Patent Publication Number: US-2022221528-A1

Title: Method and device for assessing state of health of transformer, and storage medium

Description:
PRIORITY STATEMENT 
     This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/CN2019/088191 which has an International filing date of May 23, 2019, which designated the United States of America 2020, the entire contents of each of which are hereby incorporated herein by reference. 
    
    
     FIELD 
     Embodiments of the present invention generally relate to the field of electric power systems, in particular to a method and an apparatus for assessing a health status of a transformer, a cloud platform, a server, and a storage medium. 
     BACKGROUND 
     Power quality (PQ) refers to the quality of power in a power system. In a strict sense, main indicators for measuring power quality include voltage, frequency, and waveform. In a general sense, power quality refers to high-quality power supply, including voltage quality, current quality, power supply quality, and power use quality. Power quality problems may be defined as: voltage, current, or frequency deviations that cause electrical equipment to malfunction or operate abnormally, including frequency deviations, voltage deviations, voltage fluctuations and flickers, three-phase imbalance, instantaneous or transient overvoltage, waveform distortions (harmonics), voltage sags, interruptions, and swells, and power supply continuity. 
     Continuous monitoring, analysis and assessment of power quality information is a precondition for discovering power quality problems and improving power quality. A power quality monitoring system uses a power quality monitoring terminal installed on the power grid side or the user side to transmit monitoring data, namely PQ data, back to a monitoring center (a monitoring master station or sub-station) through a network, thereby simultaneously monitoring a plurality of locations, and releases information related to power quality, providing an effective form of power quality monitoring and assessment. 
     A transformer is an important part of a power system, and, for example, a distribution transformer refers to a static electrical appliance used in a distribution system to transmit alternating-current power by transforming alternating-current voltages and currents according to the law of electromagnetic induction. It is an apparatus for changing an alternating-current voltage (current) having a certain value into another or a plurality of voltages (currents) of the same frequency with different values. When the primary winding is energized with an alternating current, alternating magnetic flux is produced and, by magnetic permeability of an iron core, induces an alternating electromotive force in the secondary winding. A distribution transformer mainly functions to transmit electrical energy. 
     On the one hand, PQ data may be used to analyze power quality, and on the other hand, it may be used to analyze a health status of a key electrical apparatus, for example, a transformer. For example, a health status of a transformer is assessable by synthesizing power, voltage, current and harmonic components thereof, and other parameters measured by a power quality monitoring system. 
     SUMMARY 
     However, the inventors have discovered that not all transformer data may be obtained and used for analysis, due to insufficiency of power quality monitoring systems to record data, and it is neither possible nor practical to monitor each transformer by using power quality monitoring systems, because installation of a power quality monitoring system is expensive and there are usually a large number of transformers even in a small city. Thus, the inventors have discovered that how to access a health status of a transformer configured with no power quality monitoring system has become a problem that needs to be solved urgently. 
     Against the above-described, in an embodiment of the present invention, on the one hand, a method for assessing a health status of a transformer is proposed, and on the other hand, an apparatus for assessing a health status of a transformer, a cloud platform, a server, and a storage medium are proposed, in order to assess a health status of a transformer configured with no power quality monitoring system. 
     A method for assessing a health status of a transformer proposed in an embodiment of the present invention comprises: using N transformers configured with a power quality monitoring system as a first group of transformers, and obtaining a first measurement dataset of each of the first group of transformers to obtain N first measurement datasets, wherein N is a positive integer greater than or equal to a first specified value; using M transformers configured with no power quality monitoring system as a second group of transformers, and obtaining a second measurement dataset of each of the second group of transformers to obtain M second measurement datasets, wherein M is a positive integer greater than or equal to a second specified value, and the first measurement dataset and the second measurement dataset comprise a common data type; clustering the N transformers in the first group of transformers based on values of the common data type in the N first measurement datasets to obtain r first groups, wherein r is a positive integer; clustering the M transformers in the second group of transformers based on values of the common data type in the M second measurement datasets to obtain r second groups; calculating a similarity between each first group and each second group, and establishing r similarity mapping relationships between the first groups and the second groups based on a maximum similarity between two groups; and assessing a health status of a transformer in each second group using a first measurement dataset of a transformer in a first group that is in a similarity mapping relationship with the second group. 
     An apparatus for assessing a health status of a transformer proposed in an embodiment of the present invention comprises: a first obtaining module configured to use N transformers configured with a power quality monitoring system as a first group of transformers, and obtain a first measurement dataset of each of the first group of transformers to obtain N first measurement datasets, wherein N is a positive integer greater than or equal to a first specified value; a second obtaining module configured to use M transformers configured with no power quality monitoring system as a second group of transformers, and obtain a second measurement dataset of each of the second group of transformers to obtain M second measurement datasets, wherein M is a positive integer greater than or equal to a second specified value, and the first measurement dataset and the second measurement dataset comprise a common data type; a first grouping module configured to cluster the N transformers in the first group of transformers based on values of the common data type in the N first measurement datasets to obtain r first groups, wherein r is a positive integer; a second grouping module configured to cluster the M transformers in the second group of transformers based on values of the common data type in the M second measurement datasets to obtain r second groups; a mapping relationship establishment module configured to calculate a similarity between each first group and each second group, and establish r similarity mapping relationships between the first groups and the second groups based on a maximum similarity between two groups; and an assessing module configured to assess a health status of a transformer in each second group using a first measurement dataset of a transformer in a first group that is in a similarity mapping relationship with the second group. 
     Another apparatus for assessing a health status of a transformer proposed in an embodiment of the present invention comprises: at least one memory and at least one processor, wherein the at least one memory is configured to store a computer program; and the at least one processor is configured to invoke the computer program stored in the at least one memory, to perform the method for assessing a health status of a transformer according to any of the described embodiments. 
     A cloud platform or server proposed in an embodiment of the present invention comprises the apparatus for assessing a health status of a transformer according to any of the described embodiments. 
     A computer-readable storage medium proposed in an embodiment of the present invention stores a computer program; the computer program is executed by a processor to implement the method for assessing a health status of a transformer according to any of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention will be described in detail below with reference to the drawings, allowing those of ordinary skill in the art to have a clearer understanding of the above-described and other features and advantages of the present invention, and among the drawings, 
         FIG. 1  is an example flowchart of a method for assessing a health status of a transformer in an embodiment of the present invention. 
         FIG. 2  is an example structural diagram of an apparatus for assessing a health status of a transformer in an embodiment of the present invention. 
         FIG. 3  is an example structural diagram of another apparatus for assessing a health status of a transformer in an embodiment of the present invention. 
     
    
    
     The meanings of the reference signs used in the drawings are as follows: 
     
       
         
           
               
               
             
               
                   
               
               
                 Reference sign 
                 Meaning 
               
               
                   
               
             
            
               
                 S101-S106 
                 Steps 
               
               
                 201 
                 First obtaining module 
               
               
                 202 
                 Second obtaining module 
               
               
                 203 
                 First grouping module 
               
               
                 204 
                 Second grouping module 
               
               
                 205 
                 Mapping relationship establishment module 
               
               
                 206 
                 Assessing module 
               
               
                 31 
                 Memory 
               
               
                 32 
                 Processor 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS 
     A method for assessing a health status of a transformer proposed in an embodiment of the present invention comprises: using N transformers configured with a power quality monitoring system as a first group of transformers, and obtaining a first measurement dataset of each of the first group of transformers to obtain N first measurement datasets, wherein N is a positive integer greater than or equal to a first specified value; using M transformers configured with no power quality monitoring system as a second group of transformers, and obtaining a second measurement dataset of each of the second group of transformers to obtain M second measurement datasets, wherein M is a positive integer greater than or equal to a second specified value, and the first measurement dataset and the second measurement dataset comprise a common data type; clustering the N transformers in the first group of transformers based on values of the common data type in the N first measurement datasets to obtain r first groups, wherein r is a positive integer; clustering the M transformers in the second group of transformers based on values of the common data type in the M second measurement datasets to obtain r second groups; calculating a similarity between each first group and each second group, and establishing r similarity mapping relationships between the first groups and the second groups based on a maximum similarity between two groups; and assessing a health status of a transformer in each second group using a first measurement dataset of a transformer in a first group that is in a similarity mapping relationship with the second group. 
     In one embodiment, the first measurement dataset comprises a voltage and/or a current, a harmonic component, and a power of a transformer; and the second measurement dataset comprises at least one of a power, a voltage, and a current of a transformer. 
     In one embodiment, a collection interval of the common data type in the first measurement dataset is shorter than a collection interval of the common data type in the second measurement dataset. 
     In one embodiment, the first measurement dataset further comprises at least one of a grid frequency, a voltage deviation, and a voltage interruption. 
     In one embodiment, M is greater than N. 
     An apparatus for assessing a health status of a transformer proposed in an embodiment of the present invention comprises: a first obtaining module configured to use N transformers configured with a power quality monitoring system as a first group of transformers, and obtain a first measurement dataset of each of the first group of transformers to obtain N first measurement datasets, wherein N is a positive integer greater than or equal to a first specified value; a second obtaining module configured to use M transformers configured with no power quality monitoring system as a second group of transformers, and obtain a second measurement dataset of each of the second group of transformers to obtain M second measurement datasets, wherein M is a positive integer greater than or equal to a second specified value, and the first measurement dataset and the second measurement dataset comprise a common data type; a first grouping module configured to cluster the N transformers in the first group of transformers based on values of the common data type in the N first measurement datasets to obtain r first groups, wherein r is a positive integer; a second grouping module configured to cluster the M transformers in the second group of transformers based on values of the common data type in the M second measurement datasets to obtain r second groups; a mapping relationship establishment module configured to calculate a similarity between each first group and each second group, and establish r similarity mapping relationships between the first groups and the second groups based on a maximum similarity between two groups; and an assessing module configured to assess a health status of a transformer in each second group using a first measurement dataset of a transformer in a first group that is in a similarity mapping relationship with the second group. 
     In one embodiment, the first measurement dataset comprises a voltage and/or a current, a harmonic component, and a power of a transformer; and the second measurement dataset comprises at least one of a power, a voltage, and a current of a transformer. 
     In one embodiment, the first measurement dataset further comprises at least one of a grid frequency, a voltage deviation, and a voltage interruption. 
     Another apparatus for assessing a health status of a transformer proposed in an embodiment of the present invention comprises: at least one memory and at least one processor, wherein the at least one memory is configured to store a computer program; and the at least one processor is configured to invoke the computer program stored in the at least one memory, to perform the method for assessing a health status of a transformer according to any of the described embodiments. 
     A cloud platform or server proposed in an embodiment of the present invention comprises the apparatus for assessing a health status of a transformer according to any of the described embodiments. 
     A computer-readable storage medium proposed in an embodiment of the present invention stores a computer program; the computer program is executed by a processor to implement the method for assessing a health status of a transformer according to any of the described embodiments. 
     It is thus clear from the above-described solution that, in an embodiment of the present invention, transformers configured with a power quality monitoring system and transformers equipped with no power quality monitoring system are considered as two types of transformers, their respective measurement datasets are obtained, the two types of transformers are clustered and grouped respectively based on a common data type comprised in respective measurement datasets, then similarity mapping relationships are established between groups of the two types of transformers, and then a health status of a transformer configured with no power quality monitoring system is assessed using power quality data on a transformer configured with a power quality monitoring system, which allows an assessment of a health status of a transformer having no power quality monitoring system to be implemented. 
     In addition, several specific embodiments of data included in several easy-to-implement measurement datasets are described. 
     Besides, setting a larger M and a larger N allows the two types of transformers to be grouped more accurately when clustered, and thus makes health status assessment more accurate. 
     For conciseness and intuitiveness of description, solutions provided by the present invention will be elaborated below by describing several representative embodiments. The great details given in the embodiments are only intended to help understand solutions provided by the present invention. However, it is obvious that the implementation of a technical solution provided by the present invention may not be limited to the details. In order to avoid unnecessary confusion with a solution provided by the present invention, some embodiments are described not in detail, but only structurally. Hereinafter, “comprising” means “including but not limited to”, and “based on . . . ” means “at least based on . . . , but not limited to being only based on . . . ”. Due to the linguistic usage pattern of Chinese, when the quantity of an element is not specifically indicated below, it means that the element may number one or more, or may be understood to number at least one. 
     In an embodiment of the present invention, considering that a large number of transformers are configured with no power quality monitoring system and that some transformers are configured with a power quality monitoring system, the transformers configured with a power quality monitoring system and the transformers configured with no power quality monitoring system may be regarded as two types of transformers; in addition, considering that health statuses of transformers with similar characteristics should be similar, the two types of transformers may be clustered and grouped according to certain characteristics, then similarity mapping relationships may be established between groups of the two types of transformers, and then a health status of a transformer configured with no power quality monitoring system is assessed using power quality data on a transformer configured with a power quality monitoring system. 
     In order to make clearer the technical solutions and advantages of the present invention, the present invention will be described in greater detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention, instead of limiting the protection scope of the present invention. 
       FIG. 1  is an example flowchart of a method for assessing a health status of a transformer in an embodiment of the present invention. As shown in  FIG. 1 , the method may comprise the following steps: 
     Step S 101 : using N transformers configured with a power quality monitoring system as a first group of transformers, and obtaining a first measurement dataset of each of the first group of transformers to obtain N first measurement datasets, wherein N is a positive integer greater than or equal to a first specified value. A first measurement dataset is power quality monitoring data, also called PQ data. 
     For example, in one embodiment, N first measurement datasets may be denoted by S1={T1, T2, . . . , TN}, where N is the number of transformers, T1 is the first measurement dataset of the first transformer, T2 is the first measurement dataset of the second transformer, and Tn is the first measurement dataset of the N-th transformer. The value of the first specified value may be an experimental value or an empirical value. 
     In one embodiment, a first measurement dataset may comprise a voltage and/or current, a harmonic component, a power, etc. of a transformer. In addition, in another embodiment, a first measurement dataset may further comprise at least one of a grid frequency, a voltage deviation, and a voltage interruption. 
     Step S 102 : using M transformers configured with no power quality monitoring system as a second group of transformers, and obtaining a second measurement dataset of each of the second group of transformers to obtain M second measurement datasets, wherein M is a positive integer greater than or equal to a second specified value. The first measurement dataset and the second measurement dataset comprise a common data type. 
     For example, in one embodiment, M second measurement datasets may be denoted by S2={N1, N2, . . . , NM}, where M is the number of transformers, N1 is the second measurement dataset of the first transformer, N2 is the second measurement dataset of the second transformer, and Nm is the second measurement dataset of the M-th transformer. M is much larger than N in most cases. The value of a second specified value may be an experimental value or an empirical value. 
     In one embodiment, a second measurement dataset may comprise at least one of a voltage, a current, and a power of a transformer. For example, if the second measurement dataset only comprises a power, then a common data type comprised in the first measurement dataset and the second measurement dataset is power; another example is that, if the second measurement dataset comprises a power and a voltage, and the first measurement dataset also comprises a power and a voltage, then a common data type comprised in the first measurement dataset and the second measurement dataset is power and voltage. Generally, since data on a transformer configured with a power quality monitoring system is collected more frequently, a collection interval of the common data type in the first measurement dataset is shorter than a collection interval of the common data type in the second measurement dataset. 
     Step S 103 : clustering the N transformers in the first group of transformers based on values of the common data type in the N first measurement datasets to obtain r first groups, wherein r is a positive integer. 
     For example, if the common data type comprised in the first measurement dataset and the second measurement dataset is power, then in step S 103 , the N transformers in the first group of transformers may be clustered based on values of power in the N first measurement datasets to obtain r first groups. For example, they may further be denoted by A1, A2, . . . , Ar respectively. 
     Step S 104 : clustering the M transformers in the second group of transformers based on values of the common data type in the M second measurement datasets to obtain r second groups. 
     For example, if the common data type comprised in the first measurement dataset and the second measurement dataset is power, then in step S 104 , the M transformers in the second group of transformers may be clustered based on values of power in the M second measurement datasets to obtain r second groups. For example, they may be denoted by B1, B2, . . . , Br. 
     Step S 105 : calculating a similarity between each first group and each second group, and establishing r similarity mapping relationships between the first groups and the second groups based on a maximum similarity between two groups. 
     In this step, a similarity mapping between A1, A2, . . . , Ar and B1, B2, . . . , Br, for example, f j :B i →A j , may be determined. In specific implementation, a similarity between any two groups of the two is calculable, for example, by representing a similarity value with a number between 0 and 1, 1 indicating the greatest similarity, 0 indicating the least similarity, and then by associating the pairwise groups that have the largest similarity value to obtain r similarity mapping relationships. 
     Step S 106 : assessing a health status of a transformer in each second group using a first measurement dataset of a transformer in a first group that is in a similarity mapping relationship with the second group. 
     For example, for the above-mentioned mapping relationship f j :B i →A j , a health status of a transformer in group B i  is assessable using a health state of a transformer in group A j , that is, being assessable using a first measurement dataset of a transformer in group A j . In addition, an assessment may also be performed in conjunction with other data, such as location environment and other factors. 
     After a method for assessing a health status of a transformer in an embodiment of the present invention has been described in detail above, an apparatus for assessing a health status of a transformer in an embodiment of the present invention will be described below, wherein the apparatus in an embodiment of the present invention may be used to implement the above-described method in an embodiment of the present invention, and, for content not disclosed in detail in the apparatus embodiments of the present invention, see the corresponding description of the above-described method embodiments, which will not be described in detail again. 
       FIG. 2  is an example structural diagram of an apparatus for assessing a health status of a transformer in an embodiment of the present invention. As shown in  FIG. 2 , the apparatus may comprise: a first obtaining module  201 , a second obtaining module  202 , a first grouping module  203 , a second grouping module  204 , a mapping relationship establishment module  205 , and an assessing module  206 . 
     The first obtaining module  201  is configured to use N transformers configured with a power quality monitoring system as a first group of transformers, and obtain a first measurement dataset of each of the first group of transformers to obtain N first measurement datasets, wherein N is a positive integer greater than or equal to a first specified value. In one embodiment, the first measurement dataset may comprise a voltage and/or current, a harmonic component, a power, etc. of a transformer; in another embodiment, the first measurement dataset may further comprise at least one of a grid frequency, a voltage deviation, and a voltage interruption. 
     The second obtaining module  202  is configured to use M transformers configured with no power quality monitoring system as a second group of transformers, and obtain a second measurement dataset of each of the second group of transformers to obtain M second measurement datasets, wherein M is a positive integer greater than or equal to a second specified value, and the first measurement dataset and the second measurement dataset comprise a common data type. In one embodiment, the second measurement dataset comprises at least one of a power, a voltage, and a current of a transformer. In one embodiment, a collection interval of the common data type in the first measurement dataset is shorter than a collection interval of the common data type in the second measurement dataset. In one embodiment, M is greater than N. 
     The first grouping module  203  is configured to cluster the N transformers in the first group of transformers based on values of the common data type in the N first measurement datasets to obtain r first groups, wherein r is a positive integer. 
     The second grouping module  204  is configured to cluster the M transformers in the second group of transformers based on values of the common data type in the M second measurement datasets to obtain r second groups. 
     The mapping relationship establishment module  205  is configured to calculate a similarity between each first group and each second group, and establish r similarity mapping relationships between the first groups and the second groups based on a maximum similarity between two groups. 
     The assessing module  206  is configured to assess a health status of a transformer in each second group using a first measurement dataset of a transformer in a first group that is in a similarity mapping relationship with the second group. 
       FIG. 3  is an example structural diagram of another apparatus for assessing a health status of a transformer in an embodiment of the present invention. As shown in  FIG. 3 , the apparatus may comprise: at least one memory  31  and at least one processor  32 . In addition, the apparatus may further comprise some other components, such as a communication port. These components communicate with one another through a bus. 
     The at least one memory  31  is configured to store a computer program. In one embodiment, the computer program may be understood as comprising the various modules of an apparatus for assessing a health status of a transformer shown in  FIG. 2 . In addition, the at least one memory  31  may also store an operating system and the like. Operating systems include, but are not limited to, Android operating system, Symbian operating system, Windows operating system, and Linux operating system. 
     At least one processor  32  is configured to invoke the computer program stored in the at least one memory  31 , to perform the method for assessing a health status of a transformer as described in an embodiment of the present invention. The processor  32  may be a CPU, a processing unit/module, an ASIC, a logic module, a programmable gate array, etc. It can receive and send data through the communication port. 
     In addition, an embodiment of the present invention further provides a server, or a server cluster, or a cloud platform that comprises the above-described apparatus for assessing a health status of a transformer shown in  FIG. 2  or  FIG. 3 . 
     It should be noted that not all the steps or modules in the above-described flows and structural diagrams are required, and certain steps or modules may be omitted as needed. The sequence of performing steps is not fixed and may be adjusted as needed. The division of modules is only intended for ease of description of the functional division adopted, and, in actual implementation, a module may be implemented by a plurality of modules, while functions of a plurality of modules may also be implemented by the same module, these modules being locatable in the same device or in different devices. 
     It is understandable that the hardware modules in the above-described embodiments may be implemented mechanically or electronically. For example, a hardware module may comprise a specially designed permanent circuit or logic element, for example, a special processor, an FPGA, or an ASIC, for completing specific operations. A hardware module may further comprise programmable logic or circuitry (for example, a general-purpose processor or any other programmable processor) that is temporarily configured by software to perform specific operations. Whether to implement a hardware module specifically in a mechanical manner or by using a circuit temporarily configured (for example, being configured by software) may be determined on the basis of cost and time considerations. 
     In addition, an embodiment of the present invention further provides computer software that may be executed on a server or a server cluster or a cloud platform, the computer software being executable by a processor to implement a method for assessing a health status of a transformer as described in an embodiment of the present invention. 
     In addition, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored, and the computer program may be executed by a processor to implement a method for assessing a health status of a transformer as described in an embodiment of the present invention. Specifically, a system or device equipped with a storage medium may be provided, the storage medium storing software program code for implementing the functions of any of the above-described embodiments, and a computer (for example, a CPU or an MPU) of the system or device is caused to read and execute the program code stored on the storage medium. In addition, by an instruction based on program code, an operating system, etc. operating on a computer may also be caused to complete part or all of the actual operations. It is also possible that functions of any one of the above-described embodiments may be implemented by writing program code read from a storage medium to a memory disposed in an expansion board inserted into a computer or to a memory disposed in an expansion unit connected to a computer, and then by, according to an instruction of program code, causing a CPU, etc. installed on the expansion board or expansion unit to execute part of all of actual operations. Examples of a storage medium for providing program code include floppy disk, hard disk, magneto-optical disk, optical disk (for example, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, or DVD+RW), magnetic tape, non-volatile memory card, and ROM. Optionally, program code may be downloaded from a server computer via a communications network. 
     It is thus clear from the above-described solution that, in an embodiment of the present invention, transformers configured with a power quality monitoring system and transformers equipped with no power quality monitoring system are considered as two types of transformers, their respective measurement datasets are obtained, the two types of transformers are clustered and grouped respectively based on a common data type comprised in respective measurement datasets, then similarity mapping relationships are established between groups of the two types of transformers, and then a health status of a transformer configured with no power quality monitoring system is assessed using power quality data on a transformer configured with a power quality monitoring system, which allows an assessment of a health status of a transformer having no power quality monitoring system to be implemented. 
     In addition, several specific embodiments of data included in several easy-to-implement measurement datasets are described. 
     Besides, setting a larger M and a larger N allows the two types of transformers to be grouped more accurately when clustered, and thus makes health status assessment more accurate. 
     The above-described embodiments are only preferred embodiments of the present invention, instead of being intended to limit the scope of the present invention, and any modifications, equivalent substitutions, and improvements made without departing from the spirit or principle of the present invention shall fall within the protection scope of the present invention.