Capacitive bushing tap grounding state detection device

Abstract

The utility model relates to the technical field of capacitance type bushing tap grounding state detection, and provides a capacitance type bushing tap grounding state detection device, which utilizes high-frequency signals to directly detect a capacitance type bushing, remarkably improves the sensitivity and response speed of grounding state detection, and ensures that the grounding condition can be quickly and accurately identified. The high-frequency signal generation module supports 0-300kHz signal output, adapts to detection requirements of capacitive bushings with different capacitances, and has relatively high applicability; the LCD man-machine interaction module is arranged, so that a user can visually display the detected capacitance, the operation convenience is improved, and the user experience is enhanced; the auxiliary circuit can provide corresponding stable voltage for each module.

Description

Technical Field

[0001] The utility model relates to the technical field of capacitance type bushing end screen grounding state detection, in particular to a capacitance type bushing end screen grounding state detection device. Background Art

[0002] A bushing is a device used to pass through partitions such as walls and boxes. Its primary function is to allow one or more conductors to pass through such partitions, providing insulation and support. Capacitor bushings are a special type of bushing. They share all the properties and functions of bushings, but differ from conventional bushings in that their primary insulation consists of a coaxial cylindrical series capacitor bank formed by alternating layers of insulating material and foil-like metal electrodes wound around a conductive rod.

[0003] Capacitive bushings above 60 kV are typically equipped with a measuring terminal. This terminal is connected to the end shield (the outermost electrode of the core) through a small porcelain sleeve and is grounded during operation. During transformer operation, real-time monitoring can be performed without removing the bushing, providing timely information on the insulation status, ensuring safe and stable operation.

[0004] Currently, the main insulating capacitor screen structure of operational capacitive bushings remains largely unchanged, but the external wiring terminals, particularly the terminal screen structure, vary significantly. According to existing technical solutions, there are generally three types of grounding methods for the terminal screen of capacitive bushings operating within a system: external, internal, and permanently grounded. With technological advancements and improved manufacturing processes, these structures have undergone significant changes. In recent years, internal grounding has become the mainstream method for the terminal screen of capacitive bushings (grounding is achieved through a grounding cover or cap).

[0005] However, this built-in grounding design brings a lot of difficulties in the process of checking the grounding restoration of the end screen after the on-site bushing test. The consequences of transformer failure caused by unreliable end screen grounding are serious and cannot be ignored.

[0006] Under the influence of high-frequency signals, capacitors can effectively charge and discharge, resulting in rapid charge movement. High-frequency signals generally refer to AC signals with frequencies between several kilohertz and several hundred megahertz. When high-frequency signals pass through a capacitor, the potential difference across the capacitor changes rapidly, affecting signal transmission and device stability.

[0007] The impedance method is suitable for measuring capacitor characteristics under AC conditions, and is particularly advantageous for measuring high-frequency characteristics. By applying an AC voltage of a certain frequency to the capacitor, the impedance method measures the impedance and phase angle of the capacitor, thereby obtaining the capacitance value and its equivalent series resistance. This provides an effective means for detecting the grounding status of capacitive bushings.

[0008] Based on this, the utility model proposes a capacitive bushing end screen grounding status detection device to efficiently and reliably check the grounding recovery of the end screen after on-site bushing testing. Utility Model Content

[0009] The purpose of the utility model is to solve the deficiencies of the prior art and to provide a capacitance type bushing end screen grounding state detection device, so as to efficiently and reliably check the grounding recovery of the end screen after a field bushing test.

[0010] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0011] A capacitive bushing end screen grounding status detection device comprises: a housing, an LCD human-machine interaction module disposed inside the housing, a high-frequency signal generation module, a detection circuit, an MCU main control and data processing module, a power supply module, and an auxiliary circuit; the MCU main control and data processing module are electrically connected to the LCD human-machine interaction module, the high-frequency signal generation module, the detection circuit, the power supply module, and the auxiliary circuit respectively; the output of the high-frequency signal generation module is electrically connected to the upper end of the capacitive bushing;

[0012] The LCD human-computer interaction module is used to present the data processed by the MCU main control and data processing modules, and transmit control commands to the MCU main control and data processing modules;

[0013] The high-frequency signal generating module is used to output a high-frequency sinusoidal AC signal through a signal output port under the control of the MCU main control and data processing module, and inject the high-frequency AC signal into the capacitive bushing; a resistor R is connected in series between the output of the high-frequency signal generating module and the capacitive bushing;

[0014] The detection circuit is used to detect the feedback signal loaded between the terminal at the top of the bushing and the transformer housing, and output the detected signal to the MCU main control and data processing module;

[0015] The MCU main control and data processing module is used to output the detection circuit after analog-to-digital conversion to the MCU main control. The MCU main control uses the signal output by the detection circuit to calculate the voltage signal applied to the capacitive bushing, and output the total capacitance of other capacitors and the bushing main capacitance in parallel, and transmit the total capacitance signal to the LCD human-computer interaction module;

[0016] The power supply module is used to supply power to the LCD human-computer interaction module, the high-frequency signal generation module, the detection circuit, the MCU main control module and the data processing module;

[0017] The auxiliary circuit is used to convert the voltage output by the power module to provide an adaptive voltage for the LCD human-computer interaction module, the high-frequency signal generation module, the detection circuit, the MCU main control and the data processing module.

[0018] Preferably, the shell is a rectangular box, the LCD human-computer interaction module is fixed to the front side of the shell, the top of the shell is provided with signal output, input and device shell grounding sockets, the high-frequency signal generating module, detection circuit, MCU main control and data processing module, auxiliary circuit and power supply module are arranged inside the shell, and a power plug is provided on the side of the shell; the signal output socket is connected to the end of the resistor R away from the high-frequency signal generating module, the signal input socket is connected to the detection circuit, and the power plug is connected to the power module.

[0019] Preferably, the high-frequency signal generating module outputs a high-frequency sinusoidal AC signal with a frequency range of 0 to 300 kHz.

[0020] Preferably, the high-frequency signal generating module includes: capacitors C1, C2, C4, inductor L1, and a common-mode gate driver U1; pin 1 of the common-mode gate driver U1 is connected to a 5V power supply, pins 2 and 4 of the common-mode gate driver U1 are grounded, pin 3 of the common-mode gate driver U1 is connected to SPWM1 output by the MCU, pin 5 of the common-mode gate driver U1 is connected in series with the inductor L1, and the idle end of the inductor L1 is the output signal port SIN1; capacitors C2 and C4 are connected in parallel between pin 1 and pin 2 of the common-mode gate driver U1.

[0021] Preferably, the detection circuit detects the voltage across the resistor R, and the detection circuit is two high-frequency voltage signal acquisition and amplification circuits, which are respectively connected between the two ends of R and the grounding point.

[0022] Preferably, the detection circuit is a high-frequency voltage signal acquisition and amplification circuit; the high-frequency voltage signal acquisition and amplification circuit includes: inductors L2, L3, inductors C38-C45, diode ZD2, resistors R6-R10, operational amplifier U2, and potentiometer U6; one end of the inductor L2 is connected to the resistor R, and the other end is grounded; one side of the inductor L2 is the inductor L3, one end of the inductor L3 is connected to pin 1 of the operational amplifier U2, and the other end is grounded, a capacitor C42 is provided between one end of the inductor L3 and pin 1 of the operational amplifier U2, pin 2 of the operational amplifier U2 is grounded, pin 3 of the operational amplifier U2 is connected to pin 1 of the potentiometer U6, and a resistor R10 is connected in series at the end of pin 4 of the operational amplifier U2, and the vacant end of the resistor R10 is the signal output port U_ADC 1. Pin 5 of the operational amplifier U2 is connected to the 3.3V power supply. C38, C39, and resistors R6 and R7 in series are connected in parallel between pin 5 of the operational amplifier U2 and ground respectively. Capacitor C40 is connected in parallel across resistor R7, and capacitor C42 is connected to capacitor C40 via resistor R8. Pin 2 of the potentiometer U6 is connected to the 3.3V power supply. Capacitor C43 is provided between pin 2 and ground. Pin 3 of the potentiometer U6 is grounded. Pins 4-6 of the potentiometer U6 are connected to the corresponding outputs of the MCU. Pin 7 of the potentiometer U6 is connected to pin 4 of the operational amplifier U2, and the connection point is grounded via resistor R9. Pin 7 of the potentiometer U6 is grounded via capacitor C41. The front end of the output port U_ADC1 is grounded via capacitor C44. Diode ZD2 is connected in parallel across the inductor L3.

[0023] Preferably, the detection circuit also includes a high-frequency current signal acquisition and amplification circuit. The current sensor of the high-frequency current signal acquisition and amplification circuit is open and installed on the external capacitive bushing end screen grounding wire to perform current detection in the end screen grounding wire.

[0024] Preferably, the MCU main control adopts an STM32F301K8T6 single-chip microcomputer, and the MCU main control is equipped with a crystal oscillator circuit, a connector, and a decoupling circuit.

[0025] Preferably, the auxiliary circuit includes a 12V to 5V circuit and a 5V to 3.3V circuit, the 2V to 5V circuit uses an LM2596 chip; the 5V to 3.3V circuit uses an LM2596 chip.

[0026] The utility model discloses a capacitance type bushing end screen grounding state detection device having the following beneficial effects.

[0027] This utility model uses high-frequency signals to directly detect capacitive bushings, significantly improving the sensitivity and response speed of grounding status detection, ensuring rapid and accurate identification of grounding conditions; the high-frequency signal generation module supports 0-300kHz signal output, adapting to the detection needs of capacitive bushings with different capacitances and having strong applicability; equipped with an LCD human-computer interaction module, users can intuitively display the grounding status, improving operational convenience and enhancing user experience; the auxiliary circuit can provide corresponding stable voltages for each module, reducing maintenance costs and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a system block diagram of the capacitive bushing end screen grounding status detection device of the present utility model.

[0029] Figure 2 This is a circuit schematic diagram of the high-frequency signal generating module of the present utility model.

[0030] Figure 3 This is the principle diagram of the high-frequency voltage signal acquisition and amplification circuit of the utility model.

[0031] Figure 4 This is the principle diagram of the high-frequency current signal acquisition and amplification circuit of the utility model

[0032] Figure 5 This is the schematic diagram of the MCU main control and some functional circuits of this utility model.

[0033] Figure 6 This is a partial circuit schematic diagram of the auxiliary circuit of the utility model.

[0034] Figure 7 This is a partial circuit schematic diagram of the auxiliary circuit of the utility model.

[0035] Figure 8 This is a schematic diagram of the external structure of a capacitive bushing end screen grounding status detection device.

[0036] In the attached figure: 1. Housing; 2. Signal output socket; 3. Signal input socket; 4. Device housing grounding socket; 5. LCD human-computer interaction module; 6. High-frequency signal generation module; 7. Detection circuit; 8. MCU main control and data processing module; 9. Auxiliary circuit; 10. Power module; 11. Input power plug; 12. Button; 13. Capacitive bushing; 14. Current sensor. DETAILED DESCRIPTION

[0037] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0038] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0039] Unless otherwise defined, the technical terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0040] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0041] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0042] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances. Example 1

[0043] Please refer to Figure 1 This embodiment provides a capacitive bushing end screen grounding state detection device, comprising: a housing 1, an LCD human-machine interaction module 5, a high-frequency signal generating module 6, a detection circuit 7, an MCU main control and data processing module 8, a power supply module 10, and an auxiliary circuit 9, disposed inside the housing 1; the MCU main control and data processing module 8 are electrically connected to the LCD human-machine interaction module 5, the high-frequency signal generating module 6, the detection circuit 7, the power supply module 10, and the auxiliary circuit 9, respectively; the output of the high-frequency signal generating module 6 is electrically connected to the upper end of the capacitive bushing 13; specifically, the outputs of the MCU main control and data processing module 8 are connected to the inputs of the LCD human-machine interaction module 5, the high-frequency signal generating module 6, and the detection circuit 7, respectively; the inputs of the MCU main control and data processing module 8 are connected to the outputs of the LCD human-machine interaction module 5, the high-frequency signal generating module 6, and the detection circuit 7, respectively;

[0044] LCD human-computer interaction module 5, used to present the data processed by MCU main control and data processing module 8, and transmit control commands to MCU main control and data processing module 8;

[0045] The high-frequency signal generating module 6 is used to output a high-frequency sinusoidal AC signal through the signal output port under the control of the MCU main control and data processing module 8, and inject the high-frequency AC signal into the capacitive bushing 13; a resistor R is connected in series between the output of the high-frequency signal generating module 6 and the capacitive bushing 13;

[0046] The detection circuit 7 is used to detect the feedback signal loaded between the top terminal of the bushing and the transformer housing 1, and output the detected signal to the MCU main control and data processing module 8; the detection circuit 7 detects the voltage across the resistor R, and the detection circuit 7 is two high-frequency voltage signal acquisition and amplification circuits, which are respectively connected between the two ends of R and the grounding point. Figure 1 The high-frequency voltage measurement circuit connected at V1 and V2 detects the voltage between the two ends of R1 and the ground;

[0047] The MCU main control and data processing module 8 is used to output the detection circuit 7 after analog-to-digital conversion to the MCU main control. The MCU main control uses the signal output by the detection circuit 7 to calculate the voltage signal loaded on the capacitive bushing 13, and output the total capacitance of other capacitors and the bushing main capacitance in parallel, and transmit the total capacitance signal to the LCD human-computer interaction module 5. The MCU main control and data processing module 8 calculates the current and voltage signals loaded on the bushing, and further calculates C (other capacitance). It should be noted that C is a fixed value that is only related to the transformer parameters. The total capacitance of C (capacitive bushing 13 capacitance) in parallel is saved by the MCU main control. Figure 5 As shown in the figure, the MCU main control adopts the STM32F301K8T6 single-chip microcomputer, and the MCU main control is equipped with functional circuits such as crystal oscillator circuit, connector, and decoupling circuit.

[0048] The power supply module 10 is used to supply power to the LCD human-computer interaction module 5, the high-frequency signal generation module 6, the detection circuit 7, and the MCU main control and data processing module 8;

[0049] The auxiliary circuit 9 is used to convert the voltage output by the power module 10 to provide an adaptive voltage for the LCD human-computer interaction module 5, the high-frequency signal generating module 6, the detection circuit 7, the MCU main control and data processing module 8. The auxiliary circuit 9 is electrically connected to the LCD human-computer interaction module 5, the high-frequency signal generating module 6, the detection circuit 7, the MCU main control and data processing module 8 respectively.

[0050] As a preference, in this embodiment, please refer to Figure 6 and Figure 7 The auxiliary circuit 9 includes a 12V to 5V circuit and a 5V to 3.3V circuit. The 2V to 5V circuit uses the TPS56320x chip; the 5V to 3.3V circuit uses the TPS56320x chip.

[0051] Please refer to Figure 8Preferably, the shell 1 is a rectangular box, the LCD human-computer interaction module 5 is fixed to the front side of the shell 1, the top of the shell 1 is provided with signal output, input and device shell grounding sockets 4, the high-frequency signal generating module 6, the detection circuit 7, the MCU main control and data processing module 8, the auxiliary circuit 9 and the power supply module 10 are arranged inside the shell 1, and a power plug is provided on the side of the shell 1; there is a button 12 on the LCD human-computer interaction module 5, and the button 12 is used to operate the LCD display screen; the signal output socket 2 is connected to the end of the resistor R away from the high-frequency signal generating module 6, the signal input socket 3 is connected to the detection circuit 7, the power plug is connected to the power module 10, the signal output socket 2 is used to output the high-frequency signal output by the high-frequency signal generating module 6, and the signal input socket 3 is used to input the current sensor 14 detection signal. The input power plug 11 is electrically connected to the power module 10 through a wire, the power module 10 is electrically connected to the LCD human-computer interaction module 5 through the auxiliary circuit 9 through a wire, the power module 10 is electrically connected to the high-frequency signal generating module 6 through the auxiliary circuit 9 through a wire, the power module 10 is electrically connected to the detection circuit 7 through the auxiliary circuit 9 through a wire, the power module 10 is electrically connected to the MCU main control and data processing module 8 through the auxiliary circuit 9 through a wire, the high-frequency signal generating module 6 is electrically connected to the MCU main control and data processing module 8 through a wire, the high-frequency signal generating module 6 is electrically connected to the detection circuit 7 through a wire, the detection circuit 7 is electrically connected to the MCU main control and data processing module 8 through a wire, the MCU main control and data processing module 8 is electrically connected to the LCD human-computer interaction module 5 through a wire, the LCD human-computer interaction module 5 uses the Taojingchi serial port screen TJC8048X543_011C_l, and its main control chip model is AIHMI T8.

[0052] Please refer to Figure 2 Preferably, the high-frequency signal generating module 6 includes: capacitors C1, C2, C4, inductor L1, and a common-mode gate driver U1; pin 1 of the common-mode gate driver U1 is connected to a 5V power supply, pins 2 and 4 of the common-mode gate driver U1 are grounded, pin 3 of the common-mode gate driver U1 is connected to the SPWM1 output of the MCU, pin 5 of the common-mode gate driver U1 is connected in series with the inductor L1, and the idle end of the inductor L1 is the output signal port SIN1; capacitors C2 and C4 are connected in parallel between pins 1 and 2 of the common-mode gate driver U1. The common-mode gate driver U1 uses the UCC27517DBVR, a 4A single-channel low-side common-mode gate driver chip;

[0053] Please refer to Figure 3As a preferred embodiment, the high-frequency voltage signal acquisition and amplification circuit includes: inductors L2, L3, inductors C38-C45, diode ZD2, resistors R6-R10, operational amplifier U2, and potentiometer U6; one end of the inductor L2 is connected to the resistor R, and the other end is grounded; one side of the inductor L2 is the inductor L3, one end of the inductor L3 is connected to pin 1 of the operational amplifier U2, and the other end is grounded, a capacitor C42 is provided between one end of the inductor L3 and pin 1 of the operational amplifier U2, pin 2 of the operational amplifier U2 is grounded, pin 3 of the operational amplifier U2 is connected to pin 1 of the potentiometer U6, a resistor R10 is connected in series at the end of pin 4 of the operational amplifier U2, the vacant end of the resistor R10 is the signal output port U_ADC1, and the operational amplifier U2 pin 5 is connected to the 3.3V power supply. Between pin 5 of operational amplifier U2 and ground, C38 and C39 are connected in parallel, along with resistors R6 and R7 in series. Resistor R7 is connected in parallel with capacitor C40, and capacitor C42 is connected to capacitor C40 via resistor R8. Potentiometer U6 pin 2 is connected to the 3.3V power supply, with capacitor C43 installed between pin 2 and ground. Potentiometer U6 pin 3 is grounded, and potentiometer U6 pins 4-6 are connected to the corresponding MCU outputs. Potentiometer U6 pin 7 is connected to pin 4 of operational amplifier U2, with the connection point connected to ground via resistor R9. Potentiometer U6 pin 7 is also connected to ground via capacitor C41. The front end of output port U_ADC1 is grounded via capacitor C44. Diode ZD2 is connected in parallel across inductor L3. Another set of voltage signal acquisition and amplification circuits has the same structure as this set, except that the sampling point is a different section of resistor R from the current set, and the output port is U_ADC2. The high-frequency voltage signal acquisition and amplification circuit includes a potentiometer U6, which adjusts the amplification factor of the operational amplifier U2 to obtain the optimal signal. Potentiometer U6 uses a TPL0501 256-tap single-channel digital potentiometer.

[0054] When the capacitive bushing end screen grounding state detection device is used, before conducting an on-site bushing test, after power is turned off, step 1 is to input a test command through the LCD human-computer interaction module 5; step 2 is to control the MCU main control and data processing module 8 to control the high-frequency signal generation module 6 to inject a high-frequency AC signal into the capacitive bushing 13, specifically loading it between the bushing top terminal and the transformer housing 1; step 3 is to detect the circuit 7 through Figure 1The high-frequency voltage measurement circuit connected at V1 and V2 detects the voltage between the two ends of R1 and the ground, and outputs it to the MCU main control and data processing module 8; in step 4, the MCU main control calculates the current and voltage signal loaded on the bushing based on the voltage between the two ends of R1 and the ground, and further calculates the total capacitance of Cqi (other capacitors) and Cmain (capacitive bushing 13 capacitors) in parallel, and the MCU main control saves the total capacitance calculation result; after the on-site bushing test, repeat steps 1-4, and compare the two saved total capacitance results. If the total capacitance before the on-site bushing test is greater than the total capacitance after the on-site bushing test, it is considered that the grounding state of the capacitive bushing end screen is unreliable; if the total capacitance before the on-site bushing test is less than or equal to the total capacitance after the on-site bushing test, it is considered that the grounding state of the capacitive bushing end screen is reliable. Example 2

[0055] Based on Example 1, please refer to Figure 1 and Figure 4 The detection circuit 7 provided in this embodiment also includes a high-frequency current signal acquisition and amplification circuit. The current sensor 14 of the high-frequency current signal acquisition and amplification circuit is an open type and is installed on the external capacitive bushing end screen grounding wire to detect the current in the end screen grounding wire; the external grounding state of the end screen of the capacitive bushing 13 can be detected. If there is no current, it proves that it is not grounded.

[0056] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Replacements may include partial structures, devices, or method steps, or they may be complete technical solutions. Equivalent replacements or modifications based on the technical solution and its concept of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A capacitive bushing end screen grounding status detection device, characterized in that: include: A housing, an LCD human-machine interaction module, a high-frequency signal generating module, a detection circuit, an MCU main control and data processing module, a power module, and an auxiliary circuit are arranged inside the housing; the MCU main control and data processing module are electrically connected to the LCD human-machine interaction module, the high-frequency signal generating module, the detection circuit, the power module, and the auxiliary circuit respectively; the output of the high-frequency signal generating module is electrically connected to the upper end of the capacitive sleeve; The LCD human-computer interaction module is used to present the data processed by the MCU main control and data processing modules, and transmit control commands to the MCU main control and data processing modules; The high-frequency signal generating module is used to output a high-frequency sinusoidal AC signal through a signal output port under the control of the MCU main control and data processing module, and inject the high-frequency AC signal into the capacitive bushing; a resistor R is connected in series between the output of the high-frequency signal generating module and the capacitive bushing; The detection circuit is used to detect the feedback signal loaded between the top terminal of the bushing and the transformer housing, and output the detected signal to the MCU main control and data processing module; The MCU main control and data processing module is used to output the detection circuit after analog-to-digital conversion to the MCU main control. The MCU main control uses the signal output by the detection circuit to calculate the voltage signal applied to the capacitive bushing, and output the total capacitance of other capacitors and the bushing main capacitance in parallel, and transmit the total capacitance signal to the LCD human-computer interaction module; The power supply module is used to supply power to the LCD human-computer interaction module, the high-frequency signal generation module, the detection circuit, the MCU main control module and the data processing module; The auxiliary circuit is used to convert the voltage output by the power module to provide an adaptive voltage for the LCD human-computer interaction module, the high-frequency signal generation module, the detection circuit, the MCU main control and the data processing module.

2. The capacitive bushing end screen grounding status detection device according to claim 1, characterized in that: The shell is a rectangular box, the LCD human-computer interaction module is fixed to the front side of the shell, the top of the shell is provided with signal output, input and device shell grounding sockets, the high-frequency signal generation module, detection circuit, MCU main control and data processing module, auxiliary circuit and power supply module are arranged inside the shell, and a power plug is provided on the side of the shell; the signal output socket is connected to the end of the resistor R away from the high-frequency signal generation module, the signal input socket is connected to the detection circuit, and the power plug is connected to the power module.

3. The capacitive bushing end screen grounding status detection device according to claim 1, characterized in that: The high-frequency signal generating module outputs a high-frequency sinusoidal AC signal with a frequency range of 0 to 300 kHz.

4. The capacitive bushing end screen grounding state detection device according to claim 3, characterized in that: The high-frequency signal generating module includes: capacitors C1, C2, C4, inductor L1, and a common-mode gate driver U1; pin 1 of the common-mode gate driver U1 is connected to a 5V power supply, pins 2 and 4 of the common-mode gate driver U1 are grounded, pin 3 of the common-mode gate driver U1 is connected to SPWM1 output by the MCU, pin 5 of the common-mode gate driver U1 is connected in series with the inductor L1, and the idle end of the inductor L1 is the output signal port SIN1; capacitors C2 and C4 are connected in parallel between pins 1 and 2 of the common-mode gate driver U1, and the common-mode gate driver U1 adopts UCC27517DBVR.

5. The capacitive bushing end screen grounding status detection device according to claim 1, characterized in that: The detection circuit detects the voltage across the resistor R, and the detection circuit comprises two high-frequency voltage signal acquisition and amplification circuits, which are respectively connected between the two ends of R and the grounding point.

6. The capacitive bushing end screen grounding state detection device according to claim 5, characterized in that: The detection circuit is a high-frequency voltage signal acquisition and amplification circuit; the high-frequency voltage signal acquisition and amplification circuit includes: inductors L2, L3, inductors C38-C45, diode ZD2, resistors R6-R10, operational amplifier U2, and potentiometer U6; one end of the inductor L2 is connected to the resistor R, and the other end is grounded; one side of the inductor L2 is the inductor L3, one end of the inductor L3 is connected to the positive input end of the operational amplifier U2, and the other end is grounded, a capacitor C42 is provided between one end of the inductor L3 and the positive input end of the operational amplifier U2, the negative power supply end of the operational amplifier U2 is grounded, the negative input end of the operational amplifier U2 is connected to pin 1 of the potentiometer U6, the output end of the operational amplifier U2 is connected in series with a resistor R10, the vacant end of the resistor R10 is the signal output port U_ADC1, and the positive input end of the operational amplifier U2 is connected to the positive input end of the operational amplifier U2. The power supply end is connected to the 3.3V power supply, and C38, C39, and series-connected resistors R6 and R7 are respectively connected in parallel between the positive power supply end of the operational amplifier U2 and the ground; a capacitor C40 is connected in parallel at both ends of the resistor R7, and capacitor C42 is connected to capacitor C40 through resistor R8; pin 2 of the potentiometer U6 is connected to the 3.3V power supply, and a capacitor C43 is provided between pin 2 and the ground, pin 3 of the potentiometer U6 is grounded, and pins 4-6 of the potentiometer U6 are connected to the corresponding outputs of the MCU; pin 7 of the potentiometer U6 is connected to the output end of the operational amplifier U2, and the connection point is grounded through resistor R9, and pin 7 of the potentiometer U6 is grounded through capacitor C41; the front end of the output port U_ADC1 is grounded through capacitor C44; a diode ZD2 is connected in parallel at both ends of the inductor L3, and the potentiometer U6 adopts TPL0501.

7. The capacitive bushing end screen grounding state detection device according to claim 5, characterized in that: The detection circuit also includes a high-frequency current signal acquisition and amplification circuit. The current sensor of the high-frequency current signal acquisition and amplification circuit is open and installed on the external capacitive bushing end screen grounding wire to detect the current in the end screen grounding wire.

8. The capacitive bushing end screen grounding status detection device according to claim 1, characterized in that: The MCU main control adopts the STM32F301K8T6 single-chip microcomputer, and the MCU main control is equipped with a crystal oscillator circuit, a connector, and a decoupling circuit.

9. The capacitive bushing end screen grounding status detection device according to claim 1, characterized in that: The auxiliary circuit includes a 12V to 5V circuit and a 5V to 3.3V circuit. The 2V to 5V circuit uses an LM2596 chip; the 5V to 3.3V circuit uses an LM2596 chip.

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