Insulation Interface Breakdown Voltage Evaluation Method, Device, Terminal Device and Storage Medium

Abstract

The present invention discloses a method, device, terminal device and storage medium for evaluating the breakdown voltage of an insulating interface. The method includes: the present invention obtains the first electrode spacing-pressure parameter and the first breakdown equivalent resistance of the insulating interface; determines the insulating interface coefficient for characterizing the state of the insulating interface; corrects the preset Paschen formula or the derived formula of the Paschen formula according to the insulating interface coefficient to obtain a corrected formula; and calculates the breakdown voltage of the insulating interface based on the corrected formula. The present invention corrects the Paschen formula, provides an important reference for expanding the generality of the "solid-gas-solid" composite insulating interface discharge in the classical gas discharge theory system, and improves the accuracy of calculating the breakdown voltage of the insulating interface.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation detection, and in particular, to a method, device, terminal device and storage medium for evaluating the breakdown voltage of an insulation interface. Background Art

[0002] Power cable accessories include cable joints and cable terminations, and are key components connecting power transmission and distribution lines and related power distribution devices. At present, faults caused by the discharge of the cross-linked polyethylene (XLPE)-silicone rubber (SiR) insulation interface of cable accessories occur frequently in China, and the explosion and combustion accidents caused by them are extremely harmful. For the analysis of insulation interface discharge, the classical gas discharge theory is currently used for qualitative explanation, such as Paschen's law, Townsend theory and streamer theory. However, due to the complex and difficult-to-quantify "solid-gas-solid" insulation interface structure, and different from air discharge, the XLPE-SiR interface insulation does not have insulation recovery. During long-term discharge, the state evolution of the interface insulation directly affects the characteristics of XLPE-SiR insulation interface discharge. Therefore, the method of directly applying the classical gas discharge theory has limitations. For Paschen's law in the classical gas discharge theory, it clearly reveals the relationship between the breakdown voltage (U b ) of air discharge under the conditions of low pressure and small gap and the product of pressure (p) and electrode spacing (d), that is, Paschen's formula U b = f(pd). To a certain extent, Paschen's law can reflect the discharge law of the XLPE-SiR insulation interface, but the change of the XLPE-SiR insulation interface state is not considered in this relational expression. Summary of the Invention

[0003] The present invention provides a method, device, terminal device and storage medium for evaluating the breakdown voltage of an insulation interface to solve the technical problem that Paschen's formula does not consider the change of the insulation interface state.

[0004] To solve the above technical problem, an embodiment of the present invention provides a method for evaluating the breakdown voltage of an insulation interface, including:

[0005] Obtaining the first electrode spacing-pressure parameter and the first breakdown equivalent resistance of the insulation interface;

[0006] Determine a first insulation interface coefficient or a second insulation interface coefficient for characterizing the state of the insulation interface according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance; wherein, the first insulation interface coefficient is generated by data fitting with the first breakdown equivalent resistance as a fixed value, each preset second electrode spacing-pressure parameter, and the breakdown voltage corresponding to each preset second electrode spacing-pressure parameter; the second insulation interface coefficient is generated by data fitting with the first electrode spacing-pressure parameter as a fixed value, each preset second breakdown equivalent resistance, and the breakdown voltage corresponding to each preset second breakdown equivalent resistance;

[0007] When determining the first insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, correct the preset Paschen formula according to the first insulation interface coefficient to obtain a corrected Paschen formula; based on the corrected Paschen formula and the first electrode spacing-pressure parameter, determine the breakdown voltage of the insulation interface;

[0008] When determining the second insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, obtain a derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance according to the preset Paschen formula; correct the derivation formula according to the second insulation interface coefficient to obtain a corrected derivation formula; based on the corrected derivation formula and the first breakdown equivalent resistance, determine the breakdown voltage of the insulation interface.

[0009] As a preferred solution, the determining the first insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance includes:

[0010] Obtain the first experimental results of a number of first discharge experiments; wherein, in the first discharge experiment, the insulation interface and air are set as the discharge interface materials for the control group, with the first breakdown equivalent resistance as a constant, the electrode spacing-pressure parameter as a variable, and a number of experiments are set according to each preset second electrode spacing-pressure parameter to test the breakdown voltages of the two discharge interface materials under different second electrode spacing-pressure parameter conditions; the first experimental results include: the first insulation interface breakdown voltage and the first air breakdown voltage;

[0011] For each of the second electrode spacing-pressure parameters, calculate the ratio of the first insulation interface breakdown voltage to the first air breakdown voltage under the condition of the second electrode spacing-pressure parameter according to the corresponding experimental results as the first breakdown voltage ratio corresponding to the second electrode spacing-pressure parameter;

[0012] According to the ratio of the first breakdown voltage corresponding to different second electrode spacing - pressure parameters, and by using the mathematical statistical fitting method, determine the functional relationship between the second electrode spacing - pressure parameter and the ratio of the first breakdown voltage, which is used as the calculation formula for the first insulation interface coefficient;

[0013] Calculate the first insulation interface coefficient according to the first insulation interface coefficient calculation formula and the first electrode spacing - pressure parameter.

[0014] As a preferred solution, the determination of the second insulation interface coefficient according to the first electrode spacing - pressure parameter and the first breakdown equivalent resistance includes:

[0015] Obtain the second experimental results of several second discharge experiments; among them, in the second discharge experiment, the insulation interface and air are used as the discharge interface materials to set a control group. With the first electrode spacing - pressure parameter as the invariant and the breakdown equivalent resistance as the variable, several experiments are set according to each preset second breakdown equivalent resistance, and the breakdown voltages of the two discharge interface materials under different second breakdown equivalent resistance conditions are tested; the second experimental results include: the second insulation interface breakdown voltage and the second air breakdown voltage;

[0016] For each of the second breakdown equivalent resistances, according to the corresponding experimental results, calculate the ratio of the second insulation interface breakdown voltage to the second air breakdown voltage under the condition of the second breakdown equivalent resistance, which is used as the second breakdown voltage ratio corresponding to the second breakdown equivalent resistance;

[0017] According to the ratio of the second breakdown voltage corresponding to different second breakdown equivalent resistances, and by using the mathematical statistical fitting method, determine the functional relationship between the second breakdown equivalent resistance and the ratio of the second breakdown voltage, which is used as the calculation formula for the second insulation interface coefficient;

[0018] Calculate the second insulation interface coefficient according to the second insulation interface coefficient calculation formula and the first breakdown equivalent resistance.

[0019] As a preferred solution, the preset Paschen's formula is:

[0020] U b = f(pd);

[0021] In the formula, pd represents the electrode spacing - pressure parameter; U b represents the breakdown voltage of air calculated according to Paschen's formula;

[0022] The calculation formula for the first insulation interface coefficient is:

[0023] α pd = q(pd);

[0024] In the formula, αpd It represents the first insulation interface coefficient when the electrode spacing - pressure parameter is pd under specific breakdown equivalent resistance conditions;

[0025] The modified Paschen's formula is:

[0026] U p d(pd) = α pd ·f(pd);

[0027] In the formula, U pd (pd) represents the breakdown voltage of the insulation interface when the electrode spacing - pressure parameter is pd under specific breakdown equivalent resistance conditions.

[0028] As a preferred solution, the derivation formula obtained according to the preset Paschen's formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance includes:

[0029] Obtain the experimental data of several groups of air discharge experiments; among them, the experimental data includes: air breakdown equivalent resistance and air electrode spacing - pressure parameter;

[0030] According to the air electrode spacing - pressure parameter of each group of experimental data, calculate the corresponding air breakdown voltage according to Paschen's formula;

[0031] According to the air breakdown equivalent resistance and the corresponding air breakdown voltage of each group of experimental data, determine the functional relationship between the air breakdown voltage and the discharge breakdown equivalent resistance according to mathematical methods as the derivation formula.

[0032] As a preferred solution, the derivation formula is:

[0033] U b ′ = h(R);

[0034] In the formula, R represents the breakdown equivalent resistance; U b ′ represents the air breakdown voltage calculated according to the derivation formula;

[0035] The calculation formula for the second insulation interface coefficient is:

[0036] α R = g(R);

[0037] In the formula, α R represents the second insulation interface coefficient when the breakdown equivalent resistance is R under specific electrode spacing - pressure parameter conditions;

[0038] The modified derivation formula is:

[0039] U R (R) = α R ·h(R);

[0040] wherein, U R (R) represents the breakdown voltage of the insulation interface when the breakdown equivalent resistance is R under specific electrode spacing - pressure parameter conditions.

[0041] Based on the above - mentioned embodiments, another embodiment of the present invention provides an insulation interface breakdown voltage evaluation device, including: a data acquisition module, an insulation coefficient determination module, and a breakdown voltage calculation module;

[0042] The data acquisition module is used to acquire the first electrode spacing - pressure parameter and the first breakdown equivalent resistance of the insulation interface;

[0043] The insulation coefficient determination module is used to determine the first insulation interface coefficient or the second insulation interface coefficient for characterizing the state of the insulation interface according to the first electrode spacing - pressure parameter and the first breakdown equivalent resistance; wherein, the first insulation interface coefficient is generated by data fitting with the first breakdown equivalent resistance as a fixed value, each preset second electrode spacing - pressure parameter, and the breakdown voltage corresponding to each preset second electrode spacing - pressure parameter; the second insulation interface coefficient is generated by data fitting with the first electrode spacing - pressure parameter as a fixed value, each preset second breakdown equivalent resistance, and the breakdown voltage corresponding to each preset second breakdown equivalent resistance;

[0044] When the breakdown voltage calculation module determines the first insulation interface coefficient according to the first electrode spacing - pressure parameter and the first breakdown equivalent resistance, it corrects the preset Paschen formula according to the first insulation interface coefficient to obtain a corrected Paschen formula; based on the corrected Paschen formula and the first electrode spacing - pressure parameter, it determines the breakdown voltage of the insulation interface; when determining the second insulation interface coefficient according to the first electrode spacing - pressure parameter and the first breakdown equivalent resistance, it obtains a derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance according to the preset Paschen formula; it corrects the derivation formula according to the second insulation interface coefficient to obtain a corrected derivation formula; based on the corrected derivation formula and the first breakdown equivalent resistance, it determines the breakdown voltage of the insulation interface.

[0045] Based on the above - mentioned embodiments, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the insulation interface breakdown voltage evaluation method described in the above - mentioned embodiments of the present invention.

[0046] On the basis of the above embodiments, another embodiment of the present invention provides a storage medium, which includes a stored computer program. When the computer program runs, it controls the device where the storage medium is located to execute the insulation interface breakdown voltage evaluation method described in the above embodiments of the present invention.

[0047] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0048] The present invention obtains the first electrode spacing-pressure parameter and the first breakdown equivalent resistance of the insulation interface; determines the insulation interface coefficient for characterizing the state of the insulation interface; corrects the preset Paschen formula or the derived formula of the Paschen formula according to the insulation interface coefficient to obtain a corrected formula; and calculates the breakdown voltage of the insulation interface based on the corrected formula. The present invention considers the influence of the insulation interface state and its evolution on pure gas discharge, corrects the Paschen formula, provides an important reference for expanding the generality of the "solid-gas-solid" composite insulation interface discharge in the classical gas discharge theory system, and improves the accuracy of calculating the breakdown voltage of the insulation interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a schematic flow chart of a method for evaluating the breakdown voltage of an insulation interface provided by an embodiment of the present invention;

[0050] Figure 2 is a schematic diagram of a parallel plate air gap discharge specimen provided by an embodiment of the present invention;

[0051] Figure 3 is a schematic diagram of a parallel plate XLPE-SiR insulation interface specimen provided by an embodiment of the present invention;

[0052] Figure 4 is a schematic diagram of the principle of an XLPE-SiR insulation interface discharge experiment platform provided by an embodiment of the present invention;

[0053] Figure 5 is a schematic structural diagram of an insulation interface breakdown voltage evaluation device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0055] Embodiment 1

[0056] Please refer to Figure 1, a method for evaluating the breakdown voltage of an insulating interface provided by an embodiment of the present invention, includes:

[0057] S1. Obtain the first electrode spacing-pressure parameter and the first breakdown equivalent resistance of the insulating interface.

[0058] It should be noted that the insulating interface refers to the XLPE-SiR insulating interface.

[0059] S2. Determine the first insulating interface coefficient or the second insulating interface coefficient for characterizing the state of the insulating interface according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance; wherein, the first insulating interface coefficient is generated by data fitting with the first breakdown equivalent resistance as a fixed value, each preset second electrode spacing-pressure parameter, and the breakdown voltage corresponding to each preset second electrode spacing-pressure parameter; the second insulating interface coefficient is generated by data fitting with the first electrode spacing-pressure parameter as a fixed value, each preset second breakdown equivalent resistance, and the breakdown voltage corresponding to each preset second breakdown equivalent resistance.

[0060] S31. When determining the first insulating interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, correct the preset Paschen formula according to the first insulating interface coefficient to obtain a corrected Paschen formula; based on the corrected Paschen formula and the first electrode spacing-pressure parameter, determine the breakdown voltage of the insulating interface.

[0061] In a preferred embodiment, the determining the first insulating interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance includes:

[0062] Obtain the first experimental results of several first discharge experiments; wherein, in the first discharge experiment, the insulating interface and air are set as the discharge interface materials for the control group, with the first breakdown equivalent resistance as a constant, and the electrode spacing-pressure parameter as a variable. According to each preset second electrode spacing-pressure parameter, several experiments are set up to test the breakdown voltages of the two discharge interface materials under different second electrode spacing-pressure parameter conditions; the first experimental results include: the first insulating interface breakdown voltage and the first air breakdown voltage;

[0063] For each of the second electrode spacing-pressure parameters, calculate the ratio of the first insulating interface breakdown voltage to the first air breakdown voltage under the condition of the corresponding second electrode spacing-pressure parameter as the first breakdown voltage ratio corresponding to the second electrode spacing-pressure parameter.

[0064] According to the ratio of the first breakdown voltage corresponding to different second electrode spacing-pressure parameters, and by using the mathematical statistical fitting method, determine the functional relationship between the second electrode spacing-pressure parameter and the ratio of the first breakdown voltage, which is used as the calculation formula for the first insulation interface coefficient;

[0065] Calculate the first insulation interface coefficient according to the first insulation interface coefficient calculation formula and the first electrode spacing-pressure parameter.

[0066] In a preferred embodiment, the preset Paschen formula is:

[0067] U b = f(pd);

[0068] In the formula, pd represents the electrode spacing-pressure parameter; U b represents the breakdown voltage of air calculated according to the Paschen formula;

[0069] The calculation formula for the first insulation interface coefficient is:

[0070] α pd = q(pd);

[0071] In the formula, α pd represents the first insulation interface coefficient when the electrode spacing-pressure parameter is pd under specific breakdown equivalent resistance conditions;

[0072] The modified Paschen formula is:

[0073] U p d(pd) = α pd ·f(pd);

[0074] In the formula, U pd (pd) represents the breakdown voltage of the insulation interface when the electrode spacing-pressure parameter is pd under specific breakdown equivalent resistance conditions.

[0075] In this embodiment, the present invention carried out an experiment on comparing the discharges between pure gas (air) and XLPE-SiR insulation interface in the same system to determine the differences between them. The specific technical solution is as follows:

[0076] 1. Preparation of experimental samples: Prepare a parallel-plate air gap discharge sample C air and a parallel-plate XLPE-SiR insulation interface sample C X-S , as shown in Figure 2 and Figure 3 . Set the electrode spacing d and pressure p of sample C air and sample C X-S to be the same. Among them, sample C airThe pressure can be achieved by injecting air into the sealed box through an air pump from the injection pipe, so that the internal pressure of the sealed box reaches the target value; Specimen C X-S The pressure can be adjusted by cooperating the spring with the rigid plexiglass pressing plate, and the setting of the target pressure value can be calculated according to Hooke's law.

[0077] 2. DC discharge breakdown experiment setup: Build a DC discharge breakdown experiment platform, and conduct DC discharge breakdown experiments on Specimen C air and Specimen C X-S under the premise of ensuring the same temperature T, as shown in Figure 4 . Use a two-port oscilloscope and a capacitive voltage divider to obtain the voltage value in the circuit. Among them, Port 1 measures the voltage value u1 on the capacitive voltage divider 1 at the power supply side, and Port 2 measures the voltage value u2 on the capacitive voltage divider 2 on the r side.

[0078] 3. Obtaining the experimental result parameters of the DC discharge breakdown: Based on the experimental parameters obtained from the DC discharge breakdown experiment platform, the current value i at the time of discharge breakdown and the specimen voltage u at the time of discharge breakdown can be obtained through the following formula C , and finally the discharge breakdown equivalent resistance R is obtained;

[0079] i = u2 / r;

[0080] u C = u1 - u2;

[0081] R = u C / i.

[0082] 4. Determination of the XLPE-SiR insulation interface coefficient under a specific XLPE-SiR insulation interface state: Through the above experimental method, by adjusting the pd value of Specimen C air , the breakdown voltage of pure gas can be obtained according to Paschen's formula U b = f(pd). Similarly, by adjusting the pd value of the specimen C X-S in a specific XLPE-SiR insulation interface state in the same way, the insulation interface discharge breakdown voltages U bx (x = 1~n) under n different pd value conditions can be obtained. Introduce the insulation interface coefficient α x (x = 1~n) in the xth pd value case, and there is the following relationship:

[0083] U bx = α x ·f(pd);

[0084] By experimentally obtaining a large amount of α x values and pd value data, the functional relationship about pd can be obtained through data statistical fitting:

[0085] α pd = q(pd).

[0086] Finally, a quantitative correlation formula for pd-discharge under a specific XLPE-SiR insulation interface state is constructed, and the following formula is obtained:

[0087] U p d(pd) = α pd ·f(pd);

[0088] 5. On the basis of the above experiments, a modified general Paschen formula for discharge at the XLPE-SiR insulation interface can be further constructed: The insulation interface coefficient α is related to the insulation interface state (R) and pd, and there is an obvious coupling relationship between the insulation interface state (R) and the pd value. Therefore, it is extremely difficult to directly statistically fit the functional relationship α = f(R, pd). For this reason, the present invention uses a piecewise function to analyze the relationship between U pd -pd under typical insulation interface states, and a modified Paschen formula for discharge at the XLPE-SiR insulation interface can be obtained, as shown below:

[0089]

[0090] In the formula, α pdx · is the XLPE-SiR insulation interface coefficient under a specific insulation interface state x (x = 1 to n).

[0091] In this embodiment, the influence of the pd value on the discharge at the XLPE-SiR insulation interface of power cable accessories is analyzed: The fluctuation of the operating load of the power cable line will cause the change of the insulation interface pressure. By substituting the fluctuation range of the pd value, the change relationship between U pd -pd under a specific insulation interface state can be calculated, so as to determine the stage where the XLPE-SiR insulation interface is prone to discharge / breakdown (such as the stage of decreasing operating load or no-load stage), which is the stage that the operation and maintenance department needs to focus on.

[0092] It should be noted that Paschen's law clearly reveals the relationship of U b = f(pd) for pure gas discharge under the conditions of low pressure and small gap. However, for the situation where the insulation interface state of the "solid-gas-solid" XLPE-SiR insulation interface is constantly evolving, directly applying U b= f(pd) has limitations, and its error source lies in that Paschen's law does not consider the influence of the evolution of the insulation interface state on gas discharge. To overcome the above disadvantages, the present invention proposes a method for correcting and extending Paschen's formula based on the discharge of the XLPE-SiR insulation interface. By establishing a quantitative correlation between the evolution of the XLPE-SiR insulation interface state and discharge, a corrected Paschen's formula for the discharge of the XLPE-SiR insulation interface is proposed. The purpose of the present invention is to explore the relationship between the discharge of the XLPE-SiR insulation interface, the evolution of the interface state, and pd, and provide an important reference for expanding the universality of the "solid-gas-solid" insulation interface discharge in the classical gas discharge theory system. At the same time, it provides an important theoretical guidance for the insulation interface discharge fault detection technology of power cable accessories.

[0093] S32. When determining the second insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, a derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance is obtained according to the preset Paschen's formula; the derivation formula is corrected according to the second insulation interface coefficient to obtain a corrected derivation formula; based on the corrected derivation formula and the first breakdown equivalent resistance, the breakdown voltage of the insulation interface is determined.

[0094] In a preferred embodiment, the determining the second insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance includes:

[0095] Obtain the second experimental results of a number of second discharge experiments; wherein, in the second discharge experiment, the insulation interface and air are used as the discharge interface materials to set a control group. With the first electrode spacing-pressure parameter as a constant and the breakdown equivalent resistance as a variable, a number of experiments are set according to each preset second breakdown equivalent resistance, and the breakdown voltages of the two discharge interface materials under different second breakdown equivalent resistance conditions are tested; the second experimental results include: the second insulation interface breakdown voltage and the second air breakdown voltage;

[0096] For each second breakdown equivalent resistance, according to the corresponding experimental results, calculate the ratio of the second insulation interface breakdown voltage to the second air breakdown voltage under the condition of the second breakdown equivalent resistance as the second breakdown voltage ratio corresponding to the second breakdown equivalent resistance;

[0097] According to the second breakdown voltage ratios corresponding to different second breakdown equivalent resistances, and by means of mathematical statistical fitting method, determine the functional relationship between the second breakdown equivalent resistance and the second breakdown voltage ratio as the second insulation interface coefficient calculation formula;

[0098] Calculate the second insulation interface coefficient according to the second insulation interface coefficient calculation formula and the first breakdown equivalent resistance.

[0099] In a preferred embodiment, the derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance obtained according to the preset Paschen formula includes:

[0100] Obtain experimental data of several groups of air discharge experiments; wherein, the experimental data includes: air breakdown equivalent resistance and air electrode spacing-pressure parameters;

[0101] According to the air electrode spacing-pressure parameters of each group of experimental data, calculate the corresponding air breakdown voltage according to the Paschen formula;

[0102] According to the air breakdown equivalent resistance and the corresponding air breakdown voltage of each group of experimental data, determine the functional relationship between the air breakdown voltage and the discharge breakdown equivalent resistance according to mathematical methods as the derivation formula.

[0103] In a preferred embodiment, the derivation formula is:

[0104] U b ′ = h(R);

[0105] In the formula, R represents the breakdown equivalent resistance; U b ′ represents the breakdown voltage of air calculated according to the derivation formula;

[0106] The calculation formula for the second insulation interface coefficient is:

[0107] α R = g(R);

[0108] In the formula, α R represents the second insulation interface coefficient when the breakdown equivalent resistance is R under specific electrode spacing-pressure parameters;

[0109] The modified derivation formula is:

[0110] U R (R) = α R ·h(R);

[0111] In the formula, U R (R) represents the breakdown voltage of the insulation interface when the breakdown equivalent resistance is R under specific electrode spacing-pressure parameters.

[0112] In this embodiment, in order to determine the quantitative relationship between the XLPE-SiR insulation interface discharge and the evolution of the insulation interface state, the construction of the quantitative correlation between the XLPE-SiR insulation interface state evolution-discharge is carried out. The specific technical solution is as follows:

[0113] Obtaining the R value corresponding to different XLPE-SiR insulation interface states: Through the above DC discharge breakdown experimental platform, for specimen CX-S Perform n breakdown experiments until the interface insulation cracks to a position where it cannot be broken down, that is, the insulation loss state. Calculate the equivalent resistance R of the discharge breakdown of the XLPE-SiR insulation interface under each breakdown experiment y (y = 1 to m). Through the above method, the quantitative relationship between the insulation interface state and R x can be established.

[0114] 2. Determination of the XLPE-SiR insulation interface coefficient αR under specific pd conditions: Through the above DC discharge breakdown experiment of pure gas, obtain the relationship formula U air ' = h(R) of the specimen C under specific pd conditions. On the other hand, under the same pd conditions, according to the DC discharge breakdown experiment of the XLPE-SiR insulation interface under different insulation interface states, n insulation interface discharge breakdown voltages U b ' (y = 1 to m) of different insulation interface states can be obtained. Introduce the insulation interface coefficient (y = 1 to m) in the insulation interface state y, and there is the following relationship: by U

[0115] U by ' = α y ·U b ' = α x ·h(R);

[0116] Obviously, the value of α y is different for each discharge breakdown of the XLPE-SiR insulation interface (caused by the change of the insulation interface state). Therefore, a large number of α y values and R y value data are obtained through experiments, and the functional relationship formula about R is obtained by mathematical statistical fitting: α R = g(R). Finally, construct the quantitative correlation formula of the XLPE-SiR insulation interface state evolution (R)-discharge under specific pd conditions, and obtain the following formula:

[0117] U R (R) = α R ·h(R);

[0118] 3. On the basis of the above experiments, a general derivation formula for modifying the Paschen formula of the XLPE-SiR insulation interface discharge can be further constructed: The insulation interface coefficient α is related to the insulation interface state (R) and pd, and there is an obvious coupling relationship between the insulation interface state (R) and the pd value. Therefore, it is extremely difficult to directly statistically fit the functional relationship formula α = f(R, pd). For this reason, the present invention uses a piecewise function method to analyze the relationship between U R -R under typical insulation interface states, and the modified Paschen formula of the XLPE-SiR insulation interface discharge can be obtained as follows:

[0119]

[0120] wherein, α Ry is the XLPE-SiR insulation interface coefficient under specific pd condition y (y = 1 to m).

[0121] It should be noted that the present invention can realize the analysis of the influence of the evolution of the insulation interface state (R value) on the XLPE-SiR insulation interface discharge: According to the evolution of the insulation interface discharge fault of the target power cable accessory, estimate the reasonable change range of the corresponding R value in different fault stages (before, during, and end stage), and calculate the change relationship between U R -R, so as to determine the evolution law of the XLPE-SiR insulation interface discharge / breakdown of the target power cable accessory, and provide a theoretical guidance for the prediction of the evolution stage of the XLPE-SiR insulation interface discharge fault of the subsequent power cable accessory.

[0122] Embodiment 2

[0123] Please refer to Figure 5 , which is a schematic structural diagram of an insulation interface breakdown voltage evaluation device provided by an embodiment of the present invention. The device includes: a data acquisition module, an insulation coefficient determination module, and a breakdown voltage calculation module;

[0124] The data acquisition module is used to acquire the first electrode spacing-pressure parameter and the first breakdown equivalent resistance of the insulation interface;

[0125] The insulation coefficient determination module is used to determine a first insulation interface coefficient or a second insulation interface coefficient for characterizing the insulation interface state according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance; wherein, the first insulation interface coefficient is generated by data fitting with the first breakdown equivalent resistance as a fixed value, each preset second electrode spacing-pressure parameter, and the breakdown voltage corresponding to each preset second electrode spacing-pressure parameter; the second insulation interface coefficient is generated by data fitting with the first electrode spacing-pressure parameter as a fixed value, each preset second breakdown equivalent resistance, and the breakdown voltage corresponding to each preset second breakdown equivalent resistance;

[0126] The breakdown voltage calculation module is configured to, when determining the first insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, correct a preset Paschen formula according to the first insulation interface coefficient to obtain a corrected Paschen formula; determine the breakdown voltage of the insulation interface based on the corrected Paschen formula and the first electrode spacing-pressure parameter; when determining the second insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, obtain a derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance according to the preset Paschen formula; correct the derivation formula according to the second insulation interface coefficient to obtain a corrected derivation formula; and determine the breakdown voltage of the insulation interface based on the corrected derivation formula and the first breakdown equivalent resistance.

[0127] Embodiment III

[0128] Correspondingly, an embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the breakdown voltage evaluation method described in the foregoing embodiment of the present invention is implemented.

[0129] Embodiment IV

[0130] Correspondingly, an embodiment of the present invention provides a storage medium, which includes a stored computer program. When the computer program runs, it controls the device where the storage medium is located to execute the breakdown voltage evaluation method described in the foregoing embodiment of the present invention.

[0131] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art can understand and implement without creative efforts.

[0132] Those skilled in the art can clearly understand that for the sake of convenience and brevity, the specific working processes of the devices described above can refer to the corresponding processes in the foregoing method embodiments and will not be described in detail here.

[0133] The terminal device may be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory.

[0134] The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor is the control center of the device and connects various parts of the entire device through various interfaces and lines.

[0135] The memory may be used to store the computer program. The processor realizes various functions of the device by running or executing the computer program stored in the memory and calling the data stored in the memory. The memory may mainly include a program storage area and a data storage area. Among them, the program storage area may store an operating system, application programs required for at least one function, etc.; the data storage area may store data created according to the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a FlashCard, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0136] The storage medium is a storage medium, and the computer program is stored in the storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0137] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. An evaluation method for the breakdown voltage of an insulating interface, characterized in that, Including: Obtaining a first electrode spacing-pressure parameter and a first breakdown equivalent resistance of an insulating interface; Determining a first insulating interface coefficient or a second insulating interface coefficient for characterizing the state of the insulating interface according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance; wherein, the first insulating interface coefficient is generated by performing data fitting with the first breakdown equivalent resistance as a fixed value, each preset second electrode spacing-pressure parameter, and the breakdown voltage corresponding to each preset second electrode spacing-pressure parameter; the second insulating interface coefficient is generated by performing data fitting with the first electrode spacing-pressure parameter as a fixed value, each preset second breakdown equivalent resistance, and the breakdown voltage corresponding to each preset second breakdown equivalent resistance; When determining the first insulating interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, correcting a preset Paschen's formula according to the first insulating interface coefficient to obtain a corrected Paschen's formula; and determining the breakdown voltage of the insulating interface based on the corrected Paschen's formula and the first electrode spacing-pressure parameter; When determining the second insulating interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, obtaining a derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance according to the preset Paschen's formula; correcting the derivation formula according to the second insulating interface coefficient to obtain a corrected derivation formula; and determining the breakdown voltage of the insulating interface based on the corrected derivation formula and the first breakdown equivalent resistance.

2. The insulation interface breakdown voltage evaluation method according to claim 1, characterized in that, The determining the first insulating interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance includes: Obtaining first experimental results of a plurality of first discharge experiments; wherein, in the first discharge experiment, an insulating interface and air are used as the discharge interface materials to set a control group, with the first breakdown equivalent resistance as a constant, the electrode spacing-pressure parameter as a variable, and a plurality of experiments are set according to each preset second electrode spacing-pressure parameter to test the breakdown voltages of the two discharge interface materials under different second electrode spacing-pressure parameter conditions; the first experimental results include: a first insulating interface breakdown voltage and a first air breakdown voltage; For each of the second electrode spacing-pressure parameters, calculating, according to the corresponding experimental results, the ratio of the first insulating interface breakdown voltage to the first air breakdown voltage under the condition of the second electrode spacing-pressure parameter as the first breakdown voltage ratio corresponding to the second electrode spacing-pressure parameter; According to the first breakdown voltage ratios corresponding to different second electrode spacing-pressure parameters, and by using a mathematical statistical fitting method, determining a functional relationship between the second electrode spacing-pressure parameter and the first breakdown voltage ratio as a first insulating interface coefficient calculation formula; Calculating the first insulating interface coefficient according to the first insulating interface coefficient calculation formula and the first electrode spacing-pressure parameter.

3. The insulation interface breakdown voltage evaluation method according to claim 1, characterized in that The determining the second insulating interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance includes: Obtain the second experimental results of several second discharge experiments; wherein, in the second discharge experiment, the insulation interface and air are set as the discharge interface materials for the control group, with the first electrode spacing-pressure parameter as the invariant, and the breakdown equivalent resistance as the variable. Several experiments are set according to each preset second breakdown equivalent resistance, and the breakdown voltages of the two discharge interface materials under different second breakdown equivalent resistance conditions are tested; the second experimental results include: the second insulation interface breakdown voltage and the second air breakdown voltage; For each of the second breakdown equivalent resistances, according to the corresponding experimental results, calculate the ratio of the second insulation interface breakdown voltage to the second air breakdown voltage under the condition of the second breakdown equivalent resistance, as the second breakdown voltage ratio corresponding to the second breakdown equivalent resistance; According to the second breakdown voltage ratios corresponding to different second breakdown equivalent resistances, and by using the mathematical statistical fitting method, determine the functional relationship between the second breakdown equivalent resistance and the second breakdown voltage ratio, as the second insulation interface coefficient calculation formula; Calculate the second insulation interface coefficient according to the second insulation interface coefficient calculation formula and the first breakdown equivalent resistance.

4. The insulation interface breakdown voltage evaluation method according to claim 1, characterized in that The preset Paschen formula is: U b = f(pd); where pd represents the electrode spacing-pressure parameter; U b represents the breakdown voltage of air calculated according to Paschen's formula; The first insulation interface coefficient calculation formula is: α pd = q(pd); where α pd represents the first insulation interface coefficient when the electrode spacing-pressure parameter is pd under specific breakdown equivalent resistance conditions; The modified Paschen formula is: U p d(pd) = α pd ·f(pd); where U pd (pd) represents the breakdown voltage of the insulating interface when the electrode spacing-pressure parameter is pd under specific breakdown equivalent resistance conditions.

5. The method for evaluating the breakdown voltage of an insulating interface according to claim 1, characterized in that, The derivation formula for obtaining the relationship between the breakdown voltage and the breakdown equivalent resistance according to the preset Paschen formula includes: Obtain the experimental data of several groups of air discharge experiments; wherein, the experimental data includes: the air breakdown equivalent resistance and the air electrode spacing-pressure parameter; According to the air electrode spacing-pressure parameter of each group of experimental data, calculate the corresponding air breakdown voltage according to the Paschen formula; According to the air breakdown equivalent resistance and the corresponding air breakdown voltage of each group of experimental data, determine the functional relationship between the air breakdown voltage and the discharge breakdown equivalent resistance by using a mathematical method, as the derivation formula.

6. The method for evaluating the breakdown voltage of an insulating interface according to claim 1, wherein The derivation formula is: U b ′ = h(R); where R represents the breakdown equivalent resistance; U b ′ represents the breakdown voltage of air calculated according to the derived formula; The second insulation interface coefficient calculation formula is: α R = g(R); where α R represents the second insulation interface coefficient when the breakdown equivalent resistance is R under specific electrode spacing-pressure parameter conditions; The modified derivation formula is: U R (R) = α R ·h(R); where, U R (R) represents the breakdown voltage of the insulation interface when the breakdown equivalent resistance is R under specific electrode spacing-pressure parameter conditions.

7. An insulating interface breakdown voltage evaluation device, characterized in that Including: A data acquisition module, an insulation coefficient determination module, and a breakdown voltage calculation module; The data acquisition module is used to obtain the first electrode spacing-pressure parameter and the first breakdown equivalent resistance of the insulation interface; The insulation coefficient determination module is used to determine the first insulation interface coefficient or the second insulation interface coefficient for characterizing the state of the insulation interface according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance; wherein, the first insulation interface coefficient is generated by data fitting with the first breakdown equivalent resistance as a fixed value, each preset second electrode spacing-pressure parameter, and the breakdown voltages corresponding to each preset second electrode spacing-pressure parameter; the second insulation interface coefficient is generated by data fitting with the first electrode spacing-pressure parameter as a fixed value, each preset second breakdown equivalent resistance, and the breakdown voltages corresponding to each preset second breakdown equivalent resistance; The breakdown voltage calculation module is configured to, when determining the first insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, correct the preset Paschen formula according to the first insulation interface coefficient to obtain a corrected Paschen formula; determine the breakdown voltage of the insulation interface based on the corrected Paschen formula and the first electrode spacing-pressure parameter; when determining the second insulation interface coefficient according to the first electrode spacing-pressure parameter and the first breakdown equivalent resistance, obtain a derivation formula for characterizing the relationship between the breakdown voltage and the breakdown equivalent resistance according to the preset Paschen formula; correct the derivation formula according to the second insulation interface coefficient to obtain a corrected derivation formula; and determine the breakdown voltage of the insulation interface based on the corrected derivation formula and the first breakdown equivalent resistance.

8. A terminal device, characterized in that It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the insulation interface breakdown voltage evaluation method according to any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium includes a stored computer program. When the computer program runs, it controls the device where the storage medium is located to execute the insulation interface breakdown voltage evaluation method according to any one of claims 1 to 6.

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