Semiconducting buffer layer electrical test circuit, evaluation method and processing terminal

Abstract

The present invention provides a semi-conductive buffer layer electrical test circuit, evaluation method and processing terminal, wherein the semi-conductive buffer layer electrical test circuit comprises: a high-voltage ring, which is in close contact with the insulating shielding layer of the cable segment to be tested and short-circuited with the conductor of the cable segment to be tested; a shielding ring, which is in close contact with the semi-conductive buffer layer of the cable segment to be tested; a direct current source component, wherein the high-voltage pole of the direct current source component is connected to the high-voltage ring, and the low-voltage pole of the direct current source component is connected to the shielding ring and the metal sleeve of the cable; wherein the semi-conductive buffer layer is arranged on both sides of the insulating shielding layer. The present invention can effectively solve the limitations and shortcomings of the existing strip testing and overall high-voltage electrical testing methods of cables; comprehensively reflect factors such as the buffer strip, the wrapping structure, and the aluminum sleeve gap, effectively evaluate the material properties, structural properties and electrical contact properties of the buffer layer, and provide method support for the inspection and evaluation of the buffer layer of the high-voltage cable finished product, thereby promoting the reliability improvement during the service life of the high-voltage cable system.

Description

Technical Field

[0001] The invention belongs to the technical field of cable testing, and relates to a circuit and a method, and in particular to a semi-conductive buffer layer electrical testing circuit, an evaluation method and a processing terminal. Background Art

[0002] High-voltage power cables of 66kV and above basically adopt a metal sheath shielding structure, and the semi-conductive buffer layer is located between the extruded insulating core and the metal sheath, and is made by a wrapping process. The semi-conductive buffer layer is a component unit for the transition from high potential to ground potential and from insulation to metal grounding in the cable, realizing continuous and effective axial grounding of the insulating core. Considering the influence of moisture in the laying environment, the buffer layer is often required to have longitudinal water-blocking properties.

[0003] At present, most metal sheaths are in the form of corrugated aluminum sheaths that are extruded or welded. There is a local contact between the corrugated aluminum sheath and the buffer layer. If the material selection, design, production or application of the buffer layer is not properly controlled, the unfavorable factors such as the performance of the semi-conductive buffer tape of the high-voltage power cable, the buffer layer wrapping process, the design of the gap inside the corrugated aluminum sheath, and the intrusion of moisture during operation will lead to poor grounding of the insulated core, which is directly reflected in the radial and axial local concentration of the capacitive current and leakage current of the insulated core during operation, and the inability to be dispersed and discharged through the buffer layer. Electrochemical reactions occur in the buffer material and interface, corroding the aluminum sheath and even the insulation shield. Under the high voltage during operation and possible internal overvoltage of the line, the buffer layer has local discharge and electrocorrosion, until the main insulation is damaged, causing a breakdown failure. This has become a difficult and painful point in the improved design of metal sheaths for high-voltage power cables, bringing challenges to high-quality manufacturing and high-reliability operation.

[0004] At present, the evaluation of the buffer layer is mainly carried out in the following ways: 1) Testing the resistance level of the buffer tape, but it cannot reflect the influence of the winding process and the gap between the buffer layer and the aluminum sheath on the electrical transition performance; 2) Before leaving the factory or before the line is put into operation, the finished cable is subjected to high-voltage electrical tests, including power frequency withstand voltage tests and partial discharge tests, which mainly assess the status of the insulation system, but cannot identify the buffer layer transition and grounding performance of each section of the cable.

[0005] Therefore, how to provide a semi-conductive buffer layer electrical test circuit, evaluation method and processing terminal to solve the defects of the existing technology that cannot identify and reflect the buffer layer transition and grounding performance status of each section of the cable, causing irreversible degradation of the cable, has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0006] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a semi-conductive buffer layer electrical test circuit / evaluation method and processing terminal, which is used to solve the problem that the prior art is unable to identify and reflect the buffer layer transition and grounding performance conditions of each section of the cable, causing irreversible degradation of the cable.

[0007] To achieve the above-mentioned purpose and other related purposes, the present invention provides, on the one hand, a semi-conductive buffer layer electrical test circuit, which is applied to a cable segment to be tested; the semi-conductive buffer layer electrical test circuit to be tested comprises: a high-voltage ring, which is in close contact with the insulating shielding layer of the cable segment to be tested and short-circuited with the conductor of the cable segment to be tested; a shielding ring, which is in close contact with the semi-conductive buffer layer of the cable segment to be tested; a DC source component, wherein the high-voltage pole of the DC source component is connected to the high-voltage ring, and the low-voltage pole of the DC source component is connected to the shielding ring and the metal sleeve of the cable; wherein the semi-conductive buffer layer is arranged on both sides of the insulating shielding layer.

[0008] In one embodiment of the present invention, one end of the DC ammeter of the DC source assembly is connected to the exposed surface of the metal sheath of the cable segment to be tested; the other end of the ammeter is grounded.

[0009] In an embodiment of the present invention, the width of the shielding ring is set between 5 mm and 15 mm.

[0010] In one embodiment of the present invention, the distance between the inner edge of the shielding ring and the outer edge of the metal sleeve surface and the outer sheath is set between 5 mm and 15 mm.

[0011] In one embodiment of the present invention, the low voltage pole of the DC source component is grounded.

[0012] In one embodiment of the present invention, the width of the high-pressure ring is set between 1 mm and 5 mm.

[0013] In one embodiment of the present invention, the distance between the high voltage ring and the outer edge of the insulating shielding layer is set between 1 mm and 5 mm.

[0014] Yet another aspect of the present invention provides a method for evaluating the electrical performance of a semiconductive buffer layer, which is characterized in that it is used to evaluate the performance parameters of the semiconductive buffer layer based on a semiconductive buffer layer electrical test circuit; the semiconductive buffer layer electrical test circuit comprises an insulating shielding layer, a semiconductive buffer layer arranged on both sides of the insulating shielding layer, a high-voltage ring close to the insulating shielding layer, and a shielding ring close to the semiconductive buffer layer; the semiconductive buffer layer electrical evaluation method comprises: obtaining circuit test parameters generated in the semiconductive buffer layer electrical test circuit under at least three test environments for the cable segment to be tested; and calculating the performance parameters of the semiconductive buffer layer under a radial DC circuit according to a preset performance evaluation method of the semiconductive buffer layer based on the circuit test parameters generated by the cable segment to be tested under at least three test environments.

[0015] In one embodiment of the present invention, the three test environments include an indoor air environment, an oven environment, and a constant temperature and humidity chamber environment.

[0016] In one embodiment of the present invention, the performance parameters of the semiconductive buffer layer include the equivalent line resistance and / or equivalent surface resistance of the semiconductive buffer layer; the performance evaluation method of the preset semiconductive buffer layer includes an evaluation method of the equivalent line resistance of the semiconductive buffer layer and an evaluation method of the equivalent surface resistance of the semiconductive buffer layer.

[0017] The last aspect of the present invention provides a processing terminal, comprising: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the processing terminal executes the electrical evaluation method of the semiconductive buffer layer.

[0018] As described above, the electrical test circuit / evaluation method and processing terminal of the semiconductive buffer layer of the present invention have the following beneficial effects:

[0019] The electrical test circuit / evaluation method and processing terminal of the semi-conductive buffer layer described in the present invention are targeted at the electrical characteristics and structural features of the semi-conductive buffer layer of the high-voltage power cable, and can effectively solve the limitations and shortcomings of the existing strip testing and overall high-voltage electrical testing methods of the cable; comprehensively reflect factors such as the buffer strip, wrapping structure, and aluminum sleeve gap, and effectively evaluate the material properties, structural properties, and electrical contact properties of the buffer layer, providing support for strip selection, product design, and process design, and providing method support for the inspection and evaluation of the buffer layer of the high-voltage cable finished product, thereby promoting the reliability improvement during the service life of the high-voltage cable system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It shows a schematic diagram of the structural connection of a semi-conductive buffer layer electrical test circuit constructed for a cable segment to be tested according to the present invention.

[0021] Figure 2 A schematic flow chart of a method for evaluating the electrical properties of a semiconducting buffer layer in one embodiment is shown.

[0022] Component number description

[0023] 1 Semiconducting buffer layer electrical test circuit 10 DC source components 11 conductor 12 Insulation shield 13 High pressure ring 14 Semiconducting buffer layer 15 Shielding ring 16 Metal sleeve 17 Outer sheath S21~S22 step DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0026] Embodiment 1

[0027] This embodiment provides a semi-conductive buffer layer electrical test circuit, which is applied to a cable segment to be tested; the semi-conductive buffer layer electrical test circuit to be tested includes:

[0028] A high voltage ring, which is in close contact with the insulating shielding layer of the cable segment to be tested and is short-circuited with the conductor of the cable segment to be tested;

[0029] A shielding ring, closely attached to the semi-conductive buffer layer of the cable segment to be tested;

[0030] A DC source component, wherein the high voltage pole of the DC source component is connected to the high voltage ring, and the low voltage pole of the DC source component is connected to the shielding ring and the metal sleeve of the cable;

[0031] Wherein, the semiconductive buffer layer is arranged on both sides of the insulating shielding layer.

[0032] The semiconductive buffer layer electrical test circuit provided by this embodiment is described in detail below with reference to the figures. The semiconductive buffer layer electrical test circuit described in this embodiment is used to test a cable segment to obtain circuit test parameters generated by the test circuit under a radial DC loop.

[0033] Before the test is performed, the cable segment needs to be preprocessed to form a cable segment to be tested. The preprocessing process of the cable segment is as follows:

[0034] Selection of cable segments: Cable samples are taken from continuously produced finished products. The total length of the selected cable segment (L S ) is generally not more than 1.5m, and longer cables can be selected according to actual requirements. For straight samples, the straightness is generally not more than 5L S ‰; For curved samples, set according to specific bending radius requirements.

[0035] Treatment of cable segments: The end of the cable segment is cut and stripped layer by layer from the outside to the inside. The metal sheath (corrugated aluminum sheath) and the outer sheath can be cut together, and the stripping length is generally not less than 100mm. Strip off part of the semi-conductive buffer tape outside the end core, and the length of the retained buffer tape from the edge of the sheath to the edge of the corrugated aluminum sheath is generally not less than 50mm. In the middle of the cable segment, peel off a section of the non-metallic sheath and clean the exposed aluminum sheath surface attachments.

[0036] The cable section must be tested immediately after processing. If it is left there for more than 4 hours, the surface of the section where the sheath is stripped needs to be wrapped with plastic film.

[0037] The electrical test circuit of the semi-conductive buffer layer described in this embodiment is aimed at the electrical characteristics and structural features of the semi-conductive buffer layer of the high-voltage power cable, and effectively solves the limitations and shortcomings of the existing strip material test and cable overall high-voltage electrical test methods.

[0038] See also Figure 1 , which shows a schematic diagram of the structural connection of the electrical test circuit of the semi-conductive buffer layer built for the cable segment to be tested. Figure 1 As shown, the semiconductive buffer layer electrical test circuit 1 includes a DC source component 10, a conductor 11, an insulating shielding layer 12, a high voltage ring 13, a semiconductive buffer layer 14, a shielding ring 15, a metal sleeve 16 and an outer sheath 17.

[0039] In this embodiment, the DC source component 10 includes a DC voltmeter and a DC ammeter. Specifically, the high voltage pole of the DC source component 10 is connected to the high voltage ring 13, that is, the DC voltmeter in the DC source component 10 is connected to the high voltage ring 13. The low voltage pole of the DC source component 10 is connected to the shielding ring 15 and the metal sleeve 16 of the cable, and the low voltage pole of the DC source component 10 is grounded. In this embodiment, the accuracy of the DC voltmeter of the DC source component 10 is not less than ±0.5%.

[0040] One end of the DC ammeter of the DC source assembly 10 is connected to the surface of the metal sleeve 16 (in this embodiment, the metal sleeve 16 is a corrugated aluminum sleeve) exposed outside the cable segment to be tested; the other end of the ammeter is grounded. The accuracy of the DC ammeter of the DC source assembly 10 is not less than ±0.5%.

[0041] In this embodiment, the conductor 11 is wrapped by the insulating shielding layer 12. The conductor 11 is connected to the DC source component 10.

[0042] like Figure 1 As shown, a high voltage ring 13 is arranged on the insulating shielding layer 12. The high voltage ring 13 is short-circuited with the conductor 11 of the cable segment to be tested. In this embodiment, the width of the high voltage ring 13 is set between 1 mm and 5 mm. The distance between the high voltage ring 13 and the outer edge of the insulating shielding layer 12 is set between 1 mm and 5 mm.

[0043] The semiconductive buffer layer 14 is as follows Figure 1 As shown, they are arranged on both sides of the insulating shielding layer 12.

[0044] Continue reading Figure 1 , the shielding ring 15 is in close contact with the semi-conductive buffer layer 14 of the cable segment to be tested. In this embodiment, the width of the shielding ring 15 is set between 5mm and 15mm. The distance between the inner edge of the shielding ring 15 and the outer edge of the metal sleeve surface and the outer sheath is set between 5mm and 15mm. In this embodiment, the high-voltage ring 13 and the shielding ring 15 can control the test stability, that is, reduce the influence of leakage current on the test stability.

[0045] Place the cable segment to be tested on an insulating pad, measure the distance L between the corrugated aluminum sleeve edges on both sides, and measure the outer diameter D of the insulating core. Place the cable segment to be tested in at least three test environments as required, such as indoor air environment, oven environment, and constant temperature and humidity chamber environment, and set up instruments to measure ambient temperature and humidity.

[0046] Specifically, placing the cable segment to be tested in the indoor air environment means: the cable segment to be tested is placed in the indoor air for no less than 2 hours; the air temperature is a preset value between 15°C and 25°C, and the air humidity does not exceed 50%; the air temperature and humidity remain stable during the test, with the temperature change not exceeding ±1°C, and the humidity change not exceeding ±2%.

[0047] After the temperature and humidity of the cable segment to be tested are stable, start the test circuit of the semi-conductive buffer layer electrical equipment built for the cable segment to be tested, slowly apply DC voltage, the voltage rise rate is a preset voltage rise rate threshold between 0.5mV / s and 50mV / s, the DC voltage rises to between 0.5V and 5V and the preset DC voltage threshold, the current rises synchronously and slowly, and the current fluctuation is within ±10% after stabilization. The DC voltage rises to the specified value and stabilizes for no less than 10s, and then reads the voltage value V1 and the corresponding current value I1 of the voltmeter every cycle, which is between 1s and 5s.

[0048] Placing the cable segment to be tested in the oven environment means: the cable segment to be tested is placed in the oven for no less than 2 hours; the oven temperature is a preset value between 50°C and 80°C, and the temperature in the oven remains stable during the test, and the temperature variation does not exceed ±1°C.

[0049] After the temperature and humidity of the cable segment to be tested are stable, start the test circuit of the semi-conductive buffer layer electrical equipment built for the cable segment to be tested, slowly apply DC voltage, the voltage rise rate is a preset voltage rise rate threshold between 0.5mV / s and 50mV / s, the DC voltage rises to the preset DC voltage threshold between 0.5V and 5V, the current rises synchronously and slowly, and the current fluctuation is within ±10% after stabilization. The DC voltage rises to the specified value and stabilizes for no less than 10s, and then reads the voltage value V2 and the corresponding current value I2 of the voltmeter every cycle, which is between 1s and 5s.

[0050] Placing the cable segment to be tested in the constant temperature and humidity chamber environment means that the cable segment to be tested is placed in the constant temperature and humidity chamber for no less than 2 hours; the temperature of the constant temperature and humidity chamber is a preset temperature value between 50°C and 80°C, and the humidity is a preset humidity value between 60% and 90%. During the test in the oven, the temperature and humidity remain stable, and the temperature change does not exceed ±1°C, and the humidity change does not exceed ±1%.

[0051] After the temperature and humidity of the cable segment to be tested are stable, start the test circuit of the semi-conductive buffer layer electrical equipment built for the cable segment to be tested, slowly apply DC voltage, the voltage rise rate is a preset voltage rise rate threshold between 0.5mV / s and 50mV / s, the DC voltage rises to the preset DC voltage threshold between 0.5V and 5V, the current rises synchronously and slowly, and the current fluctuation is within ±10% after stabilization. The DC voltage rises to the specified value and stabilizes for no less than 10s, and then reads the voltage value V3 and the corresponding current value I3 of the voltmeter every cycle, which is between 1s and 5s.

[0052] This embodiment also provides a semiconductive buffer layer electrical evaluation method, which is used to evaluate the performance parameters of the semiconductive buffer layer based on a semiconductive buffer layer electrical test circuit. The semiconductive buffer layer electrical test circuit includes an insulating shielding layer, a semiconductive buffer layer disposed on both sides of the insulating shielding layer, a high-voltage ring close to the insulating shielding layer, and a shielding ring close to the semiconductive buffer layer; the semiconductive buffer layer electrical evaluation method includes:

[0053] Obtaining circuit test parameters generated in a test circuit of the semiconductive buffer layer of the cable segment to be tested under at least three test environments;

[0054] According to the circuit test parameters generated by the cable segment to be tested under at least three test environments, the performance parameters of the semiconductive buffer layer in the radial DC circuit are calculated according to a preset performance evaluation method of the semiconductive buffer layer.

[0055] The electrical evaluation method of the semiconductive buffer layer provided in this embodiment will be described in detail below with reference to the drawings. The electrical evaluation method of the semiconductive buffer layer is based on the electrical test circuit of the semiconductive buffer layer to evaluate the performance parameters of the semiconductive buffer layer.

[0056] See also Figure 2 , which is a schematic flow chart of a method for evaluating the electrical properties of a semiconducting buffer layer in one embodiment. Figure 2 As shown, the electrical evaluation method of the semiconductive buffer layer specifically includes the following steps:

[0057] S21, obtaining circuit test parameters generated in the electrical test circuit of the semiconductive buffer layer of the cable segment to be tested under at least three test environments, a spacing L between the corrugated aluminum sheath edges on both sides, and an outer diameter D of the insulating core.

[0058] In this embodiment, the three test environments include an indoor air environment, an oven environment, and a constant temperature and humidity chamber environment.

[0059] In this embodiment, the voltage value V1 and the corresponding current value I1 generated in the electrical test circuit of the semiconductive buffer layer of the cable segment to be tested in the indoor air environment are obtained;

[0060] Obtaining a voltage value V2 and a corresponding current value I2 generated in a test circuit of the semiconductive buffer layer of the cable segment to be tested in an oven environment;

[0061] The voltage value V3 and the corresponding current value I3 generated in the electrical test circuit of the semiconductive buffer layer of the cable segment to be tested in a constant temperature and humidity chamber environment are obtained.

[0062] S22, calculating the performance parameters of the semiconductive buffer layer in the radial DC circuit according to the circuit test parameters generated by the cable segment to be tested under at least three test environments and in accordance with a preset performance evaluation method of the semiconductive buffer layer.

[0063] In this embodiment, the performance parameters of the semiconductive buffer layer include the equivalent line resistance (R L , Ω·m) and / or equivalent surface resistance (R S ,Ω·mm 2 ).

[0064] The performance evaluation method of the preset semiconductive buffer layer includes an evaluation method of the equivalent line resistance of the semiconductive buffer layer and an evaluation method of the equivalent surface resistance of the semiconductive buffer layer.

[0065] Specifically, the equivalent line resistance of the semiconductive buffer layer is evaluated as follows:

[0066] R L =L((V1 / I1)+(V2 / I2)+(V3 / I3,)) / 3;

[0067] Evaluation method of equivalent sheet resistance of semiconducting buffer layer:

[0068] R S =πDL((V1 / I1)+(V2 / I2)+(V3 / I3)) / 3;

[0069] Wherein, L is the distance between the corrugated aluminum sleeve edges on both sides; D is the outer diameter of the insulating core.

[0070] The protection scope of the electrical evaluation method of the semiconductive buffer layer described in the present invention is not limited to the execution order of the steps listed in this embodiment. All solutions implemented by adding, reducing or replacing steps in the prior art based on the principles of the present invention are included in the protection scope of the present invention.

[0071] The electrical test circuit for the semiconductive buffer layer and the electrical evaluation method for the semiconductive buffer layer described in this embodiment are targeted at the electrical characteristics and structural features of the semiconductive buffer layer of the high-voltage power cable, and can effectively solve the limitations and shortcomings of the existing strip testing and overall high-voltage electrical testing methods of the cable; they comprehensively reflect factors such as the buffer strip, wrapping structure, and aluminum sleeve gap, and effectively evaluate the material properties, structural properties, and electrical contact properties of the buffer layer, providing support for strip selection, product design, and process design, and providing method support for the inspection and evaluation of the buffer layer of high-voltage cable finished products, thereby promoting the reliability improvement during the service life of the high-voltage cable system.

[0072] Embodiment 2

[0073] This embodiment provides a processing terminal, including: a processor, a memory, a transceiver, a communication interface and / or a system bus; the memory and the communication interface are connected to the processor and the transceiver through the system bus and complete communication with each other, the memory is used to store computer programs, the communication interface is used to communicate with other devices, and the processor and the transceiver are used to run computer programs, so that the processing terminal executes each step of the above-mentioned semiconductive buffer layer electrical evaluation method.

[0074] The system bus mentioned above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The system bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. The communication interface is used to realize the communication between the database access device and other devices (such as clients, read-write libraries, and read-only libraries). The memory may include random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage.

[0075] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0076] In summary, the electrical test circuit / evaluation method and processing terminal of the semi-conductive buffer layer of the present invention are aimed at the electrical characteristics and structural characteristics of the semi-conductive buffer layer of the high-voltage power cable, which can effectively solve the limitations and shortcomings of the existing strip testing and cable overall high-voltage electrical test methods; comprehensively reflect the factors such as the buffer strip, the wrapping structure, and the aluminum sleeve gap, effectively evaluate the material properties, structural properties, and electrical contact properties of the buffer layer, provide support for strip selection, product design, and process design, and provide method support for the inspection and evaluation of the buffer layer of the high-voltage cable finished product, thereby promoting the reliability improvement during the life of the high-voltage cable system. The present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0077] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A semiconducting buffer layer electrical test circuit, characterized in that: Applied to the cable segment to be tested; the electrical test circuit of the semiconductive buffer layer to be tested comprises: A high voltage ring, which is in close contact with the insulating shielding layer of the cable segment to be tested and is short-circuited with the conductor of the cable segment to be tested; A shielding ring, closely attached to the semi-conductive buffer layer of the cable segment to be tested; A DC source component, wherein the high voltage pole of the DC source component is connected to the high voltage ring, and the low voltage pole of the DC source component is connected to the shielding ring and the metal sleeve of the cable; Wherein, the semiconductive buffer layer is arranged on both sides of the insulating shielding layer; by obtaining the circuit test parameters generated in the electrical test circuit of the semiconductive buffer layer of the cable segment to be tested under at least three test environments; according to the circuit test parameters generated by the cable segment to be tested under at least three test environments, according to the preset performance evaluation method of the semiconductive buffer layer, the performance parameters of the semiconductive buffer layer under the radial DC circuit are calculated; the test parameters are the voltage values ​​and the corresponding current values ​​generated in the test circuit; the performance parameters of the semiconductive buffer layer include the equivalent line resistance and / or equivalent surface resistance of the semiconductive buffer layer.

2. The semiconductive buffer layer electrical test circuit according to claim 1, characterized in that: One end of the DC ammeter of the DC source assembly is connected to the exposed surface of the metal sheath of the cable segment to be tested; the other end of the ammeter is grounded.

3. The electrical test circuit of the semiconductive buffer layer according to claim 2, characterized in that: The width of the shielding ring is set between 5 mm and 15 mm.

4. The electrical test circuit of the semiconductive buffer layer according to claim 3, characterized in that: The distance between the inner edge of the shielding ring and the outer edge of the metal sleeve surface and the outer sheath is set between 5mm and 15mm.

5. The semiconductive buffer layer electrical test circuit according to claim 1, characterized in that: The low voltage pole of the DC source component is grounded.

6. The semiconductive buffer layer electrical test circuit according to claim 1, characterized in that: The width of the high-pressure ring is set between 1 mm and 5 mm.

7. The semiconductive buffer layer electrical test circuit according to claim 6, characterized in that: The distance between the high voltage ring and the outer edge of the insulating shielding layer is set between 1 mm and 5 mm.

8. A method for evaluating the electrical properties of a semiconducting buffer layer, characterized in that: Used to evaluate the performance parameters of a semiconductive buffer layer based on an electrical test circuit of a semiconductive buffer layer; the electrical test circuit of the semiconductive buffer layer comprises an insulating shielding layer, a semiconductive buffer layer arranged on both sides of the insulating shielding layer, a high-voltage ring close to the insulating shielding layer, a shielding ring close to the semiconductive buffer layer and a DC source component, the high-voltage pole of the DC source component is connected to the high-voltage ring, and the low-voltage pole of the DC source component is connected to the shielding ring and the metal sleeve of the cable; The electrical evaluation method of the semiconductive buffer layer comprises: Obtaining circuit test parameters generated in a test circuit of the semiconductive buffer layer of the cable segment to be tested under at least three test environments; According to the circuit test parameters generated by the cable segment to be tested under at least three test environments, the performance parameters of the semiconductive buffer layer in the radial DC circuit are calculated according to a preset performance evaluation method of the semiconductive buffer layer; the test parameters are the voltage value and the corresponding current value generated in the test circuit; the performance parameters of the semiconductive buffer layer include the equivalent line resistance and / or equivalent surface resistance of the semiconductive buffer layer.

9. The method for evaluating the electrical properties of a semiconducting buffer layer according to claim 8, characterized in that: The three test environments include indoor air environment, oven environment and constant temperature and humidity chamber environment.

10. The method for evaluating the electrical properties of a semiconducting buffer layer according to claim 8, characterized in that: The performance evaluation method of the preset semiconductive buffer layer includes an evaluation method of the equivalent line resistance of the semiconductive buffer layer and an evaluation method of the equivalent surface resistance of the semiconductive buffer layer.

11. A processing terminal, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the processing terminal performs the electrical evaluation method of the semiconductive buffer layer according to any one of claims 8 to 10.

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