An apparatus and method for measuring space charge under a wide temperature range of oil flow electrification

Abstract

The present invention discloses a device and a measurement method for measuring space charge within a wide temperature range of oil flow electrification. The power supply of the device is connected to an external protection circuit, and the output end of the external protection circuit is connected to a liftable electrode connecting rod. An aluminum electrode is installed at the end of the electrode connecting rod extending into the box body. A fixture and an insulating paper specimen for measurement are installed at the top of the lower plate of the oil tank; a metal shielding box is installed below the lower plate, and a piezoelectric sensor, a sound-absorbing material, and an amplifier are installed inside the metal shielding box. The amplifier is connected to an oscilloscope downstream and then to a signal acquisition device. By connecting oil circulation pipelines to the side walls on both sides of the oil tank, an oil pump and a heating tape are installed on the oil circulation pipelines; the upper electrode connected to the high-voltage power supply is used in cooperation with the lower plate for testing, and the space charge distribution of the insulating paper considering the effect of oil flow electrification is measured, making up for the vacancy of not considering the factor of oil flow electrification in the measurement of the space charge of the insulating paper, meeting the precise control of temperature, electric field, and oil flow, and improving the measurement accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of high voltage and insulation, and in particular to a device and a method for measuring space charge in a wide temperature range of charged oil flow. Background Art

[0002] With the continuous improvement of voltage and capacity requirements of power systems, ultra-high and ultra-high voltage direct current transmission has been widely used and developed, becoming an important means for optimizing energy distribution in my country. In ultra-high voltage direct current transmission, converter transformers are core equipment, but due to factors such as high voltage level and uneven electric field distribution, converter transformers have a high failure rate. Data show that the failure rate of converter transformers is about twice that of ordinary power transformers, of which about 50% are caused by insulation problems.

[0003] Oil-paper insulation is one of the important insulation structures of oil-immersed transformers. Due to the strong electric field and oil-paper interface in its working environment, space charge accumulation is easy to occur inside the oil-paper insulation, which causes local electric field distortion, accelerates insulation aging, increases the risk of insulation failure, and seriously affects the safe operation of the transformer. There are many factors that affect the spatial charge distribution of the oil-paper insulation structure, including water content, aging degree, temperature, and oil flow charging. Therefore, the spatial charge distribution inside the insulation paper is studied according to different factors, the influence of various factors on the spatial charge distribution of the insulation paper is explored, and targeted transformer oil-paper insulation charge transport characteristics are proposed, so as to evaluate and predict the aging state of the transformer oil-paper, which is of great significance to ensure the safe and stable operation of power equipment.

[0004] As early as 1983, Tatsuo Takada and others in Japan proposed the electroacoustic pulse method (PEA) space charge measurement technology. Its principle is based on the Coulomb force law. By applying a narrow pulse voltage to the insulating sample, the internal space charge of the insulating sample generates Coulomb force under the action of the pulse electric field, forming a pressure pulse wave, which is then received by the piezoelectric sensor close to the electrode on the other side, and the pressure signal is converted into an electrical signal, so as to infer the internal space charge distribution of the sample based on the test and the structural parameters of the plate. Compared with other measurement methods, the PEA method has the characteristics of simple structure, convenient testing, and low cost. Therefore, it has gradually become one of the most important test methods in the field of space charge and has broad prospects.

[0005] The existing devices for measuring the space charge of insulating paper can satisfy the requirements for controlling temperature and electric field, but cannot measure the effect of the electrification of oil flow on the space charge distribution of insulating paper. Summary of the invention

[0006] Aiming at the deficiencies existing in the prior art, the present invention provides a space charge measurement device and method under a wide temperature range of oil flow electrification. This device measures the space charge distribution of insulating paper considering the effect of oil flow electrification through an oil circulation system and a tank-type PEA space charge measurement system with adjustable aluminum electrodes. The oil circulation device can achieve wide-range regulation of oil speed and oil temperature, and this device controls the temperature of the test sample by controlling the oil temperature, making its temperature distribution more uniform.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A space charge measurement device under a wide temperature range of oil flow electrification includes a power supply and a fuel tank. The fuel tank includes an end cover, side walls, and a lower electrode plate at the bottom. The two side walls of the fuel tank are connected to the two ends of the oil circulation pipeline, and a oil pump and a heating tape are installed on the oil circulation pipeline. The power supply is connected to an external protection circuit, and the output end of the external protection circuit is connected to an electrode connecting rod. The electrode connecting rod penetrates through the end cover of the fuel tank and is connected by threads at the penetration point. The end of the electrode connecting rod extending into the tank body is installed with an aluminum electrode. A clamp is installed on the top of the lower electrode plate of the fuel tank, and a test insulating paper sample is installed inside the clamp. A metal shielding box is installed below the lower electrode plate, and a PVDF piezoelectric sensor is installed at the bottom end of the lower electrode plate inside the metal shielding box. The PVDF piezoelectric sensor is installed with PMMA sound-absorbing material. The PVDF piezoelectric sensor is connected to an amplifier, and the wire downstream of the amplifier penetrates to the outside of the metal shielding box and then is connected to an oscilloscope, and the oscilloscope is connected to a computer.

[0009] As a preferred technical solution of the present invention, the power supply includes a high-voltage DC power supply and a high-voltage nanosecond pulse power supply.

[0010] As a preferred technical solution of the present invention, the external protection circuit includes a protection resistor R1, a DC-blocking capacitor C, and a coupling resistor R2. The high-voltage DC power supply is connected to the electrode connecting rod after passing through the protection resistor R1, the high-voltage nanosecond pulse power supply is connected to the electrode connecting rod after passing through the DC-blocking capacitor C, and the pulse side of the external protection circuit is grounded through the coupling resistor R2.

[0011] As a preferred technical solution of the present invention, the electrode connecting rod is an aluminum threaded rod, the aluminum electrode is disk-shaped, and a threaded hole matching the electrode connecting rod is provided at the center of the aluminum electrode, and the hole depth is 1 / 3 of the thickness of the aluminum electrode.

[0012] As a preferred technical solution of the present invention, a valve, a flowmeter, a thermometer, and an expansion joint are also installed on the oil circulation pipeline.

[0013] As a preferred technical solution of the present invention, an oil discharge pipeline is installed on the lower electrode plate of the fuel tank, and the downstream of the oil discharge pipeline is connected to an oil storage tank. The oil storage tank is located outside the metal shielding box, and the oil storage tank is connected to the oil circulation pipeline through a pipeline.

[0014] As a preferred technical solution of the present invention, the end cap is made of plexiglass;

[0015] As a preferred technical solution of the present invention, the metal shielding box is made of stainless steel, and two holes are provided on the side wall for leading out the oil discharge pipe and the lead wire of the amplifier respectively;

[0016] As a preferred technical solution of the present invention, the measurement includes the following steps:

[0017] S1: Remove the end cap of the fuel tank, fix the test sample on the lower electrode plate, fixedly connect the end cap of the fuel tank and the side wall of the fuel tank with screws, rotate the electrode connecting rod, adjust the position to keep sufficient clearance from the test sample, and read the scale on the electrode connecting rod to obtain the distance between the aluminum electrode and the test sample;

[0018] S2: Adjust the voltage values of the high-voltage DC power supply and the high-voltage nanosecond pulse power supply according to the measured distance and the required electric field strength in step S1, and adjust the power supply to the ready-to-output state;

[0019] S3: Fill the oil circulation pipeline with oil through the oil inlet pipeline, and turn on the heating tape and the thermometer;

[0020] S4: Open the valves on both sides of the oil tank, control the oil pump until the flowmeter reaches the set flow rate, and after the thermometer reaches the preset temperature, turn on the debugged high-voltage DC power supply;

[0021] S5: After reaching the set polarization time, close the valves on both sides of the oil tank, and at the same time open the oil discharge port of the lower electrode plate. After the insulating oil inside the fuel tank flows out, rotate the electrode connecting rod downward so that the aluminum electrode is closely attached to the test insulating paper;

[0022] S6: Turn on the amplifier, oscilloscope and computer, turn on the high-voltage nanosecond pulse power supply and perform synchronous acquisition of pulse signals;

[0023] S7: Perform average processing, deconvolution processing, data recovery and calibration on the collected pulse electrical signals to obtain the space charge distribution data of the test sample.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The device of the present invention connects the oil circulation pipelines to the side walls on both sides of the fuel tank, and installs an oil pump and a heating tape on the oil circulation pipelines; the upper electrode connected to the high-voltage power supply is adjusted to extend into the fuel tank and then connected to the aluminum electrode, and the aluminum electrode is used in cooperation with the lower plate for testing. The oil in the storage tank is introduced into the fuel tank, and the side walls on both sides of the fuel tank are connected to the oil circulation pipelines. The oil in the storage tank can be controllably introduced into the fuel tank through a valve and circulated, so as to measure the space charge distribution of the insulating paper considering the effect of oil flow electrification; the combined use of the liftable aluminum electrode and the oil circulation device can carry out the effect of oil flow electrification, making up for the vacancy of not considering the factor of oil flow electrification in the measurement of the space charge of the insulating paper, and being more in line with the actual working condition of the insulating paper in the oil-immersed transformer.

[0026] 2. The added oil circulation device of the present invention can realize the wide-range regulation of the oil speed and oil temperature, and the device heats the test sample by controlling the oil temperature, making the temperature distribution of the test sample more uniform.

[0027] 3. During the measurement process of the device of the present invention, the applied electric field is adjusted by adjusting the voltage values of the high-voltage DC power supply and the high-voltage nanosecond pulse power supply; through the added oil circulation device, the test temperature and the oil flow rate are accurately controlled, further improving the regulation accuracy of the field quantity factors in the measurement. Description of the Drawings

[0028] 1. High-voltage DC power supply; 2. High-voltage nanosecond pulse power supply; 3. External protection circuit; 4. Electrode connecting rod; 5. Aluminum electrode; 6. End cover; 7. Lower plate; 8. Side wall; 9. Oil discharge pipeline; 10. Metal shielding box; 11. PVDF piezoelectric sensor; 12. PMMA sound-absorbing material; 13. Amplifier; 14. Oscilloscope; 15. Computer; 16. Oil circulation pipeline; 17. Valve; 18. Oil pump; 19. Flowmeter; 20. Heating tape; 21. Thermometer; 22. Expansion joint; 23. Storage tank; 24. Pipeline; 6-1. Fixing screw for the top end cover of the fuel tank; 7-1. Test insulating paper sample; 7-2. Fixing fixture; 7-3. Fixing screw for the shielding box; 7-4. Groove of the lower plate.

[0029] Figure 1 It is a schematic diagram of the measuring device of the present invention;

[0030] Figure 2 It is a front view schematic diagram of the oil flow electrification box structure of the present invention;

[0031] Figure 3 It is a top view schematic diagram of the oil flow electrification box structure of the present invention. Detailed Embodiments

[0032] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0033] Embodiment 1:

[0034] The present invention provides a space charge measurement device for oil flow electrification in a wide temperature range, including a power supply and an oil tank. The oil tank includes an end cover 6, side walls 8, and a lower electrode plate 7 at the bottom. The two side walls 8 on both sides of the oil tank are connected to the two ends of the oil circulation pipeline 16. An oil pump 18 and a heating tape 20 are installed on the oil circulation pipeline 16; the power supply is connected to an external protection circuit 3, and the output end of the external protection circuit 3 is connected to an electrode connecting rod 4. The electrode connecting rod 4 penetrates through the end cover 6 of the oil tank and is connected by threads at the penetration point. An aluminum electrode 5 is installed at the end of the electrode connecting rod 4 extending into the tank body. A fixture 7-2 is installed on the top of the lower electrode plate 7 of the oil tank, and a test insulating paper sample 7-1 is installed inside the fixture 7-2; a metal shielding box 10 is installed below the lower electrode plate 7. A PVDF piezoelectric sensor 11 is installed at the bottom end of the lower electrode plate 7 located inside the metal shielding box 10. A PMMA sound-absorbing material 12 is installed on the PVDF piezoelectric sensor 11. The PVDF piezoelectric sensor 11 is connected to an amplifier 13. The amplifier 13 is a low-noise signal amplifier. The wire downstream of the amplifier 13 penetrates to the outside of the metal shielding box 10 and then is connected to an oscilloscope 14. The oscilloscope 14 is connected to a computer 15.

[0035] The power supply includes a high-voltage DC power supply 1 with a DC voltage and a high-voltage nanosecond pulse power supply 2. The high-voltage DC power supply 1 and the high-voltage nanosecond pulse power supply 2 are connected to the external protection circuit 3.

[0036] As Figure 1 shown, the power supply and the protection device are divided into two parts: the DC side and the pulse side. The high-voltage DC power supply 1 is connected to the electrode connecting rod 4 after passing through a protection resistor R1, and the high-voltage nanosecond pulse power supply 2 is also connected to the electrode connecting rod 4 after passing through a DC-blocking capacitor C. In addition, the pulse side is grounded through a coupling resistor R2. The upper part of the electrode connecting rod 4 is provided with a flat mouth, which is convenient for clamping and rotating with an insulating wrench; the wire connected to the electrode connecting rod 4 is a flexible wire to avoid interference during the rotation of the electrode connecting rod 4. A rotating conductive ring can also be provided at the connection between the wire and the external protection circuit 3 to eliminate the wire winding phenomenon caused by the rotation of the electrode connecting rod 4. The rotating conductive ring can be commercially purchased and is an existing technology.

[0037] The oil circulation pipeline 16 is connected to the side wall 8 of the fuel tank. The valve 17 is used to control the injection of oil into the fuel tank through the oil circulation pipeline. The oil pump 18 is used to control the oil flow rate. The flowmeter 19 is used to detect the oil flow rate. The heating tape 20 is used to heat the oil temperature. The thermometer 21 is used to detect the oil temperature inside the fuel tank. The expansion joint 22 is used to eliminate the leakage current caused by oil flow electrification. The storage tank 23 is used to store insulating oil, and the storage tank 23 is connected to the oil circulation pipeline 16 through the pipeline 24.

[0038] The metal shielding box 10 is connected to the lower aluminum electrode plate 7, which is used to shield low-frequency interference signals. The PVDF piezoelectric sensor 11 is connected to the lower aluminum electrode plate 7, which is used to collect pressure pulse signals. The PMMA sound-absorbing material 12 is connected to the PVDF piezoelectric sensor 11, which is used to prevent echo interference. The amplifier 13 is connected to the PVDF piezoelectric sensor 11, which is used to amplify signals. The oscilloscope 14 is connected to the amplifier 13 and is used to collect signals. The computer 15 is used to analyze data.

[0039] The end cover 6 of the fuel tank is made of plexiglass, which plays an insulating and protective role. There are threaded slotted holes in the middle part, which are tightly connected to the threaded liftable electrode connecting rod 4. At its four vertices, it is sealed and fixed to the side wall 8 of the transparent fuel tank by a nut structure.

[0040] The side wall 8 of the fuel tank is made of plexiglass and is directly sealed and fixedly connected to the lower aluminum electrode plate 7 by a groove structure, and it is non-removable.

[0041] Threaded hole structures are provided at the edges of the lower aluminum electrode plate 7 and are threadedly connected to the oil drain pipeline 9, so that the insulating oil in the fuel tank can be drained into and stored in the storage tank 23.

[0042] The metal shielding box 10 is made of stainless steel, and there are two holes on the side wall, which are respectively used to lead out the oil drain pipeline 9 and the lead wire of the amplifier 13.

[0043] As Figure 1 、 Figure 2 shown, the liftable electrode connecting rod 4 is an aluminum threaded rod. There is a threaded hole at the center of the aluminum electrode 5, which is matched with the electrode connecting rod 4. The depth of the hole is 1 / 3 of the thickness of the aluminum electrode 5. During the test, the electrode connecting rod 4 is tightly connected to the aluminum electrode.

[0044] As Figure 2 , Figure 3 shown, the center lines of the electrode connecting rod 4, the aluminum electrode 5, the upper end cover 6 of the fuel tank, the insulating specimen 7-1, and the lower electrode plate 7 coincide. There is a through threaded hole at the center of the upper end cover 6 of the fuel tank, and the inner diameter of the hole is the same as that of the electrode connecting rod 4, which plays a role in fixing and adjusting the height of the upper electrode plate.

[0045] As Figure 1 、Figure 2 As shown, scale lines are provided on the electrode connecting rod 4. When it is in close contact with the lower electrode plate 7, the recorded scale is d1. The electrode connecting rod 4 can be rotated according to the required distance to adjust the electrode connecting rod to scale d2. The difference between the two scales is the distance Δd between the upper and lower electrode plates.

[0046] As Figure 2 、 Figure 3 shown, an insulating specimen 7-1 is placed at the center of the lower electrode plate 7, and the four corners of the insulating specimen are fixed by insulating clamps 7-2 on the lower electrode plate 7.

[0047] As Figure 2 、 Figure 3 shown, the lower electrode plate 7 is provided with a groove structure 7-4, and the shape of the groove is exactly the same as the side wall 8 of the oil tank. During processing, it is sealed and cannot be disassembled after sealing to ensure the tightness of the oil flow electrification box.

[0048] As Figure 2 、 Figure 3 shown, the upper end cover of the oil tank and the side wall of the oil tank are fixed by screws 6-1 at the four corners, which is convenient for disassembling and replacing test samples.

[0049] As Figure 1 、 Figure 2 、 Figure 3 shown, holes are provided at the corners of the lower electrode plate 7 and are connected to the storage tank 24 through the oil discharge pipeline 9.

[0050] As Figure 2 、 Figure 3 shown, the lower electrode plate 7 and the metal shielding box are fixed by screws 7-2 at the four corners.

[0051] As Figure 1 、 Figure 2 shown, valves 17 are respectively provided in the pipelines extending from both sides of the side wall 8 of the oil tank. After the oil flow electrification effect is completed, the valves can be closed, and the insulating oil in the oil tank will no longer flow. Then, the valve on the oil discharge pipeline 9 is opened, and after the oil in the oil tank is drained, the space charge test is carried out.

[0052] As Figure 1 shown, the PVDF piezoelectric sensor 11 is closely attached to the center position on the lower side of the lower electrode plate, the PMMA sound-absorbing material 12 is closely attached to the lower side of the PVDF piezoelectric sensor 11, and the low-noise amplifier 13 is connected to the PVDF piezoelectric sensor 11.

[0053] As Figure 1 shown, the PVDF piezoelectric sensor 11, the PMMA sound-absorbing material 12, and the low-noise amplifier 13 are all built into the metal shielding box 10. Two through holes are provided on the side wall of the metal shielding box 10 to provide channels for the oil discharge pipe 9 and the signal line of the low-noise amplifier 13 respectively.

[0054] As Figure 1 shown, the amplifier 13 is connected to the oscilloscope 14 to collect piezoelectric sensor data.

[0055] As Figure 1 and Figure 2 shown, the oil circulation device is provided with a heating tape 20. The heated insulating oil flows in the circulation pipeline and the oil flow electrification box for oil bath heating. Thermometers 21 are respectively arranged in the pipelines extending from both sides of the side wall 8 of the fuel tank to detect the oil temperature. During the test, the average value of the temperatures on both sides is considered as the test temperature.

[0056] As Figure 1 and Figure 2 shown, the oil circulation device is provided with an oil pump 18 to provide power for the oil circulation pipeline device. A flow meter 19 is arranged in the oil circulation pipeline 16 near the fuel tank to detect the oil flow velocity during the test.

[0057] As Figure 1 shown, the oil circulation device is provided with an expansion joint 22, which adopts a metal mesh structure and is grounded to eliminate the charges carried away by the oil under the action of oil flow electrification.

[0058] As Figure 1 shown, the oil circulation device is provided with a two-way oil pipeline 24. At the beginning of the test, the oil in the storage tank 23 is injected into the oil circulation pipeline through it. After the test, the oil in the oil circulation device is discharged into the storage tank 23 for storage.

[0059] Example 2:

[0060] In this embodiment, the present invention also provides a method for measurement using a space charge measurement device under a wide temperature range of oil flow electrification, including the following steps:

[0061] S1: Remove the end cover 6 of the fuel tank, fix the test sample on the lower electrode plate 7, fixedly connect the end cover 6 of the fuel tank to the side wall 8 of the fuel tank with screws, rotate the electrode connecting rod 4, adjust the position to leave enough gap with the test sample, and read the scale on the electrode connecting rod 4 to obtain the distance between the aluminum electrode 5 and the test sample;

[0062] S2: Adjust the voltage values of the high-voltage DC power supply 1 and the high-voltage nanosecond pulse power supply 2 according to the measured distance and the required electric field strength in step S1, and adjust the power supply to the ready-to-output state;

[0063] S3: Fill the oil circulation pipeline 16 with oil through the oil inlet pipeline 24, and turn on the heating tape 20 and the thermometer 21;

[0064] S4: Open the valves 17 on both sides of the oil tank, control the oil pump 18 until the flowmeter 19 reaches the set flow rate, and after the thermometer 21 reaches the preset temperature, turn on the adjusted high-voltage DC power supply 1;

[0065] S5: After reaching the set polarization time, close the valves 17 on both sides of the oil tank. At the same time, open the oil drain port of the lower electrode plate 7. After the insulating oil inside the oil tank has flowed out, rotate the electrode connecting rod 4 downward so that the aluminum electrode 5 is closely attached to the insulating paper to be measured;

[0066] S6: Turn on the amplifier 13, oscilloscope 14 and computer 15, turn on the high-voltage nanosecond pulse power supply 2 and perform synchronous acquisition of pulse signals;

[0067] S7: Perform average processing, deconvolution processing, data restoration and calibration on the collected pulse electrical signals to obtain the sample space charge distribution data.

[0068] The present invention illustrates the technical concept of the present invention through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that the relevant improvements to the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A space charge measurement device for oil flow electrification under a wide temperature range, comprising a power supply and an oil tank. The oil tank includes an end cover (6), a side wall (8), and a lower electrode plate (7) at the bottom, and is characterized in that, The side walls (8) on both sides of the fuel tank are connected to both ends of the oil circulation pipeline (16). A fuel pump (18) and a heating tape (20) are installed on the oil circulation pipeline (16); the power supply is connected to the external protection circuit (3). The output end of the external protection circuit (3) is connected to the electrode connecting rod (4). The electrode connecting rod (4) penetrates through the end cover (6) of the fuel tank and is threadedly connected at the penetration point. An aluminum electrode (5) is installed at the end of the electrode connecting rod (4) extending into the tank body. A fixture (7-2) is installed on the top of the lower plate (7) of the fuel tank, and a test insulating paper sample (7-1) is installed inside the fixture (7-2); a metal shielding box (10) is installed below the lower plate (7). A PVDF piezoelectric sensor (11) is installed at the bottom end of the lower plate (7) located inside the metal shielding box (10). A PMMA sound-absorbing material (12) is installed on the PVDF piezoelectric sensor (11). The PVDF piezoelectric sensor (11) is connected to an amplifier (13). The wire downstream of the amplifier (13) penetrates outside the metal shielding box (10) and then is connected to an oscilloscope (14), and the oscilloscope (14) is connected to a computer (15); the external protection circuit (3) includes a protection resistor R1, a DC-blocking capacitor C, and a coupling resistor R2; the power supply includes a high-voltage DC power supply (1) and a high-voltage nanosecond pulse power supply (2). The high-voltage DC power supply (1) is connected to the electrode connecting rod (4) after passing through the protection resistor R1, and the high-voltage nanosecond pulse power supply (2) is connected to the electrode connecting rod (4) after passing through the DC-blocking capacitor C. The pulse side of the external protection circuit (3) is grounded through the coupling resistor R2; a drain pipe (9) is installed on the lower plate (7) of the fuel tank. The downstream of the drain pipe (9) is connected to an oil storage tank (23). The oil storage tank (23) is located outside the metal shielding box (10). The oil storage tank (23) is connected to the oil circulation pipeline (16) through a pipeline (24); the metal shielding box (10) is made of stainless steel, and two holes are provided on the side wall for leading out the drain pipe (9) and the lead wire of the amplifier (13); valves (17), flow meters (19), thermometers (21), and expansion joints (22) are also installed on the oil circulation pipeline (16).

2. The space charge measurement device for oil flow electrification under a wide temperature range according to claim 1, wherein The electrode connecting rod (4) is an aluminum threaded rod. The aluminum electrode (5) is disc-shaped. A threaded hole matching the electrode connecting rod (4) is provided at the center of the aluminum electrode (5), and the hole depth is 1 / 3 of the thickness of the aluminum electrode (5).

3. The space charge measurement device for oil flow electrification under a wide temperature range according to claim 1, wherein The end cover (6) is made of organic glass material.

4. A method for measurement using the space charge measurement device for oil flow electrification within a wide temperature range according to any one of claims 1 - 3, characterized in that, It includes the following steps: S1: Remove the end cover (6) of the fuel tank, fix the test sample on the lower plate (7), fixedly connect the end cover (6) of the fuel tank and the side wall (8) of the fuel tank with screws, rotate the electrode connecting rod (4), adjust the position to leave enough gap with the test sample, read the scale on the electrode connecting rod (4), and obtain the distance between the aluminum electrode (5) and the test sample. S2: Adjust the voltage values of the high-voltage DC power supply (1) and the high-voltage nanosecond pulse power supply (2) of the power supply according to the measured spacing and the required electric field strength in step S1, and adjust the power supply to the ready-to-output state; S3: Fill the oil circulation pipeline (16) with oil through the oil inlet pipeline (24), and turn on the heating tape (20) and the thermometer (21); S4: Open the valves (17) on both sides of the oil tank, control the oil pump (18) until the flowmeter (19) reaches the set flow rate, and after the thermometer (21) reaches the preset temperature, turn on the adjusted high-voltage DC power supply (1); S5: After reaching the set polarization time, close the valves (17) on both sides of the oil tank, and at the same time open the oil drain port of the lower electrode plate (7). After the insulating oil inside the oil tank runs out, rotate the electrode connecting rod (4) downward so that the aluminum electrode (5) is closely attached to the insulating paper to be tested; S6: Turn on the amplifier (13), oscilloscope (14) and computer (15), turn on the high-voltage nanosecond pulse power supply (2) and perform synchronous acquisition of pulse signals; S7: Perform average processing, deconvolution processing, data recovery and calibration on the collected pulse electrical signals to obtain the sample space charge distribution data.

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