Method and system for measuring earth differential leakage current of GIS (Gas Insulated Switchgear) shell

Abstract

The invention discloses a method and system for measuring earth differential leakage current of a GIS shell, and relates to the technical field of leakage current detection, and the method comprises the steps: arranging a point position optimization scheme based on a sensor, arranging a current sensor, and synchronously obtaining a current signal collected by the current sensor; filtering the collected current signal by using a self-adaptive differential filter to obtain a real leakage current signal result; and performing real-time detection and analysis on signals of different frequency bands of a real leakage current signal result by using a multi-stage frequency domain filter. Based on a method of combining adaptive differential filtering, multi-sensor fusion, multi-frequency-domain analysis and intelligent threshold detection, the leakage current signal can still be accurately identified and extracted in a complex noise environment through the test of an analog signal, and the reliability and effectiveness of GIS equipment monitoring are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of leakage current detection, and in particular to a method and system for measuring differential leakage current of a GIS shell to the ground. Background Art

[0002] In high-voltage power systems, GIS (Gas Insulated Switchgear) has been widely used in various substations and transmission networks due to its compact structural design and excellent insulation performance. GIS completely encloses the internal live components in a metal casing filled with SF6 gas, which not only effectively isolates the influence of the external environment, but also greatly improves the insulation strength of the equipment, reduces the equipment volume and maintenance frequency, thereby achieving high reliability and low maintenance requirements. However, with the increasing complexity of power systems, changes in operating environments and requirements have made real-time monitoring of GIS equipment increasingly important, especially in high-voltage environments. Since the potential risk of leakage current may affect the normal operation of the equipment, monitoring the differential leakage current of its shell to the ground has become a key means to ensure the safe operation of GIS. This differential leakage current detection can not only help discover hidden dangers in advance, but also prevent failures caused by internal insulation degradation or external interference, and play an important role in ensuring the safety and stable operation of the entire power system.

[0003] Existing GIS leakage current measurement methods usually rely on a single sensor or simple fixed filtering technology, which has limited effect in dealing with complex electromagnetic interference around GIS equipment. In a high-voltage environment, high-frequency electromagnetic waves, lightning induction, power harmonics, etc. around GIS will have a significant impact on the sensor.

[0004] The detection accuracy of many existing GIS leakage current detection technologies cannot meet the actual application requirements, especially when detecting small leakage currents, it is easy to miss reports. The patent "High-precision sensor design for low current leakage detection" (patent number XX654321) also emphasizes that many current GIS leakage current detection devices rely on traditional sensors, which have limited accuracy, especially when capturing signals under low currents, there is significant noise interference, which reduces the overall reliability of the system.

[0005] Frequent changes in environmental noise are also a major problem for traditional GIS leakage current detection systems. In complex power scenarios, the frequency and amplitude of environmental noise change over time, which can easily be confused with actual leakage current signals. In the patent "Environmental Noise Filtering and Signal Identification Method in GIS System" (patent number XX789012), the inventors tried to use frequency comparison technology to distinguish between noise and leakage signals, but due to the dynamic variability of environmental noise, the fixed frequency distinction method is difficult to achieve ideal results in practical applications, and there is still a risk of missed detection and false detection.

[0006] Research in differential current measurement, signal filtering, and multi-sensor fusion has made some progress, but there are still limitations. The following is the current status of research in various technical fields and their shortcomings.

[0007] The differential measurement method uses the difference between two or more current signals to determine the leakage current, which can effectively eliminate background noise. However, the traditional differential current measurement method usually relies on hardware design and is easily affected by external interference.

[0008] In terms of signal filtering, existing research mainly uses low-pass filters, band-pass filters and adaptive filtering techniques to suppress background noise and high-frequency interference to improve the detection accuracy of leakage current signals. Low-pass filters and band-pass filters are relatively simple, but their effects are limited in complex power environments, especially high-frequency noise and transient interference still affect the detection accuracy of leakage current. In recent years, adaptive filtering technology has received widespread attention. It can adjust filtering parameters according to changes in environmental noise and improve filtering effects. However, the adaptive filtering algorithm has shortcomings in real-time performance, has high computational complexity, and requires large hardware resources.

[0009] In GIS leakage current detection, multi-sensor fusion can compensate for the limitations of a single sensor due to location or environment. However, multi-sensor fusion technology still faces challenges in practical applications. First, the installation and maintenance costs of multi-sensor systems are high, and the complex layout will make the overall structure of the system more complex; second, the fusion algorithm needs to correct data deviations when processing data collected by different sensors, which takes a long time to process and has poor real-time performance. Finally, multi-sensor fusion has high requirements for signal consistency and data synchronization in a high-interference environment. It is difficult to fully guarantee the synchronization between sensors in actual operation, which may lead to the accumulation of data errors and affect the reliability of the detection results.

[0010] Although differential current measurement, signal filtering and multi-sensor fusion technology have potential application value in GIS leakage current detection, the existing methods still have shortcomings in anti-interference ability, real-time performance, system complexity and cost. Future GIS leakage current detection technology needs to integrate a variety of advanced technologies, such as more efficient adaptive filtering algorithms, low-cost multi-sensor layout and fast data processing fusion algorithms, to improve the reliability and accuracy of the system in complex environments.

[0011] The technical route of the patent of this invention is based on a method that combines adaptive differential filtering, multi-sensor fusion, multi-frequency domain analysis and intelligent threshold detection, aiming to achieve high-precision GIS shell-to-ground differential leakage current monitoring. Summary of the invention

[0012] In view of the above-mentioned problems, the present invention is proposed.

[0013] Therefore, the problem to be solved by the present invention is that although differential current measurement, signal filtering and multi-sensor fusion technology have potential application value in GIS leakage current detection, the existing methods still have shortcomings in anti-interference ability, real-time performance, system complexity and cost.

[0014] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for measuring the differential leakage current of a GIS shell to the ground, which comprises: arranging current sensors based on a sensor layout point optimization scheme, and synchronously acquiring current signals collected by the current sensors; filtering the collected current signals using an adaptive differential filter to obtain a true leakage current signal result; and using a multi-stage frequency domain filter to perform real-time detection and analysis of signals in different frequency bands of the true leakage current signal result.

[0015] As a preferred solution of the method for measuring the differential leakage current of the GIS shell to the ground described in the present invention, the sensor layout point optimization solution includes arranging a number of current sensors at key nodes and high-frequency interference sources, and the arrangement of the current sensors needs to meet the symmetrical arrangement, that is, the current sensors are symmetrically distributed around the GIS shell, and the symmetrical distribution is symmetrical on the left and right sides or symmetrical on the front and rear ends to form symmetrical point-to-point monitoring; the arrangement of the current sensors also needs to meet the layered arrangement, that is, the current sensors are arranged on the top, middle and bottom of the shell respectively to cover different areas of the shell; after all the current sensors are arranged, a predetermined number of current sensors are added at the corresponding positions according to the redundancy strategy.

[0016] As a preferred solution of the method for measuring the differential leakage current of the GIS shell to the ground described in the present invention, the synchronous acquisition of the current signal collected by the current sensor includes: the control end sends a unified trigger signal, and uses time synchronization technology to make the timestamps of the data collected by all current sensors consistent, and start sampling at the same moment.

[0017] As a preferred solution of the method for measuring the differential leakage current of the GIS shell to the ground described in the present invention, wherein: the filtering of the collected current signal by using an adaptive differential filter includes: if n current sensors are arranged, each sensor is denoted as S i , where i = 1, 2, ....n, the sensor collects a leakage current signal x with noise i (t), build the acquisition signal model, the acquisition signal x of each sensor i (t) is expressed as leakage current signal s(t) and noise n i The superposition of (t) is expressed as,

[0018] x i(t) = s(t) + n i (t)

[0019] The leakage current signal s(t) is extracted by differential signal calculation, and the differential signal d between each pair of sensors is calculated. ij (t), where d ij (t) = x i (t)-x j (t), for any two sensors S i and S j (i≠j), the formula is expressed as,

[0020] d ij (t) = x i (t)-x j (t)=(s(t)+n i (t))-(s(t)+n j (t)) = n i (t)-n j (t)

[0021] By calculating the difference signal, the leakage signal is cancelled out, leaving only the difference in noise.

[0022] As a preferred solution of the method for measuring the differential leakage current of the GIS shell to the ground described in the present invention, the filtering of the collected current signal by using an adaptive differential filter also includes suppressing noise by using an adaptive differential filter and optimizing the filter coefficient by using a minimum mean square error algorithm or a recursive least squares algorithm; the updating formula of the adaptive filter is expressed as:

[0023]

[0024] in, Represented as the output filtered signal, w k Expressed as the weight coefficient of the filter, x k (t) is the original signal of each sensor; the error term e(t) is expressed as When the minimum mean square error algorithm is used for parameter optimization, the weight w k Adjust according to the error e(t), and the update formula is expressed as:

[0025] w k (t+1)=w k (t)+μ·e(t)·x k (t)

[0026] Among them, w k(t+1) represents the weight value at the next moment, and μ represents the step size factor. When the recursive least squares algorithm is used for parameter optimization, the weight update is based on the sum of squares of the previous errors, and the formula is expressed as follows:

[0027]

[0028] Among them, λ represents the forgetting factor, δ represents a small constant, and P(t) represents the covariance matrix.

[0029] As a preferred solution of the method for measuring the differential leakage current of the GIS shell to the ground described in the present invention, the real-time detection and analysis of the signals of different frequency bands of the real leakage current signal result by using a multi-stage frequency domain filter includes decomposing the signal into signal components of different frequencies by Fourier transform, which is expressed as follows:

[0030]

[0031] Where S(f) is the signal Frequency domain representation, f represents the frequency, j represents the imaginary unit;

[0032] Design a multi-stage frequency domain filter, where each stage of the filter corresponds to a frequency range. If the system uses m-stage frequency domain filters, the frequency range of each filter is [f i,low , f i,high ], the frequency response of each filter is H i (f) is expressed as,

[0033]

[0034] As a preferred solution of the method for measuring the differential leakage current of the GIS shell to the ground described in the present invention, the method of using a multi-stage frequency domain filter to perform real-time detection and analysis on signals of different frequency bands of the actual leakage current signal result also includes: by combining the frequency domain representation S(f) of the leakage current signal with each filter H i (f) multiply to obtain signal components S in different frequency bands i (f) is expressed as,

[0035] S i (f) = S(f)·H i (f)

[0036] For each frequency band signal S i (f) Perform inverse Fourier transform to obtain the corresponding time domain signal s i (t) is expressed as,

[0037]

[0038] The original signal is separated into multiple frequency band components. Each time domain signal represents a signal component within a specific frequency range. i The amplitude and frequency characteristics of (t) are obtained, and the frequency components that do not meet the leakage current characteristics are filtered out, and the frequency components that meet the characteristics are reconstructed to obtain the final leakage current signal.

[0039] Another object of the present invention is to provide a system for measuring the differential leakage current of a GIS shell to the ground, which can perform real-time analysis on the collected current signal and identify the leakage current signal.

[0040] To solve the above technical problems, the present invention provides the following technical solutions: a system for measuring the differential leakage current of a GIS shell to the ground, comprising: a signal acquisition module, a filtering module and a frequency band analysis module; the signal acquisition module synchronously acquires the current signal collected by the current sensor; the filtering module uses an adaptive differential filter to filter the collected current signal to obtain a true leakage current signal result; the frequency band analysis module uses a multi-stage frequency domain filter to perform real-time detection and analysis on signals of different frequency bands of the true leakage current signal result.

[0041] A computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the above-mentioned method for measuring the differential leakage current of a GIS shell to the ground are implemented.

[0042] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for measuring a differential leakage current of a GIS shell to the ground as described above.

[0043] The beneficial effects of the present invention are as follows: although differential current measurement, signal filtering and multi-sensor fusion technology have potential application value in GIS leakage current detection, the existing methods still have deficiencies in anti-interference ability, real-time performance, system complexity and cost. The patent of the present invention is based on a method combining adaptive differential filtering, multi-sensor fusion, multi-frequency domain analysis and intelligent threshold detection. Through adaptive filtering technology, the filtering parameters are dynamically adjusted according to the real-time environmental noise to improve the extraction accuracy of the leakage current signal; using multi-sensor fusion technology, multiple high-sensitivity sensors are arranged at different positions of the GIS shell, and the signal coverage and detection accuracy are improved through data fusion; multi-frequency domain analysis separates signals of different frequency bands according to the multi-frequency characteristics of the leakage current to avoid interference from high-frequency noise; intelligent threshold detection adaptively adjusts the threshold setting through real-time analysis of historical data and environmental parameters, so that the system can sensitively respond to small changes in leakage current. The present invention effectively enhances the anti-interference ability, detection sensitivity and real-time performance of the system, and provides a reliable technical guarantee for fault warning of GIS equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 creative work. Among them:

[0045] Figure 1 This is a flow chart of a method for measuring differential leakage current of a GIS shell to ground in Example 1.

[0046] Figure 2 The leakage current and noise diagram of sensor 1 in a method for measuring differential leakage current of a GIS shell to ground in Example 2.

[0047] Figure 3 The leakage current and noise diagram of sensor 2 of a method for measuring the differential leakage current of a GIS shell to the ground in Example 2.

[0048] Figure 4 The leakage current and noise diagram of sensor 3 in a method for measuring differential leakage current of a GIS shell to ground in Example 2.

[0049] Figure 5 The leakage current and noise diagram of sensor 4 in a method for measuring differential leakage current of a GIS shell to ground in Example 2.

[0050] Figure 6 The leakage current and noise diagram of sensor 5 in a method for measuring differential leakage current of a GIS shell to ground in Example 2.

[0051] Figure 7 This is a weight update diagram of a method for measuring differential leakage current of a GIS shell to ground in Example 2 using the LMS method.

[0052] Figure 8 This is a weight update diagram of a method for measuring differential leakage current of a GIS shell to ground in Example 2 using the RLS method.

[0053] Fig. 9 This is a module structure diagram of a system for measuring differential leakage current of a GIS shell to ground in Example 3. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0056] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides a method for measuring the differential leakage current of a GIS shell to the ground, including: Figure 1 As shown:

[0057] S1. Based on the sensor layout point optimization plan, current sensors are arranged and current signals collected by the current sensors are synchronously acquired.

[0058] Multiple high-sensitivity current sensors are arranged at different locations of the GIS shell to cover various key areas of the equipment. Through multi-point arrangement, the sensors can capture leakage current signals from different locations, effectively increasing the monitoring range of the system and ensuring that there are no blind spots in monitoring.

[0059] Sensor layout optimization solution

[0060] Key node layout: Sensors are placed at the main connection parts and interfaces of GIS equipment, such as grounding connections, busbar interfaces, and near disconnectors. These locations are areas where leakage currents may be concentrated, and placing sensors can ensure that key leakage signals are captured. This type of key point layout can achieve accurate monitoring and ensure detection sensitivity.

[0061] Symmetrical arrangement: To balance signal acquisition and reduce external interference, sensors should be symmetrically distributed around the GIS shell. For example, sensors can be arranged symmetrically on the left and right sides of the shell and at the front and rear ends to form symmetrical point-to-point monitoring, which can eliminate deviations caused by equipment structure or environmental interference and achieve more consistent signal acquisition.

[0062] Arrangement near high-frequency interference sources: High-frequency current devices such as switchgear and transformers near the GIS shell are potential interference sources of leakage current. It is recommended to appropriately increase the number of sensor points in areas close to these interference sources. This arrangement can help distinguish leakage current and noise signals, assist in subsequent filtering and data fusion processing, and improve the accuracy of signal recognition.

[0063] Layered arrangement: Arrange sensors at different heights and levels of the GIS shell. For example, sensors can be arranged at the top, middle, and bottom of the shell to cover different areas of the shell. This layered layout helps capture the changing trend of leakage current in the vertical direction and avoid signal loss or weakening due to changes in the shell structure and electric field.

[0064] Local density increase: In high current areas of the GIS shell or areas where leakage is predicted to occur, the density of sensors can be appropriately increased. For example, more sensors can be arranged at the junction of the disconnector and circuit breaker, and at the busbar connection, so that more detailed leakage current information can be provided when a fault occurs, and detailed monitoring of specific areas can be achieved.

[0065] Data redundancy point arrangement: Redundant sensors are arranged at the above-mentioned important key points and high current areas, such as setting up backup sensors or dual sensors to deal with failures or errors of the main sensors. This redundant design can provide fault-tolerant protection and ensure that the system can still work stably when the sensor is abnormal or fails.

[0066] Data acquisition and synchronization: Each sensor synchronously acquires current signals, and uses high-precision time synchronization technology to ensure that the timestamps of all sensor data are consistent, reducing the possibility of delay and data misalignment. Synchronous acquisition can ensure the synchronization of leakage current signals at each location, providing a consistent data basis for subsequent data fusion.

[0067] Among them, high-precision time synchronization technology uses trigger synchronous acquisition: high-precision synchronization technology requires all sensors to collect data under the same trigger signal. This is usually done by sending a unified trigger signal to start the acquisition system of all sensors to ensure that they start sampling at the same moment. This synchronous acquisition triggering method can greatly reduce the time deviation between sensor sampling.

[0068] S2. Filter the collected current signal using an adaptive differential filter to obtain a true leakage current signal result.

[0069] In a multi-sensor system, adaptive differential filtering is used to extract the true leakage current signal from the signals collected by multiple sensors while suppressing environmental noise and interference. If n current sensors are arranged, each sensor is denoted as S i , where i = 1, 2, ....n, the sensor collects a leakage current signal x with noise i (t), build the acquisition signal model, the acquisition signal x of each sensor i (t) is expressed as leakage current signal s(t) and noise n i The superposition of (t) is expressed as,

[0070] x i (t) = s(t) + n i (t)

[0071] The leakage current signal s(t) is extracted by differential signal calculation, and the differential signal d between each pair of sensors is calculated. ij (t), where d ij (t) = x i(t)-x j (t), for any two sensors S i and S j (i≠j), the formula is expressed as,

[0072] d ij (t) = x i (t)-x j (t)=(s(t)+n i (t))-(s(t)+n j (t)) = n i (t)-n j (t)

[0073] Here we can see that by differentiating, the leakage signal is cancelled out, leaving only the difference of the noise. The differential signal only contains the noise component, so in subsequent processing, we can use adaptive filtering to suppress this noise.

[0074] Use adaptive differential filter to suppress noise, and use minimum mean square error algorithm or recursive least squares algorithm to optimize the filter coefficients so that the filter output is as close to the real leakage signal as possible. Suppose the input of the adaptive filter is the differential signal d ij (t), the output is the filtered signal

[0075] The update formula of the adaptive filter is expressed as,

[0076]

[0077] Among them, w k Expressed as the weight coefficient of the filter, dynamically adjusted by minimizing the error, x k (t) represents the raw signal of each sensor.

[0078] The error term e(t) is expressed as

[0079] When the minimum mean square error algorithm is used for parameter optimization, the weight w k Adjust according to the error e(t), and the update formula is expressed as:

[0080] w k (t+1)=w k (t)+μ·e(t)·x k (t)

[0081] Among them, w k (t+1) represents the weight value at the next moment, and μ represents the step size factor, which is used to control the weight update speed.

[0082] When using the recursive least squares algorithm for parameter optimization, the weight update is based on the sum of squares of the previous errors, expressed as,

[0083]

[0084] Among them, λ is the forgetting factor that controls the weight of historical errors, δ is a small constant to avoid the denominator being zero, and P(t) is the covariance matrix.

[0085] The output of the adaptive filter after iterative update and optimization is a result that is close to the real leakage current signal. Through the combination of multi-sensor fusion, adaptive filtering and differential calculation, the detection accuracy and anti-interference ability of the leakage current signal can be significantly improved.

[0086] S3. Use a multi-stage frequency domain filter to perform real-time detection and analysis on signals of different frequency bands of the actual leakage current signal result.

[0087] In order to effectively separate the different frequency components in the GIS leakage current, the multi-frequency domain analysis technology uses multi-stage frequency domain filters to detect and analyze signals in different frequency bands in real time. Through this method, the system can accurately identify and distinguish high-frequency interference and low-frequency leakage current signals, thereby significantly improving the accuracy of signal recognition and anti-interference performance.

[0088] Use Fourier transform to decompose the signal into signal components of different frequencies. The formula is:

[0089]

[0090] Where S(f) is the signal Frequency domain representation of , f represents the frequency, and j represents the imaginary unit.

[0091] In order to separate different frequency components, a multi-level frequency domain filter is designed. Each level of the filter corresponds to a frequency range. If the system uses m-level frequency domain filters, the frequency range of each filter is [f i,low , f i,high ], i = 1, 2, ....m, the frequency response of each filter is H i (f) is expressed as,

[0092]

[0093] The function of each frequency response is to allow signal components within the corresponding frequency range to pass while rejecting other frequency components.

[0094] By combining the frequency domain representation S(f) of the leakage current signal with each filter H i (f) multiply to obtain signal components S in different frequency bands i(f) is expressed as,

[0095] S i (f) = S(f)·H i (f)

[0096] For each frequency band signal S i (t) performs inverse Fourier transform to obtain the corresponding time domain signal s i (t) is expressed as,

[0097]

[0098] At this time, the original signal is separated into components of multiple frequency bands. Each time domain signal represents a signal component within a specific frequency range. In order to detect the real signal in the leakage current, each s i (t) and filter out the frequency components that do not meet the leakage current characteristics. If a frequency band signal belongs to high-frequency interference, the frequency band can be directly discarded; for the frequency band signal that meets the leakage current characteristics, it is retained and further fused. The final leakage current signal can be obtained by reconstructing the signals of each frequency band.

[0099] Example 2, reference Figure 2-Figure 8 , which is the second embodiment of the present invention, is different from the first embodiment in that: a method for measuring the differential leakage current of a GIS shell to the ground also includes, in order to verify and explain the technical effect adopted in the method, comparing the test results with scientific demonstration means to verify the real effect of the method.

[0100] This embodiment sets the analog signals of 5 sensors, such as Figure 2-Figure 6 , where Sensor 1~5LeakageCurrentwithNoise represents the leakage current and noise of sensors 1~5. The differential calculation process of the present invention is performed on the above signals to obtain the result as follows: Figure 7 As shown, Differential Signal represents differential signal.

[0101] It can be seen that the noisy signal shows an upward trend because we designed a linearly increasing leakage current model when generating the simulation signal, which is consistent with the situation that the leakage current may gradually increase. In addition, the noisy signal is superimposed with random noise to further simulate the fluctuation of leakage current in the actual environment.

[0102] The results of adaptive differential filtering show horizontal (stationary) characteristics, mainly because the purpose of this filtering method is to remove or attenuate gradually changing background signals (such as linear trends) and noise components to extract small differential signals with insignificant changes. When we perform differentials between different sensor data, similar linear rising trends are offset by each other, leaving only the differences. After further processing by adaptive filtering, the remaining signal fluctuations are smoothed to form an approximately horizontal output. This stable result indicates that the filtering successfully removes the rising trend and noise, retaining the true changing characteristics related to the leakage current.

[0103] When optimizing the weight coefficients of the filter, such as Figure 7 As shown in the weight update diagram of the LMS (least mean square error) algorithm, the weights gradually converge over time, where LMS Algorithm Weight Update indicates that the weights are updated using the LMS method, and Gradual Convergence indicates gradual convergence. The LMS algorithm gradually adjusts the weights based on the product of the error and the input signal to minimize the sum of squared errors. In the initial stage, the weights vary greatly because the algorithm is trying to find the optimal weights to match the input signal; as the iterations proceed, the weights gradually stabilize, indicating that the algorithm has approached the convergence point and found a better weight. This process shows the stability and gradual adjustment characteristics of the LMS algorithm, but the convergence speed is relatively slow.

[0104] like Figure 8 As shown in the weight update diagram of the RLS (recursive least squares) algorithm, the convergence speed of the weight is faster than that of the LMS algorithm, where RLS Algorithm WeightUpdate indicates that the RLS method is used to update the weight. The RLS algorithm recursively calculates the sum of squares of previous errors and updates the weights in real time, with stronger tracking ability and convergence. In the initial stage, the weights change rapidly and converge quickly to a stable value. Unlike LMS, RLS can find the optimal weights in a short time and is more adaptable. This fast convergence feature makes RLS more suitable for accurate leakage current detection in complex and changeable noise environments.

[0105] The above experiments can demonstrate the performance and reliability of the system in multi-sensor fusion and signal processing, including the authenticity of signal simulation: the simulation data contains the main characteristics of leakage current in actual applications, including the linear increase trend and the interference of environmental noise. Each sensor signal represents the measurement data at different positions of the GIS shell, and random noise is added to simulate the impact of electromagnetic interference and other environmental factors on the signal. This simulated signal can approximate the leakage current characteristics under real working conditions, which helps to test the performance of the system when processing real data.

[0106] Anti-interference capability verification: The noisy analog signals provide test conditions for multi-sensor fusion and adaptive filtering. By processing these signals, the anti-interference capability of the system can be verified, especially whether the system can accurately extract the leakage current signal under high noise levels. The random noise in the analog signals helps to demonstrate the denoising effect and stability of the filtering algorithm.

[0107] Accuracy of multi-sensor fusion: Since the signals collected by each sensor contain certain noise, multi-sensor fusion can effectively use spatial redundancy to reduce noise interference. Through simulated sensor data, it can be verified whether the fusion algorithm can integrate the data of multiple sensors to obtain a more accurate leakage current signal, and perform well in sensor data synchronization and consistency.

[0108] Signal feature extraction and analysis: Since the noise characteristics of different frequency bands in the leakage current signal are different, the multi-frequency domain analysis module can effectively separate the signal frequency bands in a noisy environment and extract the real leakage current components. Simulation data can verify whether the module can identify and filter noise in an environment with significant high-frequency interference, ensuring the integrity and accuracy of low-frequency leakage signals.

[0109] In summary, the sensor signal simulated by the present invention can effectively test the anti-interference, signal fusion and frequency domain analysis capabilities of the system, and provide strong support for the performance of the system under real working conditions. Through the test of simulated signals, it is proved that the system can still accurately identify and extract leakage current signals in a complex noise environment, ensuring the reliability and effectiveness of GIS equipment monitoring.

[0110] Example 3, reference Fig. 9 , which is the third embodiment of the present invention, and is different from the previous two embodiments in that: a system for measuring a differential leakage current of a GIS shell to the ground, comprising a signal acquisition module 100, a filtering module 200 and a frequency band analysis module 300; the signal acquisition module 100 synchronously acquires a current signal collected by a current sensor; the filtering module 200 uses an adaptive differential filter to filter the collected current signal to obtain a true leakage current signal result; the frequency band analysis module 300 uses a multi-stage frequency domain filter to perform real-time detection and analysis on signals of different frequency bands of the true leakage current signal result.

[0111] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0112] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0113] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0114] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0115] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for measuring differential leakage current of a GIS shell to ground, characterized in that: include, Based on the sensor layout point optimization plan, current sensors are arranged and current signals collected by the current sensors are acquired synchronously; The collected current signal is filtered using an adaptive differential filter to obtain the real leakage current signal result; A multi-stage frequency domain filter is used to perform real-time detection and analysis on signals of different frequency bands of the actual leakage current signal results.

2. A method for measuring differential leakage current of a GIS shell to ground as claimed in claim 1, characterized in that: The sensor layout optimization scheme includes arranging a number of current sensors at key nodes and high-frequency interference sources. The arrangement of the current sensors must meet the symmetrical arrangement, that is, the current sensors are symmetrically distributed around the GIS shell. The symmetrical distribution is symmetrical on the left and right sides or symmetrical on the front and rear ends, forming symmetrical point-to-point monitoring. The arrangement of the current sensors also needs to meet the requirements of layered arrangement, that is, current sensors are arranged at the top, middle and bottom of the shell respectively to cover different areas of the shell; After all current sensors are arranged, a predetermined number of current sensors are added at corresponding positions according to a redundancy strategy.

3. A method for measuring differential leakage current of a GIS shell to ground as claimed in claim 2, characterized in that: The synchronous acquisition of the current signal collected by the current sensor includes: the control end sends a unified trigger signal, and uses time synchronization technology to make the timestamps of the data collected by all current sensors consistent, and start sampling at the same moment.

4. A method for measuring differential leakage current of a GIS shell to ground as claimed in claim 3, characterized in that: The method of filtering the collected current signal by using an adaptive differential filter includes: if n current sensors are arranged, each sensor is denoted as S i , where i = 1, 2, ....n, the sensor collects a leakage current signal x with noise i (t), build the acquisition signal model, the acquisition signal x of each sensor i (t) is expressed as leakage current signal s(t) and noise n i The superposition of (t) is expressed as, x i (t)=s(t)+n i (t) The leakage current signal s(t) is extracted by differential signal calculation, and the differential signal d between each pair of sensors is calculated. ij (t), where d ij (t) = x i (t)-x j (t), for any two sensors S i and S j (i≠j), the formula is expressed as, d ij (t)=x i (t)-x j (t)=(s(t)+n i (t))-(s(t)+n j (t))=n i (t)-n j (t) By calculating the difference signal, the leakage signal is cancelled out, leaving only the difference in noise.

5. A method for measuring differential leakage current of a GIS shell to ground as claimed in claim 4, characterized in that: The filtering of the collected current signal by using an adaptive differential filter also includes suppressing noise by using an adaptive differential filter and optimizing the filter coefficients by using a minimum mean square error algorithm or a recursive least squares algorithm; The updating formula of the adaptive filter is expressed as: in, Represented as the output filtered signal, w k Expressed as the weight coefficient of the filter, x k (t) represents the raw signal of each sensor; The error term e(t) is expressed as When the minimum mean square error algorithm is used for parameter optimization, the weight W k Adjust according to the error e(t), and the update formula is expressed as: w k (t+1)=w k (t)+μ·e(t)·x k (t) Among them, w k (t+1) represents the weight value at the next moment, and μ represents the step size factor; When using the recursive least squares algorithm for parameter optimization, the weight update is based on the sum of squares of the previous errors, expressed as, Among them, λ represents the forgetting factor, δ represents a small constant, and P(t) represents the covariance matrix.

6. A method for measuring differential leakage current of a GIS shell to ground as claimed in claim 5, characterized in that: The use of a multi-stage frequency domain filter to perform real-time detection and analysis of signals of different frequency bands of the actual leakage current signal result includes decomposing the signal into signal components of different frequencies by Fourier transform, which is expressed as follows: Among them, S(f) represents the signal Frequency domain representation, f represents the frequency, j represents the imaginary unit; Design a multi-stage frequency domain filter. Each stage of the filter corresponds to a frequency range. If the system uses m-stage frequency domain filters, the frequency range of each filter is [fi, low, fi, high], and the frequency response of each filter is H i (f) is expressed as, 7. A method for measuring differential leakage current of a GIS shell to ground as claimed in claim 6, characterized in that: The method of using a multi-stage frequency domain filter to detect and analyze signals of different frequency bands of the actual leakage current signal result in real time also includes: i (f) multiply to obtain signal components S in different frequency bands i (f) is expressed as, S i (f)=S(f)·H i (f) For each frequency band signal S i (f) Perform inverse Fourier transform to obtain the corresponding time domain signal s i (t) is expressed as, The original signal is separated into multiple frequency band components. Each time domain signal represents a signal component within a specific frequency range. i (f) and filter out the frequency components that do not meet the leakage current characteristics, and reconstruct the frequency components that meet the characteristics to obtain the final leakage current signal.

8. A system using a method for measuring differential leakage current of a GIS shell to ground as claimed in any one of claims 1 to 7, characterized in that: It comprises a signal acquisition module (100), a filtering module (200) and a frequency band analysis module (300); The signal acquisition module (100) synchronously acquires the current signal collected by the current sensor; The filtering module (200) filters the collected current signal using an adaptive differential filter to obtain a true leakage current signal result; The frequency band analysis module (300) uses a multi-stage frequency domain filter to perform real-time detection and analysis on signals of different frequency bands of the actual leakage current signal result.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the processor implements the steps of a method for measuring the differential leakage current of a GIS shell to the ground as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for measuring a GIS shell-to-ground differential leakage current described in any one of claims 1 to 7 are implemented.

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