Electroacoustic pulse measurement system and method for gas-solid interface charges of solid insulating material

Abstract

The invention discloses an electroacoustic pulse measurement system and method for gas-solid interface charges of a solid insulating material, and relates to the technical field of high voltage and insulation. Comprising an external circuit unit, an electrode unit and a signal acquisition unit, the electrode unit comprises a working electrode, an epoxy plate, a shielding shell, an epoxy cushion layer, a flat plate sample and a lower electrode; the working electrode is a discharge electrode or a test electrode; the external circuit unit is detachably connected with the working electrode, the working electrode is detachably embedded into the epoxy plate, the epoxy plate is fixedly connected with the shielding shell, the working electrode, the epoxy plate and the shielding shell are concentric, and the lowermost end of the working electrode and the lowermost end of the shielding shell are located on the same horizontal plane; the discharge electrode is an electrode with uniformly distributed needle tips, and the test electrode is a plate electrode; the epoxy cushion layer is clamped between the shielding shell and the flat plate sample; the flat plate sample is attached to the lower electrode, and the lower electrode is grounded and connected with the signal acquisition unit. The system can accurately measure the gas-solid interface charge of the solid insulating material.

Description

Technical Field

[0001] The invention relates to the field of high voltage and insulation technology, and in particular to an electroacoustic pulse measurement system and method for gas-solid interface charge of solid insulating materials. Background Art

[0002] High-voltage direct current transmission is an important means for the world's power-producing countries to solve the problems of long-distance, large-capacity transmission and grid interconnection. It can promote the clean and efficient development and utilization of various energy sources and promote the optimal allocation of energy resources in a larger range. Compared with traditional overhead lines, direct current gas-insulated transmission lines (Gas-Insulated metal-enclosed transmission Line, GIL) have the advantages of large transmission capacity, small footprint, less impact from the external environment, and high operational stability. As an important supplementary method for the access of new energy such as offshore wind power and energy transmission for urbanization construction in the future. With the advocacy and implementation of green, low-carbon and sustainable development, the development of high-voltage electrical equipment faces new opportunities and challenges. Environmentally friendly gas-insulated substations (Gas-Insulated Substation, GIS) / GIL, DC breakers, etc. have become new development directions.

[0003] Under DC voltage, due to the long-term effect of unipolar electric field, the charged particles in sulfur hexafluoride SF6 gas and the carriers in the insulating material are gradually transferred to the gas-solid interface under the action of the electric field, resulting in significant interfacial charge accumulation on the surface of the insulator in the GIL, causing the gas-solid interface electric field distortion, which is easy to induce insulator surface flashover, seriously affecting the safe and stable operation of the DC system. However, the insulator in the DC GIL will also face the combined effects of temperature gradient, metal particles and polarity voltage reversal, and its surface charge accumulation behavior and electric field distribution characteristics are extremely complex.

[0004] Therefore, how to accurately measure the gas-solid interface charge of solid insulating materials has become a key technical problem in this field. Summary of the invention

[0005] Based on this, it is necessary to provide an electroacoustic pulse measurement system and method for the gas-solid interface charge of solid insulating materials in response to the above technical problems. The system can achieve accurate measurement of the gas-solid interface charge of solid insulating materials.

[0006] The present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials, the system comprising: an external circuit unit, an electrode unit and a signal acquisition unit; the electrode unit comprises a working electrode, an epoxy board, a shielding shell, an epoxy cushion layer, a flat sample and a lower electrode;

[0008] The external circuit unit is detachably connected to the working electrode, the working electrode is detachably embedded in the epoxy board, the epoxy board and the shielding shell are connected and fixed, the working electrode, the epoxy board and the shielding shell are concentric, and the lower end of the working electrode and the lower end of the shielding shell are in the same horizontal plane; the epoxy cushion layer is sandwiched between the shielding shell and the flat sample, and the thickness of the epoxy cushion layer is the height of the air gap between the working electrode and the flat sample; the flat sample is fitted with the lower electrode, the lower electrode is grounded, and connected to the signal acquisition unit;

[0009] An external circuit unit, used for simultaneously applying pulse excitation and DC excitation to the discharge electrode or the test electrode respectively;

[0010] A working electrode, for transmitting a voltage signal after being stimulated, and applying the voltage signal to the flat sample;

[0011] A signal acquisition unit is used to collect the acoustic signal generated after the flat sample is applied with voltage, and obtain the charge distribution of the gas-solid interface of the insulating material according to the acoustic signal;

[0012] The working electrode is a discharge electrode or a test electrode; the discharge electrode is an electrode with uniformly distributed needle tips, and the test electrode is a flat electrode, and the other dimensions and materials of the discharge electrode and the test electrode are the same;

[0013] When measuring the charge distribution at the gas-solid interface of an insulating material, the discharge electrode is used as the working electrode. After the signal acquisition unit collects the acoustic signal generated by the discharge electrode, the discharge electrode is replaced by the test electrode. The signal acquisition unit collects the acoustic signal generated by the test electrode, and obtains the charge distribution at the gas-solid interface of the insulating material based on the acoustic signals collected twice.

[0014] In one embodiment, the external circuit unit includes a pulse source, a capacitor, a coupling resistor, a protective resistor and a DC source; one end of the pulse source is respectively connected to one end of the coupling resistor and one end of the capacitor, the other end of the pulse source is grounded, the other end of the coupling resistor is grounded, one end of the DC source is connected to one end of the protective resistor, the other end of the DC source is grounded, and the other end of the capacitor and the other end of the protective resistor are both connected to the discharge electrode or the test electrode.

[0015] In one embodiment, the signal acquisition unit includes a piezoelectric sensor, a signal amplifier, an oscilloscope and a computer; the piezoelectric sensor is connected to the oscilloscope via the signal amplifier, and the oscilloscope is connected to the computer;

[0016] The piezoelectric sensor converts the acoustic signal generated when voltage is applied to the flat sample into a voltage signal, amplifies the voltage signal through a signal amplifier and displays it on an oscilloscope, which then transmits the display data to a computer; the computer collects and processes the received data to obtain the charge distribution at the gas-solid interface of the insulating material.

[0017] In one embodiment, the electrode unit is placed in a sealed environment.

[0018] In one embodiment, the diameters of the discharge electrode and the test electrode are both smaller than the inner diameter of the epoxy pad.

[0019] In one embodiment, the flat sample is an epoxy or other polymer film.

[0020] In one embodiment, the pulse source is a nanosecond pulse source; the coupling resistor is 50Ω, and the protection resistor is greater than 5MΩ.

[0021] In a second aspect, the present invention provides an electroacoustic pulse measurement method for gas-solid interface charge of a solid insulating material, the method being applied to the system described in any embodiment of the first aspect, the method comprising:

[0022] Apply pulse excitation and DC excitation to the discharge electrode simultaneously through an external circuit unit, so that the voltage generated by the discharge electrode after the excitation is applied is fully applied to the flat sample;

[0023] The signal acquisition unit collects an acoustic signal generated after a voltage is applied to the flat sample, and determines a first space charge waveform signal;

[0024] The discharge electrode is replaced with a test electrode, and the same excitation as that during the discharge electrode test is applied to the test electrode through an external circuit unit for testing;

[0025] Determine the second space charge waveform distribution according to the acoustic signal generated by the flat sample under the corresponding test electrode collected by the signal collection unit;

[0026] The second space charge waveform signal is calibrated by the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material.

[0027] In one embodiment, calibrating the second space charge waveform signal by the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material includes:

[0028] Determining the initial electric field applied to the flat sample when collecting the second space charge waveform signal according to the initial electric field applied to the flat sample when collecting the first space charge waveform signal, the amplitude of the first space charge waveform signal, and the amplitude of the second space charge waveform signal;

[0029] Calibrate the amplitude of the second space charge waveform signal during signal processing according to the initial electric field applied to the flat sample when collecting the second space charge waveform signal;

[0030] The charge distribution at the gas-solid interface of the insulating material is obtained according to the amplitude of the calibrated second space charge waveform signal.

[0031] Optionally, a method for acquiring an initial electric field applied to the flat sample when collecting the first space charge waveform signal includes:

[0032] The ratio of the voltage applied to the discharge electrode to the thickness of the flat sample is determined as the initial electric field applied to the flat sample when the first space charge waveform signal is collected.

[0033] In a third aspect, the present invention provides an electroacoustic pulse measurement device for gas-solid interface charge of a solid insulating material, the device being applied to the system described in any embodiment of the first aspect, the device comprising:

[0034] A first excitation module is used to simultaneously apply pulse excitation and DC excitation to the discharge electrode through an external circuit unit, so that the voltage generated by the discharge electrode after the excitation is applied is fully applied to the flat sample;

[0035] A first acquisition module, used to collect the acoustic signal generated by the flat sample after the voltage is applied according to the signal acquisition unit, and determine the first space charge waveform signal;

[0036] A second excitation module is used to replace the discharge electrode with a test electrode, and to apply the same excitation as that during the discharge electrode test to the test electrode through an external circuit unit for testing;

[0037] A second acquisition module, used to determine a second spatial charge waveform distribution according to an acoustic signal generated by a flat sample under a corresponding test electrode acquired by a signal acquisition unit;

[0038] The calibration module is used to calibrate the second space charge waveform signal through the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material.

[0039] The present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the electroacoustic pulse measurement method of the gas-solid interface charge of the solid insulating material is implemented.

[0040] The present invention provides a computer device, including a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, the electroacoustic pulse measurement method of the gas-solid interface charge of the solid insulating material is implemented.

[0041] At least one of the above technical solutions adopted by the present invention can achieve the following beneficial effects:

[0042] The working electrode, epoxy plate and shielding shell are concentric, and the bottom of the working electrode is at the same level as the bottom of the shielding shell. This design can ensure the symmetry of the electric field distribution. When the external circuit unit applies excitation, the symmetrical electric field structure makes the injection and distribution of charge at the gas-solid interface more uniform and predictable; in addition, the epoxy plate can fix the working electrode and insulation, and the shielding shell and the lower electrode can play a good electromagnetic shielding role, effectively reducing the impact of external electromagnetic interference on the measurement system; the epoxy cushion layer can create an air gap between the working electrode and the flat sample and adjust the air gap height. This design can accurately control the size of the air gap; the working electrode is a discharge electrode or a test electrode, and the discharge electrode uses an electrode with uniformly distributed needle tips, and the test electrode is a flat electrode, and the other dimensions and materials of the two are consistent. This design is convenient for comparison and calibration; during the measurement process, the discharge electrode can be used to inject voltage first, and then switch to the test electrode for measurement. Due to the same size and material, except for the difference caused by the electrode shape, the influence of other factors on the measurement can offset each other. For example, the same material ensures that the conductivity of the electrodes is the same, and the difference in the material itself will not lead to different charge injection amounts and speeds, thereby improving the accuracy of the measurement. Therefore, the system can achieve accurate measurement of the gas-solid interface charge of solid insulating materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0044] Figure 1 A schematic diagram of the structure of an electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials provided by the present invention;

[0045] Figure 2 A schematic diagram of the structure of another electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials provided by the present invention;

[0046] Figure 3 A schematic diagram of the structure of another electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials provided by the present invention;

[0047] Figure 4 A schematic diagram of the structure of another electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials provided by the present invention;

[0048] Figure 5 A schematic flow chart of an electroacoustic pulse measurement method for gas-solid interface charge of a solid insulating material provided by the present invention;

[0049] Figure 6A schematic diagram of an electroacoustic pulse measurement device for gas-solid interface charge of a solid insulating material provided by the present invention;

[0050] Figure 7 A schematic diagram of a computer device for realizing an electroacoustic pulse measurement method of gas-solid interface charge of solid insulating materials provided by the present invention.

[0051] Description of reference numerals:

[0052] 101, external circuit unit; 102, electrode unit; 103, signal acquisition unit; 104, discharge electrode; 105, epoxy board; 106, shielding shell; 107, epoxy cushion layer; 108, flat sample; 109, lower electrode;

[0053] 301, test electrode;

[0054] 301. Pulse source; 302. Capacitor; 303. Coupling resistor; 304. Protection resistor; 305. DC source; 306. Piezoelectric sensor; 307. Signal amplifier; 308. Oscilloscope; 309. Computer. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. 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 making creative work are within the scope of protection of the present invention.

[0056] Studying the accumulation and dissipation characteristics of the gas-solid interface of insulating materials and understanding the mechanism of flashover along the gas-solid interface are of great significance to the reliable operation of GIL.

[0057] At present, the measurement of charge distribution at the gas-solid interface is generally divided into qualitative measurement and quantitative measurement. Qualitative measurement is generally used to support quantitative measurement results and does not meet research needs. Quantitative measurement is divided into invasive and in-situ methods. Commonly used methods include dust map method (qualitative), Pockels effect method (invasive) and electrostatic probe method (invasive). The dust map method cannot quantitatively characterize the density of surface charge, and the spraying dust will affect the original charge distribution. The Pockels effect transmission method can achieve online real-time measurement, but can only measure transparent thin film materials. The Pockels effect reflection method can be used for opaque insulating materials, but it has restrictions on material thickness and electrode materials, and is mainly used for dielectric barrier discharge, and its application is limited. The measurement probe of the electrostatic probe method will affect the charge distribution at the gas-solid interface and cannot be measured in real time. The in-situ measurement method measures the electric field distribution at the gas-solid interface, and cannot directly obtain the charge distribution at the gas-solid interface, and the test system is expensive.

[0058] The Pulsed Electro-Acoustic (PEA) method is a non-destructive measurement method for measuring the space charge of solid insulating materials. The testing principle is to apply pulse excitation to the solid insulating material to make the internal charge of the medium vibrate to generate sound waves. The sound waves propagate in two opposite directions in the medium and their amplitude is linearly related to the charge density at the location where the sound waves are generated. The sound signal transmitted to the piezoelectric sensor near the electrode is converted into an electrical signal and then analyzed (waveform recovery) to obtain the internal space charge distribution of the sample. The PEA method has the advantages of strong anti-interference ability, low cost, high sensitivity, and can still be used in the presence of corona discharge. By improving the electrode system of the PEA method, the precise measurement of the gas-solid interface charge of insulating materials can be achieved, which has great application prospects.

[0059] Based on this, the present invention provides an electroacoustic pulse measurement system for the gas-solid interface charge of solid insulating materials based on PEA, which can accurately measure the real-time charge distribution of the gas-solid interface of the insulating material under different test conditions.

[0060] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0061] The present invention provides an electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials, such as Figure 1 and Figure 2 As shown, the system includes: an external circuit unit 101, an electrode unit 102 and a signal acquisition unit 103; the electrode unit 102 includes a working electrode, an epoxy board 105, a shielding shell 106, an epoxy pad 107, a flat sample 108 and a lower electrode 109.

[0062] The external circuit unit 101 is detachably connected to the working electrode, and the working electrode is detachably embedded in the epoxy board 105. The epoxy board 105 and the shielding shell 106 are connected and fixed. The working electrode, the epoxy board 105 and the shielding shell 106 are concentric, and the lower end of the working electrode and the lower end of the shielding shell 106 are in the same horizontal plane; the epoxy cushion layer 107 is sandwiched between the shielding shell 106 and the flat sample 108, and the thickness of the epoxy cushion layer 107 is the height of the air gap between the working electrode and the flat sample 108; the flat sample 108 is fitted with the lower electrode 109, the lower electrode 109 is grounded, and connected to the signal acquisition unit.

[0063] The thickness of the epoxy pad 107 is adjustable, and the height of the air gap between the working electrode and the flat sample 108 can be controlled by changing the thickness of the epoxy pad 107. The shielding shell 107 and the lower electrode 109 can play a good electromagnetic shielding role to prevent the signal from being interfered by the environment during the test.

[0064] The external circuit unit 101 is used to simultaneously apply pulse excitation and DC excitation to the detachable connection of the working electrode; the working electrode is used to apply the voltage signal generated after the excitation is applied to the flat sample 108; the signal acquisition unit 103 is used to collect the acoustic signal generated after the voltage is applied to the flat sample 108, and obtain the charge distribution at the gas-solid interface of the insulating material based on the acoustic signal.

[0065] The epoxy board 105 is used to fix the working electrode and insulate, the shielding shell 106 is used to fix the epoxy board 105 and electromagnetic shielding, the epoxy pad 107 is used to make an air gap and adjust the air gap height, and the lower electrode 109 is used to closely contact the lower surface of the flat sample 108 and transmit acoustic signals.

[0066] The working electrode is the discharge electrode 104 or the test electrode 201. The discharge electrode 104 and the test electrode 201 can be freely disassembled and replaced. Figure 1 is a schematic diagram in which the working electrode is the discharge electrode 104, Figure 2 Schematic diagram of the working electrode being the test electrode 201. The discharge electrode 104 is an electrode with uniformly distributed needle tips, and the test electrode 201 is a flat electrode. Other dimensions and materials of the discharge electrode 104 and the test electrode 201 are the same.

[0067] When measuring the charge distribution at the gas-solid interface of insulating materials, the discharge electrode is used as the working electrode (see Figure 1 ), after the signal acquisition unit acquires the acoustic signal generated by the discharge electrode, the discharge electrode is replaced by the test electrode (see Figure 2 ), the signal acquisition unit acquires the acoustic signal generated by the test electrode, and obtains the charge distribution at the gas-solid interface of the insulating material based on the acoustic signals acquired twice.

[0068] In one embodiment, the electrode unit 102 is placed in a sealed environment. For example, the electrode unit 102 can be placed in air or other sealed environments for testing, and the air pressure and gas type are adjusted according to experimental requirements.

[0069] In one embodiment, the diameters of the discharge electrode 104 and the test electrode 201 are smaller than the inner diameter of the epoxy pad 107. The diameters of the discharge electrode 104 and the test electrode 201 should be significantly smaller than the inner diameter of the epoxy pad 107 to avoid voltage being applied to the epoxy pad 107 and affecting the test results; for example, the inner diameter of the epoxy pad 107 should be larger than the preset difference between the diameters of the discharge electrode 104 and the test electrode 201.

[0070] In one embodiment, the flat coupon 108 is an epoxy or other polymer film.

[0071] like Figure 3 As shown, the external circuit unit includes a pulse source 301, a capacitor 302, a coupling resistor 303, a protection resistor 304 and a DC source 305; one end of the pulse source 301 is respectively connected to one end of the coupling resistor 303 and one end of the capacitor 302, the other end of the pulse source 301 is grounded, the other end of the coupling resistor 303 is grounded, one end of the DC source 305 is connected to one end of the protection resistor 304, the other end of the DC source 305 is grounded, and the other end of the capacitor 302 and the other end of the protection resistor 304 are both connected to the discharge electrode 104 or the test electrode 201.

[0072] The pulse source 301 is connected to the coupling resistor 303 and the capacitor 302, and the other end of the coupling resistor 303 is grounded, the DC source 305 is connected to the protection resistor 304, and the other ends of the capacitor 302 and the protection resistor 304 are connected to the discharge electrode 104 or the test electrode 201, forming a closed loop, so that the pulse excitation and the DC excitation can be applied to the discharge electrode 104 or the test electrode 201 at the same time. The pulse excitation makes the charges in the flat sample 108 vibrate, generating an acoustic signal, which propagates in the flat sample 108 in the opposite direction.

[0073] The signal acquisition unit 103 includes a piezoelectric sensor 306 , a signal amplifier 307 , an oscilloscope 308 and a computer 309 ; the piezoelectric sensor 306 is connected to the oscilloscope 308 via the signal amplifier 307 , and the oscilloscope 308 is connected to the computer 309 .

[0074] The piezoelectric sensor 306 converts the acoustic signal generated when voltage is applied to the flat sample 108 into a voltage signal, amplifies the voltage signal through the signal amplifier 307 and displays it on the oscilloscope 308, and then the oscilloscope 308 transmits the display data to the computer 309; the computer 309 collects and processes the received data to obtain the charge distribution at the gas-solid interface of the insulating material.

[0075] Specifically, the piezoelectric sensor 306 is used to convert the acoustic signal into a voltage signal, the signal amplifier 307 is used to amplify the voltage signal, the oscilloscope 308 is used to display the voltage signal waveform, and the computer 309 is used for data acquisition and processing to output the real-time charge distribution of the gas-solid interface.

[0076] In one embodiment, the pulse source is a nanosecond pulse source; the coupling resistor is 50Ω, and the protection resistor is greater than 5MΩ. The pulse power and pulse width of the pulse source can be adjusted according to experimental requirements. For example, the pulse source can output a pulse voltage signal with a pulse width of 5 to 20ns and an amplitude of 200 to 1kV. The DC source can output a DC voltage signal of 0 to 10kV.

[0077] Among them, Figure 4 As shown, Figure 4 The structural diagram of the electroacoustic pulse measurement system for the gas-solid interface charge of solid insulating materials when the test electrode is placed.

[0078] The amplitude of the space charge waveform is proportional to the electric field applied to the flat sample. When testing only with the test electrode, the initial electric field applied to the flat sample is unknown, and the amplitude of the test waveform cannot be calibrated, which affects subsequent analysis and research. Therefore, it is necessary to use a discharge electrode to obtain the initial electric field applied to the flat sample during the test.

[0079] The following is an explanation of the measurement method corresponding to the electroacoustic pulse measurement system for the gas-solid interface charge of solid insulating materials through a specific embodiment. Figure 5 As shown, Figure 5 The present invention is a schematic flow chart of an electroacoustic pulse measurement method for gas-solid interface charge of a solid insulating material, which specifically includes the following steps:

[0080] S501, applying pulse excitation and DC excitation to the discharge electrode simultaneously through an external circuit unit, so that the voltage generated by the discharge electrode after the excitation is applied is fully applied to the flat sample, and collecting the acoustic signal generated by the flat sample after the voltage is applied according to the signal acquisition unit, to determine the first space charge waveform signal.

[0081] Before the formal test, a discharge electrode is used for testing to fully discharge the gas between the discharge electrode and the flat sample. At this time, it can be considered that the voltage applied to the discharge electrode is fully applied to the flat sample. The space charge waveform signal at this time is collected as the first space charge waveform signal, and the first space charge waveform signal can be used as a calibration waveform.

[0082] S502, replacing the discharge electrode with a test electrode, and applying the same excitation as that during the discharge electrode test to the test electrode through an external circuit unit for testing, and determining the second space charge waveform distribution based on the acoustic signal generated by the flat sample under the corresponding test electrode collected by the signal acquisition unit.

[0083] The discharge electrode is replaced with a test electrode, and the same voltage as that used in the discharge electrode test is applied thereto for testing. The space charge waveform signal at this time is collected as a second space charge waveform distribution, and the second space charge waveform distribution is used as a test waveform.

[0084] It should be noted that the voltage generated by the test electrode after being excited is not only applied to the flat sample, but also applied to the gas between the test electrode and the flat sample. The collected acoustic signal is the acoustic signal generated after the voltage is applied to the gas and the flat sample.

[0085] S503, calibrating the second space charge waveform signal by using the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material.

[0086] The insulating material includes solid insulation (flat sample) and gas insulation, and the charge distribution at the gas-solid interface of the insulating material includes the charge distribution at the flat sample and the gas insulation interface.

[0087] In one embodiment, the second space charge waveform signal is calibrated by the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material, including: determining the initial electric field applied to the flat sample when collecting the second space charge waveform signal according to the initial electric field applied to the flat sample when collecting the first space charge waveform signal, the amplitude of the first space charge waveform signal, and the amplitude of the second space charge waveform signal; calibrating the amplitude of the second space charge waveform signal during signal processing according to the initial electric field applied to the flat sample when collecting the second space charge waveform signal; and obtaining the charge distribution at the gas-solid interface of the insulating material according to the amplitude of the calibrated second space charge waveform signal.

[0088] Specifically, when collecting the first space charge waveform signal, the initial electric field applied to the flat sample is known, recorded as E0, and the amplitude of the first space charge waveform signal is recorded as P0; when collecting the second space charge waveform signal, the initial electric field applied to the flat sample is recorded as E1, and the amplitude of the second space charge waveform signal is known, recorded as P1, then E1 = (E0·P1) / P0. After obtaining the initial electric field during the test electrode test, the amplitude of the second space charge waveform signal during signal processing can be calibrated to obtain the accurate space charge distribution at the interface between the flat sample and the air gap.

[0089] Among them, the method for obtaining the initial electric field applied to the flat sample when collecting the first space charge waveform signal includes: determining the ratio of the voltage applied to the discharge electrode to the thickness of the flat sample as the initial electric field applied to the flat sample when collecting the first space charge waveform signal.

[0090] In one embodiment, the present invention further provides an electroacoustic pulse measurement method for gas-solid interface charge of solid insulating materials, the method comprising the following steps:

[0091] S601, build an electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials, including an external circuit unit, an electrode unit and a signal acquisition unit. Among them, the electrode unit first uses a discharge electrode for testing.

[0092] S602, place the electrode unit in the gas environment required for the test, connect the circuit, and turn on the oscilloscope and computer.

[0093] S603, turn on the pulse source and the DC source, and adjust specific voltage parameters according to test requirements.

[0094] S604, adjusting the oscilloscope to find the space charge waveform signal, and using a computer to collect the signal at this time as a calibration waveform.

[0095] S605, replacing the discharge electrode with the test electrode, repeating steps S602 to S604, and using a computer to collect the signal at this time as a test waveform.

[0096] S606, performing corresponding calibration and waveform recovery processing on the data on a computer to obtain the real-time charge distribution of the gas-solid interface of the insulating material.

[0097] The present invention is based on the principle of measuring the space charge of solid materials by the PEA method. By improving the electrode structure and data correction, the gas-solid interface charge measurement of insulating materials under different conditions is realized. It is helpful to study the gas-solid interface charge accumulation characteristics and influence rules, clarify the gas-solid interface surface discharge mechanism, further guide the selection and optimization of GIL insulator materials, and provide a new method for future research on the surface flashover process and insulation characteristics of high-voltage gas-insulated equipment. It has the advantages of simple structure, low cost, high sensitivity, etc.

[0098] When applying the electroacoustic pulse measurement method for solid insulating material gas-solid interface charge provided by the present invention, it is not necessary to Figure 5 The steps are executed in the order shown. The specific execution order of the steps can be determined according to needs, and the present invention does not limit this.

[0099] The above is a method for measuring the gas-solid interface charge of a solid insulating material using an electroacoustic pulse, provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding device for measuring the gas-solid interface charge of a solid insulating material using an electroacoustic pulse, such as Figure 6 shown.

[0100] Figure 6 A schematic diagram of an electroacoustic pulse measurement device for gas-solid interface charge of a solid insulating material provided by the present invention, the device 600 comprises:

[0101] The first excitation module 601 is used to simultaneously apply pulse excitation and DC excitation to the discharge electrode through an external circuit unit, so that the voltage generated by the discharge electrode after the excitation is applied is fully applied to the flat sample;

[0102] The first acquisition module 602 is used to collect the acoustic signal generated by the flat sample after the voltage is applied according to the signal acquisition unit, and determine the first space charge waveform signal;

[0103] The second excitation module 603 is used to replace the discharge electrode with the test electrode, and apply the same excitation as that during the discharge electrode test to the test electrode through the external circuit unit for testing;

[0104] The second acquisition module 604 is used to determine the second space charge waveform distribution according to the acoustic signal generated by the flat sample under the corresponding test electrode acquired by the signal acquisition unit;

[0105] The calibration module 605 is used to calibrate the second space charge waveform signal by using the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material.

[0106] The specific limitations on the electroacoustic pulse measurement device for the gas-solid interface charge of solid insulating materials can be found in the above limitations on the electroacoustic pulse measurement method for the gas-solid interface charge of solid insulating materials, which will not be repeated here.

[0107] The present invention also provides a computer-readable storage medium, which stores a computer program, which can be used to execute the above Figure 5 The invention provides an electroacoustic pulse measurement method for gas-solid interface charge of solid insulating materials.

[0108] The present invention also provides Figure 7 The structural diagram of the computer device shown in FIG. Figure 7 As shown in the figure, at the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include other hardware required for the business. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to achieve the above Figure 5 The invention provides an electroacoustic pulse measurement method for gas-solid interface charge of solid insulating materials.

[0109] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0110] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. An electroacoustic pulse measurement system for gas-solid interface charge of solid insulating materials, characterized in that: include: An external circuit unit, an electrode unit and a signal acquisition unit; the electrode unit comprises a working electrode, an epoxy board, a shielding shell, an epoxy cushion layer, a flat sample and a lower electrode; The external circuit unit is detachably connected to the working electrode, the working electrode is detachably embedded in the epoxy board, the epoxy board is connected and fixed to the shielding shell, the working electrode, the epoxy board and the shielding shell are concentric, and the lower end of the working electrode and the lower end of the shielding shell are in the same horizontal plane; the epoxy cushion layer is sandwiched between the shielding shell and the flat sample, and the thickness of the epoxy cushion layer is the height of the air gap between the working electrode and the flat sample; the flat sample is attached to the lower electrode, the lower electrode is grounded, and is connected to the signal acquisition unit; The external circuit unit is used to simultaneously apply pulse excitation and DC excitation to the discharge electrode or the test electrode respectively; The working electrode is used to transmit a voltage signal after being stimulated, and apply the voltage signal to the flat sample; The signal acquisition unit is used to collect the acoustic signal generated after the flat sample is applied with voltage, and obtain the charge distribution of the gas-solid interface of the insulating material according to the acoustic signal; The working electrode is a discharge electrode or a test electrode; The discharge electrode is an electrode with uniformly distributed needle tips, and the test electrode is a flat electrode. Other dimensions and materials of the discharge electrode and the test electrode are consistent; When measuring the charge distribution at the gas-solid interface of an insulating material, the discharge electrode is used as the working electrode. After the signal acquisition unit collects the acoustic signal generated by the discharge electrode, the discharge electrode is replaced by the test electrode. The signal acquisition unit collects the acoustic signal generated by the test electrode, and obtains the charge distribution at the gas-solid interface of the insulating material based on the acoustic signals collected twice.

2. The system according to claim 1, characterized in that The external circuit unit includes a pulse source, a capacitor, a coupling resistor, a protective resistor and a DC source; one end of the pulse source is respectively connected to one end of the coupling resistor and one end of the capacitor, the other end of the pulse source is grounded, the other end of the coupling resistor is grounded, one end of the DC source is connected to one end of the protective resistor, the other end of the DC source is grounded, and the other end of the capacitor and the other end of the protective resistor are both connected to the discharge electrode or the test electrode.

3. The system according to claim 1, characterized in that The signal acquisition unit includes a piezoelectric sensor, a signal amplifier, an oscilloscope and a computer; the piezoelectric sensor is connected to the oscilloscope through the signal amplifier, and the oscilloscope is connected to the computer; The piezoelectric sensor converts the acoustic signal generated when voltage is applied to the flat sample into a voltage signal, amplifies the voltage signal through the signal amplifier and displays it on the oscilloscope, and then the oscilloscope transmits the display data to the computer; the computer collects and processes the received data to obtain the charge distribution at the gas-solid interface of the insulating material.

4. The system according to claim 1, characterized in that The electrode unit is placed in a closed environment.

5. The system according to claim 1, characterized in that The diameters of the discharge electrode and the test electrode are both smaller than the inner diameter of the epoxy cushion layer.

6. The system according to claim 1, characterized in that The flat plate sample is an epoxy resin or other polymer film.

7. The system according to claim 1, characterized in that The pulse source is a nanosecond pulse source; the coupling resistor is 50Ω, and the protection resistor is greater than 5MΩ.

8. An electroacoustic pulse measurement method for gas-solid interface charge of solid insulating materials, characterized in that: The method is applied to the system according to any one of claims 1 to 7; the method comprises: Applying pulse excitation and DC excitation to the discharge electrode simultaneously through an external circuit unit, so that the voltage generated by the discharge electrode after the excitation is applied is fully applied to the flat sample; The signal acquisition unit collects the acoustic signal generated after the voltage is applied to the flat sample, and determines the first space charge waveform signal; The discharge electrode is replaced with a test electrode, and the same excitation as that during the discharge electrode test is applied to the test electrode through the external circuit unit for testing; Determine a second space charge waveform distribution according to an acoustic signal generated by the flat sample under the corresponding test electrode collected by a signal collection unit; The second space charge waveform signal is calibrated by the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material.

9. The method according to claim 8, characterized in that The step of calibrating the second space charge waveform signal by using the first space charge waveform signal to obtain the charge distribution at the gas-solid interface of the insulating material comprises: Determining the initial electric field applied to the flat sample when collecting the second space charge waveform signal according to the initial electric field applied to the flat sample when collecting the first space charge waveform signal, the amplitude of the first space charge waveform signal, and the amplitude of the second space charge waveform signal; calibrating the amplitude of the second space charge waveform signal during signal processing according to the initial electric field applied to the flat sample when collecting the second space charge waveform signal; The charge distribution at the gas-solid interface of the insulating material is obtained according to the amplitude of the calibrated second space charge waveform signal.

10. The method according to claim 9, characterized in that The method for acquiring the initial electric field applied to the flat sample when collecting the first space charge waveform signal includes: The ratio of the voltage applied to the discharge electrode to the thickness of the flat sample is determined as the initial electric field applied to the flat sample when the first space charge waveform signal is collected.

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