Co-filing cluster
10 pairs
co-assignee pairings identified
State Grid anchors the densest collaboration cluster
The strongest co-assignee pairs all involve State Grid Corporation of China alongside provincial power-supply companies and Hohai University, each appearing three times — a pattern of joint utility-and-academic filing rather than cross-competitor collaboration.
Source: co-assignee pairs
Recent momentum
0 filings
in the latest year, across every tracked top assignee
No leading assignee is filing at pace right now
Every assignee tracked for recent-year momentum, including State Grid Corporation of China and GridBridge Inc, shows zero filings in the latest year, with State Grid and GridBridge both down 100% year-on-year — consistent with the broader post-2024 slowdown rather than any single firm pulling back.
Source: recent-year momentum by assignee
Geographic split
China 165 vs. rest 116
receiving-office split
Filing strategy outside China is fragmented
The 116 non-China filings split thinly across the US, EPO, Australia, WIPO and India, none exceeding 25 records — no single non-China venue has built the depth of prior art that a China filing strategy has to contend with.
Source: receiving-office breakdown
Recent-year filing momentum
| Assignee | Recent year | YoY |
|---|---|---|
| Accenture Global Services Limited | 0 | — |
| State Grid Corporation of China | 0 | -100% |
| GRIDBRIDGE INC | 0 | -100% |
| Electromechanical Application Consulting Co., Ltd. | 0 | — |
| Third Equation Co., Ltd. | 0 | — |
| Landis+Gyr Technology Co., Ltd. | 0 | — |
| State Grid Jiangsu Electric Power Co., Ltd. | 0 | -100% |
| China Electric Power Research Institute Co., Ltd. | 0 | -100% |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
What's next
Where to take this
Three ways to move from this overview into the specifics that matter for a filing or freedom-to-operate decision.
Search the full 281-family set
Filter by assignee, IPC subclass or receiving office to see which specific claims sit behind the aggregate counts on this page.
Open the dataset in Eureka →Check freedom-to-operate against the China filing cluster
With 165 of 281 records filed in China, a jurisdiction-specific clearance search is the difference between a real FTO opinion and a partial one.
Run a China-focused search in Eureka →Track the newest published family
WO2026040184A1 applies reinforcement learning to voltage regulation under high PV penetration — worth monitoring as this branch develops.
Follow this family in Eureka →Source: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
FAQ
Common questions about three-phase power distribution patents
This dataset identifies 281 patent families published between 2015 and mid-2026 that cover three-phase power distribution topics such as unbalanced load correction, neutral current management, protection coordination, switchgear and voltage regulation. The count is drawn from a targeted search across IPC classes H02J, H02B and H02G, so it reflects a defined technical scope rather than every patent that touches three-phase power in general. Because publication lags filing by around 18 months, the true number of families filed in 2025 and 2026 is higher than currently published records show.
State Grid Corporation of China appears repeatedly across the co-assignee data, often paired with provincial power-supply companies and Hohai University in joint filings. GridBridge Inc also appears among the tracked assignees. However, every top assignee tracked for recent-year momentum shows zero filings in the latest year, including State Grid and GridBridge, both down 100% year-on-year, which points to a broad slowdown across the leading filers rather than one company pulling ahead.
China's receiving office accounts for 165 of the 281 records in this dataset, far ahead of the United States at 25 and the European Patent Office at 23, with Australia, WIPO/PCT and India each in single or low double digits. This concentration means that a search or clearance exercise limited to US and European filings will miss the majority of the documented prior art in this field. Teams doing freedom-to-operate work should treat a China-specific search as a required step, not an optional supplement.
Filing activity rose from 18 families in 2017 to a peak of 28 in 2024, with the 2022 midpoint sitting at 18 as well — a pattern more consistent with a plateau than sustained growth. The 2025 and 2026 figures are lower still, but that is expected given the roughly 18-month lag between filing and publication, so those years should not yet be read as a genuine decline. Taken together, the evidence supports describing the field as flat to slightly declining in filing volume, not one still accelerating.
The IPC composition shows heavy concentration in H02J (power supply and grid systems, 238 records) and, to a lesser extent, H02B (switchgear and substations, 52 records), while protection circuitry, power conversion, measurement, business-process data handling and control-systems classes each sit in the high teens. That gap suggests thinner claim coverage in areas like neutral-current compensation hardware for PV-heavy feeders, phase-rotation correction at the substation edge, and protection coordination tuned for inverter-dominated microgrids. These are branches adjacent to the dense core rather than unrelated fields, which is what makes them more approachable for a new filer.
Answers are grounded in the same dataset. Derived from a Patsnap search on Three-Phase Power Distribution Systems covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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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.