Insulating material aging test system and method

Abstract

The invention discloses an aging test system and method for an insulating material, and belongs to the technical field of insulating material tests.The system is characterized in that a box body is maintained at a preset temperature through a temperature controller, and meanwhile corona discharge is generated under a preset voltage through a direct-current power source and an electrode system; ionic charges are migrated into the insulating material under the action of an electric field, synchronous application of the temperature and the electric field is realized, the real service environment of the insulating material in equipment such as a cable and the like is accurately reproduced, and aging test results under various working conditions can be obtained by setting different preset temperatures and different preset voltages. Evaluation of the aging rule of the insulation performance of the insulation material under the thermal-electric coupling effect can be achieved, the accuracy of the aging test of the insulation material is improved, and therefore the maintenance cost and the safety risk are reduced. Through implementation of the method, the problem that a test result and an actual aging state have deviation due to the fact that only single-factor evaluation can be carried out in a traditional method is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation material testing, and in particular to an insulation material aging testing system and method. Background Art

[0002] Aging testing of insulation materials is an important means of evaluating their performance degradation in practical applications. By simulating the environmental conditions in which the materials are exposed and monitoring performance changes, this provides a basis for material selection and equipment maintenance. Accurately testing and evaluating the aging state of insulation materials can proactively identify performance degradation trends, prevent equipment failures caused by insulation failure, and ensure the safe and stable operation of power systems and other fields.

[0003] However, traditional insulation material aging testing technology usually uses a single factor, such as only applying temperature or only applying an electric field for aging simulation. However, insulation materials in power equipment (such as cables) are subjected to the simultaneous influence of electrical stress and temperature rise for a long time. Traditional technology is difficult to accurately simulate the actual aging process of insulation materials under the coupling of temperature and electric field, resulting in deviations between test results and actual aging status. Equipment maintenance personnel are unable to formulate maintenance strategies based on test data science, which may cause equipment failures due to inaccurate insulation material aging assessments, increasing maintenance costs and safety risks. Summary of the Invention

[0004] The embodiments of the present invention provide an aging test system and method for insulating materials, which can evaluate the aging law of the insulating performance of insulating materials under the action of thermal-electric coupling, are more in line with the working conditions of the dual effects of electricity and heat faced by insulating materials in actual operation, improve the accuracy, reliability and efficiency of the aging test of insulating materials, and can effectively solve the problem in the prior art that only single-factor evaluation can be performed, resulting in deviations between the test results and the actual aging status.

[0005] An embodiment of the present invention provides an aging test system for insulating materials, comprising: a potentiometer, a host computer, and a box provided with a temperature controller; the box is provided with: a DC power supply, an electrode system, and a probe;

[0006] The temperature controller is used to control the temperature of the box to a preset temperature;

[0007] The host computer is used to control the DC power supply to supply power to the electrode system so that the electrode system performs corona discharge at a preset voltage; wherein the ionic charges generated by the corona discharge migrate to the surface of the insulating material under the action of the electric field and fill the interior of the insulating material;

[0008] The probe is used to detect the potential signal on the surface of the insulating material after the electrode system completes the corona discharge, and then send the detected potential signal to the potentiometer;

[0009] The potentiometer is used to convert the received potential signal into potential data and send the potential data to the host computer;

[0010] The host computer is further used to generate a potential attenuation curve of the insulating material at a preset temperature and a preset voltage based on the attenuation amplitude of the potential in the potential data; and output an aging law of the insulating material at a preset temperature and a preset voltage based on the potential attenuation curve.

[0011] Preferably, the electrode system is provided with a first electrode, a second electrode and a third electrode; wherein the third electrode is in contact with the bottom of the insulating material and is grounded via a wire;

[0012] The first electrode is used to generate a corona discharge;

[0013] The second electrode is used to regulate the flow of ionic charges generated by corona discharge to the insulating material;

[0014] The third electrode is used to attract the trapped charges.

[0015] Preferably, the diameter of the first electrode is 1 mm, and the curvature radius of the tip of the first electrode is 15 μm.

[0016] Preferably, the vertical distance between the first electrode and the second electrode, and the vertical distance between the second electrode and the insulating material are both 5 mm.

[0017] Preferably, the probe is a vibrating capacitance probe.

[0018] Preferably, the box is further provided with a humidity controller;

[0019] The humidity controller is used to control the humidity of the box to a preset humidity.

[0020] Preferably, the temperature controller adjusts the temperature of the box through a PID temperature control algorithm.

[0021] Preferably, the vertical distance between the probe and the insulating material is 3 mm.

[0022] Preferably, it further comprises: a resistor;

[0023] The DC power supply is connected to the resistor and the first electrode in sequence.

[0024] Based on the above-mentioned system embodiment, the present invention provides corresponding method embodiments.

[0025] An embodiment of the present invention provides an aging test method for an insulating material, which is applied to a host computer in an aging test system for an insulating material;

[0026] The aging test method comprises:

[0027] Controlling the DC power supply to supply power to the electrode system so that the electrode system performs corona discharge at a preset voltage;

[0028] Obtain the potential data of the insulating material after the electrode system completes corona discharge;

[0029] generating a potential decay curve of the insulating material at a preset temperature and a preset voltage according to the potential decay amplitude in the potential data;

[0030] According to the potential decay curve, the aging law of the insulating material at the preset temperature and the preset voltage is output.

[0031] The following beneficial effects are achieved by implementing the present invention:

[0032] An embodiment of the present invention provides an aging test system and method for insulating materials. The aging test system of the present invention maintains the box at a preset temperature through a temperature controller, and uses a DC power supply and an electrode system to generate corona discharge at a preset voltage, so that the ionic charge migrates to the interior of the insulating material under the action of the electric field, thereby realizing the synchronous application of temperature and electric field, accurately reproducing the actual service environment of the insulating material in equipment such as cables, and can obtain aging test results under various working conditions by setting different preset temperatures and different preset voltages, thereby solving the problem of disconnection between test conditions and actual working conditions in traditional technologies. The charge injection generated by corona discharge interacts with the temperature-induced material molecular motion, which can simulate the insulation degradation process caused by the electro-thermal synergy during long-term operation, making the test results closer to the actual aging state. Finally, the host computer generates a potential decay curve based on the potential data, and quantifies the degree of aging by the decay amplitude. The dynamic relationship between charge injection and decay during the aging process can be dynamically tracked, and the aging law under the temperature-electric field coupling can be derived, providing a scientific basis for equipment maintenance strategies. Compared with the existing technology, the present invention can realize the evaluation of the aging law of the insulation performance of insulating materials under the action of thermal-electric coupling, breaking through the limitation of traditional methods that can only perform single-factor evaluation. It is more in line with the working conditions of the dual effects of electricity and heat faced by insulating materials in actual operation, improving the accuracy, reliability and efficiency of the aging test of insulating materials, providing a more scientific basis for equipment maintenance, thereby reducing maintenance costs and safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a schematic structural diagram of an aging test system for insulating materials provided by one embodiment of the present invention.

[0034] Figure 2 It is a structural diagram of an aging test system provided by another embodiment of the present invention.

[0035] Figure 3 4 is a graph showing the potential attenuation characteristics of an insulating material provided by an embodiment of the present invention.

[0036] Figure 4 is a graph showing the potential attenuation characteristics of an insulating material provided by another embodiment of the present invention.

[0037] Figure 5 The figure is a flow chart of an aging test method for an insulating material provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] like Figure 1 As shown, in order to solve the problem in the prior art that it is difficult to accurately simulate the actual aging process of insulating materials under the coupling of temperature and electric field, resulting in deviation between the test results and the actual aging state, an embodiment of the present invention provides an aging test system for insulating materials, comprising: a potentiometer, a host computer, and a box with a temperature controller; the box is further provided with: a DC power supply, an electrode system, and a probe;

[0040] The temperature controller is used to control the temperature of the box to a preset temperature;

[0041] The host computer is used to control the DC power supply to supply power to the electrode system so that the electrode system performs corona discharge at a preset voltage; wherein the ionic charges generated by the corona discharge migrate to the surface of the insulating material under the action of the electric field and fill the interior of the insulating material;

[0042] The probe is used to detect the potential signal on the surface of the insulating material after the electrode system completes the corona discharge, and then send the detected potential signal to the potentiometer;

[0043] The potentiometer is used to convert the received potential signal into potential data and send the potential data to the host computer;

[0044] The host computer is further used to generate a potential attenuation curve of the insulating material at a preset temperature and a preset voltage based on the attenuation amplitude of the potential in the potential data; and output an aging law of the insulating material at a preset temperature and a preset voltage based on the potential attenuation curve.

[0045] Illustratively, the embodiment of the present invention maintains the box at a preset temperature through a temperature controller, and uses a DC power supply to make the electrode system perform corona discharge at a preset voltage, thereby constructing an aging environment in the box where temperature and corona discharge (electric field, ion charge) work together. This can simulate the temperature and electric field coupled aging scenarios faced by insulating materials in actual applications (such as high-voltage electrical equipment), making the test conditions closer to actual working conditions.

[0046] In a preferred embodiment, the preset temperature and voltage parameters can be adjusted according to actual conditions, and the test conditions are ensured to be consistent each time, which facilitates the comparative analysis of the aging characteristics of different insulating materials or the same material under different conditions, thereby improving the reliability and repeatability of the test results.

[0047] In the test system of the present invention, a dynamic process of charge accumulation and decay can be realized. For example, charge accumulation can be realized in the charging stage, that is, through corona discharge, the charge can be deposited on the surface of the material and enter the internal trap to form a surface potential.

[0048] In the decay stage, by removing the charging voltage, the charges in the traps of the insulating material are detrapped and migrated under the action of the electric field and thermal vibration, resulting in the decay of the surface potential.

[0049] It is understood that the embodiments of the present invention use an electrode system to perform corona discharge charging on insulating material samples, simulating the charge injection phenomenon that occurs when insulating materials are subjected to high electric fields in power equipment. This phenomenon, for example, occurs when cable insulation is subjected to partial discharge or electric field concentration during operation, leading to charge accumulation. The electric field promotes charge migration, while rising temperature accelerates charge thermal vibrations, both of which jointly influence the probability of desorption and the migration rate.

[0050] Furthermore, the surface potential decay curve of the insulating material at different temperatures and voltages is recorded by a probe and a surface potentiometer, and the potential decay curve can record the decay speed and decay amplitude of the potential.

[0051] If the surface potential decay rate accelerates, it means that under the combined action of high temperature and high electric field, charge trapping is more frequent, molecular chain breakage is aggravated, and the trap distribution and conductive properties of the insulating material are deteriorated, thereby reflecting a decrease in its insulation performance. The present invention analyzes the potential decay curve through the host computer and can output the aging law of the insulating material at a preset temperature and preset voltage.

[0052] Schematically, after receiving the surface potential data recorded by the potentiometer, the host computer processes and analyzes it, calculating parameters such as the surface potential decay rate and decay amplitude. Based on this processed data, it generates surface potential decay curves at different temperatures and voltage levels. This analysis then reveals the distribution characteristics of traps caused by corona discharge, thereby revealing the degradation patterns of the insulation material.

[0053] Specifically, assume the test conditions are:

[0054] Insulation material: a certain type of cross-linked polyethylene (XLPE, commonly used for cable insulation);

[0055] Preset temperature: 80°C (simulating high temperature operating environment);

[0056] Preset voltage: 10kV (DC voltage, causing the electrode system to generate corona discharge);

[0057] Test duration: After 1 hour of corona discharge, the surface potential decay is monitored continuously for 24 hours.

[0058] After the corona discharge ends, the probe continuously detects the potential signal on the XLPE surface, which is converted into potential data by the potentiometer and sent to the host computer. Assume that the potential data at some key time points are as follows (unit: kV):

[0059]

[0060] The host computer uses "time" as the horizontal axis (X-axis) and "potential value" as the vertical axis (Y-axis) to fit the above data into a continuous curve, namely the potential decay curve;

[0061] The host computer analyzes the material aging status through curve characteristics (such as decay rate, final residual potential, etc.). The specific logic is as follows:

[0062] As insulating materials age, more micro-defects (such as cracks and bubbles) and polar groups will be generated inside. These defects will accelerate charge migration (charges are more likely to leak through defects), causing the surface potential to decay faster.

[0063] If the XLPE is a new, unaged sample, the potential may remain at 1.0 kV after 24 hours under the same conditions (decaying slowly). However, in this test, the potential remained at only 0.3 kV after 24 hours (decaying faster), indicating that the material has aged to a certain extent.

[0064] Combining the curve trend and characteristic parameters, the host computer can output the aging law of the XLPE under the condition of "80℃+10kV":

[0065] Under 10kV corona at 80°C, the surface potential of the XLPE material decayed rapidly, with a 24-hour potential residual rate of only 6% and a half-life of 3 hours. This indicates that the coupling of high temperature and electric field accelerates the generation of internal defects in the material, leading to an increase in charge leakage and significant material aging, which is primarily manifested in an increase in microscopic defects within the insulation.

[0066] In a preferred embodiment, the electrode system comprises a first electrode, a second electrode and a third electrode; wherein the third electrode is in contact with the bottom of the insulating material and is grounded via a wire;

[0067] The first electrode is used to generate a corona discharge;

[0068] The second electrode is used to regulate the flow of ionic charges generated by corona discharge to the insulating material;

[0069] The third electrode is used to attract the trapped charges.

[0070] In a preferred embodiment, the diameter of the first electrode is 1 mm, and the radius of curvature of the tip of the first electrode is 15 μm.

[0071] Schematically, the first electrode is a needle electrode, the second electrode is a gate electrode, and the third electrode is a ground electrode, and the ground electrode serves as a ground electrode plate for supporting the insulating material to be tested. Preferably, the ground electrode uses copper foil as the electrode material.

[0072] Schematically, the ground electrode is located at the bottom of the insulating material sample. Its material is copper foil (a thin sheet of metal copper). It is grounded through a wire to form the low potential end of the entire electrode system.

[0073] It is understood that the electrode system of the present invention is a needle-grid-plate electrode system, which is used to charge the sample in a corona discharge manner, wherein the needle electrode has a diameter of 1 mm and a tip curvature radius of 15 μm.

[0074] In a preferred embodiment, the vertical distance between the first electrode and the second electrode, and the vertical distance between the second electrode and the insulating material, are both 5 mm. For example, it can be understood that the vertical distance between the tip of the needle electrode and the gate electrode is 5 mm, and the vertical distance between the gate electrode and the top of the sample (i.e., the top surface of the sample) is 5 mm.

[0075] In the embodiments of the present invention, the corona discharge principle is based on the following: when a DC power supply applies a high voltage (e.g., 10kV or 12kV) to a needle electrode, the extremely small radius of curvature of the needle electrode tip creates an extremely high local electric field intensity, ionizing the surrounding air and generating a corona discharge. At this point, molecules in the air are ionized into positive and negative ions.

[0076] Under the influence of the electric field, the ionic charge generated by ionization migrates through the gate electrode to the sample surface and deposits. Subsequently, through a process of exchange between the surface and the interior of the material, the charge is filled into the charge traps within the insulating dielectric (charge capture sites formed by molecular chain defects, impurities, etc.), thereby charging the sample. For example, the needle voltage can be controlled at 10kV and 12kV, and the gate voltage at 5kV and 7kV, respectively, to examine the trap distribution characteristics at different voltages.

[0077] Therefore, the present invention uses the above process to simulate the charge injection phenomenon of insulating materials subjected to high electric fields in power equipment, such as the charge accumulation caused by partial discharge or electric field concentration in cable insulation during operation. Furthermore, the present invention's pin-grid-plate electrode system, combined with a DC power supply and a housing capable of maintaining different temperatures, can control the intensity of corona discharge and the amount of charge injection at different temperatures (30°C to 120°C) and voltage levels (10kV / 12kV pin voltage). Furthermore, the surface potential decay curve can be used to analyze the insulation degradation pattern under thermal-electrical coupling.

[0078] Furthermore, the ionic charges generated by the needle electrode corona discharge eventually deposit on the sample surface, enter the sample interior through an exchange process, and fill the charge traps within the insulating medium. After the corona discharge charging is completed, the trapped charges are released by the electric field and the thermal vibration of the charges, migrating to the ground electrode, causing the surface potential to decay. If the ground electrode is above the sample, the ionic charges generated by the needle electrode corona discharge cannot be deposited on the sample surface and will directly migrate to the ground electrode. The reason why the present invention uses copper foil as the ground electrode is that it has a low resistivity and good conductivity of 1.68×10-8Ω.m, second only to silver and far superior to nickel and molybdenum, which can significantly reduce impedance and improve signal integrity; it has high thermal conductivity, which easily releases the heat of the discharge; and it is low cost, far lower than gold and silver.

[0079] In a preferred embodiment, the probe is a vibrating capacitance probe. Schematically, the probe of the present invention can be a Kelvin-type vibrating probe (also known as a vibrating capacitance probe), which measures the surface potential of the sample after corona discharge by measuring the potential difference between the sample to be tested and the probe. A TREK-6000B-5C, Monroe 244A, or Keyence ST-505 probe can be selected; more preferably, the TREK-6000B-5C probe is used.

[0080] In a preferred embodiment, the potentiometer is a surface potentiometer, which is used to record the surface potential of the test material. One of the TREKMODEL347-3HCE, Monroe284A or KeyenceST-403 models can be selected, or the TREKMODEL347-3HCE model can be used as the potentiometer.

[0081] In a preferred embodiment, the box is further provided with a humidity controller; the humidity controller is used to control the humidity of the box to a preset humidity.

[0082] Furthermore, the temperature controller adjusts the temperature of the box through a PID temperature control algorithm.

[0083] It is understood that the box environment of the present invention can be set to a constant temperature and humidity environment through a humidity controller and a temperature controller, so that the test experiment of the insulation material can be carried out in the constant temperature and humidity box, and the upper computer generates the insulation material at a preset temperature according to the attenuation amplitude of the potential in the potential data. , preset humidity And the potential decay curve under the preset voltage; according to the potential decay curve, the output insulation material at the preset temperature , preset humidity And the aging law under the preset voltage.

[0084] Illustratively, the humidity control can maintain the humidity environment of the box at 30% humidity, and the temperature controller maintains the temperature of the box at 30 degrees, 60 degrees, 90 degrees, and 120 degrees respectively to obtain the trap distribution characteristics of the insulating material under different temperatures.

[0085] In a preferred embodiment, the vertical distance between the probe and the insulating material is 3 mm. Schematically, the vertical distance between the Kelvin probe and the sample surface is 3 mm. This is determined by the probe's operating principle: a Kelvin-type vibrating probe measures surface potential by detecting the potential difference between the sample and the probe. A 3 mm distance ensures that the probe senses sufficient electric field signals while preventing contact between the probe and the sample, which could affect measurement accuracy.

[0086] The testing process of the present invention is:

[0087] Insulating material samples were prepared for testing, measuring 100 mm × 25 mm × 4 mm (length × width × thickness). Experiments were conducted in a constant temperature and humidity chamber, with humidity maintained at 30%. The temperature controller was adjusted to maintain temperatures at 30, 60, 90, and 120 degrees Celsius to determine the trap distribution characteristics under different temperatures. The needle voltage was controlled at 10 kV or 12 kV, and the gate voltage at 5 kV or 7 kV to examine the trap distribution characteristics under different voltages.

[0088] The insulating material sample is charged by corona discharge. The corona discharge charging time is 5 minutes. After charging is completed, the sample and temperature controller are moved to the bottom of the Kelvin type vibrating probe with a vertical distance of 3 mm between them. The surface potential test recording time is 30 minutes.

[0089] Therefore, the embodiment of the present invention changes the variation law of the sample surface potential by setting different voltage levels and different temperatures, so as to obtain the trap distribution characteristics caused by corona discharge at different temperatures and different voltage levels, thereby deriving the aging law of the insulating material under different thermal aging temperatures and different voltage levels.

[0090] In an embodiment of the present invention, after the corona discharge charging is completed, the insulating material sample needs to be moved together with the temperature controller (such as a temperature sensor, a heating plate control module, etc.) to the bottom of the Kelvin probe to ensure that the sample is still within the monitoring and adjustment range of the temperature controller during the surface potential detection stage, so that the sample temperature can be maintained at a preset value (such as 30°C, 60°C, etc.), ensuring that the temperature is constant during the surface potential decay process, and avoiding the impact of temperature fluctuations on charge trapping and migration rates.

[0091] Therefore, this invention solves the problem of conventional insulation material aging evaluation, which requires long aging times and can only evaluate a single factor. The entire testing process takes only 35 minutes, significantly reducing the operational difficulty and labor intensity compared to conventional methods that require thousands of hours. It also enables the evaluation of insulation material degradation patterns under thermal-electric coupling. Furthermore, the invention uses constant humidity technology to eliminate the effects of humidity differences on the surface charge decay process. This experiment facilitates understanding the insulation performance degradation patterns of insulation materials under thermal-electric coupling, which is of great significance for extending cable service life and maintaining power grid security.

[0092] In a preferred embodiment, the aging test system of the present invention further comprises: a resistor;

[0093] The DC power supply is connected to the resistor and the first electrode in sequence.

[0094] Schematically, in the early stages of corona discharge, the ionic charge generated by air ionization migrates rapidly, potentially generating a large instantaneous current. Without a resistor to limit the current, the excessive current could cause the needle electrode tip to overheat, oxidize, and deform, disrupting the stability of the electrode system (e.g., changing the tip's radius of curvature, affecting the electric field distribution). Furthermore, the surface of the insulating material sample could be punctured by the localized excessive current, leading to test failure.

[0095] The present invention connects a resistor in series in the circuit. According to Ohm's law, when the voltage is constant, the greater the resistance, the smaller the current. This can limit the corona discharge current to a safe range and avoid the risk of overcurrent.

[0096] In a preferred embodiment, Figure 2 The structural diagram of the insulation material aging test system shown in the figure can be divided into a power supply and discharge unit, an environmental control unit, and a detection and data processing unit, specifically:

[0097] Power supply and discharge unit:

[0098] DC power supply: provides the DC high voltage required for corona discharge, applies a preset voltage to the electrode system, is the energy source generated by corona discharge, and forms an electric field between the needle electrode and the ground electrode.

[0099] Current-limiting resistor: connected in series between the DC power supply and the electrode to limit the discharge current, prevent excessive current from damaging the electrode and sample, ensure a stable and controllable discharge process, and prevent danger or impact on test results caused by abnormal current.

[0100] Needle electrode + grid electrode ( Figure 2 (Not shown) + ground electrode: This constitutes the electrode system. The needle electrode is connected to the high-voltage side, the grid electrode controls the flow of ionic charge generated by corona discharge to the insulating material, and the ground electrode is in contact with the specimen and grounded. The electric field at the needle electrode tip is concentrated, inducing corona discharge at a preset voltage. The generated ionic charge acts on the surface and interior of the specimen, simulating the actual electrical stress aging environment of insulating materials.

[0101] Environmental Control Unit:

[0102] Heating plate + heating controller: The heating plate provides heat for the sample, and the heating controller regulates the heating power to achieve the preset temperature in the box, simulating the temperature environment of the actual service of the insulation material and establishing the temperature-electric field coupled aging condition.

[0103] Epoxy bracket: carries the sample, electrodes, heating components, etc., provides physical support, ensures the relative position of each component is stable, makes corona discharge and temperature effects evenly applied to the sample, and integrates related circuits to facilitate system layout and installation.

[0104] Relative humidity mark (30%): Although the figure does not control individual components, it reflects the humidity conditions of the test environment.

[0105] Detection and data processing unit:

[0106] Probe: After corona discharge, the test sample will be moved under the probe. The probe can detect the potential signal generated by charge migration and attenuation on the sample surface. It is a key component for obtaining electrical characteristics related to sample aging. It converts physical signals into detectable electrical signals.

[0107] Potentiometer: Receives the potential signal from the probe, converts it into potential data, realizes signal-data conversion, and provides basic quantitative information for host computer analysis.

[0108] Computer (i.e., host computer): Receives potential data from the potentiometer, generates a potential attenuation curve through an algorithm, analyzes the aging law of the insulating material under preset temperature and pressure, and can also control the DC power supply, heating controller, etc. to achieve system automation and in-depth data processing.

[0109] Therefore, through the coordinated work of the above components, a complete test process from corona discharge application, environmental simulation to signal detection and aging analysis can be constructed to realize the test and evaluation of the aging characteristics of insulating materials in a temperature and electric field coupled environment.

[0110] In a preferred embodiment, when the needle voltage is 10 kV and the grid voltage is 5 kV, it can be obtained as follows: Figure 3 The potential decay characteristic curve is shown in FIG. When the needle voltage is 12kV and the grid voltage is 7kV, the following can be obtained: Figure 4 The potential decay characteristic curve is shown.

[0111] contrast Figure 3 and Figure 4 It can be concluded that when the corona voltage and gate voltage increase, the initial value of the surface potential increases. In contrast, at the same temperature, the surface potential decays faster when the corona voltage and gate voltage increase. This indicates that under the action of the high electric field, the detrapping speed of the charges trapped inside the insulating medium is accelerated. After detrapping, the energy gained by the electrons increases rapidly, and the collision with the molecular chains intensifies, which makes it easier to cause the molecular chains to break, resulting in accelerated degradation of the insulation performance.

[0112] Therefore, by analyzing the potential decay characteristic curve, the aging state of the insulating material can be obtained, and the quantification from the microscopic charge behavior to the macroscopic aging degree can be achieved, which can reflect the performance of the material in multiple dimensions.

[0113] Materials with different aging cycles have significantly different potential decay curves, which can be used as a staging standard for aging degrees, for example:

[0114] New sample (not aged): the curve decays slowly and the platform area is long (many deep traps and stable charge);

[0115] Mild aging: the slope of the curve becomes larger (shallow traps increase and charge detrapping accelerates);

[0116] Severe aging: low initial potential + extremely fast decay (trap structure collapses and charge cannot be effectively stored).

[0117] In the embodiment of the present invention, by comparing the shapes of the curves, the aging stages (such as new → early degradation → late degradation) can be accurately divided, which can replace the traditional insulation resistance fuzzy judgment method.

[0118] like Figure 5 As shown, based on the above embodiments of the aging test system for various insulating materials, the present invention provides corresponding method embodiments;

[0119] An embodiment of the present invention provides an aging test method for an insulating material, which is applied to a host computer in an aging test system for an insulating material;

[0120] The aging test method comprises:

[0121] Controlling the DC power supply to supply power to the electrode system so that the electrode system performs corona discharge at a preset voltage;

[0122] Obtain the potential data of the insulating material after the electrode system completes corona discharge;

[0123] generating a potential decay curve of the insulating material at a preset temperature and a preset voltage according to the potential decay amplitude in the potential data;

[0124] According to the potential decay curve, the aging law of the insulating material at the preset temperature and the preset voltage is output.

[0125] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the method described above can refer to the corresponding process in the aforementioned system embodiment and will not be repeated here.

[0126] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An aging test system for insulating materials, characterized in that: include: Potentiometer, host computer and box with temperature controller; the box also contains: DC power supply, electrode system and probe; The temperature controller is used to control the temperature of the box to a preset temperature; The host computer is used to control the DC power supply to supply power to the electrode system so that the electrode system performs corona discharge at a preset voltage; wherein the ionic charges generated by the corona discharge migrate to the surface of the insulating material under the action of the electric field and fill the interior of the insulating material; The probe is used to detect the potential signal on the surface of the insulating material after the electrode system completes the corona discharge, and then send the detected potential signal to the potentiometer; The potentiometer is used to convert the received potential signal into potential data and send the potential data to the host computer; The host computer is further used to generate a potential attenuation curve of the insulating material at a preset temperature and a preset voltage based on the attenuation amplitude of the potential in the potential data; and output an aging law of the insulating material at a preset temperature and a preset voltage based on the potential attenuation curve.

2. The aging test system for insulating materials according to claim 1, characterized in that: The electrode system is provided with a first electrode, a second electrode and a third electrode; wherein the third electrode is in contact with the bottom of the insulating material and is grounded via a wire; The first electrode is used to generate a corona discharge; The second electrode is used to regulate the flow of ionic charges generated by corona discharge to the insulating material; The third electrode is used to attract the trapped charges.

3. The aging test system for insulating materials according to claim 2, characterized in that: The diameter of the first electrode is 1 mm, and the curvature radius of the tip of the first electrode is 15 μm.

4. An aging test system for insulating materials according to claim 3, characterized in that: The vertical distance between the first electrode and the second electrode, and the vertical distance between the second electrode and the insulating material are both 5 mm.

5. The aging test system for insulating materials according to claim 4, characterized in that: The probe is a vibrating capacitance probe.

6. The aging test system for insulating materials according to claim 5, characterized in that: The box is also provided with a humidity controller; The humidity controller is used to control the humidity of the box to a preset humidity.

7. An aging test system for insulating materials according to claim 6, characterized in that: The temperature controller adjusts the temperature of the box through a PID temperature control algorithm.

8. The aging test system for insulating materials according to claim 7, characterized in that: The vertical distance between the probe and the insulating material is 3 mm.

9. The aging test system for insulating materials according to claim 8, characterized in that: Also includes: resistance; The DC power supply is connected to the resistor and the first electrode in sequence.

10. A method for testing aging of insulating materials, characterized in that: A host computer used in an aging test system for insulating materials according to any one of claims 1 to 9; The aging test method comprises: Controlling the DC power supply to supply power to the electrode system so that the electrode system performs corona discharge at a preset voltage; Obtain the potential data of the insulating material after the electrode system completes corona discharge; generating a potential decay curve of the insulating material at a preset temperature and a preset voltage according to the potential decay amplitude in the potential data; According to the potential decay curve, the aging law of the insulating material at the preset temperature and the preset voltage is output.

Images