Hydro-generator ultrahigh frequency partial discharge monitoring analysis method and device and computer equipment

Abstract

The invention provides a hydro-generator ultrahigh frequency partial discharge monitoring analysis method and device and computer equipment, and belongs to the technical field of partial discharge monitoring. The method comprises the following steps: acquiring a partial discharge test signal which is acquired at an acquisition point and is transmitted by a stator winding, injecting the partial discharge test signal into the stator winding from a current injection point, setting an injection point at a head end suspension part of a first bar in the stator winding, and determining the partial discharge test signal at other injection points by considering the influence of air coupling on the signal transmission of the stator winding; selecting from the suspended parts of the head ends of other winding bars; analyzing the acquired partial discharge test signal to obtain a transfer function and a signal attenuation coefficient of a signal transmission path between the injection point and the acquisition point; reconstructing and correcting the obtained partial discharge signal under the actual working condition or the test voltage by using the maximum signal attenuation coefficient and the corresponding transfer function; and performing partial discharge event judgment by using the corrected partial discharge signal. Through the method, quantitative analysis of partial discharge monitoring is realized.

Description

Technical Field

[0001] The present application belongs to the technical field of partial discharge monitoring, and specifically relates to a method for ultra-high frequency partial discharge monitoring and analysis of a hydro-turbine generator, an ultra-high frequency partial discharge monitoring and analysis device of a hydro-turbine generator, a computer device, and a machine-readable storage medium. Background Art

[0002] As the core equipment of a hydropower station, the health of the insulation system of a hydroelectric generator is directly related to the safety and stability of the entire power system. In actual production, insulation failure does not "happen suddenly", but is affected by the long-term effects of multiple factors such as thermal stress, chemical stress, and mechanical stress. With the continuous expansion of the installed capacity of hydroelectric generators, higher requirements are placed on the monitoring and evaluation of the insulation status of hydroelectric generators.

[0003] The detection of partial discharge signals is an important means to reflect the insulation condition of large-scale power equipment. Compared with low-frequency partial discharge monitoring technology, ultra-high frequency partial discharge monitoring technology can eliminate a large amount of interference, has higher monitoring accuracy, and is very effective for the diagnosis of early insulation defects. However, due to the attenuation of ultra-high frequency partial discharge signals, it is difficult to obtain the true value of partial discharge signals through quantitative analysis. At present, in engineering applications, ultra-high frequency partial discharge monitoring usually follows the judgment method of single-machine trend comparison in foreign countries, which is essentially a qualitative partial discharge value judgment method. This qualitative analysis method has high requirements on the ability of on-site technicians and does not conform to the engineering thinking of on-site technicians to make partial discharge judgments based on the determined threshold value. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method for ultra-high frequency partial discharge monitoring and analysis of a hydro-turbine generator, a device for ultra-high frequency partial discharge monitoring and analysis of a hydro-turbine generator, a computer device and a machine-readable storage medium, so as to overcome the defects existing in the qualitative analysis process of partial discharge monitoring through single-machine trend comparison in the prior art.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a method for monitoring and analyzing ultra-high frequency partial discharge of a hydro-generator, comprising:

[0006] Acquire the partial discharge test signal collected at the collection point and transmitted through the stator winding, wherein the partial discharge test signal is injected into the stator winding from the current injection point, wherein the injection point is provided at the suspended part of the first end of the first wire bar in the stator winding, and the positions of other injection points are selected from the suspended parts of the first ends of other wire bars except the suspended part of the first end of the first wire bar in the stator winding by considering the influence of air coupling on the signal transmission of the stator winding;

[0007] Analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point;

[0008] Obtain the partial discharge signal collected at the collection point under actual working conditions or test voltage;

[0009] Reconstructing the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in the signal attenuation coefficient, and correcting the reconstructed partial discharge signal using the maximum value in the signal attenuation coefficient;

[0010] The amplitude of the corrected partial discharge signal is compared with a preset partial discharge exceeding threshold value, and it is determined whether a partial discharge event occurs in the stator winding.

[0011] In a specific embodiment of the present application, the method further includes:

[0012] Digitally filtering the collected partial discharge signal to trigger reconstruction of the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in a signal attenuation coefficient;

[0013] The parameters of the digital filter are obtained by performing an amplitude-frequency response test on the stator winding.

[0014] In a specific embodiment of the present application, the method further includes:

[0015] The product of the reconstructed partial discharge signal and the winding coefficient of the stator winding is calculated, and the product is used as a new reconstructed partial discharge signal to trigger the correction of the reconstructed partial discharge signal by using the maximum value of the signal attenuation coefficient.

[0016] In a specific embodiment of the present application, by considering the influence of air coupling on the signal transmission of the stator winding, other injection point positions are selected from the first end suspended parts of other wire bars except the first end suspended part of the first wire bar in the stator winding, including:

[0017] Determine a point selection rule based on air coupling, and select other injection point positions from the first end suspended parts of other wire bars except the first end suspended part of the first wire bar in the stator winding according to the point selection rule;

[0018] The point selection rules include at least one of the following:

[0019] After the partial discharge test signal is injected at the injection point, the in-slot coupling component collected at the collection point is lower than a first preset value;

[0020] After the partial discharge test signal is injected at the injection point, the amplitude of the end coupling component collected at the collection point is lower than the second preset value;

[0021] Among them, the in-slot coupling component is the in-slot coupling signal in the partial discharge test signal after being transmitted through the stator winding, and the end coupling component is the end coupling signal generated by the mutual coupling of the suspended parts of the wire rods in the partial discharge test signal after being transmitted through the stator winding.

[0022] In a specific embodiment of the present application, the amplitude-frequency response test is performed on the stator winding to obtain the parameters of the digital filter, including:

[0023] Injecting a plurality of sinusoidal signals of different frequencies into the stator winding from a selected injection point;

[0024] Collecting a response signal at the collection point, wherein the response signal is a sinusoidal signal propagated through the stator winding;

[0025] Determine the amplitude-frequency response characteristic of the signal transmission path between the injection point and the collection point according to the sinusoidal signal and the response signal;

[0026] The parameters for digitally filtering the collected partial discharge signal are designed according to the amplitude-frequency response characteristics.

[0027] In a specific embodiment of the present application, the analysis of the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point includes:

[0028] Analyze the collected partial discharge test signal to obtain a Smith chart of the signal transmission path between the current injection point and the collection point;

[0029] determining a transfer function of the signal transmission path from the Smith chart;

[0030] The partial discharge test signal injected at the injection point and the partial discharge test signal collected at the collection point are compared to obtain a signal attenuation coefficient of the signal transmission path.

[0031] In a specific embodiment of the present application, the partial discharge signal is reconstructed using a transfer function of a signal transmission path corresponding to a maximum value in a signal attenuation coefficient, including:

[0032] Discretizing the partial discharge signal, and converting the partial discharge pulse sequence obtained after discretization into the frequency domain;

[0033] The ratio of the partial discharge pulse sequence converted to the frequency domain to the transfer function of the signal transmission path corresponding to the maximum value in the signal attenuation coefficient is inversely Fourier transformed to obtain a reconstructed partial discharge signal.

[0034] In a specific embodiment of the present application, the signal attenuation coefficient is a ratio of the amplitude of the partial discharge test signal injected at the injection point to the amplitude of the partial discharge test signal collected at the collection point; and the reconstructed partial discharge signal is corrected using the maximum value of the signal attenuation coefficient, including:

[0035] The product of the reconstructed partial discharge signal and the maximum value of the signal attenuation coefficient is determined as the corrected partial discharge signal.

[0036] In a specific embodiment of the present application, comparing the amplitude of the corrected partial discharge signal with a preset partial discharge exceeding threshold, and determining whether a partial discharge event occurs in the stator winding, includes:

[0037] If the amplitude of the corrected partial discharge signal is less than or equal to a preset partial discharge exceeding threshold, it is determined that no partial discharge event occurs in the stator winding.

[0038] In a specific embodiment of the present application, the collection point is located at the end of the last bar in the stator winding.

[0039] The second aspect of the present application provides an ultra-high frequency partial discharge monitoring and analysis device for a hydro-turbine generator, comprising:

[0040] A first acquisition module is used to acquire a partial discharge test signal collected at a collection point and transmitted through a stator winding, wherein the partial discharge test signal is injected into the stator winding from a current injection point, and the injection point is provided at a suspended portion of a first end of a first wire bar in the stator winding, and other injection point positions are selected from suspended portions of other wire bars except the suspended portion of the first end of the first wire bar in the stator winding by considering the influence of air coupling on the signal transmission of the stator winding;

[0041] An analysis module is used to analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point;

[0042] A second acquisition module is used to acquire a partial discharge signal collected at a collection point under actual working conditions or test voltage;

[0043] A correction module, used to reconstruct the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in the signal attenuation coefficient, and to correct the reconstructed partial discharge signal using the maximum value in the signal attenuation coefficient;

[0044] The partial discharge judgment module is used to compare the amplitude of the corrected partial discharge signal with a preset partial discharge exceeding threshold value, and judge whether a partial discharge event occurs in the stator winding.

[0045] A third aspect of the present application provides a computer device, comprising:

[0046] a memory configured to store instructions; and

[0047] The processor is configured to call the instruction from the memory and implement the ultra-high frequency partial discharge monitoring and analysis method of the hydro-turbine generator according to the first aspect of the present application when executing the instruction.

[0048] The fourth aspect of the present application provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the method for ultra-high frequency partial discharge monitoring and analysis of a hydro-turbine generator according to the first aspect of the present application.

[0049] It is known that in order to monitor the partial discharge of the stator winding of the hydro-turbine generator, a plurality of coupler locations are usually predetermined, and the partial discharge monitoring of the stator winding is performed at these coupler locations, and the coupler locations are the collection points described in the above technical solution. In the above technical solution, the maximum signal attenuation coefficient and the corresponding transfer function of the signal transmission path between each injection point and the collection point are determined based on the partial discharge test method, wherein the injection point is selected based on the influence of air coupling on the signal transmission of the stator winding, and then the maximum signal attenuation coefficient and the transfer function are used to reconstruct and correct the collected real-time partial discharge signal. At this time, the amplitude of the corrected partial discharge signal can be regarded as a "partial discharge value" that can be used for quantitative analysis. After comparing it with the preset partial discharge exceeding threshold, it can be determined whether a partial discharge event has occurred in the stator winding. As described above, the above technical solution realizes the quantitative analysis of ultra-high frequency partial discharge monitoring data. Compared with the qualitative analysis method mentioned in the background technology, it reduces the requirements on the capabilities of engineering site technicians and has stronger applicability. At the same time, the injection point is determined based on the influence of air coupling on the stator winding signal transmission, ensuring the accuracy of the determined maximum signal attenuation coefficient and transfer function, thereby improving the accuracy of the partial discharge monitoring and analysis results.

[0050] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0052] Figure 1 A schematic diagram of a flow chart of a method for monitoring and analyzing ultra-high frequency partial discharge of a hydro-turbine generator according to an embodiment of the present application is shown;

[0053] Figure 2 The wiring diagram of a single wire rod test is schematically shown;

[0054] Figure 3 The wiring diagram of the double-layer bar test in the stator winding slot is schematically shown;

[0055] Figure 4 The figure schematically shows the wiring diagram of the end coupling test of adjacent wire bars (when there is no electrical connection between adjacent wire bars);

[0056] Figure 5 The figure schematically shows the wiring diagram of the end coupling test of adjacent wire bars (when there is an electrical connection between adjacent wire bars);

[0057] Figure 6 A schematic diagram of a single winding of a hydro-generator bar is shown;

[0058] Figure 7 The equivalent circuit diagram of a single winding of a hydro-generator with distributed parameters is schematically shown;

[0059] Figure 8 The schematic diagram of the principle of the wire rod potential calculation is schematically shown;

[0060] Fig. 9 The block diagram schematically shows a composition of a device for monitoring and analyzing ultra-high frequency partial discharge of a hydro-turbine generator according to an embodiment of the present application;

[0061] Fig.10 The structural block diagram of a computer device according to an embodiment of the present application is schematically shown. DETAILED DESCRIPTION

[0062] The specific implementation of the embodiment of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present application, and is not used to limit the embodiment of the present application.

[0063] If there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0064] It is known that the partial discharge signals generated by each possible partial discharge source (partial discharge source) on the stator winding of the hydro-turbine generator will experience attenuation, reflection and resonance during the propagation process, thereby changing the waveform of the partial discharge signal, resulting in distortion of the partial discharge signal collected by the coupling device, and the distortion phenomenon of the ultra-high frequency partial discharge signal is more serious than that of the low-frequency partial discharge signal. Therefore, for the ultra-high frequency partial discharge monitoring of the stator winding of the hydro-turbine generator, how to effectively identify the partial discharge signal collected by the coupling device is a difficult content. According to the investigation, scholars in the industry have proposed some propagation models to study the propagation characteristics of partial discharge signals in the stator winding, but these propagation models are difficult to associate with the detected partial discharge pulse characteristics and have poor accuracy. In addition, the differences in partial discharge monitoring equipment and monitoring methods may lead to differences in partial discharge measurement results, and the different propagation characteristics of partial discharge signals at different locations make it difficult to recover the true partial discharge value of the partial discharge signal. Therefore, in the current ultra-high frequency partial discharge monitoring, the qualitative analysis method of single-machine trend comparison is usually adopted. Compared with the quantitative analysis method, the qualitative analysis method has higher requirements on the ability of the technical personnel on the engineering site.

[0065] In order to overcome the above defects, the embodiment of the present application performs ultra-high frequency partial discharge monitoring and analysis of the hydro-generator in the following manner:

[0066] The partial discharge test signal collected at the collection point and transmitted through the stator winding is obtained. The partial discharge test signal is injected into the stator winding from the current injection point. An injection point is set at the suspended part of the first end of the first wire bar in the stator winding. Based on the influence of air coupling on the signal transmission of the stator winding, other injection point positions are selected from the suspended parts of the first ends of other wire bars except the suspended part of the first end of the first wire bar in the stator winding.

[0067] Analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point;

[0068] Obtain the partial discharge signal collected at the collection point under actual working conditions or test voltage;

[0069] Reconstructing the collected partial discharge signal using the transfer function of the signal transmission path corresponding to the maximum value in the signal attenuation coefficient, and correcting the reconstructed partial discharge signal using the maximum value in the signal attenuation coefficient;

[0070] Compare the amplitude of the corrected partial discharge signal with the preset partial discharge exceeding threshold value, and determine whether a partial discharge event occurs in the stator winding;

[0071] After the partial discharge test signal injected into the stator winding through the current injection point is obtained at the collection point, the partial discharge test signal injected into the stator winding through the next injection point is obtained again at the collection point. That is, after the partial discharge test signal injected into the stator winding through the current injection point is obtained, the partial discharge test signal is injected again through the next injection point.

[0072] As is known, the stator winding is composed of a plurality of bars, each bar having a head end and an end end, and each end including a slot portion and a suspended portion. The first bar refers to the first bar among the bars connected in series or in parallel in the stator winding.

[0073] It should be understood that the partial discharge signal collected at the collection point under actual working conditions refers to the partial discharge signal collected at the collection point during the actual operation of the hydro-turbine generator; the partial discharge signal collected at the collection point under the test voltage refers to the partial discharge signal collected at the collection point in an offline scenario by applying the test voltage to the stator winding of the hydro-turbine generator.

[0074] In the above embodiment, in order to realize the quantitative analysis of the partial discharge signal collected under the actual working condition or the test voltage, a technical concept of the maximum signal attenuation coefficient correction is proposed. Through the correction of the maximum signal attenuation coefficient, a "partial discharge value" that can be used for quantitative analysis is obtained. The partial discharge value does not represent the true amplitude of the partial discharge signal, but is the corrected maximum value. The maximum value is combined with the preset partial discharge exceeding threshold to identify whether a partial discharge event occurs in the stator winding. For example, when the maximum value is lower than the partial discharge exceeding threshold, it can be determined that no partial discharge event occurs in the stator winding. When the maximum value is greater than or equal to the partial discharge exceeding threshold, an engineering maintenance opinion can be given. The engineering maintenance opinion can be: there may be a partial discharge source in the stator winding, which should be taken seriously and corresponding maintenance measures should be taken. In addition, in the above embodiment, the influence of air coupling on the accuracy of the signal attenuation coefficient and the transfer function is also considered, that is, the injection point is selected based on the influence of air coupling on the signal transmission of the stator winding, thereby reducing the degree of influence of air coupling on the partial discharge test signal collected at the collection point, thereby improving the accuracy of the determined maximum signal attenuation coefficient and the transfer function.

[0075] Based on this, the above embodiment has at least the following technical effects: it realizes quantitative analysis of ultra-high frequency partial discharge monitoring, and compared with the qualitative analysis of partial discharge monitoring based on single-machine trend comparison, the personal ability requirements of engineering site technicians are reduced, and the applicability is stronger.

[0076] Figure 1 The flowchart of the method for monitoring and analyzing ultra-high frequency partial discharge of a hydro-turbine generator according to an embodiment of the present application is schematically shown. Figure 1As shown, the hydro-generator ultra-high frequency partial discharge monitoring and analysis method may include the following steps 101 to 109. It is understandable that the above hydro-generator ultra-high frequency partial discharge monitoring and analysis method may include all steps from step 101 to step 109, or may only include some of the steps.

[0077] Step 101: Obtain the partial discharge test signal collected at the collection point and transmitted through the stator winding.

[0078] Among them, the partial discharge test signal is injected into the stator winding from the current injection point, and the injection point is set at the suspended part of the first end of the first wire bar in the stator winding, and based on the influence of air coupling on the signal transmission of the stator winding, other injection point positions are selected from the suspended parts of the first ends of other wire bars except the suspended part of the first end of the first wire bar in the stator winding. After the partial discharge test signal injected into the stator winding through the current injection point is collected, the partial discharge test signal is injected again through the next injection point.

[0079] In this application, the collection point is located at the location of the coupling device. The coupling device refers to a device for collecting the local discharge signal generated by the stator winding in the local discharge monitoring system. It is usually an active or passive four-terminal network that converts the input current into an output voltage signal. It can also be an ultra-high frequency local discharge sensor, a local discharge antenna, etc.

[0080] As an optional embodiment of the present application, the collection point is located at the suspended portion at the end of the last wire rod in the stator winding. The collection point is set at the suspended portion at the end of the last wire rod in the stator winding. The above embodiment can realize partial discharge monitoring and analysis of the entire stator winding. In addition, the entire stator winding can also be monitored for partial discharge in sections, and accordingly, the collection points are set at the suspended portions at the ends of multiple wire rods. Specifically, it can be determined in combination with the engineering site environment which suspended portions at the ends of the wire rods meet the wiring conditions for signal collection, and the collection point positions can be selected from these positions that meet the wiring conditions.

[0081] As an optional embodiment of the present application, in order to consider the influence of air coupling on the signal transmission of the stator winding, other injection point positions are selected from the suspended head end portions of other wire bars except the suspended head end portion of the first wire bar in the stator winding in the following manner: a point selection rule is determined based on the air coupling effect, and other injection point positions are selected from the suspended head end portions of other wire bars except the suspended head end portion of the first wire bar in the stator winding according to the point selection rule.

[0082] The point selection rules include at least one of the following:

[0083] After the partial discharge test signal is injected at the injection point, the in-slot coupling component collected at the collection point is lower than the first preset value, and the in-slot coupling component is the in-slot coupling signal in the partial discharge test signal after being transmitted through the stator winding;

[0084] After the partial discharge test signal is injected at the injection point, the amplitude of the end coupling component collected at the collection point is lower than the second preset value. The end coupling component is the end coupling signal generated by the coupling of the suspended part of the wire rod in the partial discharge test signal after being transmitted through the stator winding.

[0085] It should be understood that the first preset value and the second preset value need to be set in combination with the specific engineering site.

[0086] In a specific application, a partial discharge test is performed on the stator winding to determine whether each pre-selected injection point position meets the point selection rules. Figure 2 The wiring diagram for a single wire bar test is shown schematically. Figure 3 The wiring diagram of the double-layer bar test in the stator winding slot is schematically shown. Figure 4 The wiring diagram of the end coupling test of adjacent bars (when there is no electrical connection between adjacent bars) is schematically shown. Figure 5 The wiring diagram of the end coupling test of adjacent bars (when there is an electrical connection between adjacent bars) is schematically shown.

[0087] like Figure 2 As shown in the figure, in the single bar test, a waveform generator is used to generate a waveform at the suspended part P at the head end of the stator winding bar of the turbine generator. 10 The PD test signal is injected into the P terminal. A spectrum analyzer is used as a digitizer and the first channel of the spectrum analyzer is used to measure the injected P 10 The partial discharge test signal at the end is measured using a 1MΩ high impedance. 11 The response signal is measured by the second channel of the spectrum analyzer, and the input impedance is selected as 50Ω.

[0088] like Figure 3 As shown in the figure, in the double-layer wire bar test in the stator winding slot, a waveform generator is used to generate a waveform at the suspended part P at the head end of the upper wire bar. 10 The PD test signal is injected into the P terminal. Using a spectrum analyzer as a digitizer, first measure the injected P terminal through the first channel of the spectrum analyzer. 10 The partial discharge test signal at the end of the upper wire rod is 11 The response signal is measured through the second channel of the spectrum analyzer. At this time, the suspended part P at the head end of the lower wire rod 20 The suspended part P at the end of the lower wire rod 21The impedance matching is achieved between the two ends through the two channels of the spectrum analyzer. After the measurement is completed, the test port is replaced and the suspended part P at the head end of the lower wire rod is 20 The response signal is measured through the second channel of the spectrum analyzer. After the measurement is completed, the test port is changed again and the suspended part P at the end of the lower wire rod is measured. 21 The response signal is measured by the second channel of the spectrum analyzer. During the change of the measurement port, the other conditions are kept unchanged. 11 End, P 20 End and P 21 The frequency response characteristics of the response signal measured at the three ports of the stator winding are used to determine the influence of the slot coupling on the signal transmitted along the stator winding bar. The principle of separating the slot coupling component from the response signal is as follows: 11 End, or P 21 End, or P 20 The high-frequency signal at the end is the fast component, which is transmitted to the test port P through the wire rod. 11 End, or P 21 End, or P 20 The signal at the end is the slow-reaching component.

[0089] like Figure 4 As shown in the figure, in the coupling test of the ends of adjacent bars (when there is no electrical connection between adjacent bars), a waveform generator is used to generate a waveform at the suspended part P at the head end of the second bar from top to bottom. 10 The PD test signal is injected into the P terminal. Using a spectrum analyzer as a digitizer, first measure the injected P terminal through the first channel of the spectrum analyzer. 10 The partial discharge test signal at the end of the second wire rod from top to bottom is 11 The response signal is measured through the second channel of the spectrum analyzer. At this time, the suspended part P of the first end of the first wire rod from top to bottom 20 The suspended part P at the end of the first wire rod from top to bottom 21 The impedance matching is achieved between the two ends through the two channels of the spectrum analyzer. After the measurement is completed, the test port is changed and the suspended part P at the head end of the first wire rod from top to bottom is measured. 20 The response signal is measured through the second channel of the spectrum analyzer. After the measurement is completed, the test port is changed again. The suspended part P at the end of the first wire rod from top to bottom is 21 At the end, the response signal is measured through the second channel of the spectrum analyzer. Since the distance between the two wire rods in the slot is much larger than the distance between the suspended parts, the coupling in the slot can be ignored. There are two paths for signal transmission: transmission along the wire rod and end coupling transmission. The response signal on the first wire rod from top to bottom all comes from the end coupling transmission. Figure 4The arrow in the middle indicates the direction of signal transmission.

[0090] like Figure 5 As shown in the figure, in the end coupling test of adjacent bars (when there is an electrical connection between adjacent bars), a waveform generator is used to generate a waveform at the suspended part P at the head end of the second bar from top to bottom. 10 The PD test signal is injected into the P terminal. Using a spectrum analyzer as a digitizer, first measure the injected P terminal through the first channel of the spectrum analyzer. 10 The partial discharge test signal at the end of the second wire rod from top to bottom is 11 The response signal is measured through the second channel of the spectrum analyzer. At this time, the suspended part P of the first end of the first wire rod from top to bottom 20 The suspended part P at the end of the first wire rod from top to bottom 21 The impedance matching is achieved between the two ends through the two channels of the spectrum analyzer. After the measurement is completed, the test port is changed and the suspended part P at the head end of the first wire rod from top to bottom is measured. 20 The response signal is measured through the second channel of the spectrum analyzer. After the measurement is completed, the test port is changed again. The suspended part P at the end of the first wire rod from top to bottom is 21 At the end, the response signal is measured through the second channel of the spectrum analyzer. At this time, the signal is transmitted along the two wire rods and transmitted through the end coupling. By controlling the length of the connecting cable connected to the stator winding by the coupling device, the signal transmitted along the wire rod and the signal transmitted through the end coupling can be staggered in the time domain, so as to obtain the signal strength transmitted along the wire rod and the signal strength transmitted through the end coupling respectively. Figure 5 The arrow in the middle indicates the direction of signal transmission.

[0091] By carrying out the above tests, the selection rules for the injection points of the stator winding can be clarified.

[0092] Step 103: Analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point.

[0093] As an optional embodiment of the present application, the partial discharge test signal is analyzed in the following manner to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point:

[0094] Analyze the collected partial discharge test signal to obtain a Smith chart of the signal transmission path between the current injection point and the collection point;

[0095] Determine the transfer function of the signal transmission path between the current injection point and the acquisition point from the Smith chart;

[0096] The partial discharge test signal injected at the injection point and the partial discharge test signal collected at the collection point are compared to obtain the signal attenuation coefficient of the signal transmission path between the current injection point and the collection point.

[0097] It can be known that various parameters of the transfer function can be obtained from the Smith chart, thereby constructing the transfer function. Specifically, the collected partial discharge test signal can be analyzed using a vector network analyzer to generate a Smith chart of the signal transmission path between the injection point and the collection point.

[0098] As an example, the signal attenuation coefficient is a ratio of the amplitude of the partial discharge test signal injected at the injection point to the amplitude of the partial discharge test signal collected at the collection point.

[0099] Step 105, obtaining a partial discharge signal collected at a collection point under actual working conditions or test voltage.

[0100] Step 107 , reconstructing the partial discharge signal using the transfer function of the signal transmission path corresponding to the maximum value of the signal attenuation coefficient, and correcting the reconstructed partial discharge signal using the maximum value of the signal attenuation coefficient.

[0101] In the present application, there are multiple injection points, one of which is located at the suspended part of the first end of the first wire rod in the stator winding. According to the positive correlation between the signal attenuation degree and the transmission distance, the suspended part of the first end of the first wire rod in the stator winding is the farthest from the collection point. Under normal circumstances, the signal attenuation coefficient corresponding to the farthest signal transmission path is the largest. However, under actual test conditions, affected by external interference, the maximum signal attenuation coefficient does not correspond to the farthest signal transmission path. Therefore, the present application adopts multiple injection points and finds the maximum value from the signal attenuation coefficients of the signal transmission paths corresponding to the multiple injection points, so as to obtain a more accurate maximum signal attenuation coefficient.

[0102] As an optional embodiment of the present application, after obtaining the transfer function of the signal transmission path based on the Smith chart, the collected partial discharge signal is reconstructed in the following manner:

[0103] Discretizing the collected partial discharge signal, and converting the partial discharge pulse sequence obtained after discretization into the frequency domain;

[0104] The ratio of the partial discharge pulse sequence converted to the frequency domain to the transfer function of the signal transmission path corresponding to the maximum value in the signal attenuation coefficient is inversely Fourier transformed to obtain a reconstructed partial discharge signal.

[0105] It should be understood that the above embodiment is only an optional embodiment based on discrete Fourier transform. When the obtained transfer function is expressed in the time domain, the ratio of the collected local discharge signal to the transfer function of the signal transmission path corresponding to the maximum value in the signal attenuation coefficient is determined as the reconstructed local discharge signal.

[0106] Step 109, comparing the amplitude of the corrected partial discharge signal with a preset partial discharge exceeding threshold, and determining whether a partial discharge event occurs in the stator winding.

[0107] As an optional embodiment of the present application, whether a partial discharge event occurs in the stator winding may be determined in the following manner:

[0108] If the amplitude of the corrected partial discharge signal is less than or equal to the preset partial discharge exceeding threshold value, it is determined that no partial discharge event occurs in the stator winding.

[0109] As another optional embodiment of the present application, whether a partial discharge event occurs in the stator winding may be determined in the following manner:

[0110] If the amplitude of the corrected partial discharge signal is less than or equal to the preset partial discharge exceeding threshold, it is determined that no partial discharge event occurs in the stator winding;

[0111] If the amplitude of the corrected partial discharge signal is greater than the preset partial discharge exceeding threshold, it is determined that a partial discharge event may have occurred in the stator winding, and a partial discharge warning is issued.

[0112] As an example, at the test voltage When collecting partial discharge signals through the collection points, according to the provisions of DL / T492-2009 Generator stator winding epoxy powder mica insulation aging identification guidelines, when the charge of the partial discharge signal does not exceed 10000pC, it indicates that no partial discharge event has occurred in the stator winding. When the charge of the partial discharge signal exceeds 10000pC, it indicates that a partial discharge event may occur in the stator winding. At this time, attention should be paid and corresponding maintenance measures should be taken. For example, a partial discharge warning can be issued to remind on-site technicians to perform fault inspections on the stator winding in a timely manner. Convert 10000pC into a voltage amplitude, which is the partial discharge exceeding standard threshold described in the embodiment of the present application.

[0113] As an example, when conducting partial discharge monitoring and analysis under the actual operating conditions of a hydro-turbine generator, the set partial discharge exceeding standard threshold value may be an empirical value, and then gradually optimized according to the accuracy of the partial discharge monitoring and analysis results.

[0114] As an example, the PD monitoring cycle is set by taking advantage of the periodic recurrence of the PD signal. During this cycle, real-time PD signals are collected at the collection points multiple times. The maximum value of the signal attenuation coefficient and the corresponding transfer function are used to correct these PD signals to obtain multiple corrected PD signals. The average of the amplitudes of the multiple corrected PD signals is calculated, and the average is compared with the preset PD exceeding threshold value to determine whether a PD event occurs in the stator winding. The accuracy of PD monitoring is improved by taking the average of multiple collections within the preset monitoring cycle.

[0115] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0116] As an improved embodiment of the present application, before step 107, the hydro-generator ultra-high frequency partial discharge monitoring and analysis method further includes the following steps:

[0117] Step 106: Digitally filter the collected partial discharge signal, wherein the parameters of the digital filter are obtained by performing an amplitude-frequency response test on the stator winding.

[0118] As an optional embodiment of the present application, an amplitude-frequency response test is performed on the stator winding in the following manner to obtain parameters of the digital filter:

[0119] Injecting a plurality of sinusoidal signals of different frequencies into the stator winding from a selected injection point;

[0120] Collect the response signal at the collection point, the response signal is a sinusoidal signal after being propagated through the stator winding;

[0121] Determine the amplitude-frequency response characteristics of the signal transmission path between the injection point and the collection point according to the sinusoidal signal and the response signal;

[0122] The parameters for digital filtering of the collected partial discharge signal are designed according to the amplitude-frequency response characteristics obtained from the amplitude-frequency response test.

[0123] In the present application, the selection rule of the injection point may be: having a connection condition for sinusoidal signal injection.

[0124] It should be understood that digital filtering is usually achieved through digital filters, and the parameters of digital filters mainly include: bandwidth, cutoff frequency, etc. After obtaining the amplitude-frequency response characteristics through the amplitude-frequency response test, the parameters for digital filtering of the collected partial discharge signal can be designed in the following ways:

[0125] Based on the amplitude-frequency response characteristics of the signal transmission path between the injection point and the collection point obtained by the amplitude-frequency response test, the amplitude variation characteristics of the partial discharge signal at each frequency point after propagation through the stator winding and the noise interference characteristics existing in the stator winding signal propagation process are determined;

[0126] The cutoff frequency and bandwidth of the digital filter are determined according to the determined amplitude variation characteristics and noise interference characteristics.

[0127] In the above-mentioned embodiment of the present application, the parameters for digital filtering of the collected partial discharge signal are obtained by performing an amplitude-frequency response test on the stator winding, and the actual frequency response characteristics of the stator winding are taken into consideration, so that the partial discharge signal after filtering retains the useful signal part as much as possible and filters out the useless noise interference part, thereby improving the accuracy of partial discharge monitoring.

[0128] As an example, the sinusoidal signal injected at the injection point is called the excitation signal. The frequency point selection of the amplitude-frequency response curve can consider the following three principles: 1) Start collecting from the frequency where the response signal amplitude is obviously different from the excitation signal amplitude. For example, the frequencies below 10MHz are collected in order of 10KHz, 100KHz, 1MHz and 10MHz; 2) The frequencies above 10MHz are selected according to the change law of the amplitude-frequency response. For example, if the amplitude-frequency response is an upward trend with the increase of frequency, if the amplitude-frequency response suddenly changes to a downward trend between two acquisition frequency points, the acquisition frequency point can be manually adjusted at this time, and the frequency point can be added between the two acquisition frequency points to ensure that the amplitude-frequency response curve changes smoothly; 3) The acquisition frequency point covers the frequencies corresponding to all the maximum values ​​of the amplitude-frequency response. The amplitude-frequency response curve is obtained by the above three principles. On this basis, a sinusoidal signal of some specific frequency can also be injected to supplement and verify the waveform of the response signal under the sinusoidal signal to determine whether the amplitude-frequency response at this time is consistent with the amplitude-frequency response of the frequency point in the amplitude-frequency response curve.

[0129] As an improved embodiment of the present application, in step 107, before the reconstructed partial discharge signal is corrected using the maximum value of the signal attenuation coefficient, the method further includes:

[0130] The product of the reconstructed partial discharge signal and the winding coefficient of the stator winding is calculated, and the product is used as a new reconstructed partial discharge signal.

[0131] It can be known that the winding coefficient of the stator winding refers to the product of the distribution coefficient and the short-distance coefficient.

[0132] In the above embodiments of the present application, the winding coefficient is introduced to take into account the influence of the stator winding distribution characteristics and the stator winding short-distance effect on the motor performance, thereby improving the accuracy of partial discharge monitoring.

[0133] As an example, in a specific application, the calculation process of the winding coefficient includes the calculation of the distribution coefficient and the calculation of the short-distance coefficient.

[0134] Among them, the distribution coefficient K d1 It is a coefficient that considers the influence of the stator winding distribution characteristics on the motor performance, which is related to the distribution of the motor winding in space. Distribution coefficient K d1 The size depends on the number of slots per pole per phase k. The larger k is, the larger the distribution coefficient K is. d1 When k>6, the distribution coefficient K d1 tends to a constant. Distribution coefficient K d1 The specific value of can be obtained by querying Table 1.

[0135] Table 1

[0136] Number of slots per pole and phase k 1 2 3 4 5 6 7 and above <![CDATA[Distribution coefficient K d1 > 1.0 0.996 0.960 0.958 0.957 0.956 0.956

[0137] Short distance coefficient K p1 It is a coefficient that considers the influence of the short-pitch effect of the stator winding on the motor performance, which is related to the pitch Y of the coil. The smaller the pitch Y, the shorter the coefficient K. p1 The shorter the distance, the smaller the coefficient K p1 The specific value of can be obtained by querying Table 2.

[0138] Table 2

[0139]

[0140]

[0141] As an improved embodiment of the present application, when selecting other injection point positions from the head end hanging parts of other wire bars except the head end hanging part of the first wire bar of the stator winding, the other injection point positions are selected from the head end hanging parts of other wire bars that have been pre-determined as the target injection point positions. The head end hanging parts that have been pre-determined as the target injection point positions are the N head end hanging parts with the highest voltage values. The N head end hanging parts with the highest voltage values ​​are determined based on the voltage distribution of each head end hanging part in the stator winding that is pre-input or calculated based on the stator winding structure of the hydro-turbine generator. The N head end hanging parts with the highest voltage values ​​are the N head end hanging parts with the highest voltage values ​​obtained by sorting the voltage values ​​of each head end hanging part from large to small.

[0142] As another improved embodiment of the present application, after selecting other injection point positions from the head end hanging parts of other wire rods except the head end hanging part of the first wire rod of the stator winding, the target injection point position is determined from the selected injection point positions, and the target injection point position is the N head end hanging parts with the top voltage values. The N head end hanging parts with the top voltage values ​​are determined according to the voltage distribution of each head end hanging part in the stator winding obtained by pre-input or calculation according to the stator winding structure of the hydro-turbine generator. The N head end hanging parts with the top voltage values ​​are the N head end hanging parts with the top voltage values ​​obtained by sorting the voltage values ​​of each head end hanging part from large to small.

[0143] In the above two improved embodiments, on the basis of considering the influence of air coupling on the signal transmission of the stator winding, the voltage distribution is also considered. It can be seen that the higher the electric field strength in the stator winding, the greater the possibility of it becoming a partial discharge source. By considering the voltage distribution to select the injection point, the efficiency of determining the maximum signal attenuation coefficient is improved.

[0144] As another improved embodiment of the present application, the voltage value of the partial discharge test signal injected into the stator winding from the injection point is determined according to the voltage distribution of each head-end suspended part in the stator winding that is pre-input or calculated according to the stator winding structure of the hydro-turbine generator. For example: when the partial discharge test signal is injected offline, the voltage value of the current injection point is determined according to the voltage distribution, and the voltage value of the partial discharge test signal injected into the stator winding through the injection point is calculated according to the offline test voltage and the voltage value, so that the partial discharge test signal is consistent with the partial discharge signal generated when the injection point position is used as the partial discharge source position.

[0145] In the above improved embodiment, the voltage value of the partial discharge test signal is determined by considering the voltage, so that the partial discharge test conditions are consistent with the actual operating conditions of the stator winding, thereby making the maximum signal attenuation coefficient obtained by the partial discharge test more accurate.

[0146] As an example, Figure 6 The schematic diagram of a single winding of a hydro-generator bar is shown schematically. Figure 7 The equivalent circuit diagram of a single winding of a hydro-turbine generator with distributed parameters is shown schematically. Figure 8 The schematic diagram shows the principle of the calculation of the line bar potential. In a specific application, in the offline test voltage Next, such as Figures 6 to 8 As shown, the voltage distribution of each suspended part at the first end of the stator winding is calculated by the following method:

[0147] Step A1: Establish a distributed parameter equivalent model of the stator winding. Figure 6The figure shows a schematic diagram of a single winding of a hydro-turbine generator bar, where Z1 represents the portion of the single winding buried in the core slot, and Z2 represents the suspended portion of the single winding. Figure 7 The figure shows the equivalent circuit diagram of a single winding of a hydro-turbine generator with distributed parameters, where Z1 and Z2 are composed of five elements, where Rs represents the series resistance per unit length of the generator stator winding coil, Ls1 represents the self-inductance per unit length of the stator winding coil in the core slot, Ls2 represents the self-inductance per unit length of the coil in the suspended part, parallel resistors Rp1 and Rp2 represent the resistance between the insulation and ground of the stator winding coil in the core slot and the suspended part, respectively, Cp1 represents the capacitance of the coil part of the generator stator winding in the core slot, and Cp2 represents the capacitance of the suspended coil part of the generator stator winding. In practice, the generator stator winding coil has more than one turn, which is connected by multiple turns of coils.

[0148] Step A2, calculating the potential of each coil turn on the stator winding according to the distributed parameter equivalent model.

[0149] Among them, the following first formula is first used to calculate the number of slots per pole per phase according to the stator winding structure:

[0150]

[0151] In the above formula 1, N represents the number of stator slots of the hydro-generator, p represents the number of rotor pole pairs, n represents the number of parallel branches, m represents the number of phases, δ is an integer, and ηλ is the simplest fraction.

[0152] Secondly, according to the following formula 2 (slot phase formula), the degree of phase difference between the slots can be known. Assuming that the phase of the first slot is α, the phase of the nth slot is calculated by the following formula 3:

[0153]

[0154] α n =nα=2kπ+α′ n (Formula 3);

[0155] In the above formula 2, α′ n represents the real slot phase, and α′ n <360°.

[0156] Finally, if Figure 8 As shown, the neutral point is the zero potential point, and the high voltage side is the phase voltage The effective value of the potential of each wire rod is E0. Assume that the upper wire rod of the nth turn coil of a branch is located in the n1th slot, and the lower wire rod is located in the n1+y1th slot. The potential direction of each wire rod is defined as positive when it is upward and negative when it is downward. En1 represents the potential of the wire rod in the n1th slot, and E n1+y1represents the potential of the n1+y1th slot bar, and En represents the potential of the nth coil turn. Among them:

[0157]

[0158] In a specific application of the present application, a method for ultra-high frequency partial discharge monitoring and analysis for determining stator windings of a hydro-turbine generator under actual working conditions includes the following steps:

[0159] Step 1: Follow the steps below: Figure 6 to Figure 8 , calculate the current stator winding bar voltage distribution.

[0160] Step 2: Test the amplitude-frequency response characteristics of the current stator winding.

[0161] Step 3: Calculate the winding coefficient of the stator winding.

[0162] Step 4: Follow Figure 2 to Figure 5 , carry out partial discharge test on stator winding bars;

[0163] Step 5: Using the results of steps 1 to 4, determine the injection point position, the voltage value of the partial discharge test signal injected at the injection point, and the parameters of the digital filter, and then inject the partial discharge test signal into the stator winding from each injection point position in turn according to a preset order, and collect the partial discharge test signal after being transmitted by the stator winding at the collection point, and use a vector network analyzer to determine the transfer function of the signal transmission path between the injection point and the collection point and the signal attenuation coefficient, so as to determine the maximum signal attenuation coefficient Kmax;

[0164] Step 6: obtaining a real-time partial discharge signal collected at a collection point by a coupling device under actual working conditions of the hydro-generator;

[0165] Step 7: Reconstruct the real-time partial discharge signal using the transfer function and the winding coefficient, and correct the reconstructed partial discharge signal using the maximum signal attenuation coefficient Kmax.

[0166] Step 8: Compare the corrected partial discharge signal with the partial discharge exceeding threshold value to determine whether a partial discharge event occurs in the current stator winding.

[0167] Corresponding to the ultra-high frequency partial discharge monitoring and analysis method of the hydro-turbine generator in the above embodiment, Fig. 9 The block diagram schematically shows the composition of the ultra-high frequency partial discharge monitoring and analysis device 400 for a hydro-turbine generator provided in an embodiment of the present application. For the sake of ease of explanation, only the parts related to the embodiment of the present application are shown.

[0168] like Fig. 9 As shown, the ultra-high frequency partial discharge monitoring and analysis device 400 for a hydro-turbine generator includes:

[0169] A first acquisition module 410 is used to acquire a partial discharge test signal collected at a collection point and transmitted through a stator winding, wherein the partial discharge test signal is injected into the stator winding from a current injection point, and the injection point is provided at a suspended portion of a first end of a first wire bar in the stator winding, and other injection point positions are selected from suspended portions of other wire bars except the suspended portion of the first end of the first wire bar in the stator winding by considering the influence of air coupling on the signal transmission of the stator winding;

[0170] The analysis module 420 is used to analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point;

[0171] The second acquisition module 430 is used to acquire the partial discharge signal collected at the collection point under the actual working condition or the test voltage;

[0172] A correction module 440, configured to reconstruct the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in the signal attenuation coefficient, and to correct the reconstructed partial discharge signal using the maximum value in the signal attenuation coefficient;

[0173] The partial discharge judgment module 450 is used to compare the amplitude of the corrected partial discharge signal with the preset partial discharge exceeding threshold value, and judge whether a partial discharge event occurs in the stator winding.

[0174] The process of each module in the ultra-high frequency partial discharge monitoring and analysis device 400 for a hydro-turbine generator provided in the embodiment of the present application realizing its respective functions can be specifically referred to in the aforementioned Figure 1 The description of the illustrated embodiment and other related method embodiments will not be repeated here.

[0175] It should be noted that the information interaction, execution process and other contents between the above modules are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0176] Fig.10 A schematic diagram of a computer device according to an embodiment of the present application is shown. In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as shown in FIG. Fig.10As shown. The computer device includes a processor A01, a network interface A02, a display screen A04, an input device A05 and a memory (not shown in the figure) connected through a system bus. Among them, the processor A01 of the computer device is used to provide computing and control capabilities. The memory of the computer device includes an internal memory A03 and a non-volatile storage medium A06. The non-volatile storage medium A06 stores an operating system B01 and a computer program B02. The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A06. The network interface A02 of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor A01, a method for monitoring and analyzing ultra-high frequency partial discharge of a hydro-turbine generator is implemented. The display screen A04 of the computer device can be a liquid crystal display or an electronic ink display, and the input device A05 of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse.

[0177] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0178] In one embodiment, the hydro-turbine generator ultra-high frequency partial discharge monitoring and analysis device 400 provided in the present application can be implemented in the form of a computer program. The computer program can be used in Fig.10 The computer device shown in the figure is run. The memory of the computer device can store various program modules constituting the ultra-high frequency partial discharge monitoring and analysis device 400 for a hydro-turbine generator. The computer program composed of various program modules enables the processor to execute the steps of the ultra-high frequency partial discharge monitoring and analysis method for a hydro-turbine generator in various embodiments of the present application described in this specification.

[0179] In one embodiment, the present application further provides a machine-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for monitoring and analyzing ultra-high frequency partial discharge of a hydro-turbine generator in the above embodiment is implemented.

[0180] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0181] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0182] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for monitoring and analyzing ultra-high frequency partial discharge of a hydro-generator, characterized in that: include: Acquire the partial discharge test signal collected at the collection point and transmitted through the stator winding, wherein the partial discharge test signal is injected into the stator winding from the current injection point, wherein the injection point is provided at the suspended part of the first end of the first wire bar in the stator winding, and the positions of other injection points are selected from the suspended parts of the first ends of other wire bars except the suspended part of the first end of the first wire bar in the stator winding by considering the influence of air coupling on the signal transmission of the stator winding; Analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point; Obtain the partial discharge signal collected at the collection point under actual working conditions or test voltage; Reconstructing the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in the signal attenuation coefficient, and correcting the reconstructed partial discharge signal using the maximum value in the signal attenuation coefficient; The amplitude of the corrected partial discharge signal is compared with a preset partial discharge exceeding threshold value, and it is determined whether a partial discharge event occurs in the stator winding.

2. The method according to claim 1, characterized in that Also includes: Digitally filtering the collected partial discharge signal to trigger reconstruction of the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in a signal attenuation coefficient; The parameters of the digital filter are obtained by performing an amplitude-frequency response test on the stator winding.

3. The method according to claim 1, characterized in that Also includes: The product of the reconstructed partial discharge signal and the winding coefficient of the stator winding is calculated, and the product is used as a new reconstructed partial discharge signal to trigger the correction of the reconstructed partial discharge signal by using the maximum value of the signal attenuation coefficient.

4. The method according to claim 1, characterized in that By considering the influence of air coupling on the signal transmission of the stator winding, other injection point positions are selected from the first end suspended part of other bars except the first end suspended part of the first bar in the stator winding, including: Determine a point selection rule based on air coupling, and select other injection point positions from the first end suspended parts of other wire bars except the first end suspended part of the first wire bar in the stator winding according to the point selection rule; The point selection rules include at least one of the following: After the partial discharge test signal is injected at the injection point, the in-slot coupling component collected at the collection point is lower than a first preset value; After the partial discharge test signal is injected at the injection point, the amplitude of the end coupling component collected at the collection point is lower than the second preset value; Among them, the in-slot coupling component is the in-slot coupling signal in the partial discharge test signal after being transmitted through the stator winding, and the end coupling component is the end coupling signal generated by the mutual coupling of the suspended parts of the wire rods in the partial discharge test signal after being transmitted through the stator winding.

5. The method according to claim 2, characterized in that: The amplitude-frequency response test of the stator winding is carried out to obtain the parameters of the digital filter, including: Injecting a plurality of sinusoidal signals of different frequencies into the stator winding from a selected injection point; Collecting a response signal at the collection point, wherein the response signal is a sinusoidal signal propagated through the stator winding; Determine the amplitude-frequency response characteristic of the signal transmission path between the injection point and the collection point according to the sinusoidal signal and the response signal; The parameters for digitally filtering the collected partial discharge signal are designed according to the amplitude-frequency response characteristics.

6. The method according to claim 1, characterized in that The analysis of the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point includes: Analyze the collected partial discharge test signal to obtain a Smith chart of the signal transmission path between the current injection point and the collection point; determining a transfer function of the signal transmission path from the Smith chart; The partial discharge test signal injected at the injection point and the partial discharge test signal collected at the collection point are compared to obtain a signal attenuation coefficient of the signal transmission path.

7. The method according to claim 6, characterized in that Reconstructing the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in a signal attenuation coefficient includes: Discretizing the partial discharge signal, and converting the partial discharge pulse sequence obtained after discretization into the frequency domain; The ratio of the partial discharge pulse sequence converted to the frequency domain to the transfer function of the signal transmission path corresponding to the maximum value in the signal attenuation coefficient is inversely Fourier transformed to obtain a reconstructed partial discharge signal.

8. The method according to claim 1, characterized in that The signal attenuation coefficient is the ratio of the amplitude of the partial discharge test signal injected at the injection point to the amplitude of the partial discharge test signal collected at the collection point; The reconstructed partial discharge signal is corrected using the maximum value of the signal attenuation coefficient, including: The product of the reconstructed partial discharge signal and the maximum value of the signal attenuation coefficient is determined as the corrected partial discharge signal.

9. The method according to claim 1, characterized in that: Comparing the amplitude of the corrected partial discharge signal with a preset partial discharge exceeding threshold, and determining whether a partial discharge event occurs in the stator winding, includes: If the amplitude of the corrected partial discharge signal is less than or equal to a preset partial discharge exceeding threshold, it is determined that no partial discharge event occurs in the stator winding.

10. The method according to claim 1, characterized in that The collection point is located at the end of the last bar in the stator winding.

11. A hydro-generator ultra-high frequency partial discharge monitoring and analysis device, characterized in that: include: A first acquisition module is used to acquire a partial discharge test signal collected at a collection point and transmitted through a stator winding, wherein the partial discharge test signal is injected into the stator winding from a current injection point, and the injection point is provided at a suspended portion of a first end of a first wire bar in the stator winding, and other injection point positions are selected from suspended portions of other wire bars except the suspended portion of the first end of the first wire bar in the stator winding by considering the influence of air coupling on the signal transmission of the stator winding; An analysis module is used to analyze the collected partial discharge test signal to obtain the transfer function and signal attenuation coefficient of the signal transmission path between the current injection point and the collection point; A second acquisition module is used to acquire a partial discharge signal collected at a collection point under actual working conditions or test voltage; A correction module, used to reconstruct the partial discharge signal using a transfer function of a signal transmission path corresponding to a maximum value in the signal attenuation coefficient, and to correct the reconstructed partial discharge signal using the maximum value in the signal attenuation coefficient; The partial discharge judgment module is used to compare the amplitude of the corrected partial discharge signal with a preset partial discharge exceeding threshold value, and judge whether a partial discharge event occurs in the stator winding.

12. A computer device, characterized in that: include: a memory configured to store instructions; as well as A processor is configured to call the instruction from the memory and implement the ultra-high frequency partial discharge monitoring and analysis method for a hydro-turbine generator according to any one of claims 1 to 10 when executing the instruction.

13. A machine-readable storage medium, characterized in that: The machine-readable storage medium stores instructions for enabling a machine to execute the ultra-high frequency partial discharge monitoring and analysis method for a hydro-turbine generator according to any one of claims 1 to 10.

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