Online diagnosis method for parallel transformer winding deformation

Abstract

The embodiment of the invention discloses an on-line diagnosis method for parallel transformer winding deformation, and relates to the technical field of power system equipment state monitoring, and the method comprises the steps: obtaining the electrical quantities of two transformers in parallel operation in an operation state in an on-line manner; determining the current impedance of the two transformers by reversely solving a load distribution relation between the first transformer and the second transformer based on the electrical quantities of the two transformers in the operation state; comparing the current impedances of the two transformers with corresponding reference impedances in a normal state that the windings are not deformed, and when the difference value or the change rate between the current impedances and the reference impedances exceeds a preset threshold value, determining that the windings of the corresponding transformers are deformed; diagnosis can be completed under the condition that normal operation of the transformer is not interrupted, unnecessary power failure is avoided, power supply reliability is improved, diagnosis is rapid and accurate, hidden danger of equipment can be found in advance, and power grid safety is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system equipment state monitoring, and in particular to an online diagnosis method for winding deformation of a parallel transformer. BACKGROUND

[0002] A transformer is a core equipment of a power system, which is inevitably impacted by external short-circuit current during operation. When the short-circuit current exceeds the withstand capability of the transformer itself, physical deformation of the internal winding of the transformer may occur, which constitutes a serious safety hazard. Since the winding of the transformer is enclosed in an oil tank, it has the characteristics of a "black box", and therefore accurate diagnosis of winding deformation has been a technical problem in the industry.

[0003] At present, the commonly used methods for diagnosing winding deformation of a transformer in the industry mainly include a frequency response method and a short-circuit impedance method. The frequency response method compares the frequency response characteristics of the three-phase winding of the transformer to determine deformation, but this method has inherent defects. First, due to differences in manufacturing process, lead arrangement, etc., the frequency response characteristics of the three-phase winding of a healthy transformer are inherently inconsistent. Second, the test results are easily disturbed by external factors such as the grounding condition on site, leading to a high misjudgment rate. The short-circuit impedance method is a commonly used test method, but in field application, it is affected by many factors such as three-phase voltage imbalance, differences between test conditions and factory test conditions, etc., and is also prone to misjudgment.

[0004] More importantly, both of the above two traditional methods require the transformer to be de-energized before detection. This means that after the transformer is subjected to a short-circuit impact, in order to confirm its internal state, a planned outage must be arranged, which not only affects the power supply reliability of the power grid, but also may cause unnecessary economic losses. Therefore, there is an urgent need for a method that can quickly and accurately diagnose winding deformation of a running transformer without de-energizing. SUMMARY

[0005] The main purpose of the present application is to provide an online diagnosis method for winding deformation of a parallel transformer, which can solve the technical problems of transformer winding deformation diagnosis methods requiring de-energizing operation, being unable to be performed online, being easily disturbed to cause misjudgment, and affecting power supply reliability.

[0006] To achieve the above purpose, the first aspect of the present application provides an online diagnosis method for winding deformation of a parallel transformer, which comprises: online acquiring electrical quantities of two transformers running in parallel under a running state; based on the electrical quantities of the two transformers under the running state, determining the current impedance of the two transformers by inversely solving a load distribution relationship between the first transformer and the second transformer; The current impedance of the two transformers is compared with reference impedance corresponding to a normal state in which the windings are not deformed, and it is determined that winding deformation of the corresponding transformer occurs when a difference or a change rate between the current impedance and the reference impedance exceeds a preset threshold.

[0007] The second aspect of the present application provides an online diagnosis device for winding deformation of parallel transformers, comprising: A parameter acquisition module is configured to acquire electrical quantities of two transformers operating in parallel in a running state. A processor is electrically connected to the parameter acquisition module. The processor is configured to perform the following operations: Based on the electrical quantities of the two transformers in the running state, the current impedance of the two transformers is determined by inversely solving a load distribution relationship between the first transformer and the second transformer. The current impedance of the two transformers is compared with reference impedance corresponding to a normal state in which the windings are not deformed, and it is determined that winding deformation of the corresponding transformer occurs when a difference or a change rate between the current impedance and the reference impedance exceeds a preset threshold.

[0008] The third aspect of the present application provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to make the processor perform the steps of the first aspect and any possible implementation manner thereof.

[0009] The present application provides an online diagnosis method for winding deformation of parallel transformers, which comprises the following steps: acquiring electrical quantities of two transformers operating in parallel in a running state; based on the electrical quantities of the two transformers in the running state, the current impedance of the two transformers is determined by inversely solving a load distribution relationship between the first transformer and the second transformer; the current impedance of the two transformers is compared with reference impedance corresponding to a normal state in which the windings are not deformed, and it is determined that winding deformation of the corresponding transformer occurs when a difference or a change rate between the current impedance and the reference impedance exceeds a preset threshold.

[0010] The technical scheme provided by the application has the following beneficial effects: the application can complete diagnosis without interrupting the normal operation of the transformer, avoids unplanned power outage caused by diagnosis, and significantly improves the power supply reliability and economic benefits of the power grid. The method can immediately perform online evaluation after the transformer is subjected to a short-circuit impact event, quickly judge the health status of the equipment, provide immediate basis for the decision of the operation and maintenance personnel, and effectively shorten the fault troubleshooting and response time. In addition, the method in the application is based on the internal physical law of parallel operation of the transformer, and the diagnosis is performed by reverse calculation of impedance, which has clear physical meaning and avoids interference caused by external environmental factors such as test working condition difference and poor grounding in the traditional method, thereby improving the accuracy and reliability of the diagnosis. Through timely and accurate diagnosis of winding deformation, structural hidden dangers inside the equipment can be found in advance, sudden failures caused by further deterioration of winding deformation can be effectively prevented and controlled, and the safe and stable operation of the transformer itself and the entire power grid can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0012] Among them: Figure 1 A flowchart of an online diagnosis method for winding deformation of a parallel transformer provided by an embodiment of the present application; Figure 2 A system environment diagram of a no-power-off diagnosis device provided by an embodiment of the present application; Figure 3 A structure diagram of an online diagnosis device for winding deformation of a parallel transformer provided by an embodiment of the present application; Figure 4 A structure diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0014] The terms "first", "second", and the like in the description and in the claims of the present application and above drawings are used for distinguishing between similar objects talking about the application and not necessarily for describing a specific sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and embodiments of the application. Moreover, the terms "comprise", "comprising", "have", "having", "include", "including", "contain", "containing", or any other similar phrase are intended to cover a non-exclusive inclusion, such that a process, method, system, product, or apparatus that comprises, has, includes, contains items or elements that are not listed is not excluded from the scope of embodiments of the application. Further, unless otherwise stated, terms such as "some" and "another" mean at least one, and terms such as "each" and "each separate" mean "individually."

[0015] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the same embodiments, or alternative or alternative embodiments.

[0016] The application embodiments mentioned in the application are described below in conjunction with the accompanying drawings of the application embodiments.

[0017] Figure 1 A flowchart of an online diagnosis method for winding deformation of a parallel transformer according to an embodiment of the application is provided. The technical concept of the method is to utilize the inherent load distribution physical law between two parallel transformers, to reversely solve the equivalent impedance of each transformer through online monitoring of electrical quantities in a non-power-off state, and compare the current impedance with the pre-stored baseline impedance in a healthy state, so as to realize the judgment of whether the winding has physical deformation.

[0018] Please refer to Figure 2 which is a system environment schematic diagram of the non-power-off diagnosis device in an embodiment of the application. The main figure mark explanations are as follows: 10-first transformer; 20-second transformer; 30-voltage transformer; 40-current transformer; 50-non-power-off diagnosis device; 60-high voltage bus; 70-low voltage bus; 80-load.

[0019] In a typical substation application, the high voltage side power supply of the power system is connected to the first transformer 10 and the second transformer 20 in parallel via a high voltage bus 60. Usually, the two transformers have the same or similar transformation ratio and impedance characteristics, which convert the high voltage power into low voltage power and output to the low voltage bus 70, and then supply power to various loads 80 connected to the back end. In order to monitor the operating state of the two transformers, measurement devices, i.e. voltage transformers 30 and current transformers 40, are installed on the secondary sides of the first transformer 10 and the second transformer 20. It can be understood that these transformers can accurately convert high voltage and large current in proportion, and output standard small signals for measurement instruments and protection devices.

[0020] In an embodiment of the present application, the method in the present application can be implemented by a non-stop diagnosis device 50. The non-stop diagnosis device 50 is electrically connected to the secondary output terminals of the voltage transformers 30 and the current transformers 40 corresponding to the first transformer 10 and the second transformer 20 through signal cables. In this way, the non-stop diagnosis device 50 can obtain the voltage and current signals in the running process of the two transformers in real time and online without the need of power-off operation of the transformers.

[0021] As shown in FIG. 1, Figure 1 the method comprises: 101. obtaining electrical quantities of two transformers running in parallel in an operating state online.

[0022] The execution subject of the method in the embodiment of the present application can be an online diagnosis device for parallel transformer winding deformation, which can be implemented on an electronic device in actual application.

[0023] The non-stop diagnosis device 50 can enter a continuous monitoring state. On the one hand, it can passively receive signals from the substation data acquisition and monitoring control system or the line protection device indicating that a short-circuit fault affecting the transformer has occurred in the power grid; on the other hand, it can also actively monitor the current signals collected by itself, and when detecting that the current amplitude has a sudden change far exceeding the normal load fluctuation in a very short time, it will also judge it as a suspicious impact event. When no such event is monitored, the flow remains in this step and waits in a loop.

[0024] In an optional embodiment, the above step 101 comprises: collecting voltage signals and current signals through voltage transformers and current transformers electrically connected to the above two transformers, and determining the power values of the above two transformers according to the above voltage signals and current signals.

[0025] Specifically, once the impact event is detected, the post-event diagnosis process is started immediately by the non-stop diagnosis device 50. At this time, the device can obtain the real-time operating parameters of the first transformer 10 and the second transformer 20 after the impact event, i.e., the respective voltage and current signals, while the transformers remain in parallel operation. These analog signals can be high-speed sampled and quantized by the analog-to-digital converter inside the device, converted into a digital signal sequence.

[0026] Subsequently, the processor inside the device processes these digital signals, for example, by Fourier transform algorithm, to calculate the effective value and phase angle of the output voltage of the two transformers and the effective value and phase angle of the output current. Based on these voltage and current phasors, the processor can further calculate the power S A and the power S B .

[0027] 102. Based on the electrical quantities of the two transformers in the operating state, the current impedance of the two transformers is determined by inversely solving a load distribution relationship between the first transformer and the second transformer.

[0028] Specifically, after obtaining the respective power of the two transformers, the processor can inversely solve the respective equivalent impedance by using the basic principle of load distribution of parallel transformers. According to the power system theory, the load distribution ratio of two parallel transformers is inversely proportional to their respective impedances (calculated to the same voltage level).

[0029] Based on the obtained post-impact electrical quantities, the current impedance of the two transformers after the event can be calculated by inversely solving the load distribution relationship, denoted as and .

[0030] In an alternative embodiment, the above step 102 comprises: obtaining the total load and power ratio of the two transformers; based on the load distribution relationship, calculating the current impedance ratio of the two transformers according to the total load and power ratio of the two transformers; determining the current impedance of the two transformers according to the current impedance ratio and the reference impedance.

[0031] The load distribution relationship can be described by the following formula:

[0032]

[0033] wherein, The total load shared by the two transformers. The core relationship can be derived from the above formula:

[0034] The relationship shows that the ratio of the power shared by the two transformers is equal to the inverse ratio of their equivalent impedances. At this time, since and are known quantities, the impedance ratio can be calculated.

[0035] However, only the ratio cannot determine the absolute values of and . In the embodiments of the present application, the impedance values Z A0 and Z B0 can be provided before short circuit as reference values (reference impedances), and a reference impedance database can be established in advance to query the reference impedance corresponding to the current gear. Using the load distribution ratio and the impedance ratio calculated by the foregoing steps, in combination with the reference values, the specific impedance values and after short circuit can be calculated. The specific formula is as follows:

[0036]

[0037] In the embodiments of the present application, accurate reference bases need to be established for diagnosis before the diagnosis process starts. The process is performed when the transformer is confirmed to be in a healthy state (for example, after being put into operation or after being confirmed to be normal after comprehensive maintenance).

[0038] Optionally, the foregoing method further includes: traversing the tap switch gears of the two transformers, and determining the corresponding reference impedances at each gear to establish a reference impedance database covering all the tap switch gears.

[0039] The comparison is performed between the current impedance and the reference impedance corresponding to the current gear in the reference impedance database at the current operating gear.

[0040] Further, the method of determining the reference impedance can be consistent with or similar to the foregoing method of calculating the current impedance, except that the electrical quantities are obtained in the normal operating state (when no shock event occurs). That is, it can be understood that: the same algorithm as step 102 is used, and based on the electrical quantities in the normal operating state, after obtaining the power shared by each of the two transformers, the processor uses the basic principle of load distribution of parallel transformers to inversely solve the equivalent impedances of each transformer.

[0041] Note that this is still the impedance ratio (reference impedance ratio). To solve for the absolute value, another relationship needs to be introduced. In practical applications, the short circuit impedance percentage of the transformer is usually used to perform the calculation. The short circuit impedance percentage is defined as: where is the rated current, is the rated voltage, is the equivalent impedance of the transformer. From this, it follows that where is the rated capacity of the transformer.

[0042] Therefore, the impedances of the two transformers can be expressed as:

[0043]

[0044] where and are the rated capacities of the first transformer 10 and the second transformer 20, respectively, and are known parameters. Substituting these two expressions into the impedance ratio relationship yields a relationship for the two unknown short circuit impedance percentages and .

[0045] As a specific way of solving, the load distribution formula that includes the rated capacity can be used. The load current of each transformer is expressed as a fraction of the total load current, which can be obtained as:

[0046]

[0047] This is a system of two equations with two unknowns, where , , are the electrical quantities measured online, , are the device nameplate parameters, and the unknowns are and . By solving this system of equations, the processor can accurately calculate the reference impedance Z A0 of the first transformer 10 and the reference impedance Z B0 of the second transformer 20 under the current healthy operating state. It should be noted that these impedance values are complex numbers, including resistance components and reactance components, which together constitute the "electrical fingerprint" of the transformer under this specific operating state.

[0048] Specifically, since the impedance of the transformer will change with the change of the tap changer position, in order to adapt the diagnostic method to the operation of the transformer at different positions, a reference impedance database covering all positions needs to be established. Specifically, under the cooperation of the operation and maintenance personnel, the two parallel transformers are switched to all tap changer positions in turn, and the calculation is repeated at each position to determine the reference impedance corresponding to the position. Then, the non-stop power diagnosis device 50 can store these data in the non-volatile storage module inside it. The data structure can be in table form, which is not limited here.

[0049] 103. Compare the current impedance of the above two transformers with the reference impedance corresponding to the normal state of the winding without deformation, and determine that the corresponding transformer has winding deformation when the difference or change rate between the above current impedance and the above reference impedance exceeds the preset threshold.

[0050] This step is the core judgment link of the diagnosis. As mentioned earlier, the processor can obtain the tap changer position information of the transformer currently (this information can also be obtained from the data acquisition and monitoring control system), and then query the reference impedance corresponding to the current position from the reference impedance database established in advance Z A0 And Z B0 .

[0051] Next, comparison and diagnosis are performed.

[0052] In an optional embodiment, the above step 103 comprises: Based on the difference between the above current impedance and the above reference impedance, and combined with the functional relationship between the transformer impedance and the winding physical structure parameters, it is determined whether the winding physical structure parameters of the above two transformers have changed to determine whether the corresponding transformer has winding deformation.

[0053] Further optionally, the winding physical structure parameters include at least one of the winding average reactance height and the winding space size.

[0054] Specifically, in this embodiment, a deep diagnostic method based on physical model analysis can be used. The equivalent impedance of the transformer, especially its reactance component, is closely related to the physical structure of the winding. Its theoretical formula can be simplified as where the reactance is a function of the winding geometric size, which can be expressed as Here, represents the equivalent leakage magnetic channel height of the winding, which is mainly related to the axial size and compression state of the winding; Representing the equivalent radial distance between windings, it is mainly related to the radial dimensions and deformation of the windings. When transformer windings are subjected to a large electrodynamic impact, axial compression or tension, or radial bulging or torsion may occur, all of which can lead to… or Changes occur, which in turn cause reactance Even the entire impedance The changes.

[0055] The processor calculates the difference between the current impedance and the reference impedance; for example, for the first transformer 10, it calculates... Through analysis By observing the changes in the real and imaginary parts of the and combining them with the aforementioned functional relationships, the changing trends of the physical structure parameters can be inferred. For example, if the reactance component... A significant increase may indicate axial compression of the winding, leading to a higher leakage flux path. Decrease; if A significant reduction may correspond to axial stretching. Radial deformation will affect impedance in a more complex way. The processor, based on a preset physical model and judgment logic, determines the physical structural parameters (such as...) corresponding to the calculated impedance change. or When the change in a value exceeds the safety range or the empirical threshold, the difference is considered to meet the preset diagnostic conditions.

[0056] Specifically, the structural changes of a transformer after being subjected to a short-circuit impact can be calculated using the following formula.

[0057] In the formula: f Frequency, in Hz; I Rated current; W Total number of turns when the main tap is connected ( I and W (Data for the same winding side) e t Potential per turn; H k The average reactance height of the two windings; k For additional reactance coefficient; p Lochtein coefficients; ∑ D This refers to the winding space dimensions.

[0058] Since the frequency, rated current, total number of turns at the main tap, potential per turn, additional reactance coefficient, and Rockwell coefficient are determined during transformer design, they will not change after being subjected to external short-circuit impacts; only the average reactance height of the two windings remains unchanged. H k and winding space dimensions ∑ D Both parameters will change when subjected to a short-circuit impact.

[0059] Therefore, the sum of the squares of the differences between the current impedance and the reference impedance can be calculated by the foregoing formula. D and H k The change of the sum of the squares of the differences between the current impedance and the reference impedance can be used to diagnose the winding deformation of the transformer in the running state.

[0060] If the result of the judgment is that the winding deformation occurs (for example, the first transformer 10), the no-power-off diagnosis device 50 immediately generates an alarm information. The information can be reported to a remote monitoring master station through a communication module of the device in a standard communication protocol (for example, IEC 61850 or Modbus TCP), and displayed on a human-computer interaction interface of the device itself, for example, “suspected winding deformation of the first transformer, impedance change rate: X.XX%”. The alarm information can also include more detailed data, such as the impedance values before and after the deformation, the change amount, the inferred deformation type, and the like, which provides a key basis for the subsequent decision of the operation and maintenance personnel (for example, whether to arrange a power-off for fine inspection). Then the process ends.

[0061] On the contrary, if the difference between the calculated current impedance and the reference impedance is within the allowable error range, and the preset diagnosis condition is not met, it can be confirmed that the transformer is normal and no significant deformation occurs. Then, the process can return to step 101 to continue the next round of monitoring.

[0062] As an optional implementation manner, when the comparison and diagnosis are performed, the judgment can also be directly based on the relative change rate of the impedance value.

[0063] Specifically, after the processor finds the reference impedance corresponding to the current gear from the database, the processor calculates the change rate of the current impedance relative to the reference impedance. For example, for the first transformer 10, the impedance change rate The calculation formula is as follows:

[0064] Since the impedance is a complex number, the modulus operation here represents the amplitude of the difference of the complex number. Similarly, the impedance change rate of the second transformer 20 can also be calculated.

[0065] Then, the processor compares the calculated change rate (for example, ) with a preset diagnosis threshold. The threshold is set according to the industry standard, the technical specification of the equipment out of the factory, or a large amount of operation experience data. For example, according to the relevant power industry standard or research, when the short-circuit impedance change rate caused by the winding deformation of the transformer exceeds 2%, it is generally considered that the deformation is relatively significant. Therefore, the preset threshold can be set to 2%, and the embodiment of the present application does not limit this.

[0066] The judgment logic is: if , it is determined that the difference of the first transformer 10 meets the preset diagnostic condition, and it is determined that winding deformation occurs; if , it is determined that the second transformer 20 has winding deformation.

[0067] It can be understood that this diagnostic method based on the change rate threshold has simpler calculation logic, lower requirement for the operation capacity of the processor, and can realize faster diagnostic response. Although it cannot provide detailed information about the specific physical form of deformation, it can quickly and reliably determine the occurrence of winding deformation event, meeting the needs of fast alarm and risk prompt.

[0068] In an alternative embodiment, the non-power-off diagnostic device 50 is no longer directly connected to the secondary analog loop of the mutual inductor, but can communicate with high-precision power analyzers installed on the secondary side of the first transformer 10 and the second transformer 20 through a digital communication interface (such as an Ethernet port, an RS-485 serial port, etc.). These power analyzers themselves have completed the collection, processing and calculation of voltage and current signals, and can directly provide high-precision electrical quantity measurement results, including but not limited to three-phase voltage, three-phase current, active power, reactive power and complex power.

[0069] Therefore, in the step 101 (obtaining normal operation parameters) and obtaining post-impact parameters of the present embodiment, the processor of the non-power-off diagnostic device 50 can send a data request instruction to the two power analyzers through a preset communication protocol (such as Modbus or IEC 61850), and directly read the values of the power and the power assumed by the first transformer 10 and the second transformer 20, respectively.

[0070] After obtaining the two key electrical quantities and , the subsequent diagnostic process, including calculating the reference impedance, calculating the current impedance, comparing the impedances and diagnosing, can be the same as described in the foregoing embodiments. Details are not repeated here.

[0071] This implementation transfers the front-end complex signal processing and power calculation tasks to professional measuring instruments, thereby simplifying the hardware design and software algorithm of the non-power-off diagnostic device 50 itself, and reducing the development and manufacturing costs. At the same time, since the data of the high-precision instrument is directly used, the accuracy of the input data can be further improved. The present embodiment shows that the diagnostic method proposed in the present application is not limited to specific data acquisition hardware, as long as the electrical quantities accurately reflecting the load conditions of the two parallel transformers can be obtained online, they can be used as the basic input of the method, which reflects the universality and flexibility of the technical solution.

[0072] Based on the description of the foregoing method embodiments, the embodiments of the present application further provide an online diagnosis device for winding deformation of a parallel transformer.

[0073] Figure 3 A structural schematic diagram of an online diagnosis device for winding deformation of a parallel transformer is provided in the embodiments of the present application. As shown in Figure 3 the online diagnosis device 300 for winding deformation of a parallel transformer comprises: a parameter acquisition module 310, configured to acquire electrical quantities of two transformers in parallel operation in a running state; a processor 320, electrically connected to the parameter acquisition module 310; The processor 320 is configured to perform the following operations: based on the electrical quantities of the two transformers in the running state, a load distribution relationship between the first transformer and the second transformer is solved in reverse to determine the current impedance of the two transformers; The current impedance of the two transformers is compared with the reference impedance corresponding to the normal state of the winding without deformation, and when the difference or change rate between the current impedance and the reference impedance exceeds a preset threshold, it is determined that winding deformation occurs in the corresponding transformer.

[0074] It can be understood that the related content of each module in Figure 3 has been described in detail in the foregoing method embodiments, and the specific content can be referred to in the method embodiments; that is, Figure 3 The online diagnosis device 300 for winding deformation of a parallel transformer provided in the embodiments can perform any step in the embodiments as shown in Figure 1 , which will not be described here.

[0075] In a specific embodiment, the hardware structure of a no-power-off diagnosis device 50 for winding deformation of a parallel transformer is described in detail for implementing the above diagnosis method. Please refer to Figure 2 , which is an independent physical entity and can be installed in a substation and connected to the monitored transformer system.

[0076] The no-power-off diagnosis device 50 mainly comprises the following core modules: Parameter acquisition module: This module serves as the interface for the device to connect with the external power system. It has multiple high-precision and high-isolation signal conditioning circuits integrated inside. The input end is designed with special terminals for safely connecting the output signals from the voltage transformer 30 and current transformer 40 on the secondary side of the first transformer 10 and second transformer 20. The signal conditioning circuit filters, attenuates, or amplifies the input voltage and current signals to match the range of the subsequent processing circuit. The conditioned analog signals are sent to one or more high-speed and high-resolution synchronous analog-to-digital converters. It is worth noting that "synchronous" is a key feature that ensures the sampling of multiple voltage and current signals occurs at the same time, which is crucial for accurately calculating the phase difference between each phase quantity and ensuring the accuracy of power calculation. This module is responsible for converting continuous analog electrical signals into discrete digital data streams for the processor module. Alternatively, in another embodiment (such as the scenario of embodiment 3), this module can be replaced by one or more digital communication interface cards (such as Ethernet cards or serial communication cards).

[0077] Processor module: As the core of the entire diagnostic device, this module is responsible for performing all calculations, controls, and judgments. Its core can be a high-performance digital signal processor optimized for high-speed mathematical operations (such as Fourier transform and complex number operations), which is very suitable for the large number of electrical calculations involved in this method. Alternatively, a powerful embedded microprocessor can also be used, such as an ARM-based system-on-a-chip that integrates processor cores, memory controllers, and rich peripheral interfaces. The processor module runs the operating system and diagnostic application program fixed in the storage module. This application program implements the complete diagnostic process shown, including controlling the parameter acquisition module to collect data, performing digital signal processing on the collected data to obtain electrical quantities such as power, executing the iterative algorithm for the inverse solution of the load distribution formula to calculate the reference impedance and the current impedance, managing the storage and query of the reference impedance database, the comparison diagnostic logic described in the aforementioned embodiments, and generating alarms when conditions are met, etc., which will not be repeated here. Figure 1

[0078] Storage module: This module provides storage space for data and programs for the device, usually containing two types of memory. The first is a non-volatile memory such as flash memory or solid state disk, used to store data that will not be lost due to power failure, such as the embedded operating system of the device, the firmware of the core diagnostic application, and the reference impedance database covering all tap changer positions established in the previous steps. The second is a volatile memory such as dynamic random access memory, used to provide cache space required during program execution, storing temporary calculation variables and intermediate results (such as sample data sequences, calculated current impedance values, etc.).

[0079] ​Human-machine interaction module: This is an optional module that provides a direct way for field operation and maintenance personnel to interact with the device. It can include a liquid crystal display screen and a small keyboard or touch screen. The display screen can display the key operating parameters of the two transformers being monitored in real time (such as voltage, current, active / reactive power), as well as the diagnostic status of the device (such as "monitoring", "event triggered", "diagnosis completed", etc.). When the transformer is diagnosed, the screen will display the alarm information in a prominent way. The keyboard or touch screen allows the operation and maintenance personnel to perform some basic operations, such as querying historical alarm records, viewing reference impedance values in the database, or manually triggering a diagnostic process.

[0080] Communication module: This module is responsible for the exchange of information between the device and the outside world, and is the key to realizing remote monitoring and automatic alarm. It is usually equipped with one or more standard communication interfaces, such as an Ethernet interface supporting the TCP / IP protocol, or a 4G / 5G module supporting wireless communication. Through these interfaces, when the processor module determines that winding deformation occurs in step S108, it can immediately send structured alarm messages and detailed diagnostic reports to the monitoring master station of the substation, the dispatching center in the distance, or the mobile terminal of the operation and maintenance personnel through the local area network or the wide area network, so as to realize the rapid response and processing of faults.

[0081] In actual application, the device is installed in the control cabinet or switch cabinet of the substation, and can be put into use after wiring and network configuration. After the device is powered on, the processor module loads and runs the diagnostic program, and first guides the user or automatically performs the establishment process of the reference impedance database. Thereafter, the device enters a long-term, uninterrupted online monitoring mode, and automatically performs Figure 1 the "monitoring-triggering-diagnosis-alarm" cycle shown to realize the automation, intelligence, and non-power-off early warning of the winding deformation risk of the parallelly running transformer.

[0082] In an embodiment of the present application, an electronic device is also proposed. Please refer to Figure 4 , Figure 4 A structural schematic diagram of an electronic device provided by an embodiment of the present application is shown. As Figure 4 shown, the electronic device 400 includes a processor 401 and a memory 402, the memory 402 stores a computer program, and the computer program, when executed by the processor 401, will execute any step in the method embodiment as Figure 1 shown. The electronic device 400 can also include input / output devices, etc. In a specific implementation manner, the electronic device can be a terminal device, etc.

[0083] In an embodiment, a computer readable storage medium storing a computer program is also provided. The computer program, when executed by the processor 401, causes the processor 401 to perform any of the steps of the above method embodiments.

[0084] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware. The program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiments. Any reference to memory, storage, database, or other medium used in the embodiments provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0085] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0086] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. An on-line diagnosis method of parallel transformer winding deformation, characterized in that, The method comprises: online acquisition of electrical quantities of two transformers operating in parallel in an operating state; based on the electrical quantities of the two transformers in the operating state, the current impedance of the two transformers is determined by inversely solving a load distribution relationship between the first transformer and the second transformer; comparison of the current impedance of the two transformers with the corresponding reference impedance of the two transformers in the normal state of non-deformation of the winding, when the difference or change rate between the current impedance and the reference impedance exceeds a preset threshold, it is determined that the corresponding transformer has winding deformation.

2. The online diagnosis method for parallel transformer winding deformation according to claim 1, wherein the online acquisition of electrical quantities of two transformers operating in parallel in an operating state comprises: collecting voltage signals and current signals of each transformer through voltage transformers and current transformers electrically connected with the two transformers, and determining the power value borne by each of the two transformers according to the voltage signals and current signals.

3. The method for on-line diagnosis of parallel transformer winding deformation according to claim 2, characterized in that, the determination of the current impedance of the two transformers based on the electrical quantities of the two transformers in the operating state by inversely solving a load distribution relationship between the first transformer and the second transformer comprises: acquiring the total load and power ratio of the two transformers; based on the load distribution relationship, the current impedance ratio of the two transformers is calculated according to the total load and power ratio of the two transformers; determining the current impedance of the two transformers according to the current impedance ratio and the reference impedance.

4. The method of on-line diagnosis of parallel transformer winding deformations according to claim 1, characterized in that, The method further comprises: traversing the tap changer positions of the two transformers, determining the corresponding reference impedance at each position to establish a reference impedance database covering all tap changer positions.

5. The method for on-line diagnosis of parallel transformer winding deformations according to claim 4, characterized in that, The comparison of the current impedance of the two transformers with the corresponding reference impedance of the two transformers in the normal state of non-deformation of the winding is to compare the current impedance with the reference impedance corresponding to the position in the reference impedance database at the current operating position.

6. The method of on-line diagnosis of parallel transformer winding deformations according to claim 1, characterized in that, when the difference or change rate between the current impedance and the reference impedance exceeds a preset threshold, it is determined that the corresponding transformer has winding deformation, which comprises: based on the difference between the current impedance and the reference impedance, and combining the functional relationship between transformer impedance and winding physical structure parameters, it is judged whether the winding physical structure parameters of the two transformers have changed to determine whether the corresponding transformer has winding deformation.

7. The method for on-line diagnosis of parallel transformer winding deformations according to claim 6, characterized in that, The winding physical structure parameters include at least one of winding average reactance height and winding space size.

8. An online diagnostic device for the deformation of parallel transformer windings, characterized in that, comprise: a parameter acquisition module for online acquisition of electrical quantities of two transformers operating in parallel in an operating state; a processor electrically connected with the parameter acquisition module; wherein the processor is configured to perform the following operations: based on the electrical quantities of the two transformers in the operating state, the current impedance of the two transformers is determined by inversely solving a load distribution relationship between the first transformer and the second transformer; The current impedance of the two transformers is compared with reference impedances corresponding to normal states in which the windings are not deformed, and it is determined that winding deformation of the corresponding transformer occurs when a difference or a change rate between the current impedance and the reference impedance exceeds a preset threshold.

9. An electronic device, comprising: A computer program product comprising a memory storing the computer program and a processor, wherein the computer program is executable by the processor to cause the processor to perform the steps of the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer program is executable by a processor to cause the processor to perform the steps of the method according to any one of claims 1-7.

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