A method and device for diagnosing the electrical contact status of GIS busbars based on variable frequency magnetic field excitation

Abstract

The present invention discloses a method and device for diagnosing the electrical contact status of a GIS busbar based on variable-frequency magnetic field excitation. The method relates to the field of electrical equipment measurement technology and includes the following steps: applying variable-frequency magnetic field excitation to the conductor system of the GIS busbar, collecting the measured excitation current time-domain signal and the measured magnetic flux density time-domain signals at multiple shell measurement points; selecting the shell measurement point with the largest change between the measured magnetic flux density time-domain signal and the reference magnetic flux density time-domain signal as the target shell measurement point; determining the measured amplitude ratio and phase difference at different frequencies based on the measured magnetic flux density time-domain signal and the measured excitation current time-domain signal at the target shell measurement point; determining the contact resistance sensitive frequency using each measured amplitude ratio and each measured phase difference; and determining the electrical contact status of the GIS busbar based on the measured amplitude ratio and phase difference at the contact resistance sensitive frequency. The method combines magnetic flux and current characteristics for non-invasive detection and signal processing, thereby improving the reliability of diagnosing the electrical contact status of the GIS busbar.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment measurement, and in particular to a method and device for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation. Background Art

[0002] Gas-insulated switchgear (GIS) is widely used in power systems due to its compact structure, high reliability, and low maintenance requirements. As a key component of GIS equipment, the electrical contact status of the GIS busbar is directly related to the safe and stable operation of the entire power system. Over long-term operation, GIS busbar contacts are susceptible to chemical corrosion, mechanical wear, electrical wear, and contact melting, which can lead to deterioration of contact conditions and increased contact resistance. This can cause switch failures and failures of connected electrical equipment, leading to system accidents. Therefore, effective detection of the electrical contact status of GIS busbar contacts is of great significance.

[0003] Existing methods for detecting the electrical contact status of GIS busbars primarily include loop resistance testing, infrared thermal imaging, ultrasonic testing, and chemical analysis. However, these methods all have limitations. For example, loop resistance testing requires a power outage and cannot reflect dynamic electrical contact changes during equipment operation. Furthermore, wiring is complex and requires high operator skill, which can easily introduce measurement errors. Infrared thermal imaging can only detect surface temperature, making it difficult to locate deep internal faults, susceptible to environmental interference, and prone to missing faults in obscured areas. Ultrasonic testing is susceptible to interference from complex electrical environmental noise, obscuring effective signal reception and limiting detection to a limited area. Chemical analysis methods have a long detection cycle and are susceptible to the influence of equipment materials and historical operating conditions. Therefore, further improvements are needed to improve the reliability of GIS busbar electrical contact status detection. Summary of the Invention

[0004] The present invention provides a method and device for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation, which solves the technical problem of insufficient detection reliability of existing methods for detecting the electrical contact status of a GIS busbar.

[0005] The first aspect of the present invention provides a method for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation, comprising:

[0006] Applying variable frequency magnetic field excitation to the conductor system of the GIS busbar, and synchronously collecting the measured excitation current time domain signal of the GIS busbar and the measured magnetic flux density time domain signals of multiple shell measurement points;

[0007] The shell measurement point having the largest change between the measured magnetic flux density time domain signal and the associated reference magnetic flux density time domain signal among the shell measurement points is selected as the target shell measurement point;

[0008] determining a measured amplitude ratio and a measured phase difference at different frequencies based on a measured magnetic flux density time domain signal and a measured excitation current time domain signal at a measurement point of the target housing;

[0009] Determining a contact resistance sensitive frequency from each of the frequencies using each of the measured amplitude ratios and each of the measured phase differences;

[0010] The electrical contact state of the GIS busbar is determined based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency.

[0011] Optionally, the step of taking, among the shell measurement points, a shell measurement point at which a change between a measured magnetic flux density time domain signal and an associated reference magnetic flux density time domain signal is the largest as a target shell measurement point includes:

[0012] Determining the measured magnetic flux density amplitude of each of the measured magnetic flux density time domain signals;

[0013] The shell measurement point having the largest change between the actual magnetic flux density amplitude value and the reference magnetic flux density amplitude value of the associated reference magnetic flux density time domain signal among the shell measurement points is taken as the target shell measurement point.

[0014] Optionally, determining the measured amplitude ratio and the measured phase difference at different frequencies based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal at the target housing measurement point includes:

[0015] Performing frequency domain transformation on the measured magnetic flux density time domain signal at the target housing measurement point and the measured magnetic flux density time domain signal to determine corresponding measured excitation current frequency domain signal and measured magnetic flux density frequency domain signal;

[0016] At multiple frequencies, a ratio operation is performed using the measured magnetic flux amplitude of the measured magnetic flux density frequency domain signal and the measured current amplitude of the measured excitation current frequency domain signal, and a corresponding measured amplitude ratio is output;

[0017] At each of the frequencies, a corresponding measured phase difference is constructed by subtracting a measured magnetic flux phase of the measured magnetic flux density frequency domain signal from a measured current phase of the measured excitation current frequency domain signal.

[0018] Optionally, the determining the contact resistance sensitive frequency from each of the frequencies by using each of the measured amplitude ratios and each of the measured phase differences includes:

[0019] Calculating an amplitude change value between each of the measured amplitude ratios and a corresponding reference amplitude ratio;

[0020] Calculating a phase change value between each of the measured phase differences and a corresponding reference phase difference;

[0021] The frequency associated with the absolute value of the maximum amplitude change or the absolute value of the maximum phase change is taken as the contact resistance sensitive frequency.

[0022] Optionally, determining the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency includes:

[0023] Determining the contact resistance change rate based on the absolute value of the amplitude change value corresponding to the measured amplitude ratio of the contact resistance sensitive frequency and the absolute value of the phase change value corresponding to the measured phase difference;

[0024] The contact resistance change rate is used to determine the electrical contact state of the GIS busbar.

[0025] Optionally, determining the electrical contact state of the GIS busbar by using the contact resistance change rate includes:

[0026] Obtaining a preset electrical contact state table; the electrical contact state table is used to characterize the mapping relationship between the contact resistance change rate and the electrical contact state;

[0027] The contact resistance change rate is used to perform state matching with the electrical contact state table to determine the electrical contact state of the GIS busbar.

[0028] The second aspect of the present invention provides a GIS busbar electrical contact status diagnostic device based on variable frequency magnetic field excitation, comprising: a variable frequency power supply module, a Rogowski coil, a magnetic sensor array, a signal processing module, and an electrical contact status evaluation module;

[0029] The variable frequency power supply module is connected to the GIS busbar, the Rogowski coil is arranged on the line between the variable frequency power supply module and the GIS busbar, and the magnetic sensor array is arranged on the housing of the GIS busbar;

[0030] The signal processing module is connected to the Rogowski coil, the magnetic sensor array and the electrical contact state evaluation module respectively;

[0031] The variable frequency power supply module is used to apply variable frequency magnetic field excitation to the conductor system of the GIS busbar;

[0032] The Rogowski coil is used to synchronously collect the measured excitation current time domain signal of the GIS busbar;

[0033] The magnetic sensor array is used to synchronously collect the measured magnetic flux density time domain signals of multiple shell measurement points of the GIS busbar;

[0034] The signal processing module is configured to use, among the shell measurement points, a shell measurement point at which a change between a measured magnetic flux density time domain signal and an associated reference magnetic flux density time domain signal is greatest as a target shell measurement point; determine, based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal of the target shell measurement point, a measured amplitude ratio and a measured phase difference at different frequencies; and determine a contact resistance sensitive frequency from each of the frequencies using each of the measured amplitude ratios and each of the measured phase differences;

[0035] The signal processing module is used to determine the electrical contact state of the GIS bus based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency.

[0036] The third aspect of the present invention provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as described in any one of the above items.

[0037] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as described in any one of the above items.

[0038] A fifth aspect of the present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as described in any one of the above items.

[0039] It can be seen from the above technical solutions that the present invention has the following advantages:

[0040] The above-mentioned solution of the present invention provides a method for diagnosing the electrical contact status of a GIS busbar based on variable-frequency magnetic field excitation, comprising: applying variable-frequency magnetic field excitation to the conductor system of the GIS busbar, and synchronously collecting the measured excitation current time-domain signal of the GIS busbar and the measured magnetic flux density time-domain signals of multiple shell measurement points; selecting the shell measurement point at each shell measurement point where the change between the measured magnetic flux density time-domain signal and the associated reference magnetic flux density time-domain signal is the largest as the target shell measurement point; determining the measured amplitude ratio and measured phase difference at different frequencies based on the measured magnetic flux density time-domain signal and the measured excitation current time-domain signal of the target shell measurement point; determining the contact resistance sensitive frequency at each frequency using each measured amplitude ratio and each measured phase difference; and determining the electrical contact status of the GIS busbar based on the measured amplitude ratio and measured phase difference at the contact resistance sensitive frequency. Based on the above-mentioned solution, the reliability of the GIS busbar electrical contact status diagnosis is improved by combining magnetic flux and current characteristics for non-invasive detection and signal processing analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0042] Figure 1 A flowchart of a method for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation provided by an embodiment of the present invention;

[0043] Figure 2 A schematic structural diagram of a GIS busbar electrical contact status diagnostic device based on variable frequency magnetic field excitation provided by an embodiment of the present invention;

[0044] In the figure: 1. GIS busbar, 2. Variable frequency power supply module, 3. Rogowski coil, 4. Magnetic sensor array, 5. Signal processing module, 6. Electrical contact status assessment module. DETAILED DESCRIPTION

[0045] The embodiments of the present invention provide a method and device for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation, which are used to solve the technical problem of insufficient detection reliability of existing methods for detecting the electrical contact status of a GIS busbar.

[0046] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] See also Figure 1 , Figure 1 A flowchart of the steps of a method for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation is provided in an embodiment of the present invention.

[0048] This embodiment provides a method for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation, including:

[0049] Step 101: Apply variable frequency magnetic field excitation to the conductor system of the GIS busbar, and synchronously collect the measured excitation current time domain signal of the GIS busbar and the measured magnetic flux density time domain signals of multiple shell measurement points.

[0050] Variable frequency magnetic field refers to an alternating magnetic field whose frequency changes with time, usually generated by variable frequency current.

[0051] The excitation current time domain signal refers to the time series of the variable frequency current that generates the variable frequency magnetic field used for electrical contact status analysis. The measured data represents the actual data determined during the GIS busbar electrical contact status diagnosis process.

[0052] The magnetic flux density time domain signal refers to the magnetic flux density time series that changes with time and is used for electrical contact status analysis.

[0053] The shell measurement points refer to the locations in the shell space of the GIS busbar where the magnetic flux density is collected. It is understood that the selection of these shell measurement points is determined based on the shell structure of the GIS busbar and the expected magnetic field distribution.

[0054] It should be noted that this embodiment applies variable-frequency magnetic field excitation to the conductor system of the GIS busbar by using a variable-frequency power supply. Since the variable-frequency power supply can generate variable-frequency currents of different frequencies, these variable-frequency currents will act on the conductor system of the GIS busbar, thereby stimulating the electromagnetic response of the GIS busbar conductor system at different frequencies. Therefore, the electromagnetic characteristics of the GIS busbar conductor system can be obtained through measurement. In this process, the measured excitation current time domain signal and the measured magnetic flux density time domain signals of multiple shell measurement points set in the shell space of the GIS busbar are synchronously collected and determined. By collecting the magnetic flux density data at these shell measurement points, a magnetic field response spectrum of the GIS busbar conductor system can be constructed.

[0055] It can be understood that the purpose of applying variable frequency magnetic field excitation is to simulate the electromagnetic environment of the GIS bus in actual operation, so that the electrical contact status of the GIS bus can be accurately measured and analyzed subsequently. In one implementation method, the original data directly collected can be called the original excitation current time domain signal and the original magnetic flux density time domain signal, that is, the original excitation current time domain signal of the GIS bus and the original magnetic flux density time domain signals of multiple shell measurement points are first synchronously collected, and then the median filtering is performed and the standard deviation threshold method is used to determine whether there is abnormal data. If so, the abnormal data is eliminated and the data is completed to determine the measured excitation current time domain signal and the measured magnetic flux density time domain signal. Among them, the median filtering can remove single abnormal peaks caused by instantaneous strong interference, and the standard deviation threshold method can further check whether the data is within a reasonable range, providing necessary data support for subsequent analysis.

[0056] Step 102 : Among the shell measurement points, the shell measurement point with the largest change between the measured magnetic flux density time domain signal and the associated reference magnetic flux density time domain signal is selected as the target shell measurement point.

[0057] The reference magnetic flux density time domain signal refers to the magnetic flux density time domain signal of the GIS busbar in a normal electrical contact state. It is understood that the reference represents the data determined when the GIS busbar is in a normal electrical contact state before the GIS busbar electrical contact state diagnosis.

[0058] It should be noted that this embodiment uses the reference magnetic flux density time domain signal as a reference basis, selects the measurement data of one of the shell measurement points as the data input for subsequent analysis, and the selection rule is to find the shell measurement point with the largest change between the measured magnetic flux density time domain signal measured at each shell measurement point and the associated reference magnetic flux density time domain signal.

[0059] It can be understood that since the state variable is the electrical contact state of the busbar contact, which is mainly reflected in the contact resistance, changes in the contact resistance will significantly affect the current distribution, eddy current path and magnetic field leakage pattern of the conductor system. These changes will change the magnetic field intensity and spatial distribution pattern generated by the conductor system, and affect the eddy current distribution in the casing.

[0060] In a specific implementation of this embodiment, step 102 includes the following sub-steps:

[0061] S11, determining the measured magnetic flux density amplitude of each measured magnetic flux density time domain signal;

[0062] S12. The shell measurement point having the largest change between the actual magnetic flux density amplitude value and the reference magnetic flux density amplitude value of the associated reference magnetic flux density time domain signal among the shell measurement points is selected as the target shell measurement point.

[0063] The magnetic flux density amplitude refers to the amplitude index value of the magnetic flux density time domain signal in the frequency domain.

[0064] It should be noted that, in this embodiment, the magnetic flux density amplitude can be considered as an indicator to judge the change of the magnetic flux density. In the specific implementation, the magnetic flux density time domain signal is subjected to frequency domain conversion processing such as Fourier transform to obtain the corresponding magnetic flux density frequency domain signal, and the corresponding magnetic flux density amplitude is calculated based on the magnetic flux density frequency domain signal. For example, the magnetic flux density amplitude can include but is not limited to the maximum magnetic flux density amplitude, the average magnetic flux density amplitude and other amplitude-related indicators. For example, the maximum magnetic flux density amplitude can be the largest single magnetic flux density amplitude among the single magnetic flux density amplitudes of multiple frequencies in the magnetic flux density frequency domain signal, and the average magnetic flux density amplitude can be the average of the single magnetic flux density amplitudes of multiple frequencies in the magnetic flux density frequency domain signal. The specific process of determining the amplitude of the frequency domain signal can be referred to the existing technology and will not be repeated here.

[0065] Step 103 : Determine the measured amplitude ratio and the measured phase difference at different frequencies based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal at the target housing measurement point.

[0066] In a specific implementation of this embodiment, step 103 includes the following sub-steps:

[0067] S21, performing frequency domain transformation on the measured magnetic flux density time domain signal and the measured magnetic flux density time domain signal at the target housing measurement point to determine the corresponding measured excitation current frequency domain signal and the measured magnetic flux density frequency domain signal;

[0068] S22. At multiple frequencies, perform a ratio operation using the measured magnetic flux amplitude of the measured magnetic flux density frequency domain signal and the measured current amplitude of the measured excitation current frequency domain signal, and output a corresponding measured amplitude ratio;

[0069] S23. At each frequency, subtract the measured magnetic flux phase of the measured magnetic flux density frequency domain signal from the measured current phase of the measured excitation current frequency domain signal to construct a corresponding measured phase difference.

[0070] Amplitude ratio refers to the amplitude of the magnetic flux density (magnetic flux amplitude) in the frequency domain. ) relative to the current amplitude (current amplitude ) ratio.

[0071] Phase difference refers to the phase of the magnetic flux density in the frequency domain (flux phase ) and the phase of the current (current phase ) is the difference between them.

[0072] It should be noted that the electrical contact state of the busbar contact is mainly reflected in the change of contact resistance, which will eventually lead to the amplitude ratio of the measured magnetic flux amplitude relative to the current amplitude at different frequency points ω in the frequency domain of the magnetic flux density time domain signal and the excitation current time domain signal. ( ) and phase difference ( ) changes, so this embodiment determines the measured amplitude ratio and the measured phase difference of the target shell measurement point at different frequencies.

[0073] Step 104 : Using the measured amplitude ratios and the measured phase differences, determine the contact resistance sensitive frequency from the frequencies.

[0074] Contact resistance sensitive frequency refers to the frequency point that is most sensitive to changes in contact resistance.

[0075] It should be noted that this embodiment uses the amplitude ratio and the phase difference as indicators to evaluate and find the frequency point most sensitive to the contact resistance change among multiple frequencies.

[0076] In a specific implementation of this embodiment, step 104 includes the following sub-steps:

[0077] S31, calculating the amplitude change value between each measured amplitude ratio and the corresponding reference amplitude ratio;

[0078] S32, calculating the phase change value between each measured phase difference and the corresponding reference phase difference;

[0079] S33. Use the frequency associated with the absolute value of the maximum amplitude change or the absolute value of the maximum phase change as the contact resistance sensitive frequency.

[0080] The amplitude change value refers to the difference between the measured amplitude ratio and the reference amplitude ratio. The absolute value of the amplitude change value refers to the absolute value of the amplitude change value.

[0081] The phase change value refers to the difference between the measured phase difference and the reference phase difference. The absolute value of the phase change value refers to the absolute value of the phase change value.

[0082] It should be noted that for each frequency point ω, this embodiment determines the frequency points that show a strong correlation with the contact resistance by using the changes in the measured amplitude ratio and the measured phase difference relative to the reference. These points are usually manifested as amplitude changes. or phase change The absolute value of is large; in specific implementation, the calculation process of the relative change of amplitude includes ,in, For the frequencies, For the The amplitude change of each frequency, For the The measured amplitude ratio of the frequencies is As the reference amplitude ratio, the calculation process of phase change includes ,in, is the phase change value, For the The measured phase difference at each frequency, The absolute value of the amplitude change value and the phase change value are respectively calculated as the reference phase difference, thereby obtaining the absolute value of the amplitude change value and the absolute value of the phase change value.

[0083] Step 105 : Determine the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency.

[0084] In a specific implementation of this embodiment, step 105 includes the following sub-steps:

[0085] S41, determining the contact resistance change rate based on the absolute value of the amplitude change value corresponding to the measured amplitude ratio of the contact resistance sensitive frequency and the absolute value of the phase change value corresponding to the measured phase difference;

[0086] S41. Use the contact resistance change rate to determine the electrical contact state of the GIS busbar.

[0087] In a more specific implementation of this embodiment, sub-step S41 includes:

[0088] Obtaining a preset electrical contact state table; the electrical contact state table is used to represent a mapping relationship between a contact resistance change rate and an electrical contact state;

[0089] The contact resistance change rate is used to match the electrical contact state table to determine the electrical contact state of the GIS busbar.

[0090] The electrical contact state table refers to a table that represents the mapping relationship between the contact resistance change rate and the electrical contact state.

[0091] It should be noted that when determining the contact resistance sensitive frequency, the frequency point may be the frequency point that satisfies the maximum amplitude change value, the maximum phase change value, or both. Therefore, there may be n selected contact resistance sensitive frequencies ωs. The contact resistance change rate can be determined based on the amplitude change value and phase change value of the contact resistance sensitive frequency using a pre-calibrated physical mapping model. The contact resistance change rate refers to the relative rate at which the contact resistance changes. The electrical contact state of the GIS busbar can be determined through the mapping relationship between the contact resistance change rate and the electrical contact state.

[0092] In specific implementation, the calculation process of the contact resistance change rate includes:

[0093] ;

[0094] Where, is the contact resistance change rate, For the The contact resistance sensitive frequency, is the number of contact resistance sensitive frequencies, is the first sensitivity coefficient (constant), For the The amplitude change value of the contact resistance sensitive frequency, For the The absolute value of the amplitude change of the contact resistance sensitive frequency, For the The phase change value of the contact resistance sensitive frequency, For the The absolute value of the phase change of the contact resistance sensitive frequency, is the second sensitivity coefficient (constant); it can be understood that , For the measured contact resistance, is the reference contact resistance; the above-mentioned contact resistance change rate is a dimensionless calculation process. Since there is a certain physical correlation between the changes in the measured amplitude ratio and the measured phase difference and the changes in the contact resistance, under normal circumstances, the greater the absolute value of the amplitude change value and the absolute value of the phase change value of the contact resistance sensitive frequency, the greater the contact resistance change and the contact resistance change rate is used to characterize it. The corresponding sensitivity coefficient is determined by experimental measurement to obtain a linear fitting relationship between the contact resistance change rate and the absolute value of the phase change value and the absolute value of the amplitude change value;

[0095] In specific implementation, for the electrical contact status table, the mapping relationship can be set according to the threshold range of the contact resistance change rate of different electrical contact states. For example: ΔRc≤5% is normal contact, 5%<ΔRc≤15% is mild poor contact, 15%<ΔRc≤30% is moderate poor contact, 30%<ΔRc≤50% is severe poor contact, and ΔRc>50% is a crisis state; through this electrical contact status table, the magnetic flux density response can be converted into the electrical contact status information of the GIS busbar contact, providing important reference information for the maintenance and fault diagnosis of the GIS busbar.

[0096] In a specific implementation of this embodiment, it also includes:

[0097] Apply variable frequency magnetic field excitation to the conductor system of the GIS busbar in normal electrical contact state, and synchronously collect the reference excitation current time domain signal of the GIS busbar and the reference magnetic flux density time domain signal of multiple shell measurement points;

[0098] The reference amplitude ratio and the reference phase difference corresponding to different frequencies are calculated by respectively using each reference magnetic flux density time domain signal and the associated reference excitation current time domain signal.

[0099] It should be noted that, while ensuring that the GIS busbar contact is in a known good state, i.e., the normal electrical contact state referred to in this embodiment, its DC contact resistance is measured as the baseline contact resistance, and variable frequency current excitation is applied to synchronously collect the baseline magnetic flux density time domain signal b(t) and the baseline excitation current time domain signal i(t). These signals are then Fourier transformed to obtain the baseline excitation current frequency domain signal and the baseline magnetic flux density frequency domain signal, thereby determining the baseline amplitude ratio and the baseline phase difference, thereby obtaining a reference basis for the measured data. For the electrical contact state table, a series of known and controllable contact state degradations, i.e., different contact resistances, can also be set. Data collection and processing are repeated for each set contact state, thereby determining the contact resistance change rate threshold range corresponding to different electrical contact states.

[0100] In an embodiment of the present invention, non-invasive detection and signal processing analysis are performed in combination with magnetic flux and current characteristics, thereby improving the reliability of the diagnosis of the electrical contact status of the GIS busbar. In specific applications, for example, non-invasive detection of the GIS interval conductive circuit before commissioning can be achieved, thereby improving the reliability of the electrical connection of the GIS interval conductive circuit, which is of great significance for improving the operation and maintenance efficiency of GIS equipment and ensuring the safe and stable operation of the equipment.

[0101] See also Figure 2 , Figure 2 A schematic structural diagram of a GIS busbar electrical contact status diagnostic device based on variable frequency magnetic field excitation provided by an embodiment of the present invention.

[0102] The present invention provides a GIS busbar electrical contact state diagnosis device based on variable frequency magnetic field excitation, comprising: a variable frequency power supply module 2, a Rogowski coil 3, a magnetic sensor array 4, a signal processing module 5 and an electrical contact state evaluation module 6;

[0103] The variable frequency power supply module 2 is connected to the GIS busbar 1, the Rogowski coil 3 is arranged on the line between the variable frequency power supply module 2 and the GIS busbar 1, and the magnetic sensor array 4 is arranged on the housing of the GIS busbar 1;

[0104] The signal processing module 5 is connected to the Rogowski coil 3, the magnetic sensor array 4 and the electrical contact state evaluation module 6 respectively;

[0105] The variable frequency power supply module 2 is used to apply variable frequency magnetic field excitation to the conductor system of the GIS bus 1;

[0106] Rogowski coil 3 is used to synchronously collect the time domain signal of the measured excitation current of GIS bus 1;

[0107] The magnetic sensor array 4 is used to synchronously collect the time domain signals of the measured magnetic flux density at multiple shell measurement points of the GIS busbar 1;

[0108] The signal processing module 5 is configured to determine, among the shell measurement points, the shell measurement point at which the change between the measured magnetic flux density time domain signal and the associated reference magnetic flux density time domain signal is the largest, as a target shell measurement point; determine, based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal at the target shell measurement point, the measured amplitude ratio and the measured phase difference at different frequencies; and determine the contact resistance sensitive frequency from each frequency using each measured amplitude ratio and each measured phase difference;

[0109] The signal processing module 5 is used to determine the electrical contact state of the GIS busbar 1 based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency.

[0110] It should be noted that, in this embodiment, the variable frequency power supply module 2 forms a loop with the GIS bus 1. The variable frequency power supply module 2 is responsible for applying variable frequency magnetic field excitation to the GIS bus 1. The Rogowski coil 3 and the magnetic sensor array 4 are respectively responsible for synchronously measuring the excitation current signal of the GIS bus 1 and the magnetic flux density time domain signal at the shell measurement point. The Rogowski coil is suitable for measuring alternating current within a wide frequency range and can meet the test measurement requirements, while the magnetic sensor array can accurately measure the magnetic flux density response at multiple measurement points. The signal processing module 5 is connected to the Rogowski coil 3 and the magnetic sensor array 4, and is responsible for processing the magnetic flux density time domain signal and the excitation current signal at the shell space measurement point. The signal processing module 5 is connected to the electrical contact status evaluation module 6, and can receive the data transmitted by the signal processing module 5 to determine the electrical contact status of the GIS bus 1.

[0111] The electrical contact state evaluation module 6 is connected to the signal processing module 5 and performs feature extraction on the magnetic field transfer function to obtain the electrical contact state of the GIS busbar contact.

[0112] In a specific implementation of this embodiment, the shell measurement point at which the change between the measured magnetic flux density time domain signal and the associated reference magnetic flux density time domain signal is the largest among all shell measurement points is used as the target shell measurement point, including:

[0113] determining a measured magnetic flux density amplitude of each measured magnetic flux density time domain signal;

[0114] The shell measurement point with the largest change between the measured magnetic flux density amplitude and the reference magnetic flux density amplitude of the associated reference magnetic flux density time domain signal among the shell measurement points is taken as the target shell measurement point.

[0115] In a specific implementation of this embodiment, determining the measured amplitude ratio and the measured phase difference at different frequencies based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal at the target housing measurement point includes:

[0116] Performing frequency domain transformation on the measured magnetic flux density time domain signal and the measured magnetic flux density time domain signal at the target housing measurement point to determine the corresponding measured excitation current frequency domain signal and the measured magnetic flux density frequency domain signal;

[0117] At multiple frequencies, a ratio operation is performed between the measured magnetic flux amplitude of the measured magnetic flux density frequency domain signal and the measured current amplitude of the measured excitation current frequency domain signal, and the corresponding measured amplitude ratio is output;

[0118] At each frequency, the measured flux phase of the measured flux density frequency domain signal is subtracted from the measured current phase of the measured excitation current frequency domain signal to construct the corresponding measured phase difference.

[0119] In a specific implementation of this embodiment, the contact resistance sensitive frequency is determined from each frequency using each measured amplitude ratio and each measured phase difference, including:

[0120] Calculating the amplitude change between each measured amplitude ratio and the corresponding reference amplitude ratio;

[0121] Calculating the phase change value between each measured phase difference and the corresponding reference phase difference;

[0122] The frequency associated with the absolute value of the maximum amplitude change or the absolute value of the maximum phase change is taken as the contact resistance sensitive frequency.

[0123] In a specific implementation of this embodiment, determining the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency includes:

[0124] Determine the contact resistance change rate based on the absolute value of the amplitude change value corresponding to the measured amplitude ratio of the contact resistance sensitive frequency and the absolute value of the phase change value corresponding to the measured phase difference;

[0125] The contact resistance change rate is used to determine the electrical contact status of the GIS busbar.

[0126] In a specific implementation of this embodiment, the electrical contact state of the GIS busbar is determined using the contact resistance change rate, including:

[0127] Obtaining a preset electrical contact state table; the electrical contact state table is used to represent a mapping relationship between a contact resistance change rate and an electrical contact state;

[0128] The contact resistance change rate is used to match the electrical contact state table to determine the electrical contact state of the GIS busbar.

[0129] An embodiment of the present invention also provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory; when the computer program is executed by the processor, the processor executes the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as in any of the above embodiments.

[0130] An embodiment of the present invention also provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as in any of the above embodiments are implemented.

[0131] An embodiment of the present invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as in any of the above embodiments.

[0132] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0133] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0134] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0135] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0136] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0137] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. 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 invention.

Claims

1. A method for diagnosing the electrical contact status of a GIS busbar based on variable frequency magnetic field excitation, characterized in that: include: Applying variable frequency magnetic field excitation to the conductor system of the GIS busbar, and synchronously collecting the measured excitation current time domain signal of the GIS busbar and the measured magnetic flux density time domain signals of multiple shell measurement points; The shell measurement point having the largest change between the measured magnetic flux density time domain signal and the associated reference magnetic flux density time domain signal among the shell measurement points is selected as the target shell measurement point; determining a measured amplitude ratio and a measured phase difference at different frequencies based on a measured magnetic flux density time domain signal and a measured excitation current time domain signal at a measurement point of the target housing; Determining a contact resistance sensitive frequency from each of the frequencies using each of the measured amplitude ratios and each of the measured phase differences; determining the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency; The step of using the measured amplitude ratios and the measured phase differences to determine the contact resistance sensitive frequency from the frequencies includes: Calculating an amplitude change value between each of the measured amplitude ratios and a corresponding reference amplitude ratio; Calculating a phase change value between each of the measured phase differences and a corresponding reference phase difference; The frequency associated with the absolute value of the maximum amplitude change or the absolute value of the maximum phase change is taken as the contact resistance sensitive frequency; The determining of the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency includes: Determining the contact resistance change rate based on the absolute value of the amplitude change value corresponding to the measured amplitude ratio of the contact resistance sensitive frequency and the absolute value of the phase change value corresponding to the measured phase difference; The contact resistance change rate is used to determine the electrical contact state of the GIS busbar.

2. The GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation according to claim 1 is characterized in that: The step of taking, among the shell measurement points, the shell measurement point at which the change between the measured magnetic flux density time domain signal and the associated reference magnetic flux density time domain signal is the largest as the target shell measurement point comprises: Determining the measured magnetic flux density amplitude of each of the measured magnetic flux density time domain signals; The shell measurement point having the largest change between the actual magnetic flux density amplitude value and the reference magnetic flux density amplitude value of the associated reference magnetic flux density time domain signal among the shell measurement points is taken as the target shell measurement point.

3. The GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation according to claim 1 is characterized in that: Determining the measured amplitude ratio and the measured phase difference at different frequencies based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal at the target housing measurement point includes: Performing frequency domain transformation on the measured magnetic flux density time domain signal at the target housing measurement point and the measured magnetic flux density time domain signal to determine corresponding measured excitation current frequency domain signal and measured magnetic flux density frequency domain signal; At multiple frequencies, a ratio operation is performed using the measured magnetic flux amplitude of the measured magnetic flux density frequency domain signal and the measured current amplitude of the measured excitation current frequency domain signal, and a corresponding measured amplitude ratio is output; At each of the frequencies, a corresponding measured phase difference is constructed by subtracting a measured magnetic flux phase of the measured magnetic flux density frequency domain signal from a measured current phase of the measured excitation current frequency domain signal.

4. The GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation according to claim 1 is characterized in that: The method of determining the electrical contact state of the GIS busbar by using the contact resistance change rate includes: Obtaining a preset electrical contact state table; the electrical contact state table is used to characterize the mapping relationship between the contact resistance change rate and the electrical contact state; The contact resistance change rate is used to perform state matching with the electrical contact state table to determine the electrical contact state of the GIS busbar.

5. A GIS busbar electrical contact status diagnostic device based on variable frequency magnetic field excitation, characterized in that: include: Variable frequency power supply module, Rogowski coil, magnetic sensor array, signal processing module and electrical contact status evaluation module; The variable frequency power supply module is connected to the GIS busbar, the Rogowski coil is arranged on the line between the variable frequency power supply module and the GIS busbar, and the magnetic sensor array is arranged on the housing of the GIS busbar; The signal processing module is connected to the Rogowski coil, the magnetic sensor array and the electrical contact state evaluation module respectively; The variable frequency power supply module is used to apply variable frequency magnetic field excitation to the conductor system of the GIS busbar; The Rogowski coil is used to synchronously collect the measured excitation current time domain signal of the GIS busbar; The magnetic sensor array is used to synchronously collect the measured magnetic flux density time domain signals of multiple shell measurement points of the GIS busbar; The signal processing module is configured to use, among the shell measurement points, a shell measurement point at which a change between a measured magnetic flux density time domain signal and an associated reference magnetic flux density time domain signal is greatest as a target shell measurement point; determine, based on the measured magnetic flux density time domain signal and the measured excitation current time domain signal of the target shell measurement point, a measured amplitude ratio and a measured phase difference at different frequencies; and determine a contact resistance sensitive frequency from each of the frequencies using each of the measured amplitude ratios and each of the measured phase differences; The signal processing module is used to determine the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency; The step of using the measured amplitude ratios and the measured phase differences to determine the contact resistance sensitive frequency from the frequencies includes: Calculating an amplitude change value between each of the measured amplitude ratios and a corresponding reference amplitude ratio; Calculating a phase change value between each of the measured phase differences and a corresponding reference phase difference; The frequency associated with the absolute value of the maximum amplitude change or the absolute value of the maximum phase change is taken as the contact resistance sensitive frequency; The determining of the electrical contact state of the GIS busbar based on the measured amplitude ratio and the measured phase difference of the contact resistance sensitive frequency includes: Determining the contact resistance change rate based on the absolute value of the amplitude change value corresponding to the measured amplitude ratio of the contact resistance sensitive frequency and the absolute value of the phase change value corresponding to the measured phase difference; The contact resistance change rate is used to determine the electrical contact state of the GIS busbar.

6. A computer device, characterized in that: It includes a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as described in any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as described in any one of claims 1 to 4 are implemented.

8. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the GIS busbar electrical contact status diagnosis method based on variable frequency magnetic field excitation as described in any one of claims 1 to 4 are implemented.

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