A device and method for online monitoring of leakage current of high voltage bushing end screen

Abstract

The present invention provides an online monitoring device and method for leakage current of an end screen of a high-voltage bushing, which judges whether an end screen is in an abnormal state, so as to adjust the leakage current signal acquisition state of the end screen, reduce the interference noise of the acquired leakage current signal and improve the reliability of the leakage current signal; analyze the acquired leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing, obtain the theoretical leakage current signal corresponding to the high-voltage bushing based on the working voltage signal of the transformer, so as to determine the theoretical leakage current change characteristic information of the high-voltage bushing, and perform multi-faceted identification of the leakage current state of the high-voltage bushing; and judge whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, so as to obtain the insulation performance change characteristic information of the high-voltage bushing, ensure accurate online monitoring of the leakage current and improve the reliability of identifying the insulation performance of the high-voltage bushing.

Description

Technical Field

[0001] The invention relates to the field of high voltage bushings, and in particular to an online monitoring device and method for leakage current of a high voltage bushing end screen. Background Art

[0002] The transformer high-voltage bushing is the core equipment of the transformer. As an insulating isolation device between the transformer and the outside world, it can ensure the working safety of the transformer. The leakage current of the high-voltage bushing refers to the weak current that flows through the insulation structure of the high-voltage bushing and finally flows into the earth through the end screen of the high-voltage bushing. The magnitude of the leakage current directly reflects the insulation performance of the high-voltage bushing, and the insulation dissipation coefficient of the high-voltage bushing can also be calculated based on the leakage current, thereby providing a reliable basis for the identification of the insulation performance of the high-voltage bushing. Due to the high voltage at the end screen of the high-voltage bushing, if the end screen of the high-voltage bushing is not reliably grounded, it will lead to inaccurate leakage current detection and detection safety problems. In addition, the existing detection of leakage current of high-voltage bushings is directly detected using the corresponding current sensor, which does not consider whether the high-voltage bushing has abnormal conditions such as breakdown, and cannot ensure the accuracy of the leakage current finally detected, so it cannot provide reliable data support for the subsequent judgment of the insulation performance of the high-voltage bushing. Summary of the invention

[0003] The object of the present invention is to provide an online monitoring device and method for leakage current of an end screen of a high-voltage bushing, which collects and analyzes a high-frequency pulse current signal of an end screen of a high-voltage bushing, determines whether the end screen is in an abnormal state, thereby adjusting the leakage current signal collection state of the end screen, reducing the interference noise of the collected leakage current signal and improving the reliability of the leakage current signal; analyzing the collected leakage current signal to obtain actual leakage current change characteristic information of the high-voltage bushing, and based on the working voltage signal of the transformer, obtaining a theoretical leakage current signal corresponding to the high-voltage bushing, thereby determining the theoretical leakage current change characteristic information of the high-voltage bushing, and performing multi-faceted identification of the leakage current state of the high-voltage bushing; and also based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, determining whether the high-voltage bushing has an insulation performance degradation trend, thereby obtaining the insulation performance change characteristic information of the high-voltage bushing, ensuring accurate online monitoring of the leakage current and improving the reliability of identifying the insulation performance of the high-voltage bushing.

[0004] The present invention is achieved through the following technical solutions:

[0005] An online monitoring device for leakage current of a high-voltage bushing end screen, comprising:

[0006] The end screen sensor module is used to collect high-frequency pulse current signals and leakage current signals at the end screen of the high-voltage bushing;

[0007] An end screen state identification module is used to analyze the high-frequency pulse current signal to determine whether the end screen of the high-voltage bushing is in an abnormal state;

[0008] A leakage current signal acquisition adjustment module, used for adjusting the leakage current signal acquisition state of the end-screen sensing module on the end-screen end of the high-voltage bushing based on the judgment result of the abnormal state;

[0009] An actual leakage current variation characteristic determination module is used to analyze the collected leakage current signal to obtain actual leakage current variation characteristic information of the high-voltage bushing;

[0010] a module for determining a change characteristic of a theoretical leakage current, for obtaining a working voltage signal of a transformer corresponding to the high-voltage bushing, analyzing the working voltage signal, and obtaining a theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; and determining the change characteristic information of the theoretical leakage current of the high-voltage bushing based on the theoretical leakage current signal;

[0011] A bushing insulation state identification module, used to determine whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information;

[0012] The bushing insulation performance quantitative determination module is used to quantitatively identify the insulation performance of the high-voltage bushing based on the judgment result of the insulation performance degradation trend, and obtain the insulation performance change characteristic information of the high-voltage bushing.

[0013] Optionally, the end-screen sensor module includes a grounding shield, a grounding extension rod is arranged inside the grounding shield, and the grounding extension rod is connected to the grounding end of the high-voltage bushing; a leakage current sensor and a high-frequency pulse current sensor are arranged inside the grounding shield and on the periphery of the grounding extension rod; the grounding shield is also provided with a leakage current signal aviation plug and a high-frequency pulse current signal aviation plug respectively connected to the leakage current sensor and the high-frequency pulse current sensor;

[0014] The end screen state identification module is used to analyze the high-frequency pulse current signal to determine whether the end screen of the high-voltage bushing is in an abnormal state, including:

[0015] The high-frequency pulse current signal at the end screen of the high-voltage bushing is collected through a high-frequency pulse current signal aviation plug located at the end screen of the high-voltage bushing, and the time variation analysis of the high-frequency pulse current signal is performed to obtain the variation information of the intensity of the current signal components of different frequencies under the high-frequency pulse current signal over time; if the variation information of the intensity over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, it is judged that the high-voltage bushing is in an abnormal state; otherwise, it is judged that the high-voltage bushing is not in an abnormal state;

[0016] The leakage current signal acquisition adjustment module is used to adjust the leakage current signal acquisition state of the end screen sensor module on the end screen end of the high-voltage bushing based on the judgment result of the abnormal state, including:

[0017] When the high-voltage bushing is in an abnormal state, the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is pre-processed by noise filtering; when the high-voltage bushing is not in an abnormal state, the current leakage current signal acquisition frequency of the leakage current aviation plug is kept unchanged.

[0018] Optionally, when the duration that the high-voltage bushing is not in an abnormal state exceeds a preset time length threshold, the current leakage current signal acquisition frequency of the leakage current aviation plug is reduced and adjusted, which includes:

[0019] Step S1, when the duration of the high-voltage bushing not being in an abnormal state exceeds a preset time length threshold, the following formula (1) is used to control the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end screen of the high-voltage bushing according to the increase in the intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal in the intensity variation information over time. (1) In the above formula (1), Indicates the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing; Indicates the current moment; Indicates unit duration; Indicates the multiple of the total duration to the unit duration in the information of intensity variation over time; Indicates the information of the intensity change over time The frequency value of the current signal with the highest frequency among the high-frequency pulse current signals at the time; Indicates the information of the intensity change over time The frequency value of the current signal with the highest frequency among the high-frequency pulse current signals at the time; Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates that The value ranges from 0 to Get the maximum value in brackets; Integer variable, whose value range is from 0 to ;

[0020] Step S2, using the following formula (2), according to the high-frequency pulse current signal in the information of the change of the intensity over time, the collected leakage current signal is subjected to noise filtering preprocessing, (2)

[0021] In the above formula (2), Indicates the cutoff frequency for noise filtering preprocessing, which is about to exceed the cutoff frequency The current signal is filtered; Indicates that The value ranges from 0 to Get the minimum value in brackets; Indicates the intensity variation over time The frequency value of the current signal with the highest frequency among the high-frequency pulse current signals at the time;

[0022] Step S3, using the following formula (3), determine the reduction multiple corresponding to the reduction adjustment of the current leakage current signal acquisition frequency of the leakage current aviation plug, (3)

[0023] In the above formula (3), Indicates the reduction multiple corresponding to the reduction adjustment of the current leakage current signal acquisition frequency of the leakage current aviation plug; Indicates the current leakage current signal acquisition frequency value of the leakage current aviation plug; Indicates the acquisition frequency value of the initial leakage current signal of the leakage current aviation plug; Represents a non-positive number judgment function. If the value in the brackets is 0 or a negative number, the function value of the non-positive number judgment function is 1. If the value in the brackets is a positive number, the function value of the non-positive number judgment function is 0.

[0024] Optionally, the actual leakage current change characteristic determination module is used to analyze the collected leakage current signal to obtain actual leakage current change characteristic information of the high-voltage bushing, including:

[0025] Extracting effective leakage current components from the collected leakage current signal to obtain an effective leakage current component signal; then performing current phase analysis on the effective leakage current component signal to obtain actual leakage current phase change characteristic information of the high-voltage bushing;

[0026] The theoretical leakage current change characteristic determination module is used to obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; based on the theoretical leakage current signal, determine the theoretical leakage current change characteristic information of the high-voltage bushing, including:

[0027] An electromagnetic induction transient voltage signal generated by a transformer corresponding to the high-voltage bushing is obtained, and based on a disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal, a theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer is determined; and current phase analysis is performed on the theoretical leakage current signal to obtain theoretical leakage current phase change characteristic information of the high-voltage bushing.

[0028] Optionally, the bushing insulation state identification module is used to determine whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, including:

[0029] Compare the actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information with the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information to obtain a phase difference between the two; if the phase difference is greater than a preset phase difference threshold, it is judged that the high-voltage bushing has an insulation performance degradation trend; otherwise, it is judged that the high-voltage bushing does not have an insulation performance degradation trend;

[0030] The bushing insulation performance quantitative determination module is used to perform insulation performance quantitative identification on the high-voltage bushing based on the judgment result of the insulation performance degradation trend, and obtain insulation performance change characteristic information of the high-voltage bushing, including:

[0031] When the insulation performance of the high-voltage bushing shows a trend of deterioration, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induced transient voltage generated by the transformer corresponding to the high-voltage bushing to obtain the insulation dissipation coefficient of the high-voltage bushing.

[0032] A method for online monitoring of leakage current of a high-voltage bushing end screen, comprising:

[0033] Collecting a high-frequency pulse current signal from the end screen of the high-voltage bushing, analyzing the high-frequency pulse current signal, and judging whether the end screen of the high-voltage bushing is in an abnormal state; adjusting the leakage current signal collection state of the end screen of the high-voltage bushing based on the judgment result of the abnormal state;

[0034] Analyze the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing; obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal to obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; determine the theoretical leakage current change characteristic information of the high-voltage bushing based on the theoretical leakage current signal;

[0035] Based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, it is judged whether the high-voltage bushing has an insulation performance degradation trend; and based on the judgment result of the insulation performance degradation trend, the insulation performance of the high-voltage bushing is quantitatively identified to obtain the insulation performance change characteristic information of the high-voltage bushing.

[0036] Optionally, collecting a high-frequency pulse current signal at the end screen of the high-voltage bushing, analyzing the high-frequency pulse current signal, and judging whether the end screen of the high-voltage bushing is in an abnormal state; and adjusting the leakage current signal collection state of the end screen of the high-voltage bushing based on the judgment result of the abnormal state, including:

[0037] The high-frequency pulse current signal at the end screen of the high-voltage bushing is collected through a high-frequency pulse current signal aviation plug located at the end screen of the high-voltage bushing, and the time variation analysis of the high-frequency pulse current signal is performed to obtain the variation information of the intensity of the current signal components of different frequencies under the high-frequency pulse current signal over time; if the variation information of the intensity over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, it is judged that the high-voltage bushing is in an abnormal state; otherwise, it is judged that the high-voltage bushing is not in an abnormal state;

[0038] When the high-voltage bushing is in an abnormal state, the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is pre-processed by noise filtering; when the high-voltage bushing is not in an abnormal state, the current leakage current signal acquisition frequency of the leakage current aviation plug is kept unchanged.

[0039] Optionally, analyzing the collected leakage current signal to obtain actual leakage current change characteristic information of the high-voltage bushing; acquiring a working voltage signal of a transformer corresponding to the high-voltage bushing, analyzing the working voltage signal to obtain a theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; and determining theoretical leakage current change characteristic information of the high-voltage bushing based on the theoretical leakage current signal, including:

[0040] Extracting effective leakage current components from the collected leakage current signal to obtain an effective leakage current component signal; then performing current phase analysis on the effective leakage current component signal to obtain actual leakage current phase change characteristic information of the high-voltage bushing;

[0041] An electromagnetic induction transient voltage signal generated by a transformer corresponding to the high-voltage bushing is obtained, and based on a disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal, a theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer is determined; and current phase analysis is performed on the theoretical leakage current signal to obtain theoretical leakage current phase change characteristic information of the high-voltage bushing.

[0042] Optionally, based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, judging whether the high-voltage bushing has an insulation performance degradation trend; and based on the judgment result of the insulation performance degradation trend, performing insulation performance quantitative identification on the high-voltage bushing to obtain the insulation performance change characteristic information of the high-voltage bushing, including:

[0043] Compare the actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information with the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information to obtain a phase difference between the two; if the phase difference is greater than a preset phase difference threshold, it is judged that the high-voltage bushing has an insulation performance degradation trend; otherwise, it is judged that the high-voltage bushing does not have an insulation performance degradation trend;

[0044] When the insulation performance of the high-voltage bushing shows a trend of deterioration, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induced transient voltage generated by the transformer corresponding to the high-voltage bushing to obtain the insulation dissipation coefficient of the high-voltage bushing.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The device and method for online monitoring of leakage current at the end screen of a high-voltage bushing provided in the present application collect and analyze high-frequency pulse current signals at the end screen of the high-voltage bushing, determine whether the end screen is in an abnormal state, thereby adjusting the leakage current signal collection state of the end screen, reducing the interference noise of the collected leakage current signal and improving the reliability of the leakage current signal; analyzing the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing, and based on the working voltage signal of the transformer, obtaining the theoretical leakage current signal corresponding to the high-voltage bushing, thereby determining the theoretical leakage current change characteristic information of the high-voltage bushing, and performing multi-faceted identification of the leakage current state of the high-voltage bushing; also based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, determining whether the high-voltage bushing has an insulation performance degradation trend, thereby obtaining the insulation performance change characteristic information of the high-voltage bushing, ensuring accurate online monitoring of the leakage current and improving the reliability of identifying the insulation performance of the high-voltage bushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 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 prior art descriptions. 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:

[0048] Figure 1 A schematic structural diagram of a high-voltage bushing end screen leakage current online monitoring device provided by the present invention.

[0049] Figure 2 A schematic structural diagram of an end-screen end sensing module in an online monitoring device for end-screen leakage current of a high-voltage bushing provided by the present invention.

[0050] Figure 3 A schematic flow chart of a method for online monitoring of leakage current of a high-voltage bushing end screen provided by the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0052] The terms "include" and "have" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, device, method, product or equipment comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, devices, products or equipment.

[0053] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0054] See also Figure 1 As shown, an embodiment of the present application provides an online monitoring device for leakage current of a high-voltage bushing end screen. The online monitoring device for leakage current of a high-voltage bushing end screen comprises:

[0055] The end screen sensor module is used to collect high-frequency pulse current signals and leakage current signals at the end screen of the high-voltage bushing;

[0056] The end screen state identification module is used to analyze the high-frequency pulse current signal to determine whether the end screen of the high-voltage bushing is in an abnormal state;

[0057] A leakage current signal acquisition adjustment module is used to adjust the leakage current signal acquisition state of the end screen sensing module on the end screen end of the high-voltage bushing based on the judgment result of the abnormal state;

[0058] An actual leakage current variation characteristic determination module is used to analyze the collected leakage current signal to obtain actual leakage current variation characteristic information of the high-voltage bushing;

[0059] Theoretical leakage current change characteristic determination module is used to obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; based on the theoretical leakage current signal, determine the theoretical leakage current change characteristic information of the high-voltage bushing;

[0060] A bushing insulation state identification module is used to determine whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information;

[0061] The bushing insulation performance quantitative determination module is used to quantitatively identify the insulation performance of the high-voltage bushing based on the judgment result of the insulation performance degradation trend, and obtain the insulation performance change characteristic information of the high-voltage bushing.

[0062] The beneficial effects of the above embodiments are as follows: the high-voltage bushing end screen leakage current online monitoring device collects and analyzes the high-frequency pulse current signal of the high-voltage bushing end screen, determines whether the end screen is in an abnormal state, thereby adjusting the leakage current signal collection state of the end screen, reducing the interference noise of the collected leakage current signal and improving the reliability of the leakage current signal; analyzing the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing, based on the working voltage signal of the transformer, obtaining the theoretical leakage current signal corresponding to the high-voltage bushing, thereby determining the theoretical leakage current change characteristic information of the high-voltage bushing, and performing multi-faceted identification of the leakage current state of the high-voltage bushing; also based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, judging whether the high-voltage bushing has an insulation performance degradation trend, thereby obtaining the insulation performance change characteristic information of the high-voltage bushing, ensuring accurate online monitoring of the leakage current and improving the reliability of identifying the insulation performance of the high-voltage bushing.

[0063] In another embodiment, the end screen sensor module includes a grounding shield, a grounding extension rod is arranged inside the grounding shield, and the grounding extension rod is connected to the grounding end of the high-voltage bushing; a leakage current sensor and a high-frequency pulse current sensor are arranged inside the grounding shield and on the periphery of the grounding extension rod; the grounding shield is also provided with a leakage current signal aviation plug and a high-frequency pulse current signal aviation plug respectively connected to the leakage current sensor and the high-frequency pulse current sensor;

[0064] The end screen state identification module is used to analyze the high-frequency pulse current signal to determine whether the end screen of the high-voltage bushing is in an abnormal state, including:

[0065] The high-frequency pulse current signal at the end screen of the high-voltage bushing is collected through a high-frequency pulse current signal aviation plug located at the end screen of the high-voltage bushing, and a time variation analysis is performed on the high-frequency pulse current signal to obtain information on the variation of the intensity of current signal components of different frequencies under the high-frequency pulse current signal over time; if the information on the variation of the intensity over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, it is judged that the high-voltage bushing is in an abnormal state; otherwise, it is judged that the high-voltage bushing is not in an abnormal state;

[0066] The leakage current signal acquisition adjustment module is used to adjust the leakage current signal acquisition state of the end screen sensor module on the end screen end of the high-voltage bushing based on the judgment result of the abnormal state, including:

[0067] When the high-voltage bushing is in an abnormal state, the leakage current signal collection frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is pre-processed by noise filtering; when the high-voltage bushing is not in an abnormal state, the current leakage current signal collection frequency of the leakage current aviation plug is kept unchanged.

[0068] The beneficial effect of the above embodiment is that the end screen of the high-voltage bushing has a high voltage danger, and direct manual current detection on the end screen of the high-voltage bushing is prone to safety problems. For this reason, the end screen sensing module of the above structure is connected to the end screen, and the leakage current sensor and high-frequency pulse current sensor inside the end screen sensing module are used to detect the leakage current and high-frequency pulse current of the end screen respectively. In this way, the leakage current and high-frequency pulse current of the end screen can be obtained online in real time, thereby improving the safety and reliability of current detection. Among them, the structure of the end screen sensing module is as follows: Figure 2As shown, no detailed description is given here. The electrical properties of the high-voltage bushing directly affect the leakage current at the end screen. If the high-voltage bushing is broken down or has electromagnetic interference, it will affect the leakage current flowing through the high-voltage bushing. For this reason, the high-frequency pulse current signal at the end screen of the high-voltage bushing is first collected, and the high-frequency pulse current signal is analyzed for time changes to obtain the intensity change information of the current signal components of different frequencies under the high-frequency pulse current signal over time. The greater the proportion of the highest frequency pulse current component intensity in the high-frequency pulse current signal, the higher the proportion of the high-voltage bushing in the high-frequency electromagnetic interference and the more likely it is that the high-voltage bushing is in a state of being interfered with by high-frequency electromagnetic interference and is very likely to be broken down. This will amplify the leakage current flowing through the high-voltage bushing, thereby affecting the detection accuracy of the leakage current. In order to improve the detection accuracy of leakage current, according to the information of the intensity change of the current signal components of different frequencies under the high-frequency pulse current signal over time, it is judged that the intensity change information over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, so that it can accurately judge whether the high-voltage bushing is currently in an abnormal state, which is convenient for the subsequent targeted adjustment of the collection operation of the leakage current, thereby ensuring the accuracy of the collected leakage current. Specifically, when the high-voltage bushing is in an abnormal state, the leakage current signal collection frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is pre-processed by noise filtering, so that the effective signal component of the collected leakage current signal can be increased, and sufficient data can be provided for the subsequent leakage current analysis; when the high-voltage bushing is not in an abnormal state, the current leakage current signal collection frequency of the leakage current aviation plug is kept unchanged, so that the workload of leakage current signal collection and processing can be reduced.

[0069] In another embodiment, when the duration that the high-voltage bushing is not in an abnormal state exceeds a preset time length threshold, the current leakage current signal acquisition frequency of the leakage current aviation plug is reduced and adjusted, which includes:

[0070] Step S1, when the duration of the high-voltage bushing not being in an abnormal state exceeds a preset time length threshold, the following formula (1) is used to control the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end screen of the high-voltage bushing according to the increase in the intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal in the intensity variation information over time, (1) In the above formula (1), Indicates the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing; Indicates the current moment; Indicates unit duration; Indicates the value of the multiple of the total duration to the unit duration in the information of the intensity change over time; Indicates the change of intensity over time The frequency value of the current signal with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the change of intensity over time The frequency value of the current signal with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the change of intensity over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the change of intensity over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment;

[0071] Step S2, using the following formula (2), according to the high-frequency pulse current signal in the information of the intensity change over time, the collected leakage current signal is subjected to noise filtering preprocessing, (2)

[0072] In the above formula (2), Indicates the cutoff frequency for noise filtering preprocessing, which is about to exceed the cutoff frequency The current signal is filtered; Indicates that The value ranges from 0 to Get the minimum value in brackets; Indicates the change of intensity over time The frequency value of the current signal with the highest frequency in the high-frequency pulse current signal at the moment;

[0073] Step S3, using the following formula (3), determine the reduction multiple corresponding to the reduction adjustment of the current leakage current signal acquisition frequency of the leakage current aviation plug, Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates that The value ranges from 0 to Get the maximum value in brackets; Integer variable, whose value range is from 0 to ; (3)

[0074] In the above formula (3), Indicates the reduction multiple corresponding to the reduction adjustment of the current leakage current signal acquisition frequency of the leakage current aviation plug; Indicates the current leakage current signal acquisition frequency value of the leakage current aviation plug; Indicates the acquisition frequency value of the initial leakage current signal of the leakage current aviation plug; Represents a non-positive number judgment function. If the value in the brackets is 0 or a negative number, the function value of the non-positive number judgment function is 1. If the value in the brackets is a positive number, the function value of the non-positive number judgment function is 0.

[0075] The beneficial effect of the above embodiment is that, by using the above formula (1), according to the increase in the intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal in the intensity variation information over time, the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end screen of the high-voltage bushing is controlled, so as to ensure that the change speed of the acquisition frequency is not lower than the change speed of the intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal in the intensity variation information over time, so as to ensure the reliability of the acquisition frequency for signal acquisition; then, by using the above formula (2), according to the high-frequency pulse current signal in the intensity variation information over time, the collected leakage current signal is subjected to noise filtering preprocessing, so as to reduce part of the high-frequency noise, facilitate the reduction of the amount of data analyzed in the subsequent analysis and facilitate the subsequent further filtering processing; then, by using the above formula (3), the corresponding reduction multiple of the current leakage current signal acquisition frequency of the leakage current aviation plug is determined, so as to appropriately reduce the acquisition frequency when the high-voltage bushing is not in an abnormal state for a long time, thereby saving system energy consumption.

[0076] In another embodiment, the actual leakage current variation characteristic determination module is used to analyze the collected leakage current signal to obtain the actual leakage current variation characteristic information of the high-voltage bushing, including:

[0077] Extracting effective leakage current components from the collected leakage current signal to obtain an effective leakage current component signal; then performing current phase analysis on the effective leakage current component signal to obtain actual leakage current phase change characteristic information of the high-voltage bushing;

[0078] The theoretical leakage current change characteristic determination module is used to obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; based on the theoretical leakage current signal, determine the theoretical leakage current change characteristic information of the high-voltage bushing, including:

[0079] An electromagnetic induction transient voltage signal generated by a transformer corresponding to the high-voltage bushing is obtained, and based on the disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal, a theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer is determined; and current phase analysis is performed on the theoretical leakage current signal to obtain characteristic information of theoretical leakage current phase change of the high-voltage bushing.

[0080] The beneficial effect of the above embodiment is that the collected leakage current signal is processed by Kalman filtering to extract the effective leakage current component signal, which can reduce the negative impact of the invalid components in the signal on the subsequent calculation and processing. Then the current phase analysis is performed on the effective leakage current component signal to obtain the actual leakage current phase change characteristic information of the high-voltage bushing, and the actual leakage current phase change characteristic information reflects the phase change of the leakage current actually flowing through the high-voltage bushing. The leakage current of the high-voltage bushing is actually formed by the voltage disturbance applied to the high-voltage bushing by the electromagnetic induction transient voltage formed by the transformer corresponding to the high-voltage bushing itself during operation. In order to determine the theoretical leakage current flowing inside the high-voltage bushing, the electromagnetic induction transient voltage signal generated by the transformer corresponding to the high-voltage bushing is first obtained, and the disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal is determined based on the theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer, so that the theoretical value of the leakage current flowing inside the high-voltage bushing can be accurately calculated. The theoretical leakage current signal is then subjected to current phase analysis to obtain characteristic information of theoretical leakage current phase change of the high-voltage bushing, thereby providing a reliable reference benchmark for subsequent judgment of whether the high-voltage bushing has a trend of insulation performance degradation.

[0081] In another embodiment, the bushing insulation state identification module is used to determine whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, including:

[0082] Compare the actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information with the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information to obtain a phase difference between the two; if the phase difference is greater than a preset phase difference threshold, it is judged that the high-voltage bushing has an insulation performance degradation trend; otherwise, it is judged that the high-voltage bushing does not have an insulation performance degradation trend;

[0083] The bushing insulation performance quantitative determination module is used to perform insulation performance quantitative identification on the high-voltage bushing based on the judgment result of the insulation performance degradation trend, and obtain insulation performance change characteristic information of the high-voltage bushing, including:

[0084] When the insulation performance of the high-voltage bushing shows a trend of deterioration, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induced transient voltage generated by the transformer corresponding to the high-voltage bushing to obtain the insulation dissipation coefficient of the high-voltage bushing.

[0085] The beneficial effect of the above embodiment is to compare the actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information with the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information, obtain the phase difference between the two, and compare the threshold of the phase difference, so as to accurately judge whether the high-voltage bushing has a trend of insulation performance degradation. In addition, when the high-voltage bushing has a trend of insulation performance degradation, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induction transient voltage generated by the transformer corresponding to the high-voltage bushing, and the insulation dissipation coefficient of the high-voltage bushing is obtained, wherein the insulation dissipation coefficient calculated according to the actual leakage current of the high-voltage bushing and the electromagnetic induction transient voltage generated by the transformer corresponding to the high-voltage bushing belongs to the conventional technical means in this field, and will not be described in detail here. The insulation dissipation coefficient obtained by calculation can truly and accurately reflect the insulation performance of the high-voltage bushing. When the insulation dissipation coefficient is larger, it indicates that the insulation performance of the high-voltage bushing has deteriorated, providing an accurate basis for subsequent maintenance operations on the high-voltage bushing.

[0086] See also Figure 3 As shown, an embodiment of the present application provides an online monitoring method for leakage current of a high-voltage bushing end screen. The online monitoring method for leakage current of a high-voltage bushing end screen comprises:

[0087] Collecting a high-frequency pulse current signal from the end screen of the high-voltage bushing, analyzing the high-frequency pulse current signal, and judging whether the end screen of the high-voltage bushing is in an abnormal state; adjusting the leakage current signal collection state of the end screen of the high-voltage bushing based on the judgment result of the abnormal state;

[0088] Analyze the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing; obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; determine the theoretical leakage current change characteristic information of the high-voltage bushing based on the theoretical leakage current signal;

[0089] Based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, it is judged whether the high-voltage bushing has an insulation performance degradation trend; and based on the judgment result of the insulation performance degradation trend, the insulation performance of the high-voltage bushing is quantitatively identified to obtain the insulation performance change characteristic information of the high-voltage bushing.

[0090] The beneficial effects of the above embodiments are as follows: the online monitoring method for leakage current of the end screen of the high-voltage bushing collects and analyzes the high-frequency pulse current signal of the end screen of the high-voltage bushing, determines whether the end screen is in an abnormal state, thereby adjusting the leakage current signal collection state of the end screen, reducing the interference noise of the collected leakage current signal and improving the reliability of the leakage current signal; analyzing the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing, based on the working voltage signal of the transformer, obtaining the theoretical leakage current signal corresponding to the high-voltage bushing, thereby determining the theoretical leakage current change characteristic information of the high-voltage bushing, and performing multi-faceted identification of the leakage current state of the high-voltage bushing; also based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, judging whether the high-voltage bushing has an insulation performance degradation trend, thereby obtaining the insulation performance change characteristic information of the high-voltage bushing, ensuring accurate online monitoring of the leakage current and improving the reliability of identifying the insulation performance of the high-voltage bushing.

[0091] In another embodiment, a high-frequency pulse current signal is collected from a high-voltage bushing end screen, and the high-frequency pulse current signal is analyzed to determine whether the high-voltage bushing end screen is in an abnormal state; based on the determination result of the abnormal state, a leakage current signal collection state of the high-voltage bushing end screen is adjusted, including:

[0092] The high-frequency pulse current signal at the end screen of the high-voltage bushing is collected through a high-frequency pulse current signal aviation plug located at the end screen of the high-voltage bushing, and a time variation analysis is performed on the high-frequency pulse current signal to obtain information on the variation of the intensity of current signal components of different frequencies under the high-frequency pulse current signal over time; if the information on the variation of the intensity over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, it is judged that the high-voltage bushing is in an abnormal state; otherwise, it is judged that the high-voltage bushing is not in an abnormal state;

[0093] When the high-voltage bushing is in an abnormal state, the leakage current signal collection frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is pre-processed by noise filtering; when the high-voltage bushing is not in an abnormal state, the current leakage current signal collection frequency of the leakage current aviation plug is kept unchanged.

[0094] The beneficial effect of the above embodiment is that the electrical properties of the high-voltage bushing directly affect the leakage current at the end screen. If the high-voltage bushing is broken down or electromagnetic interference occurs, the leakage current flowing through the high-voltage bushing will be affected. For this purpose, a high-frequency pulse current signal at the end screen of the high-voltage bushing is first collected, and the high-frequency pulse current signal is analyzed for time changes to obtain information on the intensity changes of current signal components of different frequencies under the high-frequency pulse current signal over time. The greater the proportion of the highest frequency pulse current component intensity in the high-frequency pulse current signal, the higher the proportion of the high-voltage bushing in the high-frequency electromagnetic interference and the more likely it is that the high-voltage bushing is in a state of being interfered with by high-frequency electromagnetic interference and is very likely to be broken down. This will amplify the leakage current flowing through the high-voltage bushing, thereby affecting the detection accuracy of the leakage current. In order to improve the detection accuracy of leakage current, according to the information of the intensity change of the current signal components of different frequencies under the high-frequency pulse current signal over time, it is judged that the intensity change information over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, so that it can accurately judge whether the high-voltage bushing is currently in an abnormal state, which is convenient for the subsequent targeted adjustment of the collection operation of the leakage current, thereby ensuring the accuracy of the collected leakage current. Specifically, when the high-voltage bushing is in an abnormal state, the leakage current signal collection frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is pre-processed by noise filtering, so that the effective signal component of the collected leakage current signal can be increased, and sufficient data can be provided for the subsequent leakage current analysis; when the high-voltage bushing is not in an abnormal state, the current leakage current signal collection frequency of the leakage current aviation plug is kept unchanged, so that the workload of leakage current signal collection and processing can be reduced.

[0095] In another embodiment, the collected leakage current signal is analyzed to obtain actual leakage current change characteristic information of the high-voltage bushing; the working voltage signal of the transformer corresponding to the high-voltage bushing is obtained, and the working voltage signal is analyzed to obtain a theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; based on the theoretical leakage current signal, the theoretical leakage current change characteristic information of the high-voltage bushing is determined, including:

[0096] Extracting effective leakage current components from the collected leakage current signal to obtain an effective leakage current component signal; then performing current phase analysis on the effective leakage current component signal to obtain actual leakage current phase change characteristic information of the high-voltage bushing;

[0097] An electromagnetic induction transient voltage signal generated by a transformer corresponding to the high-voltage bushing is obtained, and based on the disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal, a theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer is determined; and current phase analysis is performed on the theoretical leakage current signal to obtain characteristic information of theoretical leakage current phase change of the high-voltage bushing.

[0098] The beneficial effect of the above embodiment is that the collected leakage current signal is processed by Kalman filtering to extract the effective leakage current component signal, which can reduce the negative impact of the invalid components in the signal on the subsequent calculation and processing. Then the current phase analysis is performed on the effective leakage current component signal to obtain the actual leakage current phase change characteristic information of the high-voltage bushing, and the actual leakage current phase change characteristic information reflects the phase change of the leakage current actually flowing through the high-voltage bushing. The leakage current of the high-voltage bushing is actually formed by the voltage disturbance applied to the high-voltage bushing by the electromagnetic induction transient voltage formed by the transformer corresponding to the high-voltage bushing itself during operation. In order to determine the theoretical leakage current flowing inside the high-voltage bushing, the electromagnetic induction transient voltage signal generated by the transformer corresponding to the high-voltage bushing is first obtained, and the disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal is determined based on the theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer, so that the theoretical value of the leakage current flowing inside the high-voltage bushing can be accurately calculated. The theoretical leakage current signal is then subjected to current phase analysis to obtain characteristic information of theoretical leakage current phase change of the high-voltage bushing, thereby providing a reliable reference benchmark for subsequent judgment of whether the high-voltage bushing has a trend of insulation performance degradation.

[0099] In another embodiment, based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, it is judged whether the high-voltage bushing has an insulation performance degradation trend; and based on the judgment result of the insulation performance degradation trend, the insulation performance of the high-voltage bushing is quantitatively identified to obtain the insulation performance change characteristic information of the high-voltage bushing, including:

[0100] Compare the actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information with the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information to obtain a phase difference between the two; if the phase difference is greater than a preset phase difference threshold, it is judged that the high-voltage bushing has an insulation performance degradation trend; otherwise, it is judged that the high-voltage bushing does not have an insulation performance degradation trend;

[0101] When the insulation performance of the high-voltage bushing shows a trend of deterioration, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induced transient voltage generated by the transformer corresponding to the high-voltage bushing to obtain the insulation dissipation coefficient of the high-voltage bushing.

[0102] The beneficial effect of the above embodiment is to compare the actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information with the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information, obtain the phase difference between the two, and compare the threshold of the phase difference, so as to accurately judge whether the high-voltage bushing has a trend of insulation performance degradation. In addition, when the high-voltage bushing has a trend of insulation performance degradation, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induction transient voltage generated by the transformer corresponding to the high-voltage bushing, and the insulation dissipation coefficient of the high-voltage bushing is obtained, wherein the insulation dissipation coefficient calculated according to the actual leakage current of the high-voltage bushing and the electromagnetic induction transient voltage generated by the transformer corresponding to the high-voltage bushing belongs to the conventional technical means in this field, and will not be described in detail here. The insulation dissipation coefficient obtained by calculation can truly and accurately reflect the insulation performance of the high-voltage bushing. When the insulation dissipation coefficient is larger, it indicates that the insulation performance of the high-voltage bushing has deteriorated, providing an accurate basis for subsequent maintenance operations on the high-voltage bushing.

[0103] In general, the online monitoring device and method for leakage current of the end screen of a high-voltage bushing collects and analyzes the high-frequency pulse current signal of the end screen of the high-voltage bushing, determines whether the end screen is in an abnormal state, thereby adjusting the leakage current signal collection state of the end screen, reducing the interference noise of the collected leakage current signal and improving the reliability of the leakage current signal; analyzing the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing, based on the working voltage signal of the transformer, obtaining the theoretical leakage current signal corresponding to the high-voltage bushing, thereby determining the theoretical leakage current change characteristic information of the high-voltage bushing, and performing multi-faceted identification of the leakage current state of the high-voltage bushing; also based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, determining whether the high-voltage bushing has an insulation performance degradation trend, thereby obtaining the insulation performance change characteristic information of the high-voltage bushing, ensuring accurate online monitoring of the leakage current and improving the reliability of identifying the insulation performance of the high-voltage bushing.

[0104] The above is only a specific implementation of the present invention, and any other improvements made based on the concept of the present invention are considered to be within the protection scope of the present invention.

Claims

1. An online monitoring device for leakage current of a high-voltage bushing end screen, characterized in that: include: The end screen sensor module is used to collect high-frequency pulse current signals and leakage current signals at the end screen of the high-voltage bushing; An end screen state identification module is used to analyze the high-frequency pulse current signal to determine whether the end screen of the high-voltage bushing is in an abnormal state; A leakage current signal acquisition adjustment module, used for adjusting the leakage current signal acquisition state of the end-screen sensing module on the end-screen end of the high-voltage bushing based on the judgment result of the abnormal state; An actual leakage current variation characteristic determination module is used to analyze the collected leakage current signal to obtain actual leakage current variation characteristic information of the high-voltage bushing; A theoretical leakage current variation characteristic determination module is used to obtain a working voltage signal of a transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain a theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; Based on the theoretical leakage current signal, determining theoretical leakage current change characteristic information of the high-voltage bushing; A bushing insulation state identification module, used to determine whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information; A bushing insulation performance quantitative determination module, used to perform insulation performance quantitative identification on the high-voltage bushing based on the judgment result of the insulation performance degradation trend, and obtain insulation performance change characteristic information of the high-voltage bushing; Wherein, the end screen sensor module includes a grounding shield, a grounding extension rod is arranged inside the grounding shield, and the grounding extension rod is connected to the grounding end of the high-voltage bushing; a leakage current sensor and a high-frequency pulse current sensor are arranged inside the grounding shield and on the periphery of the grounding extension rod; the grounding shield is also provided with a leakage current signal aviation plug and a high-frequency pulse current signal aviation plug respectively connected to the leakage current sensor and the high-frequency pulse current sensor; The end screen state identification module is used to analyze the high-frequency pulse current signal to determine whether the end screen of the high-voltage bushing is in an abnormal state, including: The high-frequency pulse current signal at the end screen of the high-voltage bushing is collected through a high-frequency pulse current signal aviation plug located at the end screen of the high-voltage bushing, and the time variation analysis of the high-frequency pulse current signal is performed to obtain the variation information of the intensity of the current signal components of different frequencies under the high-frequency pulse current signal over time; if the variation information of the intensity over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, it is judged that the high-voltage bushing is in an abnormal state; otherwise, it is judged that the high-voltage bushing is not in an abnormal state; The leakage current signal acquisition adjustment module is used to adjust the leakage current signal acquisition state of the end screen sensor module on the end screen end of the high-voltage bushing based on the judgment result of the abnormal state, including: When the high-voltage bushing is in an abnormal state, the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is preprocessed by noise filtering; when the high-voltage bushing is not in an abnormal state, the current leakage current signal acquisition frequency of the leakage current aviation plug is kept unchanged; The bushing insulation state identification module is used to determine whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, including: The actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information and the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information are compared to obtain a phase difference between the two; if the phase difference is greater than a preset phase difference threshold, it is determined that the high-voltage bushing has an insulation performance degradation trend; otherwise, it is determined that the high-voltage bushing does not have an insulation performance degradation trend.

2. The online monitoring device for leakage current of the high-voltage bushing end screen according to claim 1, characterized in that: When the duration that the high-voltage bushing is not in an abnormal state exceeds a preset time length threshold, the current leakage current signal acquisition frequency of the leakage current aviation plug is reduced and adjusted, which includes: Step S1, when the duration of the high-voltage bushing not being in an abnormal state exceeds a preset time length threshold, the following formula (1) is used to control the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end screen of the high-voltage bushing according to the increase in the intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal in the intensity variation information over time. （1） In the above formula (1), Indicates the increase multiple of the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing; Indicates the current moment; Indicates unit duration; Indicates the multiple of the total duration to the unit duration in the information of intensity variation over time; Indicates the information of the intensity change over time The frequency value of the current signal with the highest frequency among the high-frequency pulse current signals at the time; Indicates the intensity variation over time The frequency value of the current signal with the highest frequency among the high-frequency pulse current signals at the time; Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the intensity variation over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates the information of the intensity change over time The intensity ratio of the current signal component with the highest frequency in the high-frequency pulse current signal at the moment; Indicates that The value ranges from 0 to Get the maximum value in brackets; Integer variable, whose value range is from 0 to ; Step S2, using the following formula (2), according to the high-frequency pulse current signal in the information of the change of the intensity over time, the collected leakage current signal is subjected to noise filtering preprocessing, （2） In the above formula (2), Indicates the cutoff frequency for noise filtering preprocessing, which is about to exceed the cutoff frequency The current signal is filtered; Indicates that The value ranges from 0 to Get the minimum value in brackets; Indicates the information of the intensity change over time The frequency value of the current signal with the highest frequency among the high-frequency pulse current signals at the time; Step S3, using the following formula (3), determine the reduction multiple corresponding to the reduction adjustment of the current leakage current signal acquisition frequency of the leakage current aviation plug, （3） In the above formula (3), Indicates the reduction multiple corresponding to the reduction adjustment of the current leakage current signal acquisition frequency of the leakage current aviation plug; Indicates the current leakage current signal acquisition frequency value of the leakage current aviation plug; Indicates the acquisition frequency value of the initial leakage current signal of the leakage current aviation plug; Represents a non-positive number judgment function. If the value in the brackets is 0 or a negative number, the function value of the non-positive number judgment function is 1. If the value in the brackets is a positive number, the function value of the non-positive number judgment function is 0.

3. The online monitoring device for leakage current of the high-voltage bushing end screen according to claim 1 is characterized in that: The actual leakage current change characteristic determination module is used to analyze the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing, including: Extracting effective leakage current components from the collected leakage current signal to obtain an effective leakage current component signal; then performing current phase analysis on the effective leakage current component signal to obtain actual leakage current phase change characteristic information of the high-voltage bushing; The theoretical leakage current change characteristic determination module is used to obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; based on the theoretical leakage current signal, determine the theoretical leakage current change characteristic information of the high-voltage bushing, including: An electromagnetic induction transient voltage signal generated by a transformer corresponding to the high-voltage bushing is obtained, and based on a disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal, a theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer is determined; and current phase analysis is performed on the theoretical leakage current signal to obtain theoretical leakage current phase change characteristic information of the high-voltage bushing.

4. The online monitoring device for leakage current of the high-voltage bushing end screen according to claim 1 is characterized in that: The bushing insulation performance quantitative determination module is used to perform insulation performance quantitative identification on the high-voltage bushing based on the judgment result of the insulation performance degradation trend, and obtain insulation performance change characteristic information of the high-voltage bushing, including: When the insulation performance of the high-voltage bushing shows a trend of deterioration, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induced transient voltage generated by the transformer corresponding to the high-voltage bushing to obtain the insulation dissipation coefficient of the high-voltage bushing.

5. A method for online monitoring of leakage current of a high-voltage bushing end screen, characterized in that: include: Collecting a high-frequency pulse current signal from the end screen of the high-voltage bushing, analyzing the high-frequency pulse current signal, and determining whether the end screen of the high-voltage bushing is in an abnormal state; Based on the judgment result of the abnormal state, adjusting the leakage current signal collection state of the end screen of the high-voltage bushing; Analyze the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing; obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal to obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; determine the theoretical leakage current change characteristic information of the high-voltage bushing based on the theoretical leakage current signal; Based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information, judging whether the high-voltage bushing has an insulation performance degradation trend; and based on the judgment result of the insulation performance degradation trend, performing insulation performance quantitative identification on the high-voltage bushing to obtain insulation performance change characteristic information of the high-voltage bushing; The method includes collecting a high-frequency pulse current signal from the end screen of the high-voltage bushing, analyzing the high-frequency pulse current signal, and judging whether the end screen of the high-voltage bushing is in an abnormal state; and adjusting the leakage current signal collection state of the end screen of the high-voltage bushing based on the judgment result of the abnormal state, including: The high-frequency pulse current signal at the end screen of the high-voltage bushing is collected through a high-frequency pulse current signal aviation plug located at the end screen of the high-voltage bushing, and the time variation analysis of the high-frequency pulse current signal is performed to obtain the variation information of the intensity of the current signal components of different frequencies under the high-frequency pulse current signal over time; if the variation information of the intensity over time indicates that the intensity proportion of the current signal component with the highest frequency in the high-frequency pulse current signal increases over time, it is judged that the high-voltage bushing is in an abnormal state; otherwise, it is judged that the high-voltage bushing is not in an abnormal state; When the high-voltage bushing is in an abnormal state, the leakage current signal acquisition frequency of the leakage current aviation plug located at the end of the high-voltage bushing is increased, and the collected leakage current signal is preprocessed by noise filtering; when the high-voltage bushing is not in an abnormal state, the current leakage current signal acquisition frequency of the leakage current aviation plug is kept unchanged; Wherein, judging whether the high-voltage bushing has an insulation performance degradation trend based on the actual leakage current change characteristic information and the theoretical leakage current change characteristic information includes: The actual leakage current phase change characteristic information corresponding to the actual leakage current change characteristic information and the theoretical leakage current phase change characteristic information corresponding to the theoretical leakage current change characteristic information are compared to obtain a phase difference between the two; if the phase difference is greater than a preset phase difference threshold, it is determined that the high-voltage bushing has an insulation performance degradation trend; otherwise, it is determined that the high-voltage bushing does not have an insulation performance degradation trend.

6. The method for online monitoring of leakage current of the high-voltage bushing end screen according to claim 5, characterized in that: Analyze the collected leakage current signal to obtain the actual leakage current change characteristic information of the high-voltage bushing; obtain the working voltage signal of the transformer corresponding to the high-voltage bushing, analyze the working voltage signal, and obtain the theoretical leakage current signal formed by the high-voltage bushing under the influence of the working voltage of the transformer; Determining theoretical leakage current change characteristic information of the high-voltage bushing based on the theoretical leakage current signal includes: Extracting effective leakage current components from the collected leakage current signal to obtain an effective leakage current component signal; then performing current phase analysis on the effective leakage current component signal to obtain actual leakage current phase change characteristic information of the high-voltage bushing; An electromagnetic induction transient voltage signal generated by a transformer corresponding to the high-voltage bushing is obtained, and based on a disturbance voltage applied to the high-voltage bushing by the electromagnetic induction transient voltage signal, a theoretical leakage current signal formed by the high-voltage bushing under the influence of the transformer is determined; and current phase analysis is performed on the theoretical leakage current signal to obtain theoretical leakage current phase change characteristic information of the high-voltage bushing.

7. The method for online monitoring of leakage current of the high-voltage bushing end screen according to claim 5, characterized in that: Based on the judgment result of the insulation performance degradation trend, the insulation performance of the high-voltage bushing is quantitatively identified to obtain the insulation performance change characteristic information of the high-voltage bushing, including: When the insulation performance of the high-voltage bushing shows a trend of deterioration, the insulation performance of the high-voltage bushing is quantitatively identified based on the actual leakage current of the high-voltage bushing and the electromagnetic induced transient voltage generated by the transformer corresponding to the high-voltage bushing to obtain the insulation dissipation coefficient of the high-voltage bushing.

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