High-voltage switch cabinet insulation diagnosis device circuit based on pulse current method and use method

Abstract

The invention relates to a high-voltage switch cabinet insulation diagnosis device circuit based on a pulse current method and a use method. The high-voltage switch cabinet insulation diagnosis device circuit comprises a three-phase pulse current signal conditioning circuit module, an arc light monitoring signal conditioning circuit module, a communication circuit module, a storage circuit module, a display circuit module, an MCU master control circuit module, a power supply circuit module, an environment temperature and humidity detection circuit module, a background noise acquisition circuit module, a three-phase cable sheath circulation monitoring and acquisition circuit module and the like. The pulse current signal conditioning circuit module is composed of a coupling capacitance sensor, a pulse current filtering sub-module and the like and can achieve the functions of pulse current data measurement and the like. In addition, functions such as pulse current transient break variable suppression and filtering are added, the problems such as error interference are effectively solved, the product judgment accuracy is improved, the arc phenomenon can be sensed in advance, the secondary circuit and personal safety are protected, misjudgment is reduced, equipment insulation monitoring is assisted, the switch cabinet pulse current detection method is more perfect, and the detection efficiency is improved. And the operation and maintenance efficiency and the switch cabinet health and stability level are improved.

Description

Technical Field

[0001] The present application relates to the field of power monitoring, and more specifically, to a circuit and a method for using a high-voltage switch cabinet insulation diagnostic device based on a pulse current method. Background Art

[0002] At present, the main methods for partial discharge detection of switch cabinets at home and abroad include ultrasonic method, transient ground voltage method, ultra-high frequency method, etc. The main principle of judgment is to independently install partial discharge sensors on the wall of the primary high-voltage cable room when the high-voltage switch cabinet is under maintenance, and indirectly sample the data change through the strength of the spatial conduction magnetic field for fault warning. This traditional method of measurement is limited by the power outage plan for maintenance of distribution switch equipment and its own principle, and cannot directly and accurately measure the insulation change process. In addition, most sensors use low-power design for timing detection, and cannot detect the insulation data change process and the accuracy of signal time domain changes in real time, and cannot effectively improve operation and maintenance efficiency.

[0003] Partial discharge testing based on the pulse current method is usually used in type tests, factory tests and other offline tests of electrical equipment, and is achieved through a controllable boost measurement system without partial discharge. However, due to the presence of various forms of electromagnetic interference at the actual operating equipment site, there are no partial discharge boost test conditions compared to offline testing, so live or online partial discharge testing based on the pulse current method is rarely used.

[0004] In the switch cabinet insulation system, when the applied voltage is large enough, the electric field strength in the insulation system is sufficient to cause discharge in some areas. This discharge will form an unfixed discharge channel in the insulation part, but it is not enough to form a conductive channel, that is, the insulation system is not broken down. This phenomenon is called partial discharge - when partial discharge occurs, a certain amount of charge will pass through the dielectric. This discharge time is very short, which is characterized by a steep current pulse. The method of measuring this pulse is the pulse current method.

[0005] The pulse current method is the mainstream partial discharge test method at present. It is sensitive to sudden change signals and the measured discharge current pulse information is rich. It can measure the discharge repetition rate, discharge amount (apparent discharge charge), discharge energy, average current, etc.

[0006] Prior art, such as a Chinese patent with patent number "CN112577550A", discloses a comprehensive intelligent pre-inspection system and pre-inspection method for a switch cabinet, comprising a monitoring unit, an intelligent acquisition unit, a communication unit and a cloud server connected in sequence, wherein the monitoring unit comprises an online monitoring unit for mechanical characteristics, and the online monitoring unit for mechanical characteristics is used to detect the mechanical action signal of the circuit breaker; the present invention is based on online monitoring of intelligent sensors, and realizes unified access, storage and management of comprehensive information of the switch cabinet by analyzing various status data such as mechanical characteristics, temperature characteristics, insulation characteristics, ambient temperature and humidity of the equipment collected by on-site physical layer sensors, so as to realize intelligent switch cabinet operation monitoring, comprehensive analysis and intelligent pre-inspection, and quickly diagnose problems arising during the operation of the switch cabinet to avoid accidents.

[0007] The problem with the above-mentioned prior art is that it only monitors the pulse current value of the high-voltage capacitor sensor of the cabinet simply, and does not suppress and filter the transient mutation of the pulse current, which easily leads to misjudgment and interference data; when the pulse current value in the switch cabinet changes greatly, the insulation performance in the cabinet is declining, and arcs are easily generated at this time. The existing technology products only measure the pulse current value, and do not synchronously monitor the arc in the cabinet, which is easy to cause accidents; when the high-voltage capacitor sensor is broken down, the pulse current is not limited and suppressed; when the switch cabinet circuit breaker, grounding knife, etc. perform opening / closing actions, a large background noise is generated inside the switch cabinet, which seriously affects the collection and screening of pulse current; the invention does not have the circulating current monitoring of the high-voltage cable sheath of the high-voltage switch cabinet, and cannot assist in judging the insulation performance of the cable. Summary of the invention

[0008] In order to solve the above technical problems, the present invention proposes a method for using a circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method.

[0009] The technical solution of the present invention is as follows:

[0010] The present invention proposes a circuit of a high-voltage switch cabinet insulation diagnosis device based on a pulse current method, comprising: a three-phase pulse current signal conditioning circuit module, a three-phase arc light monitoring signal conditioning circuit module, a communication circuit module, a storage circuit module, a display circuit module, an MCU main control circuit module, a power supply circuit module, an ambient temperature and humidity detection circuit module, a background noise acquisition module, and a three-phase cable sheath circulating current monitoring and acquisition circuit module;

[0011] The three-phase pulse current signal conditioning circuit module is used for pulse current data measurement, transient mutation suppression and filtering, pulse current signal amplification processing, and outputs the processed pulse current data to the input end of the MCU main control circuit module;

[0012] The three-phase arc light monitoring signal conditioning circuit module is used to collect arc light signals at the three-phase busbar cable and output the collected arc light signals to the input end of the MCU main control circuit module;

[0013] The communication circuit module is connected to the data serial port of the MCU main control circuit module for remote transmission of pulse current data and waveform;

[0014] The storage circuit module is connected to the MCU main control circuit module and is used for local storage of pulse current waveform and data;

[0015] The display circuit module is connected to the MCU main control circuit module and is used to display the collected pulse current waveform and data on the local LCD screen;

[0016] The MCU main control circuit module receives sensor data collected by the three-phase pulse current signal conditioning circuit module, the three-phase arc monitoring signal conditioning circuit module, the ambient temperature and humidity detection circuit module, the background noise acquisition module, and the three-phase cable sheath circulating current monitoring acquisition circuit module, and coordinates and controls each circuit module to ensure that the system can work normally according to the predetermined logic and process;

[0017] The power supply circuit module is used for converting the system circuit level and converting the voltage into the voltage value required by different chips;

[0018] The ambient temperature and humidity detection circuit module is used to collect the ambient temperature and humidity values ​​in the switch cabinet, and output the collected ambient temperature and humidity values ​​to the input end of the MCU main control circuit module;

[0019] The background noise acquisition module is used to collect the noise signal generated in the switch cabinet and output the collected noise signal to the input end of the MCU main control circuit module;

[0020] The three-phase cable sheath circulating current monitoring and acquisition circuit module is used to collect the circulating current size of phase A, phase B and phase C of the three-phase high-voltage cable, and output the collected circulating current signal to the input end of the MCU main control circuit module.

[0021] As a preferred embodiment, the three-phase pulse current signal conditioning circuit module includes: an A-phase pulse current signal conditioning circuit module, a B-phase pulse current signal conditioning circuit module and a C-phase pulse current signal conditioning circuit module; the three-phase pulse current signal conditioning circuit modules are based on the same topological structure; each phase pulse current signal conditioning circuit module includes: a capacitive sensor, a pulse current filter, a signal protection, a bandpass filter, a signal conditioning, and an A / D conversion submodule, wherein:

[0022] The module structure of the A-phase pulse current signal conditioning circuit includes:

[0023] Capacitive sensor submodule: including a capacitive sensor C20, one end of the capacitive sensor C20 is connected to the high-voltage busbar, and the other end is connected to the detection impedance R14;

[0024] Pulse current filtering submodule: including: capacitor C17, capacitor C18, capacitor C19, capacitor C21, capacitor C22, resistor R3, resistor R4, resistor R5, resistor R6, resistor R13, resistor R16, amplifier U30A and amplifier U30B; one end of capacitor C21 is connected to detection impedance R14, and the other end is connected to one end of capacitor C22, and the other end of capacitor C22 is connected to the input end of amplifier U30A for filtering interference signals; resistor R3, resistor R4 and amplifier U30A constitute a first-stage amplifier circuit, and the output end of the first-stage amplifier circuit is connected to one end of capacitor C18 for amplifying and outputting the signal; resistor R5, resistor R6 The two-stage amplifier circuit is formed with the amplifier U30B, the input end of the two-stage amplifier circuit is connected to the other end of the capacitor C18 through the capacitor C19, and the output end is connected to one end of the capacitor C17, which is used to amplify and output the signal; one end of the resistor R16 is connected to one end of the capacitor C18 close to the two-stage amplifier circuit, and the other end is grounded, which is used to increase the circuit impedance; the capacitor C18, the capacitor C17, and the capacitor C19 are used to filter out the DC component in the circuit; the other end of the capacitor C17 is connected to the input end of the A / D conversion chip U4, one end of the resistor R13 is connected to the connection line between the capacitor C17 and the A / D conversion chip U4, and the other end is grounded, which is used to divide the voltage of the amplified signal;

[0025] Signal protection submodule: including a signal protection circuit composed of a diode D1, a diode D2, a diode D3, a resistor R17, and a transistor Q1, wherein the signal protection circuit is connected to the connection line between the capacitor C21 and the detection impedance R14, wherein the anode of the diode D1 is connected to the connection line between the capacitor C21 and the detection impedance R14, the cathode of the diode D1 is connected to one end of the resistor R17, the other end of the resistor R17 is connected to the base of the transistor Q1, the anode of the diode D2 is connected to the connection line between the capacitor C21 and the detection impedance R14, the cathode of the diode D2 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is grounded, the resistor R17 is a current limiting resistor, and when the pulse current at the front end is too large, the transistor Q1 is triggered to turn on through the diode D1 and the resistor R17, and the signal is transmitted to the ground end;

[0026] Bandpass filter submodule: One end of the low-pass filter L1 is connected to the detection impedance R14, and the other end is connected to the capacitor C21. The low-pass filter L1 is used to prevent the high-frequency pulse being measured or the high-frequency component in the power supply from passing through, so that the high-frequency pulse current is mainly applied to the first-stage amplification circuit, so that the back-end circuit can capture the partial discharge signal;

[0027] Signal conditioning submodule: including current limiting resistor R12 and current limiting resistor R15, one end of the current limiting resistor R12 is connected to one end of the low-pass filter L1 close to the first-stage amplifier circuit, and the other end is connected to the capacitor C21, one end of the current limiting resistor R15 is connected to the connection line between the current limiting resistor R12 and the capacitor C21, and the other end is grounded;

[0028] A / D conversion submodule: includes A / D conversion chip U4, resistor R7 and resistor R8. The input end of A / D conversion chip U4 is connected to capacitor C17, and the output end is connected to the corresponding input end of integrated circuit chip U1 via a pull-up resistor circuit composed of resistor R7 and resistor R8. A / D conversion chip U4 is used to convert analog signal quantity into digital signal quantity and transmit it to integrated circuit chip U1 for data processing.

[0029] As a preferred implementation, the three-phase arc light monitoring signal conditioning circuit module includes: an A-phase arc light monitoring signal conditioning circuit module, a B-phase arc light monitoring signal conditioning circuit module, and a C-phase arc light monitoring signal conditioning circuit module; the three-phase arc light monitoring signal conditioning circuit modules are based on the same topology; wherein:

[0030] The module structure of the A-phase arc supervision circuit includes:

[0031] The SDA pin, SCL pin and INT pin of the arc sensor U5 are connected to the corresponding input terminals of the main control microcontroller unit U1. Resistors R9, R10 and R11 are connected between the SDA pin, SCL pin and INT pin of the arc sensor U5 and the power supply. Resistors R9, R10 and R11 are pull-up resistors to increase the pin driving capability. The REXT pin of the arc sensor U5 is connected to resistor R18, and the other end of resistor R18 is grounded. The VDD pin of the arc sensor U5 is connected to the system power supply. Capacitors C23 and C24 are connected in parallel between the system power supply and the ground terminal. Capacitors C23 and C24 make the power supply voltage entering the arc sensor U5 more stable.

[0032] As a preferred embodiment, the communication circuit module, the communication chip U12 The RO pin and the DI pin are respectively connected to the RS485-RX and RS485-TX serial ports of the main control microcontroller unit U1 for data exchange; PE is the enable end of the communication chip U12, which is connected to the power supply through the resistor R61; the output A pin of the communication chip U12 is respectively connected to the resistor R63 and the resistor R65, the other end of the resistor R63 is connected to the power supply, and the other end of the resistor R65 is connected to the TVS diode VP1; the output B pin of the communication chip U12 is respectively connected to the resistor R62 and the resistor R64, the other end of the resistor R62 is grounded, and the other end of the resistor R64 is connected to the TVS diode VP1; the resistor R62 and the resistor R63 are pull-up resistors to increase the driving capability, and the resistor R64 and the resistor R65 are current limiting resistors to prevent the communication chip U12 from being broken down when the external signal is connected; one end of the TVS diode VP1 is connected to the resistor R64 and the other end is connected to the resistor R65 to prevent the voltage difference between the output A pin and the B pin of the communication chip U12 from breaking down the RS485 communication chip U12.

[0033] As a preferred embodiment, the MCU main control circuit module, the system power supply terminal and the ground terminal of the main control micro control unit U1 are connected with capacitors C1-C7 in parallel, and the capacitors C1-C7 are filtering decoupling capacitors of the power supply to the ground, which are used to protect the main control micro control unit U1 from working stably; a crystal oscillator circuit composed of capacitors C15, capacitors C16, and crystal oscillator circuit element XT2 is connected between pins 3 and 4 of the main control micro control unit U1; a crystal oscillator circuit composed of capacitors C12, capacitors C13, and crystal oscillator circuit element XT1 is connected between pins 5 and 6 of the main control micro control unit U1, and a reset pin of the main control micro control unit U1 is connected to a reset circuit composed of resistor R2 and capacitor C14.

[0034] As a preferred embodiment, the external power supply voltages L and N of the power supply circuit module are connected to the incoming line fuse F1 and the varistor R1, the other ends of the incoming line fuse F1 and the resistor R1 are connected to the voltage conversion chip U3, the output end of the voltage conversion chip U3 is connected to capacitor C8 and capacitor C10, the other ends of capacitor C8 and capacitor C10 are grounded, the output end of the voltage conversion chip U3 is also connected to the input end of the low voltage difference linear regulator U2, the output end of the low voltage difference linear regulator U2 is connected to capacitor C9 and capacitor C11 in parallel, and the other ends of capacitor C9 and capacitor C11 are grounded.

[0035] As a preferred embodiment, the ambient temperature and humidity detection circuit module includes: a thermistor R68 and a capacitor C53 connected in parallel, the thermistor R68 reflects the ambient temperature value through resistance changes, one end of the thermistor R68 is connected to a voltage divider resistor R66, and the other end is grounded; and also includes: a humidity resistor R69 and a capacitor C54 connected in parallel, the humidity resistor R69 reflects the ambient humidity value through resistance changes, one end of the humidity resistor R69 is connected to a voltage divider resistor R67, and the other end is grounded.

[0036] As a preferred embodiment, the background noise collection module includes: one end of the capacitive micro-microphone LS2 is connected to the voltage-dividing circuit composed of resistors R70 and R71, and the capacitor C55 is connected in parallel with the resistor R71, so that the collected voltage is more stable; one end of the capacitor C56 is connected to the voltage-dividing circuit composed of resistors R70 and R71, and the other end is connected to the base of the transistor Q12, the collector of the transistor Q12 is connected to the reverse input end of the amplifier U14, and the emitter of the transistor Q12 is grounded; one end of the capacitor C57 is connected to the reverse input end of the amplifier U14, and the other end is grounded, so that the signal waveform is smoother; the output end of the amplifier U14 is connected to the corresponding input end of the main control micro-control unit U1, and the amplifier U14 amplifies the sound voltage signal, one end of the resistor R74 is connected to the forward input end of the amplifier U14, and the other end is grounded.

[0037] As a preferred embodiment, the three-phase cable sheath circulating current monitoring and acquisition circuit module includes: an A-phase cable sheath circulating current monitoring and acquisition circuit module, a B-phase cable sheath circulating current monitoring and acquisition circuit module, and a C-phase cable sheath circulating current monitoring and acquisition circuit module; the three-phase cable sheath circulating current monitoring and acquisition circuit modules are based on the same topological structure; each phase cable sheath circulating current monitoring and acquisition circuit module includes: signal acquisition, filtering and protection circuit and amplification circuit submodules, wherein:

[0038] The module structure of the A-phase cable sheath circulating current monitoring and acquisition circuit includes:

[0039] The signal acquisition submodule includes: a leakage current sensor HG1, which is installed in an open manner at the outer sheath of the A-phase high-voltage cable and is used to collect the leakage current of the A-phase cable;

[0040] The filtering and protection circuit submodule includes: a capacitor C55 and an electronic resistor R80. The capacitor C55 is connected in parallel to the acquisition signal output end of the leakage current sensor HG1. The capacitor C55 is used to make the current waveform smoother. The resistor R80 is connected in parallel with the leakage current sensor HG1 and the capacitor C55 to prevent the current collected from being too large to break through the back-end circuit when HG1 is saturated.

[0041] The amplification circuit submodule includes: resistor R81 is an input protection resistor of amplifier U20, one end of which is connected to the signal collection output end of leakage current sensor HG1, and the other end is connected to the reverse input end of operational amplifier U20 to prevent excessive current from breaking down amplifier U20B; one end of resistor R82 is connected to the signal collection output end of leakage current sensor HG1, and the other end is respectively connected to the positive input end of amplifier U20B and one end of resistor R83, the other end of resistor R83 is connected to the output end of amplifier U20B, resistor R82, resistor R83 and amplifier U20B constitute a primary amplification circuit; resistor R84, resistor R85 and amplifier U20C constitute a secondary amplification circuit, which is connected to the output end of the primary amplification circuit; the input end of filter follower U20A is connected to the output end of the secondary amplification circuit to stabilize the current signal waveform, and the output end of filter follower U20A is connected to the input port corresponding to the main control micro control unit U1.

[0042] On the other hand, the present invention also provides a method for using a circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method, comprising: step S1: collecting pulse current signals and arc signals through a three-phase pulse current signal conditioning circuit module and a three-phase arc monitoring signal conditioning circuit module;

[0043] Step S2: collecting ambient temperature and humidity signals through the ambient temperature and humidity detection circuit module; collecting sound signals generated by the circuit breaker and the grounding knife in the switch cabinet when they are opened and closed through the background noise collection module;

[0044] Step S3: collecting cable sheath circulating current signals through a three-phase cable sheath circulating current monitoring and collection circuit module;

[0045] Step S4: The MCU main control circuit module processes and analyzes the digital signals from each circuit module. The analysis includes: judging the partial discharge situation according to the pulse current data, judging whether there is an arc phenomenon caused by partial discharge in combination with the arc light signal, assisting in judging the insulation environment of the switch cabinet according to the ambient temperature and humidity data, judging whether the noise affects the pulse current collection and causes misjudgment according to the background noise data, and assisting in judging the insulation performance of the cable through the cable sheath circulation data; outputting the analysis results;

[0046] Step S5: The display circuit module displays the collected pulse current waveform and data on the local LCD screen to provide a basis for judgment for on-site personnel. The storage circuit module stores the pulse current waveform and data locally to prevent data loss due to abnormal power failure. The RS485 communication circuit module transmits the pulse current data and waveform remotely through the RS480 communication standard for remote monitoring and analysis.

[0047] The present invention has the following beneficial effects:

[0048] 1: The pulse current transient mutation suppression and filtering are added to solve the problems of false interference and false indication in the existing pulse current detection method, effectively improve the accuracy of product judgment, and provide a basis for operation and maintenance personnel;

[0049] 2: The arc detection function is added to solve the problem that the existing device only detects pulse current but not arc. It can effectively sense the arc phenomenon caused by partial discharge in advance and understand the hidden dangers of equipment as early as possible;

[0050] 3: Pulse current limiting protection and clamping voltage protection have been added to solve the hidden danger of breakdown of secondary instruments caused by high voltage breakdown of high voltage capacitor sensors, effectively protecting the secondary circuit and personal safety.

[0051] 4: The background noise collection and analysis in the cabinet has been added, which solves the problem of misjudgment caused by the large noise generated when the circuit breaker / grounding knife of the switch cabinet affects the pulse current collection, effectively reducing the misjudgment of the equipment and misleading the operating personnel.

[0052] 5: The detection and collection of the ambient temperature and humidity in the cabinet has been added to solve the insulation degradation problem caused by high temperature, high humidity, and low temperature in the cabinet, and further assist the insulation monitoring of the equipment;

[0053] 6: The sheath circulating current monitoring of three-phase high-voltage cables has been added to solve the insulation breakdown problem caused by the insulation degradation of the cable itself, and further assist the insulation monitoring of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0055] Figure 1 This is the principle block diagram of the insulation diagnostic device for high-voltage switchgear;

[0056] Figure 2 This is the circuit diagram of the insulation diagnostic device for high-voltage switchgear;

[0057] Figure 3 This is the pulse current method measurement principle diagram;

[0058] Figure 4 This is the module structure diagram of the A-phase pulse current signal conditioning circuit;

[0059] Figure 5 This is the module structure diagram of the B-phase pulse current signal conditioning circuit;

[0060] Figure 6 This is the module structure diagram of the C-phase pulse current signal conditioning circuit;

[0061] Figure 7 This is the module structure diagram of the A-phase arc monitoring signal conditioning circuit;

[0062] Figure 8 This is the module structure diagram of the B-phase arc light monitoring signal conditioning circuit;

[0063] Fig. 9 This is the module structure diagram of the C-phase arc monitoring signal conditioning circuit;

[0064] Fig.10 This is the module structure diagram of RS485 communication circuit;

[0065] Fig.11 It is a structural diagram of the storage circuit module;

[0066] Fig.12 To display the circuit module structure diagram;

[0067] Fig.13 This is the structure diagram of the MCU main control circuit module;

[0068] Fig.14 This is the module structure diagram of the power supply circuit;

[0069] Fig.15 This is the structure diagram of the ambient temperature and humidity detection circuit module;

[0070] Fig.16 This is the structural diagram of the background noise acquisition circuit module;

[0071] Fig.17 This is the module structure diagram of the A-phase sheath circulating current monitoring and acquisition circuit;

[0072] Fig.18 This is the module structure diagram of the B-phase sheath circulating current monitoring and acquisition circuit;

[0073] Fig.19 This is the module structure diagram of the C-phase sheath circulating current monitoring and acquisition circuit;

[0074] Fig. 20 This is the pulse current partial discharge detection spectrum. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0077] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0078] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0079] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0080] Embodiment 1:

[0081] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following will be combined with the specific embodiments of the present application and refer to the attached Figure 1 , clearly and completely describe the technical solution of the present invention.

[0082] The pulse current method is a method that uses Rogowski coils or impedance measurement to obtain partial discharge pulse current signals generated by various insulation defects. This method has been widely used in partial discharge detection of power equipment such as high-voltage switchgear, transformers, power cables, GIS, etc. Its principle is as follows: Figure 3 shown. Figure 3 In, C a is the sample capacitance; Z m is the detection impedance; D is the partial discharge detector; C k C is a coupling capacitor, which provides a high-frequency channel for partial discharge signals; L is a low-pass filter, which blocks the high-frequency pulses or high-frequency components in the power supply from passing through. When the defects inside the equipment generate partial discharge under high voltage, C a The loop formed will generate pulse current, and its frequency is usually above tens of kilohertz. Due to the existence of L, only a small part of the high-frequency pulse current passes through the loop where L is located, and the main current is applied to the detection impedance Z m In the circuit where the partial discharge is located, the partial discharge detection device can capture the partial discharge signal.

[0083] In view of the complex operating conditions of switchgear, the many types of faults, the single and unrelated traditional online monitoring methods, the poor monitoring effect, and the inability to comprehensively and accurately obtain the overall insulation fault diagnosis of the switchgear, a local discharge detection method for high-voltage switchgear based on the pulse current method is studied to realize the perception of the local discharge state of the high-voltage switchgear, and to perform real-time, accurate and distributed monitoring of the insulation state information of the switchgear. Combined with arc monitoring technology, it can realize the rapid positioning, pre-diagnosis and reporting of insulation faults, improve the operation and maintenance efficiency of operation and maintenance personnel, reduce manual operation and maintenance costs, actively operate and maintain to reduce equipment maintenance costs, and improve the health and stability of the switchgear.

[0084] In order to solve the problems of the prior art, the present invention provides a circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method, such as Figure 2 As shown, it includes: a three-phase pulse current signal conditioning circuit module, a three-phase arc monitoring signal conditioning circuit module, a communication circuit module, a storage circuit module, a display circuit module, an MCU main control circuit module, a power supply circuit module, an ambient temperature and humidity detection circuit module, a background noise acquisition module, and a three-phase cable sheath circulating current monitoring and acquisition circuit module;

[0085] The three-phase pulse current signal conditioning circuit module is used for pulse current data measurement, transient mutation suppression and filtering, pulse current signal amplification processing, and outputs the processed pulse current data to the input end of the MCU main control circuit module;

[0086] The three-phase arc light monitoring signal conditioning circuit module is used to collect arc light signals at the three-phase busbar cable and output the collected arc light signals to the input end of the MCU main control circuit module;

[0087] The communication circuit module is connected to the data serial port of the MCU main control circuit module for remote transmission of pulse current data and waveform;

[0088] The storage circuit module is connected to the MCU main control circuit module and is used for local storage of pulse current waveform and data;

[0089] The display circuit module is connected to the MCU main control circuit module and is used to display the collected pulse current waveform and data on the local LCD screen;

[0090] The MCU main control circuit module receives sensor data collected by the three-phase pulse current signal conditioning circuit module, the three-phase arc monitoring signal conditioning circuit module, the ambient temperature and humidity detection circuit module, the background noise acquisition module, and the three-phase cable sheath circulating current monitoring acquisition circuit module, and coordinates and controls each circuit module to ensure that the system can work normally according to the predetermined logic and process;

[0091] The power supply circuit module is used for converting the system circuit level and converting the voltage into the voltage value required by different chips;

[0092] The ambient temperature and humidity detection circuit module is used to collect the ambient temperature and humidity values ​​in the switch cabinet, and output the collected ambient temperature and humidity values ​​to the input end of the MCU main control circuit module;

[0093] The background noise acquisition module is used to collect the noise signal generated in the switch cabinet and output the collected noise signal to the input end of the MCU main control circuit module;

[0094] The three-phase cable sheath circulating current monitoring and acquisition circuit module is used to collect the circulating current size of phase A, phase B and phase C of the three-phase high-voltage cable, and output the collected circulating current signal to the input end of the MCU main control circuit module;

[0095] The three-phase pulse current signal conditioning circuit module includes: A-phase pulse current signal conditioning circuit module, B-phase pulse current signal conditioning circuit module and C-phase pulse current signal conditioning circuit module; the three-phase pulse current signal conditioning circuit module is based on the same topological structure; each phase pulse current signal conditioning circuit module includes: capacitive sensor, pulse current filtering, signal protection, bandpass filtering, signal conditioning, A / D conversion submodule, wherein:

[0096] The module structure of the A-phase pulse current signal conditioning circuit includes:

[0097] Capacitive sensor submodule: including a capacitive sensor C20, one end of the capacitive sensor C20 is connected to the high-voltage busbar, and the other end is connected to the detection impedance R14;

[0098] Pulse current filtering submodule: including: capacitor C17, capacitor C18, capacitor C19, capacitor C21, capacitor C22, resistor R3, resistor R4, resistor R5, resistor R6, resistor R13, resistor R16, amplifier U30A and amplifier U30B; one end of capacitor C21 is connected to detection impedance R14, and the other end is connected to one end of capacitor C22, and the other end of capacitor C22 is connected to the input end of amplifier U30A for filtering interference signals; resistor R3, resistor R4 and amplifier U30A constitute a first-stage amplifier circuit, and the output end of the first-stage amplifier circuit is connected to one end of capacitor C18 for amplifying and outputting the signal; resistor R5, resistor R6 The two-stage amplifier circuit is formed with the amplifier U30B, the input end of the two-stage amplifier circuit is connected to the other end of the capacitor C18 through the capacitor C19, and the output end is connected to one end of the capacitor C17, which is used to amplify and output the signal; one end of the resistor R16 is connected to one end of the capacitor C18 close to the two-stage amplifier circuit, and the other end is grounded, which is used to increase the circuit impedance; the capacitor C18, the capacitor C17, and the capacitor C19 are used to filter out the DC component in the circuit; the other end of the capacitor C17 is connected to the input end of the A / D conversion chip U4, one end of the resistor R13 is connected to the connection line between the capacitor C17 and the A / D conversion chip U4, and the other end is grounded, which is used to divide the voltage of the amplified signal;

[0099] Signal protection submodule: including a signal protection circuit composed of a diode D1, a diode D2, a diode D3, a resistor R17, and a transistor Q1, wherein the signal protection circuit is connected to the connection line between the capacitor C21 and the detection impedance R14, wherein the anode of the diode D1 is connected to the connection line between the capacitor C21 and the detection impedance R14, the cathode of the diode D1 is connected to one end of the resistor R17, the other end of the resistor R17 is connected to the base of the transistor Q1, the anode of the diode D2 is connected to the connection line between the capacitor C21 and the detection impedance R14, the cathode of the diode D2 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is grounded, the resistor R17 is a current limiting resistor, and when the pulse current at the front end is too large, the transistor Q1 is triggered to turn on through the diode D1 and the resistor R17, and the signal is transmitted to the ground end;

[0100] Bandpass filter submodule: One end of the low-pass filter L1 is connected to the detection impedance R14, and the other end is connected to the capacitor C21. The low-pass filter L1 is used to prevent the high-frequency pulse being measured or the high-frequency component in the power supply from passing through, so that the high-frequency pulse current is mainly applied to the first-stage amplification circuit, so that the back-end circuit can capture the partial discharge signal;

[0101] Signal conditioning submodule: including current limiting resistor R12 and current limiting resistor R15, one end of the current limiting resistor R12 is connected to one end of the low-pass filter L1 close to the first-stage amplifier circuit, and the other end is connected to the capacitor C21, one end of the current limiting resistor R15 is connected to the connection line between the current limiting resistor R12 and the capacitor C21, and the other end is grounded;

[0102] A / D conversion submodule: includes A / D conversion chip U4, resistor R7 and resistor R8. The input end of A / D conversion chip U4 is connected to capacitor C17, and the output end is connected to the corresponding input end of integrated circuit chip U1 via a pull-up resistor circuit composed of resistor R7 and resistor R8. A / D conversion chip U4 is used to convert analog signal quantity into digital signal quantity and transmit it to integrated circuit chip U1 for data processing.

[0103] In this embodiment, Figure 4-6 As shown:

[0104] A phase pulse current signal conditioning circuit module

[0105] C20 is a high-voltage capacitance sensor for switch cabinets. One end is connected to the high-voltage busbar, where HV represents the high-voltage end, and the other end is connected to the back-end circuit. C20 can sense pulsed low current signals. R14 is the ground detection impedance. The function of the detection impedance R14 is to obtain the high-frequency pulse signal generated by partial discharge. Since the signal amplitude is very small, it needs to be amplified by an amplifier, so R14 and the back-end op amp need to match each other in characteristics. They are related to the measurement sensitivity and pulse resolution.

[0106] L1 is a low-pass filter, which is used to prevent the high-frequency pulses or high-frequency components in the power supply from passing through. Due to the existence of L1, only a small part of the high-frequency pulse current passes through the loop where L1 is located, and the main current is applied to the loop where the detection impedance R4 is located, so that the back-end circuit can capture the partial discharge signal.

[0107] R12 and R15 are current limiting resistors, forming a voltage divider circuit to prevent the front-end pulse current from being too large and breaking through the back-end circuit.

[0108] In view of the impact of the transient mutation of pulse current on the back-end circuit, a signal protection circuit is added, which is composed of D1, D2, D3, R17, and Q3. This circuit can solve the leakage current problem well, thereby improving the input impedance of the conditioning circuit. At the same time, it can also effectively protect the back-end operational amplifier from damage, and the circuit can meet the input impedance of 500M ohms. D1 and D2 are transient suppression diodes, which can clamp the voltage to 10V and 3.3V respectively to prevent the front-end signal from being too large. R17 is a current limiting resistor. When the front-end pulse current is too large, the JFET tube Q1 is triggered to turn on through D1 and R17, and the signal is pulled to the ground for protection.

[0109] Since the working environment of the high-voltage capacitance sensor inevitably has various interferences (such as power supply interference, electromagnetic radiation interference, suspended potential discharge interference, power frequency interference, etc.), the local signal needs to pass through the filtering circuit first to eliminate the interference signals below the working frequency band. The present invention designs an active second-order high-pass filtering circuit. The filter capacitors C21 and C22 are selected to be 32pF. After filtering, they are output through the C18 0.1μF isolation capacitor. The filtering system can filter out interference signals within 500-20MHz. R3 and R4 form an amplification factor = 1+R3 / R4 = 11 times, and R5 and R6 form an amplification factor = 1+R5 / R6 = 11 times. The signal is effectively amplified and output through secondary amplification. R16 is a ground resistor to increase the circuit impedance. C17 and C19 are DC isolation capacitors to filter out the DC component in the circuit. R13 is a voltage divider resistor, which divides the amplified signal and outputs it to the U4 chip for processing. U4 is an A / D conversion chip that can convert analog signals into digital signals and transmit them to IC U1 for data processing. R7 and R8 are pull-up resistors that increase the current driving capability of the corresponding pins.

[0110] B-phase pulse current signal conditioning circuit module

[0111] C28 is a high-voltage capacitance sensor for switch cabinets. One end is connected to the high-voltage busbar, where HV represents the high-voltage end, and the other end is connected to the back-end circuit. C28 can sense pulsed small current signals. R30 is the ground detection impedance. The function of the detection impedance R30 is to obtain the high-frequency pulse signal generated by partial discharge. Since the signal amplitude is very small, it needs to be amplified by an amplifier, so R30 and the back-end op amp need to match each other in characteristics. They are related to the measurement sensitivity and pulse resolution.

[0112] L2 is a low-pass filter, which is used to prevent the high-frequency pulses or high-frequency components in the power supply from passing through. Due to the existence of L2, only a small part of the high-frequency pulse current passes through the loop where L2 is located, and the main current is applied to the loop where the detection impedance R4 is located, so that the back-end circuit can capture the partial discharge signal.

[0113] R28 and R31 are current limiting resistors, forming a voltage divider circuit to prevent the front-end pulse current from being too large and breaking through the back-end circuit.

[0114] In view of the impact of the transient mutation of pulse current on the back-end circuit, a signal protection circuit is added, which is composed of D4, D5, D6, R33, and Q2. This circuit can solve the leakage current problem well, thereby improving the input impedance of the conditioning circuit. At the same time, it can also effectively protect the back-end operational amplifier from damage, and the circuit can meet the input impedance of 500M ohms. D4 and D5 are transient suppression diodes, which can clamp the voltage to 10V and 3.3V respectively to prevent the front-end signal from being too large. R33 is a current limiting resistor. When the front-end pulse current is too large, the JFET tube Q2 is triggered to turn on through D6 and R33, and the signal is pulled to the ground for protection.

[0115] Since the working environment of the high-voltage capacitance sensor inevitably has various interferences (such as power supply interference, electromagnetic radiation interference, suspended potential discharge interference, power frequency interference, etc.), the local signal needs to pass through the filtering circuit first to eliminate the interference signals below the working frequency band. The present invention designs an active second-order high-pass filtering circuit. The filter capacitors C29 and C30 are selected to be 32pF. After filtering, they are output through the C26 0.1μF isolation capacitor. The filtering system can filter out interference signals within 500-20MHz. R19 and R20 form an amplification factor = 1+R19 / R20 = 11 times, and R21 and R22 form an amplification factor = 1+R21 / R22 = 11 times. The signal is effectively amplified and output through secondary amplification. R32 is a ground resistor to increase the circuit impedance. C25 and C27 are DC isolation capacitors to filter out the DC component in the circuit. R29 is a voltage divider resistor, which divides the amplified signal and outputs it to the U6 chip for processing. U6 is an A / D conversion chip that can convert analog signals into digital signals and transmit them to IC U1 for data processing. R23 and R24 are pull-up resistors to improve the current driving capability of the corresponding pins.

[0116] C-phase pulse current signal conditioning circuit module

[0117] C36 is a high-voltage capacitance sensor for switch cabinets. One end is connected to the high-voltage busbar, where HV represents the high-voltage end, and the other end is connected to the back-end circuit. C36 can sense pulsed small current signals. R46 is the ground detection impedance. The function of the detection impedance R46 is to obtain the high-frequency pulse signal generated by partial discharge. Since the signal amplitude is very small, it needs to be amplified by an amplifier, so R46 and the back-end op amp need to match each other in characteristics. They are related to the sensitivity and pulse resolution of the measurement.

[0118] L3 is a low-pass filter, which is used to prevent the high-frequency pulses or high-frequency components in the power supply from passing through. Due to the existence of L3, only a small part of the high-frequency pulse current passes through the loop where L3 is located, and the main current is applied to the loop where the detection impedance R46 is located, so that the back-end circuit can capture the partial discharge signal.

[0119] R44 and R47 are current limiting resistors, forming a voltage divider circuit to prevent the front-end pulse current from being too large and breaking through the back-end circuit.

[0120] In view of the impact of the transient mutation of pulse current on the back-end circuit, a signal protection circuit is added, which is composed of D7, D8, D9, R50, and Q3. This circuit can solve the leakage current problem well, thereby improving the input impedance of the conditioning circuit. At the same time, it can also effectively protect the back-end operational amplifier from damage, and the circuit can meet the input impedance of 500M ohms. D7 and D8 are transient suppression diodes, which can clamp the voltage to 10V and 3.3V respectively to prevent the front-end signal from being too large. R50 is a current limiting resistor. When the front-end pulse current is too large, the JFET tube Q3 is triggered to turn on through D9 and R50, and the signal is pulled to the ground for protection.

[0121] Since the working environment of the high-voltage capacitance sensor inevitably has various interferences (such as power supply interference, electromagnetic radiation interference, suspended potential discharge interference, power frequency interference, etc.), the local signal needs to pass through the filtering circuit first to remove the interference signal below the working frequency band. The present invention designs an active second-order high-pass filtering circuit. The filter capacitors C37 and C8 are selected to be 32pF. After filtering, they are output through the C340.1μF isolation capacitor. The filtering system can filter out interference signals within 500-20MHz. R35 and R36 form an amplification factor = 1+R35 / R36 = 11 times, and R37 and R38 form an amplification factor = 1+R37 / R38 = 11 times. The signal is effectively amplified and output through secondary amplification. R48 is a ground resistor to increase the circuit impedance. C35 and C33 are DC isolation capacitors to filter out the DC component in the circuit. R45 is a voltage divider resistor, which divides the amplified signal and outputs it to the U8 chip for processing. U8 is an A / D conversion chip that can convert analog signals into digital signals and transmit them to IC U1 for data processing. R42 and R43 are pull-up resistors to improve the current driving capability of the corresponding pins.

[0122] In this embodiment, the collected pulse current partial discharge detection spectrum is as follows: Fig. 20 shown.

[0123] The three-phase arc light monitoring signal conditioning circuit module is used to collect arc light signals at the three-phase busbar cable and output the collected arc light signals to the input end of the MCU main control circuit module;

[0124] The three-phase arc light monitoring signal conditioning circuit module includes: an A-phase arc light monitoring signal conditioning circuit module, a B-phase arc light monitoring signal conditioning circuit module, and a C-phase arc light monitoring signal conditioning circuit module; the three-phase arc light monitoring signal conditioning circuit modules are based on the same topological structure; wherein:

[0125] The module structure of the A-phase arc light monitoring signal conditioning circuit includes:

[0126] The SDA pin, SCL pin and INT pin of the arc sensor U5 are connected to the corresponding input terminals of the main control microcontroller unit U1. Resistors R9, R10 and R11 are connected between the SDA pin, SCL pin and INT pin of the arc sensor U5 and the power supply. Resistors R9, R10 and R11 are pull-up resistors to increase the pin driving capability. The REXT pin of the arc sensor U5 is connected to resistor R18, and the other end of resistor R18 is grounded. The VDD pin of the arc sensor U5 is connected to the system power supply. Capacitors C23 and C24 are connected in parallel between the system power supply and the ground terminal. Capacitors C23 and C24 make the power supply voltage entering the arc sensor U5 more stable.

[0127] In this embodiment, Figure 8-9 As shown:

[0128] Phase A arc monitoring signal conditioning circuit module

[0129] The arc signal modulation unit block can collect arc signals sensed by arc sensors from different positions. The arc sensor uses the illuminance sensor ISL29023, which is an integrated digital ambient light sensor with an interrupt function. It can convert light signals into digital signals and transmit data through a compatible interface. PC4 of IC U1 is connected to the data bus SDA end of ISL29023, and PC5 is connected to the clock bus SCL end.

[0130] R9, R10, and R11 are pull-up resistors that increase the driving capability of U5's 4, 5, and 6 pins to prevent communication interruption. U5's 4-pin is a chip select pin that can control the sensor's on / off through IC U1. R18 is U5's fixed ground discharge resistor. C23 and C24 are filter capacitors that make the power supply voltage entering U5 more stable.

[0131] Phase B arc monitoring signal conditioning circuit module

[0132] The arc signal modulation unit block can collect arc signals sensed by arc sensors from different positions. The arc sensor uses the illuminance sensor ISL29023, which is an integrated digital ambient light sensor with an interrupt function. It can convert light signals into digital signals and transmit data through a compatible interface. PC4 of IC U1 is connected to the data bus SDA end of ISL29023, and PC5 is connected to the clock bus SCL end.

[0133] R25, R26, and R27 are pull-up resistors that increase the driving capability of U7's 4, 5, and 6 pins to prevent communication interruption. U7's 4-pin is a chip select pin that can control the sensor's on / off via IC U1. R34 is U7's fixed ground discharge resistor. C31 and C32 are filter capacitors that make the power supply voltage entering U7 more stable.

[0134] C-phase arc monitoring signal conditioning circuit module

[0135] The arc signal modulation unit block can collect arc signals sensed by arc sensors from different positions. The arc sensor uses the illuminance sensor ISL29023, which is an integrated digital ambient light sensor with an interrupt function. It can convert light signals into digital signals and transmit data through a compatible interface. PC4 of IC U1 is connected to the data bus SDA end of ISL29023, and PC5 is connected to the clock bus SCL end.

[0136] R39, R40, and R41 are pull-up resistors that increase the driving capability of U9's 4, 5, and 6 pins to prevent communication interruption. U9's 4-pin is a chip select pin that can control the sensor's on / off through IC U1. R49 is U9's fixed ground discharge resistor. C39 and C40 are filter capacitors that make the power supply voltage entering U9 more stable.

[0137] The communication circuit module is connected to the data serial port of the MCU main control circuit module for remote transmission of pulse current data and waveform;

[0138] In the communication circuit module, the RO pin and DI pin of the communication chip U12 are respectively connected to the RS485-RX and RS485-TX serial ports of the main control microcontroller unit U1 for data exchange; PE is the enable end of the communication chip U12 connected to the power supply through the resistor R61; the output A pin of the communication chip U12 is respectively connected to the resistor R63 and the resistor R65, the other end of the resistor R63 is connected to the power supply, and the other end of the resistor R65 is connected to the TVS diode VP1; the output B pin of the communication chip U12 is respectively connected to the resistor R62 and the resistor R64, the other end of the resistor R62 is grounded, and the other end of the resistor R64 is connected to the TVS diode VP1; the resistor R62 and the resistor R63 are pull-up resistors to increase the driving capability, and the resistor R64 and the resistor R65 are current limiting resistors to prevent the communication chip U12 from being broken down when the external signal is connected; one end of the TVS diode VP1 is connected to the resistor R64 and the other end is connected to the resistor R65 to prevent the voltage difference between the output A pin and the B pin of the communication chip U12 from breaking down the RS485 communication chip U12.

[0139] In this embodiment, Fig.10 As shown:

[0140] RS485_RX and RS485_TX are respectively connected to the serial port of MCU U1 for data exchange; PE is the enable terminal of U12, where R61 is a pull-up resistor to increase the driving capability; R62 and R63 are pull-up resistors for RS485 output port A and port B respectively to increase the driving capability; R64 and R65 are current limiting resistors to prevent the RS485 communication chip U12 from being broken down when external signals are connected; VP1 is a protection diode to prevent the RS485 communication chip U12 from being broken down due to excessive voltage difference between RS485 output port A and port B.

[0141] The storage circuit module is connected to the MCU main control circuit module and is used for local storage of pulse current waveform and data;

[0142] In this embodiment, Fig.11 As shown:

[0143] U10 is a memory chip with storage function, which can store pulse current waveform and data locally. Pins 1, 2, 5, and 6 of U10 are connected to MCU U1 for data exchange; C50 is a filter capacitor, which makes the power supply voltage of U10 more stable.

[0144] The display circuit module is connected to the MCU main control circuit module and is used to display the collected pulse current waveform and data on the local LCD screen to provide a basis for judgment for on-site personnel;

[0145] In this embodiment, Fig.12 As shown:

[0146] U11 is a liquid crystal display screen, which is used to display the collected pulse current waveform and data grounding display, providing a basis for judgment for on-site operation and maintenance personnel.

[0147] C51 is the input power filter capacitor of U11, which makes the working power of U11 more stable. R60 is a current limiting resistor, so that the CS_1 level can generate a base current through R60, driving the transistor Q5 to conduct, and controlling whether VCC3.3V is conducted to the 8th pin of U11. The main function of CS_1 is to control whether the backlight of the U11 LCD screen is turned on. C52 is a ground filter capacitor, which makes the CS_1 level more stable.

[0148] 1, 3, 4, 5, and 6 of U11 are connected correspondingly to U1 and are used for data connection and transmission between the two.

[0149] The MCU main control circuit module receives sensor data collected by the three-phase pulse current signal conditioning circuit module, the three-phase arc monitoring signal conditioning circuit module, the ambient temperature and humidity detection circuit module, the background noise acquisition module, and the three-phase cable sheath circulating current monitoring acquisition circuit module, and coordinates and controls each circuit module to ensure that the system can work normally according to the predetermined logic and process;

[0150] In the MCU main control circuit module, capacitors C1-C7 are connected in parallel between the system power supply terminal and the ground terminal of the main control micro control unit U1. Capacitors C1-C7 are filtering decoupling capacitors of the power supply to the ground, which are used to protect the main control micro control unit U1 from working stably; a crystal oscillator circuit composed of capacitors C15, capacitors C16, and crystal oscillator circuit element XT2 is connected between pins 3 and 4 of the main control micro control unit U1; a crystal oscillator circuit composed of capacitors C12, capacitors C13, and crystal oscillator circuit element XT1 is connected between pins 5 and 6 of the main control micro control unit U1, and a reset pin of the main control micro control unit U1 is connected to a reset circuit composed of resistor R2 and capacitor C14.

[0151] In this embodiment, Fig.13 As shown:

[0152] U1 is the main control MCU, used for the entire system program operation. Among them, C1, C2, C3, C4, C5, C6, and C7 are filter decoupling capacitors of the power supply VCC to GND, which are used to protect the MCU from working stably. C15, C16, and XT2 are one crystal oscillator circuit of MCU U1; C12, C13, and XT1 are another crystal oscillator circuit of MCU U1. R2 and C14 are the connection method of the fixed reset circuit of U4.

[0153] The power supply circuit module is used for converting the system circuit level and converting the voltage into the voltage value required by different chips;

[0154] The external power supply voltages L and N of the power supply circuit module are connected to the incoming line fuse F1 and the varistor R1, the other ends of the incoming line fuse F1 and the resistor R1 are connected to the voltage conversion chip U3, the output end of the voltage conversion chip U3 is connected to the capacitor C8 and the capacitor C10, the other ends of the capacitor C8 and the capacitor C10 are grounded, the output end of the voltage conversion chip U3 is also connected to the input end of the low voltage difference linear regulator U2, the output end of the low voltage difference linear regulator U2 is connected to the capacitor C9 and the capacitor C11 in parallel, and the other ends of the capacitor C9 and the capacitor C11 are grounded.

[0155] In this embodiment, Fig.14 As shown:

[0156] L and N are external power supply voltages, F1 is an incoming line fuse to prevent overcurrent or short circuit access; R1 is a varistor for lightning protection; U5 is an AC-DC power module that can convert AC220V into DC5V output; C8 and C10 are 5V output voltage filter capacitors, U2 is an LDO that can step down the 5V voltage to the 3.3V voltage required by the system, and C9 and C11 are output voltage filter capacitors.

[0157] The ambient temperature and humidity detection circuit module is used to collect the ambient temperature and humidity values ​​in the switch cabinet, and output the collected ambient temperature and humidity values ​​to the input end of the MCU main control circuit module;

[0158] The ambient temperature and humidity detection circuit module includes a thermistor R68 and a capacitor C53 connected in parallel. The thermistor R68 reflects the ambient temperature value by changing its resistance. One end of the thermistor R68 is connected to a voltage-dividing resistor R66, and the other end is grounded. It also includes: a hygroscopic resistor R69 and a capacitor C54 connected in parallel. The hygroscopic resistor R69 reflects the ambient humidity value by changing its resistance. One end of the hygroscopic resistor R69 is connected to a voltage-dividing resistor R67, and the other end is grounded.

[0159] In this embodiment, Fig.15 As shown:

[0160] R68 is a thermistor, and the change in resistance can reflect the ambient temperature. C53 is a filter capacitor, which makes the voltage at the WD_SEN point more stable. When the ambient temperature changes, the voltage at the WD_SEN point can be converted into the ambient temperature value by collecting it, and its voltage = 3.3V*R68 / (R68+R66);

[0161] R69 is a humidity-sensitive resistor, which can reflect the ambient humidity value through resistance changes. C54 is a filter capacitor, which makes the voltage at the SD_SEN point more stable. When the ambient humidity changes, the voltage at the SD_SEN point can be converted into the ambient humidity value by collecting it, and its voltage = 3.3V*R69 / (R69+R67).

[0162] The background noise collection module is used to collect the large background noise generated inside the switch cabinet when the circuit breaker and the grounding knife perform opening and closing actions in the switch cabinet, and output the collected noise signal to the input end of the MCU main control circuit module;

[0163] The background noise collection module comprises: one end of a capacitive micro-microphone LS2 is connected to a voltage-dividing circuit composed of resistors R70 and R71, and a capacitor C55 is connected in parallel with the resistor R71, so that the collected voltage is more stable; one end of a capacitor C56 is connected to the voltage-dividing circuit composed of resistors R70 and R71, and the other end is connected to the base of a transistor Q12, the collector of the transistor Q12 is connected to the reverse input end of an amplifier U14, and the emitter of the transistor Q12 is grounded; one end of a capacitor C57 is connected to the reverse input end of the amplifier U14, and the other end is grounded, so that the signal waveform is smoother; the output end of the amplifier U14 is connected to the input end corresponding to the main control micro-control unit U1, and the amplifier U14 amplifies the sound voltage signal, one end of the resistor R74 is connected to the positive input end of the amplifier U14, and the other end is grounded.

[0164] In this embodiment, Fig.16 As shown:

[0165] LS2 is a capacitive micro microphone. The input signal is a sound signal and the output is a voltage signal. R70 and R71 form a voltage divider circuit, which can raise the voltage value of the output voltage signal of LS2. C55 is a filter capacitor, which makes the collected voltage more stable. C56 is a DC blocking capacitor, which can remove the AC component in the signal collected by LS2. R72 is a pull-up resistor to increase the signal driving capability. Q12 is a JFET transistor, which can output the input signal to the 2-pin input terminal of U14. R73 is a pull-up drive resistor, which can provide signal driving capability. C57 is a ground filter capacitor, which makes the signal waveform smoother. U14 is an amplifier, which can amplify the sound voltage signal. R74 is a ground balancing resistor, and R75 is a pull-up resistor to submit the signal driving capability. After the signal is collected, it is input to the interface PA2 of MCU U1 for analysis and processing to determine the noise interference inside the switch cabinet.

[0166] The three-phase cable sheath circulating current monitoring and acquisition circuit module is used to collect the circulating current size of phase A, phase B and phase C of the three-phase high-voltage cable, and output the collected circulating current signal to the input end of the MCU main control circuit module.

[0167] The three-phase cable sheath circulating current monitoring and acquisition circuit module includes: an A-phase cable sheath circulating current monitoring and acquisition circuit module, a B-phase cable sheath circulating current monitoring and acquisition circuit module, and a C-phase cable sheath circulating current monitoring and acquisition circuit module; the three-phase cable sheath circulating current monitoring and acquisition circuit modules are based on the same topological structure; each phase cable sheath circulating current monitoring and acquisition circuit module includes: signal acquisition, filtering and protection circuit and amplification circuit submodules, wherein:

[0168] The module structure of the A-phase cable sheath circulating current monitoring and acquisition circuit includes:

[0169] The signal acquisition submodule includes: a leakage current sensor HG1, which is installed in an open manner at the outer sheath of the A-phase high-voltage cable and is used to collect the leakage current of the A-phase cable;

[0170] The filtering and protection circuit submodule includes: a capacitor C55 and an electronic resistor R80. The capacitor C55 is connected in parallel to the acquisition signal output end of the leakage current sensor HG1. The capacitor C55 is used to make the current waveform smoother. The resistor R80 is connected in parallel with the leakage current sensor HG1 and the capacitor C55 to prevent the current collected from being too large to break through the back-end circuit when HG1 is saturated.

[0171] The amplification circuit submodule includes: resistor R81 is an input protection resistor of amplifier U20, one end of which is connected to the signal collection output end of leakage current sensor HG1, and the other end is connected to the reverse input end of operational amplifier U20 to prevent excessive current from breaking down amplifier U20B; one end of resistor R82 is connected to the signal collection output end of leakage current sensor HG1, and the other end is respectively connected to the positive input end of amplifier U20B and one end of resistor R83, the other end of resistor R83 is connected to the output end of amplifier U20B, resistor R82, resistor R83 and amplifier U20B constitute a primary amplification circuit; resistor R84, resistor R85 and amplifier U20C constitute a secondary amplification circuit, which is connected to the output end of the primary amplification circuit; the input end of filter follower U20A is connected to the output end of the secondary amplification circuit to stabilize the current signal waveform, and the output end of filter follower U20A is connected to the input port corresponding to the main control micro control unit U1.

[0172] In this embodiment, Figure 17-19 As shown:

[0173] A-phase sheath circulation monitoring and acquisition circuit module

[0174] HG1 is a leakage current sensor with a range of 0-5A and an accuracy of 5%. It is installed in an open-type manner on the outer sheath of the A-phase high-voltage cable. It can accurately collect the leakage current of the A-phase cable, and its current value is an AC signal.

[0175] C55 is a filter capacitor. When the AC current collected by HG1 is subject to grid fluctuations, C55 can effectively make its current waveform smoother. R80 is the phase leakage protection resistor of the transformer HG1, which prevents the current collected when HG1 is saturated from being too large and breaking through the back-end circuit.

[0176] R81 is the input protection resistor of operational amplifier U20, which prevents excessive current from breaking through pin 6 of U20. R83 and R82 form a first-level current amplifier, and its amplification factor = 1 + R83 / R82 = 6 times, which can amplify the current signal by 6 times. R84 and R85 form a second-level amplifier, and its amplification factor: = 1 + R85 / R84 = 2 times, which can amplify the current signal by 2 times. U20A is a filter follower, which stabilizes the current signal waveform and sends it to MCU U1 for analysis.

[0177] B-phase sheath circulation monitoring and acquisition circuit module

[0178] HG2 is a leakage current sensor with a range of 0-5A and an accuracy of 5%. It is installed in an open-type manner on the outer sheath of the B-phase high-voltage cable. It can accurately collect the leakage current of the B-phase cable, and its current value is an AC signal.

[0179] C56 is a filter capacitor. When the AC current collected by HG2 is subject to grid fluctuations, C56 can effectively make its current waveform smoother. R86 is the phase leakage protection resistor of the transformer HG2, which prevents the current collected when HG2 is saturated from being too large and breaking through the back-end circuit.

[0180] R87 is the input protection resistor of operational amplifier U21, which prevents excessive current from breaking through pin 6 of U21. R89 and R88 form a first-level current amplifier, and its amplification factor = 1 + R89 / R88 = 6 times, which can amplify the current signal by 6 times. R90 and R91 form a second-level amplifier, and its amplification factor: = 1 + R91 / R90 = 2 times, which can amplify the current signal by 2 times. U21A is a filter follower, which stabilizes the current signal waveform and sends it to MCU U1 for analysis.

[0181] C-phase sheath circulation monitoring and acquisition circuit module

[0182] HG3 is a leakage current sensor with a range of 0-5A and an accuracy of 5%. It is installed in an open-type manner on the outer sheath of the C-phase high-voltage cable. It can accurately collect the leakage current of the C-phase cable, and its current value is an AC signal.

[0183] C57 is a filter capacitor. When the AC current collected by HG3 is subject to grid fluctuations, C57 can effectively make its current waveform smoother. R92 is the phase leakage protection resistor of the transformer HG3, which prevents the current collected when HG3 is saturated from being too large and breaking through the back-end circuit.

[0184] R93 is the input protection resistor of operational amplifier U22, which prevents excessive current from breaking through pin 6 of U22. R95 and R94 form a first-stage current amplifier, and its amplification factor = 1 + R95 / R94 = 6 times, which can amplify the current signal by 6 times. R97 and R96 form a second-stage amplifier, and its amplification factor: = 1 + R97 / R96 = 2 times, which can amplify the current signal by 2 times. U22A is a filter follower, which stabilizes the current signal waveform and sends it to MCU U1 for analysis.

[0185] Embodiment 2:

[0186] This embodiment provides a method for using a circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method, comprising the following steps:

[0187] Step S1: collecting pulse current signals and arc signals through a three-phase pulse current signal conditioning circuit module and a three-phase arc monitoring signal conditioning circuit module;

[0188] Step S2: collecting ambient temperature and humidity signals through the ambient temperature and humidity detection circuit module; collecting sound signals generated by the circuit breaker and the grounding knife in the switch cabinet when they are opened and closed through the background noise collection module;

[0189] Step S3: collecting cable sheath circulating current signals through a three-phase cable sheath circulating current monitoring and collection circuit module;

[0190] Step S4: The MCU main control circuit module processes and analyzes the digital signals from each circuit module. The analysis includes: judging the partial discharge situation according to the pulse current data, judging whether there is an arc phenomenon caused by partial discharge in combination with the arc light signal, assisting in judging the insulation environment of the switch cabinet according to the ambient temperature and humidity data, judging whether the noise affects the pulse current collection and causes misjudgment according to the background noise data, and assisting in judging the insulation performance of the cable through the cable sheath circulation data; outputting the analysis results;

[0191] Step S5: The display circuit module displays the collected pulse current waveform and data on the local LCD screen to provide a basis for judgment for on-site personnel. The storage circuit module stores the pulse current waveform and data locally to prevent data loss due to abnormal power failure. The RS485 communication circuit module transmits the pulse current data and waveform remotely through the RS480 communication standard for remote monitoring and analysis.

[0192] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0193] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0194] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0195] In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk, and other media that can store program codes.

[0196] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method, characterized in that: include: Three-phase pulse current signal conditioning circuit module, three-phase arc monitoring signal conditioning circuit module, communication circuit module, storage circuit module, display circuit module, MCU main control circuit module, power supply circuit module, ambient temperature and humidity detection circuit module, background noise acquisition module, three-phase cable sheath circulating current monitoring acquisition circuit module; The three-phase pulse current signal conditioning circuit module is used for pulse current data measurement, transient mutation suppression and filtering, pulse current signal amplification processing, and outputs the processed pulse current data to the input end of the MCU main control circuit module; The three-phase arc light monitoring signal conditioning circuit module is used to collect arc light signals at the three-phase busbar cable and output the collected arc light signals to the input end of the MCU main control circuit module; The communication circuit module is connected to the data serial port of the MCU main control circuit module for remote transmission of pulse current data and waveform; The storage circuit module is connected to the MCU main control circuit module and is used for local storage of pulse current waveform and data; The display circuit module is connected to the MCU main control circuit module and is used to display the collected pulse current waveform and data on the local LCD screen; The MCU main control circuit module receives sensor data collected by the three-phase pulse current signal conditioning circuit module, the three-phase arc monitoring signal conditioning circuit module, the ambient temperature and humidity detection circuit module, the background noise acquisition module, and the three-phase cable sheath circulating current monitoring acquisition circuit module, and coordinates and controls each circuit module to ensure that the system can work normally according to the predetermined logic and process; The power supply circuit module is used for converting the system circuit level and converting the voltage into the voltage value required by different chips; The ambient temperature and humidity detection circuit module is used to collect the ambient temperature and humidity values ​​in the switch cabinet, and output the collected ambient temperature and humidity values ​​to the input end of the MCU main control circuit module; The background noise acquisition module is used to collect the noise signal generated in the switch cabinet and output the collected noise signal to the input end of the MCU main control circuit module; The three-phase cable sheath circulating current monitoring and acquisition circuit module is used to collect the circulating current size of phase A, phase B and phase C of the three-phase high-voltage cable, and output the collected circulating current signal to the input end of the MCU main control circuit module.

2. The circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method according to claim 1 is characterized in that: The three-phase pulse current signal conditioning circuit module includes: A-phase pulse current signal conditioning circuit module, B-phase pulse current signal conditioning circuit module and C-phase pulse current signal conditioning circuit module; the three-phase pulse current signal conditioning circuit module is based on the same topological structure; each phase pulse current signal conditioning circuit module includes: capacitive sensor, pulse current filtering, signal protection, bandpass filtering, signal conditioning, A / D conversion submodule, wherein: The module structure of the A-phase pulse current signal conditioning circuit includes: Capacitive sensor submodule: including a capacitive sensor C20, one end of the capacitive sensor C20 is connected to the high-voltage busbar, and the other end is connected to the detection impedance R14; Pulse current filtering submodule: including: capacitor C17, capacitor C18, capacitor C19, capacitor C21, capacitor C22, resistor R3, resistor R4, resistor R5, resistor R6, resistor R13, resistor R16, amplifier U30A and amplifier U30B; one end of capacitor C21 is connected to detection impedance R14, and the other end is connected to one end of capacitor C22, and the other end of capacitor C22 is connected to the input end of amplifier U30A for filtering interference signals; resistor R3, resistor R4 and amplifier U30A constitute a first-stage amplifier circuit, and the output end of the first-stage amplifier circuit is connected to one end of capacitor C18 for amplifying and outputting the signal; resistor R5, resistor R6 The two-stage amplifier circuit is formed with the amplifier U30B, the input end of the two-stage amplifier circuit is connected to the other end of the capacitor C18 through the capacitor C19, and the output end is connected to one end of the capacitor C17, which is used to amplify and output the signal; one end of the resistor R16 is connected to one end of the capacitor C18 close to the two-stage amplifier circuit, and the other end is grounded, which is used to increase the circuit impedance; the capacitor C18, the capacitor C17, and the capacitor C19 are used to filter out the DC component in the circuit; the other end of the capacitor C17 is connected to the input end of the A / D conversion chip U4, one end of the resistor R13 is connected to the connection line between the capacitor C17 and the A / D conversion chip U4, and the other end is grounded, which is used to divide the voltage of the amplified signal; Signal protection submodule: including a signal protection circuit composed of a diode D1, a diode D2, a diode D3, a resistor R17, and a transistor Q1, wherein the signal protection circuit is connected to the connection line between the capacitor C21 and the detection impedance R14, wherein the anode of the diode D1 is connected to the connection line between the capacitor C21 and the detection impedance R14, the cathode of the diode D1 is connected to one end of the resistor R17, the other end of the resistor R17 is connected to the base of the transistor Q1, the anode of the diode D2 is connected to the connection line between the capacitor C21 and the detection impedance R14, the cathode of the diode D2 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is grounded, the resistor R17 is a current limiting resistor, and when the pulse current at the front end is too large, the transistor Q1 is triggered to turn on through the diode D1 and the resistor R17, and the signal is transmitted to the ground end; Bandpass filter submodule: One end of the low-pass filter L1 is connected to the detection impedance R14, and the other end is connected to the capacitor C21. The low-pass filter L1 is used to prevent the high-frequency pulse being measured or the high-frequency component in the power supply from passing through, so that the high-frequency pulse current is mainly applied to the first-stage amplification circuit, so that the back-end circuit can capture the partial discharge signal; Signal conditioning submodule: including current limiting resistor R12 and current limiting resistor R15, one end of the current limiting resistor R12 is connected to one end of the low-pass filter L1 close to the first-stage amplifier circuit, and the other end is connected to the capacitor C21, one end of the current limiting resistor R15 is connected to the connection line between the current limiting resistor R12 and the capacitor C21, and the other end is grounded; A / D conversion submodule: includes A / D conversion chip U4, resistor R7 and resistor R8. The input end of A / D conversion chip U4 is connected to capacitor C17, and the output end is connected to the corresponding input end of integrated circuit chip U1 via a pull-up resistor circuit composed of resistor R7 and resistor R8. A / D conversion chip U4 is used to convert analog signal quantity into digital signal quantity and transmit it to integrated circuit chip U1 for data processing.

3. The circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method according to claim 1 is characterized in that: The three-phase arc light monitoring signal conditioning circuit module includes: an A-phase arc light monitoring signal conditioning circuit module, a B-phase arc light monitoring signal conditioning circuit module, and a C-phase arc light monitoring signal conditioning circuit module; the three-phase arc light monitoring signal conditioning circuit module is based on the same topological structure; wherein: The module structure of phase A arc supervision circuit includes: The SDA pin, SCL pin and INT pin of the arc sensor U5 are connected to the corresponding input terminals of the main control microcontroller unit U1. Resistors R9, R10 and R11 are connected between the SDA pin, SCL pin and INT pin of the arc sensor U5 and the power supply. Resistors R9, R10 and R11 are pull-up resistors to increase the pin driving capability. The REXT pin of the arc sensor U5 is connected to resistor R18, and the other end of resistor R18 is grounded. The VDD pin of the arc sensor U5 is connected to the system power supply. Capacitors C23 and C24 are connected in parallel between the system power supply and the ground terminal. Capacitors C23 and C24 make the power supply voltage entering the arc sensor U5 more stable.

4. The method of the circuit of the high-voltage switch cabinet insulation diagnosis device based on the pulse current method according to claim 1 is characterized in that: In the communication circuit module, the RO pin and DI pin of the communication chip U12 are respectively connected to the RS485-RX and RS485-TX serial ports of the main control microcontroller unit U1 for data exchange; PE is the enable end of the communication chip U12 connected to the power supply through the resistor R61; the output A pin of the communication chip U12 is respectively connected to the resistor R63 and the resistor R65, the other end of the resistor R63 is connected to the power supply, and the other end of the resistor R65 is connected to the TVS diode VP1; the output B pin of the communication chip U12 is respectively connected to the resistor R62 and the resistor R64, the other end of the resistor R62 is grounded, and the other end of the resistor R64 is connected to the TVS diode VP1; the resistor R62 and the resistor R63 are pull-up resistors to increase the driving capability, and the resistor R64 and the resistor R65 are current limiting resistors to prevent the communication chip U12 from being broken down when the external signal is connected; one end of the TVS diode VP1 is connected to the resistor R64 and the other end is connected to the resistor R65 to prevent the voltage difference between the output A pin and the B pin of the communication chip U12 from breaking down the RS485 communication chip U12.

5. The method of the circuit of the high-voltage switch cabinet insulation diagnosis device based on the pulse current method according to claim 1 is characterized in that: In the MCU main control circuit module, capacitors C1-C7 are connected in parallel between the system power supply terminal and the ground terminal of the main control micro control unit U1. Capacitors C1-C7 are filtering decoupling capacitors of the power supply to the ground, which are used to protect the main control micro control unit U1 from working stably; a crystal oscillator circuit composed of capacitors C15, capacitors C16, and crystal oscillator circuit element XT2 is connected between pins 3 and 4 of the main control micro control unit U1; a crystal oscillator circuit composed of capacitors C12, capacitors C13, and crystal oscillator circuit element XT1 is connected between pins 5 and 6 of the main control micro control unit U1, and a reset pin of the main control micro control unit U1 is connected to a reset circuit composed of resistor R2 and capacitor C14.

6. The method of the circuit of the high-voltage switch cabinet insulation diagnosis device based on the pulse current method according to claim 1 is characterized in that: The external power supply voltages L and N of the power supply circuit module are connected to the incoming line fuse F1 and the varistor R1, the other ends of the incoming line fuse F1 and the resistor R1 are connected to the voltage conversion chip U3, the output end of the voltage conversion chip U3 is connected to the capacitor C8 and the capacitor C10, the other ends of the capacitor C8 and the capacitor C10 are grounded, the output end of the voltage conversion chip U3 is also connected to the input end of the low voltage difference linear regulator U2, the output end of the low voltage difference linear regulator U2 is connected to the capacitor C9 and the capacitor C11 in parallel, and the other ends of the capacitor C9 and the capacitor C11 are grounded.

7. The method of the circuit of the high-voltage switch cabinet insulation diagnosis device based on the pulse current method according to claim 1 is characterized in that: The ambient temperature and humidity detection circuit module includes: a thermistor R68 and a capacitor C53 connected in parallel, the thermistor R68 reflects the ambient temperature value through resistance changes, one end of the thermistor R68 is connected to a voltage divider resistor R66, and the other end is grounded; and also includes: a humidity resistor R69 and a capacitor C54 connected in parallel, the humidity resistor R69 reflects the ambient humidity value through resistance changes, one end of the humidity resistor R69 is connected to a voltage divider resistor R67, and the other end is grounded.

8. The method of the circuit of the high-voltage switch cabinet insulation diagnosis device based on the pulse current method according to claim 1 is characterized in that: The background noise collection module comprises: one end of a capacitive micro-microphone LS2 is connected to a voltage-dividing circuit composed of resistors R70 and R71, and a capacitor C55 is connected in parallel with the resistor R71, so that the collected voltage is more stable; one end of a capacitor C56 is connected to the voltage-dividing circuit composed of resistors R70 and R71, and the other end is connected to the base of a transistor Q12, the collector of the transistor Q12 is connected to the reverse input end of an amplifier U14, and the emitter of the transistor Q12 is grounded; one end of a capacitor C57 is connected to the reverse input end of the amplifier U14, and the other end is grounded, so that the signal waveform is smoother; the output end of the amplifier U14 is connected to the input end corresponding to the main control micro-control unit U1, and the amplifier U14 amplifies the sound voltage signal, one end of a resistor R74 is connected to the forward input end of the amplifier U14, and the other end is grounded.

9. The method of the circuit of the high-voltage switch cabinet insulation diagnosis device based on the pulse current method according to claim 1 is characterized in that: The three-phase cable sheath circulating current monitoring and acquisition circuit module includes: an A-phase cable sheath circulating current monitoring and acquisition circuit module, a B-phase cable sheath circulating current monitoring and acquisition circuit module, and a C-phase cable sheath circulating current monitoring and acquisition circuit module; the three-phase cable sheath circulating current monitoring and acquisition circuit modules are based on the same topological structure; each phase cable sheath circulating current monitoring and acquisition circuit module includes: signal acquisition, filtering and protection circuit and amplification circuit submodules, wherein: The module structure of the A-phase cable sheath circulating current monitoring and acquisition circuit includes: The signal acquisition submodule includes: a leakage current sensor HG1, which is installed in an open manner at the outer sheath of the A-phase high-voltage cable and is used to collect the leakage current of the A-phase cable; The filtering and protection circuit submodule includes: a capacitor C55 and an electronic resistor R80, the capacitor C55 is connected in parallel to the acquisition signal output end of the leakage current sensor HG1, and the capacitor C55 is used to make the current waveform smoother; the resistor R80 is connected in parallel with the leakage current sensor HG1 and the capacitor C55 to prevent the current collected from being too large to break through the back-end circuit when HG1 is saturated; The amplification circuit submodule includes: resistor R81 is an input protection resistor of amplifier U20, one end of which is connected to the signal collection output end of leakage current sensor HG1, and the other end is connected to the reverse input end of operational amplifier U20 to prevent excessive current from breaking down amplifier U20B; one end of resistor R82 is connected to the signal collection output end of leakage current sensor HG1, and the other end is respectively connected to the positive input end of amplifier U20B and one end of resistor R83, the other end of resistor R83 is connected to the output end of amplifier U20B, resistor R82, resistor R83 and amplifier U20B constitute a primary amplification circuit; resistor R84, resistor R85 and amplifier U20C constitute a secondary amplification circuit, which is connected to the output end of the primary amplification circuit; the input end of filter follower U20A is connected to the output end of the secondary amplification circuit to stabilize the current signal waveform, and the output end of filter follower U20A is connected to the input port corresponding to the main control micro control unit U1.

10. A method for using a circuit of a high-voltage switch cabinet insulation diagnostic device based on a pulse current method as claimed in any one of claims 1 to 9, characterized in that: include: Step S1: collecting pulse current signals and arc signals through a three-phase pulse current signal conditioning circuit module and a three-phase arc monitoring signal conditioning circuit module; Step S2: collecting ambient temperature and humidity signals through the ambient temperature and humidity detection circuit module; collecting sound signals generated by the circuit breaker and the grounding knife in the switch cabinet when they are opened and closed through the background noise collection module; Step S3: collecting cable sheath circulating current signals through a three-phase cable sheath circulating current monitoring and collection circuit module; Step S4: The MCU main control circuit module processes and analyzes the digital signals from each circuit module. The analysis includes: judging the partial discharge situation according to the pulse current data, judging whether there is an arc phenomenon caused by partial discharge in combination with the arc light signal, assisting in judging the insulation environment of the switch cabinet according to the ambient temperature and humidity data, judging whether the noise affects the pulse current collection and causes misjudgment according to the background noise data, and assisting in judging the insulation performance of the cable through the cable sheath circulation data; outputting the analysis results; Step S5: The display circuit module displays the collected pulse current waveform and data on the local LCD screen to provide a basis for judgment for on-site personnel. The storage circuit module stores the pulse current waveform and data locally to prevent data loss due to abnormal power failure. The RS485 communication circuit module transmits the pulse current data and waveform remotely through the RS480 communication standard for remote monitoring and analysis.

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