Transformer short circuit monitoring method and device
By performing differential calculation and discrete Fourier transform on the current signals on the high-voltage and low-voltage sides of the transformer, the transformer ratio is calculated, and the problem of insufficient quality of the transformer short-circuit state detection signal in the prior art is solved, and precise monitoring of the transformer winding state is achieved. and early warning ensure the safe and stable operation of the transformer.
Patent Information
- Application Number
- CN202411194575.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2024-12-31
AI Technical Summary
In the prior art, in the short-circuit state detection of transformers, the signal quality is damaged and it is difficult to accurately map the internal conditions of the winding, resulting in insufficient coupling, affecting the operational safety and stability of the transformer.
By obtaining the current signals on the high-voltage and low-voltage sides of the transformer, performing differential calculations and discrete Fourier transforms, calculating the transformer ratio, and determining whether the winding is deformed, thereby achieving short-circuit monitoring.
It significantly improves the coupling accuracy with the transformer winding state, realizes direct and precise monitoring of the transformer's working state, and provides an early warning mechanism to ensure the safe and stable operation of the transformer.
Smart Images
Figure CN119224650A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of transformer state monitoring, and in particular relates to a transformer short circuit monitoring method and device. Background Art
[0002] Transformer is an electrical device widely used in power systems. Its main function is to change the voltage level of alternating current through the principle of electromagnetic induction without changing the frequency of the current. Transformer consists of two or more mutually insulated coils (usually called windings) wound on a core. Among them, the winding plays a vital role as the core component of voltage conversion. When alternating current passes through the primary winding (also called input winding or primary winding), an alternating magnetic field is generated in the iron core. This magnetic field will induce the secondary winding (also called output winding or secondary winding), thereby generating an electromotive force in the secondary winding to increase or decrease the voltage. According to the connection method between the winding and the power supply, transformers can be divided into two types: step-up transformer (which increases the voltage) and step-down transformer (which reduces the voltage).
[0003] As one of the most important equipment in the power system, the transformer occupies a very important position in the power system. When the transformer fails, it will affect the normal operation of the power system and cause power supply shortage. When the transformer has an external short-circuit fault, a short-circuit current with an amplitude of dozens of times the rated current is generated, and its winding will be subjected to an electromagnetic force with an amplitude proportional to the square of the current. The short-circuit electromagnetic force will cause the winding structure to deform axially or radially, endangering the stability of the winding, and causing transformer insulation failure, discharge and other accidents. At present, the detection of the short-circuit state of the transformer mainly relies on vibration sensors or sound sensors installed on the transformer box. However, the limitation of this method is that the vibration and acoustic signals will encounter attenuation, scattering and external interference when passing through the transformer box and internal medium, resulting in signal quality damage, making it difficult to accurately map the real situation inside the winding, that is, the coupling degree with the winding state is still insufficient. Summary of the invention
[0004] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the objects of the present invention is to at least solve one or more of the above-mentioned problems in the prior art. In other words, one of the objects of the present invention is to provide a transformer short-circuit monitoring method and device that meets one or more of the above-mentioned needs, aiming to significantly improve the coupling accuracy with the transformer winding state, directly and accurately monitor the working state of the transformer, and then realize real-time monitoring and forward-looking warning of its operating conditions, so as to ensure the safety and stability of the transformer operation.
[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:
[0006] In a first aspect, the present invention provides a transformer short-circuit monitoring method, comprising the steps of: S1, obtaining a high-voltage side current signal and a low-voltage side current signal of a transformer; S2, performing differential calculation on the high-voltage side current signal and the low-voltage side current signal, respectively, to obtain a high-voltage side differential current signal and a low-voltage side differential current signal; S3, performing discrete Fourier transform on the high-voltage side differential current signal and the low-voltage side differential current signal, respectively, to obtain a high-voltage side frequency domain signal and a low-voltage side frequency domain signal corresponding to a preset frequency; S4, calculating a transformer transformation ratio based on the high-voltage side frequency domain signal and the low-voltage side frequency domain signal, and judging whether the transformer winding is deformed based on the transformer transformation ratio, thereby realizing transformer short-circuit monitoring.
[0007] As a preferred solution, the differential calculation formula of the high-voltage side current signal and / or the low-voltage side current signal is:
[0008]
[0009] In the formula, x[n] represents the high-voltage side differential current signal and / or the low-voltage side differential current signal; i[n+1] and i[n] respectively represent two temporally adjacent high-voltage side current signals and / or two temporally adjacent low-voltage side current signals; dt represents the sampling time interval of two temporally adjacent high-voltage side current signals and / or two temporally adjacent low-voltage side current signals.
[0010] As a preferred solution, the preset frequency is 50 Hz, and the discrete Fourier transform formula of the high-voltage side differential current signal and / or the low-voltage side differential current signal is:
[0011]
[0012] Where X[k] represents the complex point corresponding to index k obtained after discrete Fourier transform, which contains the amplitude and phase information of the kth frequency component in the frequency domain. When N is the length of discrete Fourier transform and N=fs / 50, fs is the sampling frequency, and when f=50 Hz, k=fN / fs=1.
[0013] As a preferred solution, the preset frequency is 50 Hz, and the calculation formula of the transformer ratio is:
[0014]
[0015] In the formula, A represents the transformer ratio, X L represents the low-voltage side frequency domain signal corresponding to 50 Hz after discrete Fourier transform of the low-voltage side differential current signal, X H Represents the high-voltage side frequency domain signal corresponding to 50 Hz after discrete Fourier transform of the high-voltage side differential current signal.
[0016] As a preferred solution, the step S4 of judging whether the transformer winding is deformed based on the transformer transformation ratio comprises the following steps:
[0017] Obtaining the transformer transformation ratio corresponding to the current moment and multiple consecutive moments before and after the current moment;
[0018] Calculating corresponding transformation ratio change rates based on a plurality of transformer transformation ratios;
[0019] Whether the transformer winding is deformed is determined based on the transformation ratio change rate.
[0020] As a preferred solution, after judging whether the transformer winding is deformed based on the transformation ratio change rate, the method further includes the following steps:
[0021] Get the preset trigger alarm threshold;
[0022] The transformation ratio change rate is compared with the value of the trigger alarm threshold, and an alarm is triggered when the transformation ratio change rate is greater than the trigger alarm threshold.
[0023] As a preferred solution, the calculation formula of the transformation ratio change rate is:
[0024]
[0025] Wherein, β represents the transformation ratio change rate, A(i) represents the transformer transformation ratio at time t=-i / fs, t=0 is the current time, N is the calculation length and N / fs<0.02s, N0 is the interval comparison length and N0 / fs>0.1s.
[0026] As a preferred solution, the setting range of the trigger alarm threshold is [1.5%, 2.5%].
[0027] In a second aspect, the present invention provides a transformer short-circuit monitoring device, which, according to a transformer short-circuit monitoring method described in the first aspect, includes an acquisition module, a calculation module, a discrete Fourier transform module, and a judgment module; the acquisition module is used to acquire the high-voltage side current signal and the low-voltage side current signal of the transformer; the calculation module is used to perform differential calculation on the high-voltage side current signal and the low-voltage side current signal, respectively, to obtain the high-voltage side differential current signal and the low-voltage side differential current signal; the discrete Fourier transform module is used to perform discrete Fourier transform on the high-voltage side differential current signal and the low-voltage side differential current signal, respectively, to obtain the high-voltage side frequency domain signal and the low-voltage side frequency domain signal corresponding to the preset frequency; the calculation module calculates based on the high-voltage side frequency domain signal and the low-voltage side frequency domain signal to obtain the transformer ratio; the judgment module judges whether the transformer winding is deformed based on the transformer ratio, thereby realizing transformer short-circuit monitoring.
[0028] As a preferred scheme, it also includes a comparison module and an alarm module; the acquisition module is also used to obtain the transformer ratio corresponding to the current moment and multiple consecutive moments before and after the current moment; the calculation module is also based on multiple transformer ratios to calculate the corresponding ratio change rate; the acquisition module is also used to obtain a preset trigger alarm threshold; the comparison module is used to compare the numerical values of the ratio change rate and the trigger alarm threshold; the alarm module is based on the comparison result of the comparison module. When the ratio change rate is greater than the trigger alarm threshold, an alarm is issued.
[0029] Compared with the prior art, the present invention has the following beneficial effects:
[0030] 1. By measuring the current signals on the high-voltage and low-voltage sides of the transformer through current transformers, the transformer ratio and its dynamic changes can be calculated in real time, and then the subtle changes in the number of turns of the transformer winding can be deeply analyzed, and short-circuit discharge can be effectively monitored inside the transformer winding to ensure early warning and timely intervention.
[0031] 2. By performing discrete Fourier transform on the current signals on the high-voltage and low-voltage sides of the transformer, the monitoring accuracy related to the transformer winding status is significantly improved, and direct and accurate monitoring of the transformer working status is achieved. This innovation not only enhances the real-time grasp of the transformer operating status, but also provides a forward-looking early warning mechanism, building a solid line of defense for the safe and stable operation of the transformer.
[0032] Further or more detailed beneficial effects will be described in detail in conjunction with specific examples in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0034] Figure 1 It is a flow chart of the monitoring method described in Example 1 of the present invention.
[0035] Figure 2 It is a schematic diagram of the structure of the monitoring device described in Example 2 of the present invention.
[0036] Figure 3 It is a schematic diagram of the flow of the monitoring test described in Example 3 of the present invention.
[0037] Figure 4 It is a schematic diagram of the transformation ratio change rate results of the monitoring test described in Example 3 of the present invention. DETAILED DESCRIPTION
[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0039] In the following description, multiple embodiments of the present invention are provided, and different embodiments may be replaced or combined, so the present invention may also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present invention should also be considered to include embodiments containing one or more of A, B, C, and D, all other possible combinations, even though the embodiment may not be clearly described in the following text.
[0040] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements described without departing from the scope of the present invention. Various processes or components may be appropriately omitted, substituted or added to each example. For example, the described method may be performed in an order different from the described order, and various steps may be added, omitted or combined. In addition, the features described in some examples may be combined in other examples.
[0041] In order to facilitate a better understanding of the embodiments of the present invention, before explaining the specific implementation modes of the present invention in detail, its application scenarios are first described.
[0042] The transformer short-circuit monitoring method and device described in the embodiments of this specification are applied to power grid substations, industrial production line power supply systems, large data center power supply security, and power conversion and distribution processes of wind power, photovoltaic and other new energy power stations. In these scenarios, the application of the transformer short-circuit monitoring method and device provides users with high-quality power service experience through precise monitoring, rapid response, stable security and optimized operation and maintenance, and promotes the development of the power system towards a more intelligent, efficient and safe direction.
[0043] Embodiment 1:
[0044] like Figure 1As shown, this embodiment provides a transformer short-circuit monitoring method, including the steps of: S1, obtaining a high-voltage side current signal and a low-voltage side current signal of the transformer; S2, performing differential calculation on the high-voltage side current signal and the low-voltage side current signal, respectively, to obtain a high-voltage side differential current signal and a low-voltage side differential current signal; S3, performing discrete Fourier transform on the high-voltage side differential current signal and the low-voltage side differential current signal, respectively, to obtain a high-voltage side frequency domain signal and a low-voltage side frequency domain signal corresponding to a preset frequency; S4, calculating the transformer ratio based on the high-voltage side frequency domain signal and the low-voltage side frequency domain signal, and judging whether the transformer winding is deformed based on the transformer ratio, thereby realizing transformer short-circuit monitoring.
[0045] It is understandable that when a short-circuit discharge occurs in the transformer, which in turn causes insulation breakdown, this microscopic change will directly lead to the adjustment of the number of winding turns, which will be reflected in the macroscopic aspect as a significant change in the transformer ratio. This embodiment can calculate the current ratio of the transformer in real time by precisely measuring the current values on the high-voltage side and the low-voltage side of the transformer and applying the discrete Fourier transform algorithm for processing and analysis. Furthermore, monitoring the rate of change of this ratio becomes an efficient and direct means to evaluate whether a short-circuit discharge fault has occurred in the internal winding of the transformer, thereby ensuring that timely countermeasures are taken.
[0046] More specifically, this embodiment obtains the high-voltage side current signal and the low-voltage side current signal of the transformer through a current transformer.
[0047] Specifically, this embodiment provides a preferred implementation, and the differential calculation formula of the high-voltage side current signal and / or the low-voltage side current signal is:
[0048]
[0049] In the formula, x[n] represents the high-voltage side differential current signal and / or the low-voltage side differential current signal; i[n+1] and i[n] respectively represent two temporally adjacent high-voltage side current signals and / or two temporally adjacent low-voltage side current signals; dt represents the sampling time interval of two temporally adjacent high-voltage side current signals and / or two temporally adjacent low-voltage side current signals.
[0050] Specifically, this embodiment provides a preferred implementation, the preset frequency is 50 Hz, and the discrete Fourier transform formula of the high-voltage side differential current signal and / or the low-voltage side differential current signal is:
[0051]
[0052] Where X[k] represents the complex point corresponding to index k obtained after discrete Fourier transform, which contains the amplitude and phase information of the kth frequency component in the frequency domain. When N is the length of discrete Fourier transform and N=fs / 50, fs is the sampling frequency, and when f=50 Hz, k=fN / fs=1.
[0053] Specifically, this embodiment provides a preferred implementation, the preset frequency is 50 Hz, and the calculation formula of the transformer ratio is:
[0054]
[0055] In the formula, A represents the transformer ratio, X L represents the low-voltage side frequency domain signal corresponding to 50 Hz after discrete Fourier transform of the low-voltage side differential current signal, X H Represents the high-voltage side frequency domain signal corresponding to 50 Hz after discrete Fourier transform of the high-voltage side differential current signal.
[0056] Specifically, this embodiment provides a preferred implementation method, in which the step S4 of judging whether the transformer winding is deformed based on the transformer transformation ratio comprises the following steps:
[0057] Obtaining the transformer transformation ratio corresponding to the current moment and multiple consecutive moments before and after the current moment;
[0058] Calculating corresponding transformation ratio change rates based on the plurality of transformer transformation ratios;
[0059] Whether the transformer winding is deformed is determined based on the transformation ratio change rate.
[0060] Specifically, this embodiment provides a preferred implementation manner, wherein after judging whether the transformer winding is deformed based on the transformation ratio change rate, the method further includes the following steps:
[0061] Get the preset trigger alarm threshold;
[0062] The transformation ratio change rate is compared with the value of the trigger alarm threshold, and an alarm is triggered when the transformation ratio change rate is greater than the trigger alarm threshold.
[0063] Specifically, this embodiment provides a preferred implementation, and the calculation formula of the transformation ratio change rate is:
[0064] Wherein, β represents the transformation ratio change rate, A(i) represents the transformer transformation ratio at time t=-i / fs, t=0 is the current time, N is the calculation length and N / fs<0.02s, N0 is the interval comparison length and N0 / fs>0.1s.
[0065] As a preferred solution, the setting range of the trigger alarm threshold is [1.5%, 2.5%].
[0066] Embodiment 2:
[0067] like Figure 2 As shown, this embodiment provides a transformer short-circuit monitoring device, according to a transformer short-circuit monitoring method described in Example 1, including an acquisition module, a calculation module, a discrete Fourier transform module, and a judgment module; the acquisition module is used to obtain the high-voltage side current signal and the low-voltage side current signal of the transformer; the calculation module is used to perform differential calculation on the high-voltage side current signal and the low-voltage side current signal respectively to obtain the high-voltage side differential current signal and the low-voltage side differential current signal; the discrete Fourier transform module is used to perform discrete Fourier transform on the high-voltage side differential current signal and the low-voltage side differential current signal respectively to obtain the high-voltage side frequency domain signal and the low-voltage side frequency domain signal corresponding to the preset frequency; the calculation module calculates based on the high-voltage side frequency domain signal and the low-voltage side frequency domain signal to obtain the transformer ratio; the judgment module judges whether the transformer winding is deformed based on the transformer ratio, thereby realizing transformer short-circuit monitoring.
[0068] Specifically, this embodiment provides a preferred implementation, which also includes a comparison module and an alarm module; the acquisition module is also used to obtain the transformer ratio corresponding to the current moment and multiple consecutive moments before and after the current moment; the calculation module is also based on multiple transformer ratios to calculate the corresponding ratio change rate; the acquisition module is also used to obtain a preset trigger alarm threshold; the comparison module is used to compare the numerical values of the ratio change rate and the trigger alarm threshold; the alarm module, based on the comparison result of the comparison module, alarms when the ratio change rate is greater than the trigger alarm threshold.
[0069] Embodiment three:
[0070] In order to verify the effectiveness of the transformer short circuit monitoring method and device described in this specification, this embodiment Figure 4 Flow chart, a 220kV transformer was selected as the test object, and a series of condition monitoring tests were carried out. The test aims to evaluate the winding condition of the transformer under short-circuit impact through the following steps:
[0071] Step 1, data collection;
[0072] First, the current transformers connected in series to the high-voltage and low-voltage sides of the transformer are used to continuously collect short-circuit current signals for 5 seconds at a sampling frequency of 5000 Hz.
[0073] Step 2: differential processing;
[0074] Next, the collected current signal is differentially processed to effectively reduce or eliminate the DC component and low-frequency noise in the signal. The current signal differential calculation formula is:
[0075]
[0076] In formula (5), x[n] is the transformer current signal after differentiation; i[n+1] and i[n] represent two current signal data adjacent in time; dt is the sampling time interval, dt=1 / fs=0.0002s;
[0077] Step 3, discrete Fourier transform;
[0078] Subsequently, a discrete Fourier transform (DFT) is performed on the current signal after differential processing to analyze the signal frequency domain characteristics. The discrete Fourier transform formula is:
[0079]
[0080] In formula (6), X[k] represents the kth component of discrete Fourier transform. When N = fs / 50 = 100, the signal of f = 50 Hz corresponds to k = fN / fs = 1;
[0081] Step 4, frequency component extraction;
[0082] The 50 Hz frequency component is specifically extracted, i.e., k=1 in the DFT formula is set to focus on the main frequency component;
[0083] Step 5, calculation of transformation ratio;
[0084] Calculate the ratio of the 50Hz frequency component on the low-voltage side to the high-voltage side using the formula:
[0085]
[0086] In formula (7), A represents the transformer ratio, X L (1) represents the 50Hz component of the transformer low-voltage side current differential Fourier transform, X H (1) represents the 50Hz component after the Fourier transform of the differential current on the high-voltage side of the transformer.
[0087] Step 6: Status judgment and protection strategy;
[0088] The change of the transformation ratio can determine whether the winding is deformed, so as to provide a short-circuit protection strategy. The specific process is to calculate the transformation ratio change rate:
[0089]
[0090] The rate of change of the transformation ratio is monitored. When it exceeds 2% after a specific test (such as the third short-circuit test), it is considered that the winding may be deformed and the alarm mechanism is triggered. Figure 4 The variation curve of the transformation ratio in each test is intuitively displayed, verifying the effectiveness of the monitoring method and device.
[0091] Based on the above, this embodiment verifies the effectiveness and practicality of a transformer short-circuit monitoring method and device in this specification in identifying transformer winding state changes and preventing short-circuit faults.
[0092] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.
[0093] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0094] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. The present invention is intended to cover any variation, use or adaptive change of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.
Claims
1. A transformer short circuit monitoring method, characterized in that: Includes steps: S1, obtaining the current signal of the high-voltage side and the current signal of the low-voltage side of the transformer; S2, performing differential calculation on the high-voltage side current signal and the low-voltage side current signal respectively to obtain a high-voltage side differential current signal and a low-voltage side differential current signal; S3, performing discrete Fourier transform on the high-voltage side differential current signal and the low-voltage side differential current signal respectively to obtain a high-voltage side frequency domain signal and a low-voltage side frequency domain signal corresponding to a preset frequency; S4. Calculate the transformer ratio based on the high-voltage side frequency domain signal and the low-voltage side frequency domain signal, and determine whether the transformer winding is deformed based on the transformer ratio, thereby realizing transformer short circuit monitoring.
2. A transformer short circuit monitoring method according to claim 1, characterized in that: The differential calculation formula of the high-voltage side current signal and / or the low-voltage side current signal is: In the formula, x[n] represents the high-voltage side differential current signal and / or the low-voltage side differential current signal; i[n+1] and i[n] respectively represent two temporally adjacent high-voltage side current signals and / or two temporally adjacent low-voltage side current signals; dt represents the sampling time interval of two temporally adjacent high-voltage side current signals and / or two temporally adjacent low-voltage side current signals.
3. A transformer short circuit monitoring method according to claim 1, characterized in that: The preset frequency is 50 Hz, and the discrete Fourier transform formula of the high-voltage side differential current signal and / or the low-voltage side differential current signal is: Wherein, X[k] represents the complex point corresponding to index k obtained after discrete Fourier transform, which contains the amplitude and phase information of the kth frequency component in the frequency domain, N is the length of discrete Fourier transform and N=fs / 50, fs represents the sampling frequency, and when f=50 Hz, k=fN / fs=1.
4. A transformer short circuit monitoring method according to claim 1, characterized in that: The preset frequency is 50 Hz, and the calculation formula of the transformer ratio is: In the formula, A represents the transformer ratio, X L represents the low-voltage side frequency domain signal corresponding to 50 Hz after discrete Fourier transform of the low-voltage side differential current signal, X H Represents the high-voltage side frequency domain signal corresponding to 50 Hz after discrete Fourier transform of the high-voltage side differential current signal.
5. A transformer short circuit monitoring method according to claim 1, characterized in that: The step S4 of judging whether the transformer winding is deformed based on the transformer transformation ratio comprises the following steps: Obtaining the transformer transformation ratio corresponding to the current moment and multiple consecutive moments before and after the current moment; Calculating corresponding transformation ratio change rates based on a plurality of transformer transformation ratios; Whether the transformer winding is deformed is determined based on the transformation ratio change rate.
6. A transformer short circuit monitoring method according to claim 5, characterized in that: After judging whether the transformer winding is deformed based on the transformation ratio change rate, the method further comprises the following steps: Get the preset trigger alarm threshold; The transformation ratio change rate is compared with the value of the trigger alarm threshold, and an alarm is triggered when the transformation ratio change rate is greater than the trigger alarm threshold.
7. A transformer short circuit monitoring method according to claim 6, characterized in that: The calculation formula of the transformation ratio change rate is: Wherein, β represents the transformation ratio change rate, A(i) represents the transformer transformation ratio at time t=-i / fs, t=0 is the current time, N is the calculation length and N / fs<0.02s, N0 is the interval comparison length and N0 / fs>0.1s.
8. A transformer short circuit monitoring method according to claim 6 or 7, characterized in that: The setting range of the trigger alarm threshold is [1.5%, 2.5%].
9. A transformer short-circuit monitoring device, according to a transformer short-circuit monitoring method according to any one of claims 6 to 8, characterized in that: It includes an acquisition module, a calculation module, a discrete Fourier transform module, and a judgment module; The acquisition module is used to acquire the high-voltage side current signal and the low-voltage side current signal of the transformer; The calculation module is used to perform differential calculation on the high-voltage side current signal and the low-voltage side current signal respectively to obtain a high-voltage side differential current signal and a low-voltage side differential current signal; The discrete Fourier transform module is used to perform discrete Fourier transform on the high-voltage side differential current signal and the low-voltage side differential current signal, respectively, to obtain a high-voltage side frequency domain signal and a low-voltage side frequency domain signal corresponding to a preset frequency; The calculation module calculates to obtain the transformer ratio based on the high-voltage side frequency domain signal and the low-voltage side frequency domain signal; The judgment module judges whether the transformer winding is deformed based on the transformer transformation ratio, thereby realizing transformer short circuit monitoring.
10. A transformer short circuit monitoring device according to claim 9, characterized in that: It also includes a comparison module and an alarm module; The acquisition module is further used to acquire the transformer transformation ratio corresponding to the current moment and multiple consecutive moments before and after the current moment; The calculation module further calculates corresponding transformation ratio change rates based on the multiple transformer transformation ratios; The acquisition module is also used to obtain a preset trigger alarm threshold; The comparison module is used to compare the value of the transformation ratio change rate and the value of the trigger alarm threshold; The alarm module generates an alarm when the transformation ratio change rate is greater than the trigger alarm threshold based on the comparison result of the comparison module.