CN106841930A - A kind of detection method of transmission line malfunction traveling wave - Google Patents

A kind of detection method of transmission line malfunction traveling wave Download PDF

Info

Publication number
CN106841930A
CN106841930A CN201710239938.2A CN201710239938A CN106841930A CN 106841930 A CN106841930 A CN 106841930A CN 201710239938 A CN201710239938 A CN 201710239938A CN 106841930 A CN106841930 A CN 106841930A
Authority
CN
China
Prior art keywords
traveling wave
wave data
imf
layer
characteristic quantity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201710239938.2A
Other languages
Chinese (zh)
Inventor
黄然
马仪
沐润志
张广斌
韩鸣
韩一鸣
周仿荣
董俊
钱国超
马御棠
申元
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Electric Power Research Institute of Yunnan Power System Ltd
Original Assignee
Electric Power Research Institute of Yunnan Power System Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Electric Power Research Institute of Yunnan Power System Ltd filed Critical Electric Power Research Institute of Yunnan Power System Ltd
Priority to CN201710239938.2A priority Critical patent/CN106841930A/en
Publication of CN106841930A publication Critical patent/CN106841930A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/088Aspects of digital computing

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)

Abstract

This application provides a kind of detection method of transmission line malfunction traveling wave, each traveling wave data is decomposed using empirical mode decomposition algorithm, obtain the characteristic quantity of each traveling wave data;Characteristic quantity to all traveling wave data carries out Gaussian Mixture cluster, obtain cluster result, classify with to the interference traveling wave and fault traveling wave in traveling wave data, the application can accurately identify the type of traveling wave data, it is accurate to interference traveling wave and fault traveling wave classification, the workload of staff's screening is reduced, operating efficiency is improved.

Description

A kind of detection method of transmission line malfunction traveling wave
Technical field
The application is related to power failure detection field, more particularly to a kind of detection method of transmission line malfunction traveling wave.
Background technology
At present, with the raising and the increase of transmission distance of transmission line of electricity voltage class, especially surpass, extra-high voltage transmission line The fast development on road, new challenge is proposed to electric network protection technology and fault localization technology.Traveling wave data contain abundant letter Breath, if the feature of traveling wave data can be excavated effectively, must lift the accuracy of travelling wave ranging, fault type and differentiate and nature of trouble Identification capability, is that follow-up traveling wave data lay the foundation in the research work of the aspect such as fault localization and main website construction.
In order to detect the traveling wave of transmission line of electricity, transmission line of electricity installs substantial amounts of traveling wave measurement apparatus, for obtaining during failure Quarter information.Existing traveling wave measurement apparatus use Sudden Changing Rate Starting mode, to ensure the monitoring to transmission line of electricity Weak fault, OK Wave measuring apparatus are typically provided with relatively low traveling wave activation threshold value.But, traveling wave measurement apparatus record substantial amounts of interference traveling wave, cause Interference traveling wave and fault traveling wave ratio serious unbalance, increase the workload of data identification and screening.
The content of the invention
It is a large amount of to solve traveling wave measurement apparatus record this application provides a kind of detection method of transmission line malfunction traveling wave Interference traveling wave, cause interference traveling wave and fault traveling wave proportional imbalance, increase the problem of data identification and the workload of screening.
Include this application provides a kind of detection method of transmission line malfunction traveling wave:
Obtain multiple traveling wave data;
Each traveling wave data is decomposed using empirical mode decomposition algorithm, obtains the characteristic quantity of each traveling wave data;
Characteristic quantity to all traveling wave data carries out Gaussian Mixture cluster, obtains cluster result, with traveling wave data Interference traveling wave and fault traveling wave are classified.
Further, it is described each traveling wave data is decomposed using empirical mode decomposition algorithm, obtain each traveling wave number According to characteristic quantity, including:
Each traveling wave data is decomposed using empirical mode decomposition algorithm, obtains M layers of IMF component of each traveling wave data;
According to the M layers of IMF component, selection meets pre-conditioned n-layer IMF components;The n is the just whole of no more than M Number;
According to the n-layer IMF components, the characteristic quantity of each traveling wave data is obtained.
Further, it is described each traveling wave data is decomposed using empirical mode decomposition algorithm, obtain each traveling wave number According to M layers of IMF component, including:
The maximum point and minimum point of each traveling wave data are obtained, maximum point sequence and minimum point sequence is obtained;
Row interpolation is entered to maximum point sequence and minimum point sequence respectively using cubic spline function method, obtains upper and lower Envelope;
According to upper and lower envelope, average envelope line m (t) is calculated;
Calculate according to the following formula, obtain the traveling wave data and the average difference including line,
H (t)=y (t)-m (t),
Wherein, y (t) represents traveling wave data, and m (t) represents average envelope line;
If difference h (t) is unsatisfactory for the condition of intrinsic mode function, using h (t) as new traveling wave data, weight The step of obtaining the maximum point and minimum point of each traveling wave data again;
If difference h (t) meets the condition of intrinsic mode function, difference h (t) is defined as the traveling wave The IMF components of data;
By the IMF components from corresponding traveling wave data separating, traveling wave data discrepance is obtained;
If the traveling wave data discrepance can continue to decompose, using the traveling wave data discrepance as new traveling wave number According to repetition is the step of obtain the maximum point and minimum point of each traveling wave data;
If the traveling wave data discrepance can not continue to decompose, M layers of component of each traveling wave data is obtained.
Further, described according to the M layers of IMF component, selection meets pre-conditioned n-layer IMF components, including,
According to the M layers of IMF component, every layer of spectrum kurtosis of IMF components is obtained;
According to every layer of spectrum kurtosis of IMF, n-layer IMF component of the spectrum kurtosis more than preset value is chosen.
Further, it is described according to the n-layer IMF components, the characteristic quantity of each traveling wave data is obtained, including,
According to the n-layer IMF components, calculate according to the following formula, obtain the corresponding traveling wave data of the n-layer IMF components Energy-Entropy.
The Energy-Entropy is defined as the characteristic quantity of correspondence traveling wave data.
From above technical scheme, this application provides a kind of detection method of transmission line malfunction traveling wave, using warp Test mode decomposition algorithm to decompose each traveling wave data, obtain the characteristic quantity of each traveling wave data;To all traveling wave data Characteristic quantity carry out Gaussian Mixture cluster, obtain cluster result, carried out with to the interference traveling wave and fault traveling wave in traveling wave data Classification, the application can accurately identify the type of traveling wave data, accurate to interference traveling wave and fault traveling wave classification, reduce staff The workload of screening, improves operating efficiency.
Brief description of the drawings
In order to illustrate more clearly of the technical scheme of the application, letter will be made to the accompanying drawing to be used needed for embodiment below Singly introduce, it should be apparent that, for those of ordinary skills, without having to pay creative labor, Other accompanying drawings can also be obtained according to these accompanying drawings.
A kind of flow chart of the detection method of transmission line malfunction traveling wave that Fig. 1 is provided for the application.
Specific embodiment
Referring to Fig. 1, include this application provides a kind of detection method of transmission line malfunction traveling wave:
Step 11:Obtain multiple traveling wave data.
Traveling wave data are the data of traveling wave measurement apparatus record, and traveling wave data include interference traveling wave and fault traveling wave.Interference Traveling wave is the waveform of traveling wave measurement apparatus record after causing traveling wave measurement apparatus error starting.Fault traveling wave is due to transmission line of electricity Failure and cause traveling wave measurement apparatus start after, traveling wave measurement apparatus record waveform.
Step 12:Each traveling wave data is decomposed using empirical mode decomposition algorithm, obtains each traveling wave data Characteristic quantity.
Empirical mode decomposition algorithm (Empirical Mode Decomposition, abbreviation EMD), the algorithm is according to certainly The time scale feature of body carries out signal decomposition, without presetting any basic function, sophisticated signal can be made to be decomposed into limited Card modular function (Intrinsic Mode Function, abbreviation IMF), can decomposite the individual IMF components for coming and contain original signal The Local Features signal of different time scales.Experience skyscraping decomposition algorithm can make the Non-stationary Data carry out steady words treatment, due to Basic function is to be decomposed to obtain in itself by data, and it is the local feature based on signal sequence time scale to decompose, with Fu in short-term In the method such as leaf transformation, wavelet decomposition compared to having more adaptivity.
Step 13:Characteristic quantity to all traveling wave data carries out Gaussian Mixture cluster, obtains cluster result, with to traveling wave number Interference traveling wave and fault traveling wave in are classified.
From above technical scheme, this application provides a kind of detection method of transmission line malfunction traveling wave, using warp Test mode decomposition algorithm to decompose each traveling wave data, obtain the characteristic quantity of each traveling wave data;To all traveling wave data Characteristic quantity carry out Gaussian Mixture cluster, obtain cluster result, carried out with to the interference traveling wave and fault traveling wave in traveling wave data Classification, the application can accurately identify the type of traveling wave data, accurate to interference traveling wave and fault traveling wave classification, reduce staff The workload of screening, improves operating efficiency.
The application provides another embodiment, and a kind of detection method of transmission line malfunction traveling wave includes:
Step 21:Obtain multiple traveling wave data.
Step 22:The maximum point and minimum point of each traveling wave data are obtained, maximum point sequence and minimum is obtained Point sequence.
Step 23:Row interpolation is entered to maximum point sequence and minimum point sequence respectively using cubic spline function method, is obtained To upper and lower envelope.
Step 24:According to upper and lower envelope, average envelope line m (t) is calculated;
Step 25:Calculate according to the following formula, obtain the traveling wave data and the average difference including line,
H (t)=y (t)-m (t),
Wherein, y (t) represents traveling wave data, and m (t) represents average envelope line.
Step 26:If difference h (t) is unsatisfactory for the condition of intrinsic mode function, using h (t) as new traveling wave Data, perform step 21;If difference h (t) meets the condition of intrinsic mode function, step 27 is performed.
Step 27:Difference h (t) is defined as the IMF components of the traveling wave data;By the IMF components from correspondence Traveling wave data separating, obtain traveling wave data discrepance.
Step 28:If the traveling wave data discrepance can continue to decompose, using the traveling wave data discrepance as new Traveling wave data, perform step 21;If the traveling wave data discrepance can not continue to decompose, each traveling wave data is obtained M layers of IMF component.
Step 29:According to every layer of spectrum kurtosis of IMF, n-layer IMF component of the spectrum kurtosis more than preset value is chosen.
Alternatively, according to below equation, the spectrum kurtosis of every layer of IMF of each traveling wave data is calculated,
Wherein, D represents every layer of spectrum kurtosis of IMF, and ξ () represents and expect that μ and σ represents each layer IMF of former travelling wave signal x The average and standard variance of component.
Optionally, the application is taken after spectrum kurtosis sorts from big to small, and the larger sequence of spectrum kurtosis is located at preceding four IMF point Amount.Play a part of dimensionality reduction by composing kurtosis selection IMF components simultaneously.
Step 30:According to the n-layer IMF components, calculate according to the following formula, obtain the corresponding row of the n-layer IMF components The Energy-Entropy of wave number evidence.
Wherein, WEEjRepresent j-th Energy-Entropy of traveling wave data, EjkRepresent j-th kth layer IMF component of traveling wave data Energy value, k is the no more than positive integer of n;EjRepresent j-th gross energy of traveling wave data.
Step 31:The Energy-Entropy is defined as the characteristic quantity of correspondence traveling wave data.
Step 32:It is 2 to set Gaussian Mixture cluster classification, 2 traveling wave data of arbitrary extracting in multiple traveling wave data, meter Calculate initial parameter value and start iteration;
Step 33:According to the following formula, according to "current" model parameter, the IMF components of traveling wave data are calculated to the traveling wave data Responsiveness,
Wherein, p () represents probability-distribution function, xjRepresent j-th Energy-Entropy of traveling wave data, θkRepresent j-th traveling wave The covariance matrix of the kth layer IMF components of data, αkRepresent j-th weight of the kth layer IMF components of traveling wave data.
Step 34:According to following formula, the model parameter of a new wheel iteration is calculated,
Wherein, μkRepresent the j-th average of the kth layer IMF components of traveling wave data, ∑ k2Represent the of j traveling wave data The k layers of variance of IMF components, αkJ-th weight of the kth layer IMF components of traveling wave data is represented, N is the sum of traveling wave data.
Step 35:If clustering cluster center is less than or equal to preset value, cluster result is obtained, with to interference traveling wave or event Barrier traveling wave classification, if clustering cluster center is more than preset value, the average that will be obtained, weight, variance iteration to step 33.
From above technical scheme, this application provides a kind of detection method of transmission line malfunction traveling wave, using warp Test mode decomposition algorithm to decompose each traveling wave data, obtain the characteristic quantity of each traveling wave data;To all traveling wave data Characteristic quantity carry out Gaussian Mixture cluster, obtain cluster result, carried out with to the interference traveling wave and fault traveling wave in traveling wave data Classification, the application can accurately identify the type of traveling wave data, accurate to interference traveling wave and fault traveling wave classification, reduce staff The workload of screening, improves operating efficiency.

Claims (5)

1. a kind of detection method of transmission line malfunction traveling wave, it is characterised in that methods described includes:
Obtain multiple traveling wave data;
Each traveling wave data is decomposed using empirical mode decomposition algorithm, obtains the characteristic quantity of each traveling wave data;
Characteristic quantity to all traveling wave data carries out Gaussian Mixture cluster, obtains cluster result, with to the interference in traveling wave data Traveling wave and fault traveling wave are classified.
2. the method for claim 1, it is characterised in that the utilization empirical mode decomposition algorithm is to each traveling wave data Decomposed, obtained the characteristic quantity of each traveling wave data, including:
Each traveling wave data is decomposed using empirical mode decomposition algorithm, obtains M layers of IMF component of each traveling wave data;
According to the M layers of IMF component, selection meets pre-conditioned n-layer IMF components;The n is the no more than positive integer of M;
According to the n-layer IMF components, the characteristic quantity of each traveling wave data is obtained.
3. method as claimed in claim 2, it is characterised in that the utilization empirical mode decomposition algorithm is to each traveling wave data Decomposed, obtained M layers of IMF component of each traveling wave data, including:
The maximum point and minimum point of each traveling wave data are obtained, maximum point sequence and minimum point sequence is obtained;
Row interpolation is entered to maximum point sequence and minimum point sequence respectively using cubic spline function method, upper and lower envelope is obtained Line;
According to upper and lower envelope, average envelope line m (t) is calculated;
Calculate according to the following formula, obtain the traveling wave data and the average difference including line,
H (t)=y (t)-m (t),
Wherein, y (t) represents traveling wave data, and m (t) represents average envelope line;
If difference h (t) is unsatisfactory for the condition of intrinsic mode function, using h (t) as new traveling wave data, repetition is obtained The step of taking the maximum point and minimum point of each traveling wave data;
If difference h (t) meets the condition of intrinsic mode function, difference h (t) is defined as the traveling wave data IMF components;
By the IMF components from corresponding traveling wave data separating, traveling wave data discrepance is obtained;
If the traveling wave data discrepance can continue to decompose, using the traveling wave data discrepance as new traveling wave data, The step of repetition obtains the maximum point and minimum point of each traveling wave data;
If the traveling wave data discrepance can not continue to decompose, M layers of component of each traveling wave data is obtained.
4. method as claimed in claim 2, it is characterised in that described according to the M layers of IMF component, chooses and meets default bar The n-layer IMF components of part, including,
According to the M layers of IMF component, every layer of spectrum kurtosis of IMF components is obtained;
According to every layer of spectrum kurtosis of IMF, n-layer IMF component of the spectrum kurtosis more than preset value is chosen.
5. method as claimed in claim 2, it is characterised in that described according to the n-layer IMF components, obtains each traveling wave number According to characteristic quantity, including,
According to the n-layer IMF components, the Energy-Entropy of the corresponding traveling wave data of the n-layer IMF components is obtained;
The Energy-Entropy is defined as the characteristic quantity of correspondence traveling wave data.
CN201710239938.2A 2017-04-13 2017-04-13 A kind of detection method of transmission line malfunction traveling wave Pending CN106841930A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710239938.2A CN106841930A (en) 2017-04-13 2017-04-13 A kind of detection method of transmission line malfunction traveling wave

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201710239938.2A CN106841930A (en) 2017-04-13 2017-04-13 A kind of detection method of transmission line malfunction traveling wave

Publications (1)

Publication Number Publication Date
CN106841930A true CN106841930A (en) 2017-06-13

Family

ID=59147578

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710239938.2A Pending CN106841930A (en) 2017-04-13 2017-04-13 A kind of detection method of transmission line malfunction traveling wave

Country Status (1)

Country Link
CN (1) CN106841930A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109917223A (en) * 2019-03-08 2019-06-21 广西电网有限责任公司电力科学研究院 A kind of transmission line malfunction current traveling wave feature extracting method
CN110161320A (en) * 2019-05-31 2019-08-23 北京无线电计量测试研究所 A kind of waveform widths uncertainty determines method and system
CN112505481A (en) * 2020-11-20 2021-03-16 云南电网有限责任公司普洱供电局 35kV power line fault traveling wave extraction method based on neighbor propagation clustering
CN115754599A (en) * 2022-11-10 2023-03-07 海南电网有限责任公司乐东供电局 Cable fault positioning method and device based on transfer learning

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101976826A (en) * 2010-10-18 2011-02-16 昆明理工大学 EMD (Empirical Mode Decomposition) based boundary element method for ultra high voltage DC transmission lines
CN102788926A (en) * 2012-07-04 2012-11-21 河南理工大学 Single-phase ground fault section positioning method of small-current ground system
CN103454562A (en) * 2013-09-22 2013-12-18 福州大学 One-phase grounding clustering line selection method of resonant grounding system
CN104597376A (en) * 2015-01-07 2015-05-06 西安理工大学 Method for measuring fault location of HVDC (High Voltage Direct Current) transmission line under consideration of measured wave velocity
CN106019046A (en) * 2016-05-18 2016-10-12 成都理工大学 Novel small-current grounding system transient line selection method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101976826A (en) * 2010-10-18 2011-02-16 昆明理工大学 EMD (Empirical Mode Decomposition) based boundary element method for ultra high voltage DC transmission lines
CN102788926A (en) * 2012-07-04 2012-11-21 河南理工大学 Single-phase ground fault section positioning method of small-current ground system
CN103454562A (en) * 2013-09-22 2013-12-18 福州大学 One-phase grounding clustering line selection method of resonant grounding system
CN104597376A (en) * 2015-01-07 2015-05-06 西安理工大学 Method for measuring fault location of HVDC (High Voltage Direct Current) transmission line under consideration of measured wave velocity
CN106019046A (en) * 2016-05-18 2016-10-12 成都理工大学 Novel small-current grounding system transient line selection method

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
徐丽兰: "谐振接地系统单相接地暂态特征量聚类选线", 《中国优秀硕士学位论文全文数据库 工程科技II辑》 *
李天友 等: "采用EMD谱带通滤波和近似熵识别的配电网单相接地故障区段定位新方法", 《供用电》 *
黄忠棋: "采用行波固有频率的混合线路故障测距新方法", 《电力系统及其自动化学报》 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109917223A (en) * 2019-03-08 2019-06-21 广西电网有限责任公司电力科学研究院 A kind of transmission line malfunction current traveling wave feature extracting method
CN110161320A (en) * 2019-05-31 2019-08-23 北京无线电计量测试研究所 A kind of waveform widths uncertainty determines method and system
CN110161320B (en) * 2019-05-31 2021-08-06 北京无线电计量测试研究所 Method and system for determining waveform width uncertainty
CN112505481A (en) * 2020-11-20 2021-03-16 云南电网有限责任公司普洱供电局 35kV power line fault traveling wave extraction method based on neighbor propagation clustering
CN115754599A (en) * 2022-11-10 2023-03-07 海南电网有限责任公司乐东供电局 Cable fault positioning method and device based on transfer learning

Similar Documents

Publication Publication Date Title
CN106841930A (en) A kind of detection method of transmission line malfunction traveling wave
Guo et al. Online identification of power system dynamic signature using PMU measurements and data mining
CN108646149A (en) Fault electric arc recognition methods based on current characteristic extraction
Motlagh et al. Power quality disturbances recognition using adaptive chirp mode pursuit and grasshopper optimized support vector machines
CN110119570B (en) Actually measured data driven wind farm model parameter checking method
CN114090396B (en) Cloud environment multi-index unsupervised anomaly detection and root cause analysis method
CN108732528A (en) A kind of digitalized electrical energy meter method for diagnosing faults based on depth confidence network
CN107704992A (en) The method and device of transmission line lightning stroke risk assessment
CN111612651A (en) Abnormal electric quantity data detection method based on long-term and short-term memory network
CN111398679B (en) Sub-synchronous oscillation identification and alarm method based on PMU (phasor measurement Unit)
CN107478963A (en) Single-phase ground fault line selecting method of small-electric current grounding system based on power network big data
CN110137947B (en) Grid voltage sag severity assessment method based on ITIC curve
Jia et al. A fast contingency screening technique for generation system reliability evaluation
CN112200038B (en) CNN-based quick identification method for oscillation type of power system
CN115932484B (en) Power transmission line fault identification and fault location method and device and electronic equipment
CN104407273A (en) Electric energy quality disturbance source positioning method considering monitoring reliability
Razavi-Far et al. Incremental design of a decision system for residual evaluation: A wind turbine application
Mahela et al. Recognition of power quality disturbances using S-transform and rule-based decision tree
CN110244099A (en) Stealing detection method based on user's voltage
Biswal et al. A novel high impedance fault detection in the micro-grid system by the summation of accumulated difference of residual voltage method and fault event classification using discrete wavelet transforms and a decision tree approach
Chen et al. Fault detection for covered conductors with high-frequency voltage signals: From local patterns to global features
Moravej et al. Power transformer protection scheme based on time‐frequency analysis
CN106021452A (en) Electromagnetic environment measurement data cleaning method
Fahim et al. A novel wavelet aided probabilistic generative model for fault detection and classification of high voltage transmission line
Hong et al. Locating High-Impedance Fault Section in Electric Power Systems Using Wavelet Transform,-Means, Genetic Algorithms, and Support Vector Machine

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
CB03 Change of inventor or designer information
CB03 Change of inventor or designer information

Inventor after: Huang Ran

Inventor after: Mu Runzhi

Inventor after: Ma Yi

Inventor after: Li Hao

Inventor after: Zhang Guangbin

Inventor after: Dong Jun

Inventor after: Cao Pulin

Inventor after: Wang Huichun

Inventor before: Huang Ran

Inventor before: Shen Yuan

Inventor before: Ma Yi

Inventor before: Mu Runzhi

Inventor before: Zhang Guangbin

Inventor before: Han Yiming

Inventor before: Zhou Fangrong

Inventor before: Dong Jun

Inventor before: Qian Guochao

Inventor before: Ma Yutang

RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20170613