CN113588488A - Cable defect detection method and device, terminal equipment and storage medium - Google Patents

Abstract

The invention discloses a cable defect detection method, device, terminal equipment and storage medium. The method comprises: obtaining the total air volume between the corrugated sheath and the buffer layer of the cable to be detected; obtaining the reference of the cable to be detected volume; wherein, the reference volume is the total volume of the insulated wire core not wrapped with the buffer layer, the total volume of the insulated wire core wrapped with the buffer layer, or the total internal volume of the corrugated sheath; Calculate The ratio of the total air volume of the cable to be inspected to the reference volume is obtained to obtain the air ratio of the cable to be inspected; it is judged whether the air ratio of the cable to be inspected is greater than or equal to the defect ratio threshold, and if so, the air ratio of the cable to be inspected is determined. The cable is defective, if not, it is determined that the cable to be tested is not defective. By adopting the embodiments of the present invention, the defects of the cables can be accurately detected.

Description

Cable defect detection method, device, terminal equipment and storage medium

technical field

The present invention relates to the technical field of power cables, and in particular, to a cable defect detection method, device, terminal equipment and storage medium.

Background technique

In recent years, the number of defects in high-voltage power cables has gradually increased, which has become one of the important hidden dangers that threaten the security of the power grid. Therefore, how to accurately detect the defects of the cables is of great significance to the safe and reliable operation of the power system.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a cable defect detection method, device, terminal device, and storage medium, which can accurately detect cable defects.

An embodiment of the present invention provides a cable defect detection method, including:

Obtain the total air volume between the corrugated sheath and the buffer layer of the cable to be tested;

Obtain the reference volume of the cable to be tested; wherein, the reference volume is the total volume of the insulated wire core not wrapped with the buffer layer, the total volume of the insulated wire core wrapped with the buffer layer, or the wrinkle the total internal volume of the sheath;

Calculate the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected;

Determine whether the air ratio of the cable to be tested is greater than or equal to the defect ratio threshold, and if so, determine that the cable to be tested is defective, if not, determine that the cable to be tested is not defective; wherein, the defect ratio threshold is configured according to the ratio of the total air volume between the corrugated jacket and the buffer layer of the at least one faulty cable to the reference volume.

As an improvement of the above solution, the obtaining of the total air volume between the corrugated sheath and the buffer layer of the cable to be tested includes:

Obtain the total length of the cable to be tested and the specification parameters within a single wrinkle pitch; wherein, the specification parameters include the inner radius of the corrugated sheath, the outer radius of the buffer layer, and the diameter of the insulated wire core not wrapped around the buffer layer. the radius, the wrinkle pitch, the wrinkle depth and the thinnest point thickness of the buffer layer;

Obtain the approximate function expression of the contact surface of the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z ; wherein, the pole of the cylindrical coordinate system is the center of the corrugated sheath, and the polar axis is any radial direction of the center of the corrugated sheath, and the Z-axis direction is the cable axial direction;

According to the thickness of the thinnest point of the buffer layer, the radius of the insulated wire core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, the contact criticality between the corrugated sheath and the buffer layer is determined point angle;

According to one or more parameters of the air volume calculation formula, the approximate function expression, the angle of the contact critical point and the specification parameters, the corrugated sheath and the corrugated sheath within a single corrugated pitch are calculated and obtained The air volume between the buffer layers; wherein, the air volume calculation formula is based on the air volume between the corrugated sheath and the buffer layer, the inner volume of the corrugated sheath, the surrounding The corresponding relationship between the volume of the insulated wire core of the buffer layer and the volume of the force-deformed part of the buffer layer is determined;

According to the air volume, the total length and the corrugated pitch, the total air volume between the corrugated sheath and the buffer layer is calculated.

As an improvement of the above solution, the obtained approximate function expression of the contact surface of the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z includes:

，k=1，…，n；Based on the cylindrical coordinate system ρ-θ-Z , n interpolation data points are selected from the contact surface between the corrugated sheath and the buffer layer; wherein, the coordinates of the k-th interpolation data point are

, k=1,...,n;

The interpolation calculation is performed according to the n interpolation data points to obtain an approximate function expression of the contact surface in the cylindrical coordinate system ρ-θ-Z .

As an improvement of the above scheme, the air volume calculation formula is:

；

;

；

表示在单个所述皱纹节距内的所述皱纹护套与所述缓冲层之间的空气体积；d _OA 表示所述皱纹护套的内侧半径；d _O’C 表示所述缓冲层的外侧半径；d _O’B 表示所述绝缘线芯的半径；d _dep 表示所述皱纹深度；d _len 表示所述皱纹节距；d _BB’ 表示所述缓冲层的最薄点厚度；f(ρ)表示所述近似函数表达式；θ _A 表示所述接触临界点的角度。in,

;

represents the air volume between the corrugated sheath and the buffer layer within a single corrugation pitch; d _OA represents the inner radius of the corrugated sheath; d _O'C represents the outer radius of the buffer layer ; d _O'B represents the radius of the insulating core; d _dep represents the depth of the wrinkles; d _len represents the pitch of the wrinkles; d _BB' represents the thickness of the thinnest point of the buffer layer; f(ρ) represents The approximate function expression; θ _A represents the angle of the contact critical point.

As an improvement of the above scheme, the approximate function expression is:

；

;

Among them, T ₃ , T ₂ , T ₁ and T ₀ are polynomial coefficients.

As an improvement of the above scheme, the approximate function expression is:

；

;

Wherein, d _OA represents the inner radius of the wrinkle sheath; d _dep represents the wrinkle depth; d _len represents the wrinkle pitch.

As an improvement of the above solution, the specification parameters further include the maximum distance from the center of the corrugated sheath to the outer side of the buffer layer on the radial plane;

时，所述空气体积计算公式为：When the approximate function expression is

, the air volume calculation formula is:

；

;

表示在单个所述皱纹节距内的所述皱纹护套与所述缓冲层之间的空气体积；d _O’C 表示所述缓冲层的外侧半径；d _OC 表示所述皱纹护套的中心至所述缓冲层的外侧的最大距离；θ _A 表示所述接触临界点的角度。in,

represents the air volume between the corrugated sheath and the buffer layer within a single corrugation pitch; d _O'C represents the outer radius of the buffer layer; d _OC represents the center of the corrugated sheath to The maximum distance to the outside of the buffer layer; θ _A represents the angle of the contact critical point.

As an improvement to the above solution, the corrugated sheath is determined according to the thickness of the thinnest point of the buffer layer, the radius of the insulated wire core, the outer radius of the buffer layer and the inner radius of the corrugated sheath The angle of the critical point of contact with the buffer layer, including:

Determine whether the sum of the thickness of the thinnest point of the buffer layer, the radius of the insulating wire core and the outer radius of the buffer layer is less than or equal to twice the inner radius of the corrugated sheath;

If yes, then according to the calculation formula of the inner radius of the corrugated sheath, the outer radius of the buffer layer, the radius of the insulating wire core, the thickness of the thinnest point of the buffer layer and the angle of the contact critical point, the the angle of the critical point of contact between the corrugated sheath and the buffer layer;

If not, determining that the angle of the critical point of contact between the corrugated sheath and the buffer layer is equal to π;

Wherein, the calculation formula of the contact critical point angle is:

；

;

；d _BB’ 表示所述缓冲层的最薄点厚度；d _O’B 表示所述绝缘线芯的半径；d _O’C 表示所述缓冲层的外侧半径；d _OA 表示所述皱纹护套的内侧半径。Among them, θ _A represents the angle of the contact critical point;

; d _BB' represents the thickness of the thinnest point of the buffer layer; d _O'B represents the radius of the insulated wire core; d _O'C represents the outer radius of the buffer layer; d _OA represents the corrugated sheath's radius Inside radius.

As an improvement of the above solution, the specification parameters further include the inner maximum radius and inner minimum radius of the corrugated sheath;

When the reference volume is the total internal volume of the corrugated sheath, acquiring the reference volume of the cable to be tested includes:

According to the corrugation pitch, the inner maximum radius of the corrugated sheath, the inner minimum radius of the corrugated sheath, the approximate function expression and the calculation of the The calculation formula of the first volume of the insulated wire core of the buffer layer is used to calculate the first volume corresponding to the cable to be detected;

According to the corresponding first volume of the cable to be detected, the total length and the corrugated pitch, the total internal volume of the corrugated sheath is calculated to be used as the reference volume of the cable to be detected;

Wherein, the calculation formula of the first volume VA is _:

；

;

_Wherein , VA represents the first volume; d _len represents the wrinkle pitch; d _OK represents the inner maximum radius of the corrugated sheath; d _OD represents the inner minimum radius of the corrugated sheath; f(ρ) represents the approximate function expression.

As an improvement of the above solution, when the reference volume is the total volume of the insulated wire core wrapped with the buffer layer, the obtaining the reference volume of the cable to be tested includes:

According to the outer radius of the buffer layer, the corrugation pitch and the calculation formula for calculating the second volume of the insulated wire core wrapped with the buffer layer within a single corrugation pitch, the calculation is obtained. the second volume corresponding to the cable to be detected;

According to the second volume corresponding to the cable to be detected, the total length and the wrinkle pitch, the total volume of the insulated wire core wrapped with the buffer layer is calculated and obtained as the total volume of the cable to be detected. base volume;

Wherein, the calculation formula of the second volume is:

；

;

Wherein, VB represents the second volume; d _len represents the wrinkle pitch; d _O'C represents the outer radius _of the buffer layer.

As an improvement of the above scheme, the method also includes:

obtaining the total air volume between the corrugated jacket and the buffer layer of the plurality of said faulty cables;

obtaining the reference volume of a plurality of the faulty cables;

Calculate the ratio of the total air volume of the plurality of faulty cables to the reference volume to obtain the air ratio of the plurality of faulty cables;

The minimum value among the air ratios of the plurality of faulty cables is selected as the defect ratio threshold.

As an improvement of the above scheme, the method also includes:

When it is determined that the cable to be inspected is defective, adding the cable to be inspected to the risk list;

When it is determined that the risk list output condition is satisfied, the risk list is output to the setting terminal.

Correspondingly, another embodiment of the present invention provides a cable defect detection device, including:

The air volume acquisition module is used to acquire the total air volume between the corrugated sheath and the buffer layer of the cable to be tested;

A reference volume acquisition module, used for acquiring the reference volume of the cable to be detected; wherein, the reference volume is the total volume of the insulated wire cores not wrapped with the buffer layer and the insulated wire cores wrapped with the buffer layer the total volume or the total internal volume of the corrugated sheath;

an air ratio calculation module, used to calculate the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected;

A defect judgment module, used for judging whether the air ratio of the cable to be tested is greater than or equal to the defect ratio threshold, and if so, it is judged that the cable to be tested is defective, and if not, it is judged that the cable to be tested is not defective; wherein , the defect ratio threshold is configured according to the ratio of the total air volume between the corrugated jacket and the buffer layer of the at least one faulty cable and the reference volume.

Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, where the processor implements the above when executing the computer program The defect detection method of any one of the cables.

Another embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium includes a stored computer program, wherein when the computer program runs, the device where the computer-readable storage medium is located is controlled to execute any of the above A method of defect detection of the cable.

Compared with the prior art, the cable defect detection method, device, terminal device and storage medium disclosed in the embodiments of the present invention can obtain the total air between the corrugated sheath and the buffer layer of the cable to be detected and the air volume of the cable to be detected. Reference volume, and calculate the ratio of the total air volume of the cable to be tested to the reference volume to obtain the air ratio of the cable to be tested, and then compare the air ratio of the cable to be tested with the ratio of the corrugated sheath and buffer layer of at least one faulty cable The size relationship between the defect ratio threshold configured by the ratio between the total air volume and the reference volume is used to determine whether the cable to be tested has defects, so that the defect of the cable can be accurately detected.

Description of drawings

1 is a flowchart of a method for detecting defects in a cable according to an embodiment of the present invention;

2 is a schematic structural diagram of a cable provided by an embodiment of the present invention;

3 is a cross-sectional view of the plane of the cable without contact between the corrugated sheath above the cable and the buffer layer provided by an embodiment of the present invention;

平面截面图；FIG. 4 is the contact surface between the corrugated sheath and the buffer layer provided by the embodiment of the present invention.

Plane sectional view;

5 is a cross-sectional view of a cable plane in which there is contact between the corrugated sheath above the cable and the buffer layer provided by an embodiment of the present invention;

平面截面图；FIG. 6 is the approximate contact surface between the corrugated sheath and the buffer layer provided by the embodiment of the present invention.

Plane sectional view;

7 is a structural block diagram of a cable defect detection device provided by an embodiment of the present invention;

FIG. 8 is a structural block diagram of a terminal device provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below 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, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Referring to FIG. 1 , FIG. 1 is a schematic flowchart of a cable defect detection method provided by an embodiment of the present invention.

The air volume between the corrugated sheath and the buffer layer on the entire cable depends on the actual cable length, insulation thickness and other dimensional information, and the high-voltage cable size design of various cable suppliers is not consistent, because the air volume mainly reflects the insulation of the cable. The contact between the wire core and the corrugated sheath through the buffer layer, in order to realize the comparison of cables of different sizes, the present invention uses the air ratio to detect the defects of the cables. The defect detection method of the cable provided by this embodiment includes:

S1. Obtain the total air volume between the corrugated sheath and the buffer layer of the cable to be tested;

S2. Obtain the reference volume of the cable to be tested; wherein, the reference volume is the total volume of the insulated wire cores not wrapped with the buffer layer, the total volume of the insulated wire cores wrapped with the buffer layer, or the total volume of the insulated wire cores wrapped with the buffer layer. the total internal volume of the wrinkle sheath;

S3, calculating the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected;

S4, judging whether the air ratio of the cable to be tested is greater than or equal to the defect ratio threshold, and if so, it is determined that the cable to be tested has defects, if not, it is determined that the cable to be tested does not have defects; wherein, the defect The ratio threshold is configured according to the ratio of the total air volume between the corrugated jacket and the buffer layer of the at least one faulty cable to the reference volume.

。其中，w为所述待检测电缆的空气比率，V_total为所述待检测电缆的总空气体积，V_base为所述待检测电缆的基准体积。It should be noted that the formula for calculating the air ratio of the cable to be detected is:

. Wherein, w is the air ratio of the cable to be detected, V _total is the total air volume of the cable to be detected, and V _base is the reference volume of the cable to be detected.

In an optional embodiment, the internal volume of the corrugated sheath of the cable to be tested can be determined by measuring the internal volume of the corrugated sheath in the cable to be tested and the total volume of the insulated core wrapped with the buffer layer, and then set the internal volume of the corrugated sheath of the cable to be tested. The total air volume is obtained by subtracting the total volume of the buffered insulated wire core.

Exemplarily, the total volume of the insulated wire core not wrapped with the buffer layer, the total volume of the insulated wire core wrapped with the buffer layer, or the total internal volume of the corrugated sheath may be obtained by X-ray measurement .

In one embodiment, the defects of the cable may include ablation defects of the buffer layer. The occurrence of ablation defects in the cable buffer layer is generally accompanied by the following two phenomena: first, the water blocking buffer layer is damp; second, the corrugated sheath , The electrical connection between the buffer layer and the insulating shielding material is relatively weak. The former can be prevented by strengthening control in the cable production stage and construction stage, while the latter is still difficult to find a replacement for the combination of corrugated sheath-buffer-insulation shielding material in a short time. Therefore, under the premise that the material cannot be changed, the air volume between the corrugated sheath and the buffer layer becomes the evaluation of the connection between the corrugated sheath and the insulating shielding layer under the condition that the buffer tape has been tightly wrapped around the insulating core. key information. In the step S4, the defect ratio threshold may include a buffer layer ablation defect ratio threshold. Correspondingly, the faulty cable may include a buffer layer ablation defect ratio threshold, and the buffer layer ablation defect ratio threshold may be based on at least The ratio of the total air volume between the corrugated sheath and the buffer layer of a faulty cable with buffer layer ablation and the reference volume is configured. Therefore, in the embodiment of the present invention, the ratio between the corrugated sheath and the buffer layer of the cable to be tested is obtained by obtaining the ratio of the corrugated sheath and the buffer layer. The total air volume between the total air volume of the cable to be tested and the reference volume of the cable to be tested, and the ratio of the total air volume of the cable to be tested to the reference volume is calculated to obtain the air ratio of the cable to be tested, and then the air ratio of the cable to be tested is ablated with the buffer layer. The defect ratio threshold is compared to determine whether the buffer layer of the cable to be tested has ablation defects, so that the ablation defects of the cable buffer layer can be accurately detected.

In another embodiment, extensive fault analysis has found that the vertical cable section below the cable terminal is longer, and the cable has a larger dead weight. If the corrugated sheath does not hold enough force to the insulated core, the cable will be affected by gravity after long-term operation. It will cause insufficient spring force of the terminal support, resulting in the discharge of the air gap between the stress cone and the epoxy sleeve, which will lead to failure. defect. Although the construction unit has set up multiple vertical fixings according to the anti-accident measures, because the vertical hoop can only hold the cable sheath tightly, and the holding force of the corrugated sheath to the internal buffer layer and the insulating core is only related to the structure of the cable itself , has nothing to do with the number of vertical hoops, and the air volume between the corrugated sheath and the buffer layer is an intuitive quantitative index reflecting the holding force of the corrugated sheath to the insulated wire core. In the step S4, the defect ratio threshold may be the defect ratio threshold including the holding force. Correspondingly, the faulty cable may be the faulty cable including the wrinkled sheath with insufficient holding force to the insulated core, then the holding force defect ratio threshold It can be configured according to the ratio of the total air volume and the reference volume between the corrugated sheath and the buffer layer of at least one faulty cable whose corrugated sheath is insufficient to hold the insulated core. Detect the total air volume between the corrugated sheath of the cable and the buffer layer and the reference volume of the cable to be detected, and calculate the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected. Detect the air ratio of the cable and compare it with the ratio threshold of the holding force defect to judge whether the cable to be tested has the defect that the wrinkled sheath does not hold the insulating core tightly, so that the wrinkled sheath of the cable buffer layer can be accurately detected. Insulated wire core holding force defect condition.

As an optional embodiment, the obtaining the total air volume between the corrugated sheath and the buffer layer of the cable to be tested includes:

S11. Obtain the total length of the cable to be tested and the specification parameters within a single wrinkle pitch; wherein, the specification parameters include the inner radius of the corrugated sheath, the outer radius of the buffer layer, and the insulated wire not wrapped around the buffer layer. the radius of the core, the wrinkle pitch, the wrinkle depth, and the thinnest point thickness of the buffer layer;

S12. Obtain the approximate function expression of the contact surface of the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z ; wherein, the pole of the cylindrical coordinate system is the center of the corrugated sheath, The polar axis is any radial direction of the center of the corrugated sheath, and the Z-axis direction is the cable axial direction;

S13. Determine the relationship between the corrugated sheath and the buffer layer according to the thickness of the thinnest point of the buffer layer, the radius of the insulating wire core, the outer radius of the buffer layer, and the inner radius of the corrugated sheath The angle of contact with the critical point;

S14. According to the air volume calculation formula, the approximate function expression, the angle of the contact critical point, and one or more parameters of the specification parameters, calculate the wrinkle protection within a single wrinkle pitch The air volume between the sleeve and the buffer layer; wherein, the air volume calculation formula is based on the air volume between the corrugated sheath and the buffer layer, the inner volume of the corrugated sheath, the surrounding determined by the corresponding relationship between the volume of the insulated wire core covered with the buffer layer and the volume of the force-deformed portion of the buffer layer;

S15. Calculate the total air volume between the corrugated sheath and the buffer layer according to the air volume, the total length and the corrugated pitch.

Referring to FIG. 2 , the cable according to the embodiment of the present invention includes a cell (conductor) 10 , a shielding layer 20 , a corrugated sheath 40 , and a buffer layer 30 disposed between the shielding layer 20 and the corrugated sheath 40 , wherein the cell The (conductor) 10 and the shielding layer 20 constitute an insulated wire core. During specific implementation, the total length of the cable to be tested and the specification parameters within a single wrinkle pitch can be obtained by measurement according to the factory test report or actual measurement result of the cable. Among them, the total length of the cable to be tested d _cable , the inner radius d _OA of the corrugated sheath, the outer radius d _O'C of the buffer layer, the radius d _O'B of the insulated core without the buffer layer, and the corrugation pitch d _len , wrinkle depth d _dep , thickness of the thinnest point of the buffer layer d _BB' . Wherein, the above-mentioned overall length and specification parameters within a single wrinkle pitch may be nominal values. 3 and 5, 41 denotes the outer side of the corrugated sheath, 42 denotes the inner side of the corrugated sheath, 31 denotes the outer side of the buffer layer, and 32 denotes the inner side of the buffer layer.

平面极坐标。O’为电缆线芯圆心位置，缓冲层与皱纹护套接触的临界点记为A和A’。如图4所示，在

平面坐标基础上，以电缆轴向方向为Z方向可建立三维坐标系，图中虚线部分即为缓冲层与皱纹护套接触面示意。显然，在一个皱纹节距内，空气体积可用下式计算：It should be noted that, considering that the actual contact surface between the corrugated sheath and the buffer layer is a space curved surface, in the radial plane of the cable, the center position O of the corrugated sheath is taken as the origin, as shown in Figure 3.

Plane polar coordinates. O' is the position of the center of the cable core, and the critical points where the buffer layer contacts the corrugated sheath are denoted as A and A' . As shown in Figure 4, in

Based on the plane coordinates, a three-dimensional coordinate system can be established with the cable axial direction as the Z direction. The dotted line in the figure is the schematic diagram of the contact surface between the buffer layer and the corrugated sheath. Obviously, within a wrinkle pitch, the air volume can be calculated as:

Wherein, VA is the inner volume of the corrugated sheath; VB is the _volume of the insulated wire core wrapped with the buffer layer; VC is the volume of the force _- deformed part of the buffer layer _. Both V _A and V _C are closely related to the inner surface function of the corrugated sheath. In this embodiment, the approximate function expression of the contact surface in the cylindrical coordinate system ρ-θ-Z is obtained, and then combined with the angle of the contact critical point and the specification parameters One or more parameters of , the inner volume of the corrugated sheath and the volume of the force-deformed portion of the buffer layer can be approximated.

It should be noted that, due to the existence of peak and valley positions in the wrinkled sheath, in order to calculate the air volume between the wrinkled sheath and the buffer layer, the following basic assumptions, which are in line with engineering practice, can be made: the air volume in each wrinkle pitch is approximately the same ; the inclination angle of the wrinkle has a negligible effect on the air volume. Then, the air volume between the corrugated sheath and the buffer layer can be decomposed into the sum of the air volume between the corrugated sheath and the buffer layer in each corrugated pitch. Since a single wrinkle pitch is small compared to the full length of the line, the air volume within less than one wrinkle pitch at both ends of the cable can be approximated by a corresponding ratio. Therefore:

where V _total is the total air volume of the cable; V _U is the air volume within a single corrugated pitch; d _cable is the total length of the cable; d _len is the corrugated pitch.

At present, ignoring the influence of cable bending, the intuitive estimation method of the air volume between the corrugated sheath and the buffer layer (hereinafter referred to as the air volume) is to use a circular cylinder formed along the cable axis at the "valley" position inside the corrugated sheath. The difference between the shape volume and the cylindrical volume formed by the outer circle of the buffer layer on the cable along the cable axis is used as the air volume. The premise of this method is that the surface of the corrugated sheath is smooth and straight without wrinkles, which is consistent with the actual cable The situation does not match, resulting in a large error in defect detection. Furthermore, power cable suppliers generally use metal wrinkle production lines for the production of wrinkled sheaths, and control the technical parameters of sheath wrinkles through the two production parameters of wrinkle pitch and wrinkle depth, but this method cannot directly determine the smooth wrinkle and the curvature radius. It is a typical shape parameter, and due to the peak and valley positions of the corrugated sheath, the contact mode with the buffer layer in the axial direction of the cable is generally discontinuous. These problems are the mathematical construction of the air volume between the corrugated sheath and the buffer layer. Difficulties in models and calculations. Secondly, the current corrugated sheath and buffer layer still lack corresponding standard constraints in terms of size matching. Considering the mechanical strength of the cable, axial water resistance and other performance requirements, different power cable suppliers have "wave valleys" on the inner side of the corrugated sheath. "Whether the diameter is larger than the outer diameter of the cable with the buffer layer, different technical solutions will be adopted. Therefore, under the action of gravity, the inner side of the corrugated sheath above the cable of some suppliers does not form effective contact with the buffer layer, as shown in Figure 3. As shown in Figure 5, the inner side of the corrugated sheath above the cable of another supplier forms an effective contact with the buffer layer, as shown in Figure 5. Obviously, an air volume calculation method that can take into account both situations is required. In addition, due to the lack of information such as factory test reports for the early cables, the basic data of the cables are incomplete, and it is difficult to provide sufficient information for calculating the air volume, and the air volume cannot be accurately calculated, resulting in an inability to accurately determine whether the cable buffer layer has ablation defects. In order to solve the above problems, in this embodiment, by calculating the air volume between the wrinkle sheath and the buffer layer within a single wrinkle pitch, and then combining the total length and the wrinkle pitch, the total amount between the wrinkle sheath and the buffer layer can be accurately calculated. air volume.

Further, the obtained approximate function expression of the contact surface of the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z includes:

，k=1，…，n；S121. Based on the cylindrical coordinate system ρ-θ-Z , select n interpolation data points from the contact surface between the corrugated sheath and the buffer layer; wherein, the coordinates of the k-th interpolation data point are

, k=1,...,n;

S122. Perform interpolation calculation according to the n interpolation data points to obtain an approximate function expression of the contact surface in the cylindrical coordinate system ρ-θ-Z .

为接触曲面在z=0平面上的投影，对于任意点

，记其坐标为

。在z=0平面上，从原点O向点P做射线，与绝缘线芯的外侧交点记为B；与缓冲层的外侧交点记为C；与皱纹护套的内侧交点记为D；单个皱纹节距内皱纹护套与缓冲层的接触临界点分别为E、F两点；皱纹护套的内侧直径最大点在射线方向上的投影为K点。在电缆轴向方向上，通过对皱纹曲线EDF进行近似，可得到皱纹护套与缓冲层的接触曲面的一个近似曲面。示例性地，可应用多项式插值、三角插值等方法对皱纹护套内侧曲线DE进行近似。在确定插值方法之后，可以确定插值基点

，k=1,…,n，n为所选定插值方法所需插值数据点的个数；对全部k=1,…,n，在所关注电缆或供应商提供同型号同批次电缆上，在不同皱纹内插值基点k位置处多点测量皱纹内侧Z方向坐标，取平均值后可得到插值数据点的坐标

；根据n个插值数据点进行插值计算，由此可以得到近似曲面在

区间内的近似函数表达式

。It should be noted that, as shown in Figure 4,

is the projection of the contact surface on the z = 0 plane, for any point

, record its coordinates as

. On the z =0 plane, make a ray from the origin O to the point P , and the intersection with the outer side of the insulated core is marked as B ; the intersection with the outer side of the buffer layer is marked as C ; the intersection with the inner side of the corrugated sheath is marked as D ; a single wrinkle The critical points of contact between the corrugated sheath and the buffer layer in the pitch are points E and F respectively; the projection of the largest point of the inner diameter of the corrugated sheath in the ray direction is point K. In the axial direction of the cable, by approximating the corrugated curve EDF , an approximate curved surface of the contact curved surface between the corrugated sheath and the buffer layer can be obtained. Illustratively, methods such as polynomial interpolation, triangular interpolation, etc. may be applied to approximate the curve DE inside the corrugated sheath. After determining the interpolation method, the interpolation base point can be determined

, k=1,…,n, n is the number of interpolation data points required by the selected interpolation method; for all k=1,…,n, on the concerned cable or the same type and same batch of cables provided by the supplier , measure the coordinates of the inner Z direction of wrinkles at multiple points at the position of the interpolation base point k in different wrinkles, and obtain the coordinates of the interpolation data points after taking the average value.

; According to the interpolation calculation of n interpolation data points, the approximate surface can be obtained in

Approximate function expressions in intervals

.

Specifically, a cubic polynomial interpolation method can be used, and this method requires 4 interpolation data points, then the approximate function expression is:

；

;

Among them, T ₃ , T ₂ , T ₁ and T ₀ are polynomial coefficients.

Of course, in the specific implementation, other interpolation methods such as triangular interpolation can also be used to approximate the inner curve DE of the corrugated sheath, so as to obtain approximate function expressions of different forms, and the expression forms of the approximate function expressions are omitted here. be limited.

Further, the air volume calculation formula is:

；

;

；d _OA 表示所述皱纹护套的内侧半径；d _O’C 表示所述缓冲层的外侧半径；d _O’B 表示所述绝缘线芯的半径；d _dep 表示所述皱纹深度；d _len 表示所述皱纹节距；d _BB’ 表示所述缓冲层的最薄点厚度；f(ρ)表示所述近似函数表达式；θ _A 表示所述接触临界点的角度。in,

; d _OA represents the inner radius of the corrugated sheath; d _O'C represents the outer radius of the buffer layer; d _O'B represents the radius of the insulated wire core; d _dep represents the depth of the corrugation; d _len represents the The corrugation pitch; d _BB' represents the thickness of the thinnest point of the buffer layer; f(ρ) represents the approximate function expression; θ _A represents the angle of the contact critical point.

方向的直线对称，且单个皱纹节距内的内侧曲面以z=0平面对称，故计算V _A 以及V _C 的值只需要在

区间完成体积计算乘以4倍即可。采用柱坐标系三重积分对V _A ，V _B 以及V _C 进行计算可得：It should be noted that since the projection of the inner surface of the corrugated sheath on the z = 0 plane is

The straight line in the direction is symmetrical, and the inner surface within a single wrinkle pitch is symmetrical with the z ₌ 0 plane, so the calculation of the _{values of VA and VC} only needs to be in the

After the interval is completed, the volume calculation can be multiplied by 4 times. Using the cylindrical coordinate system triple integral to calculate V _A , V _B and V _C , we can get:

。

.

Among them, d _OK is the inner maximum radius of the corrugated sheath; d _OD is the inner minimum radius of the corrugated sheath; d _OC is the distance from the origin O to point C.

方向上，BD两点之间距离有最小值，为缓冲层在重力作用下被挤压最薄点厚度，记为d _BB’ 。可以发现有：In terms of the upper and lower limits of the integral, it is easy to know that in

In the direction, the distance between the two points BD has a minimum value, which is the thickness of the thinnest point where the buffer layer is squeezed under the action of gravity, denoted as d _BB' . It can be found that:

Among them, d _OO' is the distance between the centers of the two circles.

According to the cosine law, it can be found that:

Since d _OC >0, it can be obtained by derivation:

，可以得到单个皱纹节距内的空气体积近似值定积分表达式，也即，所述空气体积计算公式，具体为：According to the calculation formula of V _A , V _B , V _C and d _OC , combined with

, the definite integral expression of the approximate air volume within a single wrinkle pitch can be obtained, that is, the air volume calculation formula, specifically:

。

.

In a specific implementation, the air volume calculation formula can be solved by numerical integration methods, such as trapezoidal method, Simpson's law, Newton-Cotes formula, Romberg method, Gauss integration method, Chebyshev integration method and Monte Carlo method Numerical integration methods such as Luo integration method and its improved form can be used to obtain the above air volume calculation formula, so as to obtain the approximate value of the air volume between the wrinkle sheath and the buffer layer in a single wrinkle pitch, and then obtain the total air volume of the entire cable. Approximate value of volume.

为接触曲面在z=0平面上的投影，对于任意点

，记其坐标为

。在z=0平面上，从原点O向点P做射线，与绝缘线芯的外侧交点记为B；与缓冲层的外侧交点记为C；与皱纹护套的内侧交点记为D；单个皱纹节距内皱纹护套与缓冲层的接触临界点分别为E、F两点；皱纹护套的内侧直径最大点在射线方向上的投影为K点。在电缆轴向方向上，通过对皱纹曲线EDF进行近似，可得到皱纹护套与缓冲层的接触曲面的一个近似曲面。可得到近似曲面在

区间内的函数表达式，也即所述近似函数表达式，具体为：Optionally, as shown in Figure 6, note

is the projection of the contact surface on the z = 0 plane, for any point

, record its coordinates as

. On the z =0 plane, make a ray from the origin O to the point P , and the intersection with the outer side of the insulated core is marked as B ; the intersection with the outer side of the buffer layer is marked as C ; the intersection with the inner side of the corrugated sheath is marked as D ; a single wrinkle The critical points of contact between the corrugated sheath and the buffer layer in the pitch are points E and F respectively; the projection of the largest point of the inner diameter of the corrugated sheath in the ray direction is point K. In the axial direction of the cable, by approximating the corrugated curve EDF , an approximate curved surface of the contact curved surface between the corrugated sheath and the buffer layer can be obtained. An approximate surface can be obtained in

The function expression in the interval, that is, the approximate function expression, is specifically:

；

;

Wherein, d _OA represents the inner radius of the wrinkle sheath; d _dep represents the wrinkle depth; d _len represents the wrinkle pitch.

方向的直线对称，且单个皱纹节距内的内侧曲面以z = 0 平面对称，故计算V _A 以及V _C 的值只需要在

区间完成体积计算乘以4倍即可，则，当所述近似函数表达式为

时，采用柱坐标系三重积分对V _A ，V _B 以及V _C 进行计算可得：On this basis, the specification parameters also include the maximum distance from the center of the corrugated sheath to the outside of the buffer layer on the radial plane. As shown in Fig. 6, in the axial direction of the cable, the wrinkle curve is approximated by a straight line connecting the peak and valley positions of the wrinkle. Since the projection of the inner surface of the wrinkle sheath on the z = 0 plane is

The straight line in the direction is symmetrical, and the inner surface within a single wrinkle pitch is symmetrical with the z ₌ 0 plane, so the calculation of the _{values of VA and VC} only needs to be in the

The volume calculation in the interval can be multiplied by 4 times, then, when the approximate function expression is

When , the triple integral of cylindrical coordinate system is used to calculate V _A , V _B and V _C to get:

和

，可得所述空气体积计算公式为：and combine

and

, the calculation formula of the air volume can be obtained as:

；

;

Wherein, d _O'C represents the outer radius of the buffer layer; d _OC represents the maximum distance from the center of the corrugated sheath to the outer side of the buffer layer; d _BB' represents the thickness of the thinnest point of the buffer layer; θ _A represents the angle of the contact critical point.

In a specific implementation, the air volume calculation formula can be solved by numerical integration methods, such as trapezoidal method, Simpson's law, Newton-Cotes formula, Romberg method, Gauss integration method, Chebyshev integration method and Monte Carlo method Numerical integration methods such as Luo integration method and its improved form can be used to obtain the above air volume calculation formula, so as to obtain the approximate value of the air volume between the wrinkle sheath and the buffer layer in a single wrinkle pitch, and then obtain the total air volume of the entire cable. Approximate value of volume.

Further, according to the thickness of the thinnest point of the buffer layer, the radius of the insulating wire core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the corrugated sheath and the corrugated sheath. The angle of the contact critical point of the buffer layer, including:

S131. Determine whether the thickness of the thinnest point of the buffer layer, the sum of the radius of the insulating wire core and the outer radius of the buffer layer is less than or equal to twice the inner radius of the corrugated sheath;

S132. If yes, then according to the calculation formula of the inner radius of the corrugated sheath, the outer radius of the buffer layer, the radius of the insulating wire core, the thickness of the thinnest point of the buffer layer and the contact critical point angle, the calculation formula is obtained. the angle of the critical point of contact between the corrugated sheath and the buffer layer;

S133, if no, determine that the angle of the contact critical point between the corrugated sheath and the buffer layer is equal to π;

Wherein, the calculation formula of the contact critical point angle is:

；

;

；d _BB’ 表示所述缓冲层的最薄点厚度；d _O’B 表示所述绝缘线芯的半径；d _O’C 表示所述缓冲层的外侧半径；d _OA 表示所述皱纹护套的内侧半径。Among them, θ _A represents the angle of the contact critical point;

; d _BB' represents the thickness of the thinnest point of the buffer layer; d _O'B represents the radius of the insulated wire core; d _O'C represents the outer radius of the buffer layer; d _OA represents the corrugated sheath's radius Inside radius.

。显然，当电缆上方皱纹护套与缓冲层之间存在接触的情况下，即d _BB’ +d _O’B +d _O‘C >2d _OA 时，有

。It should be noted that, referring to Fig. 4, when there is no contact between the corrugated sheath above the cable and the buffer layer, that is, when d _BB' + d _O'B + d _O'C ≤ 2 d _OA , the corrugated sheath is not in contact with the buffer layer. The critical point A in contact with the buffer layer is:

. Obviously, when there is contact between the corrugated sheath above the cable and the buffer layer, that is, d _BB' + d _O'B + d _O'C > 2 d _OA , there is

.

As an optional embodiment, the specification parameters further include an inner maximum radius and an inner minimum radius of the corrugated sheath;

When the reference volume is the total internal volume of the corrugated sheath, acquiring the reference volume of the cable to be tested includes:

S211, according to the corrugation pitch, the inner maximum radius of the corrugated sheath, the inner minimum radius of the corrugated sheath, the approximate function expression, and for calculating the unwound in a single corrugation pitch Calculate the first volume corresponding to the cable to be detected by calculating the formula for the first volume of the insulated wire core covering the buffer layer;

S212, according to the first volume corresponding to the cable to be detected, the total length and the wrinkle pitch, calculate and obtain the total internal volume of the corrugated sheath as a reference volume of the cable to be detected;

Wherein, the calculation formula of the first volume VA is _:

；

;

_Wherein , VA represents the first volume; d _len represents the wrinkle pitch; d _OK represents the inner maximum radius of the corrugated sheath; d _OD represents the inner minimum radius of the corrugated sheath; f(ρ) represents the approximate function expression.

It should be noted that, the derivation process of the calculation formula of VA may _refer to the foregoing embodiments, which will not be repeated here.

。Wherein, the reference volume V _base of the cable to be detected is shown in the following formula:

.

As an optional embodiment, when the reference volume is the total volume of the insulated wire core wrapped with the buffer layer, the acquiring the reference volume of the cable to be tested includes:

S221. According to the outer radius of the buffer layer, the corrugation pitch, and the calculation formula for calculating the second volume of the insulating wire core wrapped with the buffer layer within a single corrugation pitch, obtain the second volume corresponding to the cable to be detected;

S222. Calculate the total volume of the insulated wire core wrapped with the buffer layer according to the second volume corresponding to the cable to be detected, the total length and the wrinkle pitch, as the to-be-detected cable the base volume of the cable;

Wherein, the calculation formula of the second volume is:

；

;

Wherein, VB represents the second volume; d _len represents the wrinkle pitch; d _O'C represents the outer radius _of the buffer layer.

It should be noted that, the derivation process of the calculation formula of VB may _refer to the foregoing embodiments, which will not be repeated here.

。Wherein, the reference volume V _base of the cable to be detected is shown in the following formula:

.

As an optional embodiment, the method further includes:

S1', obtaining the total air volume between the corrugated sheath and the buffer layer of the plurality of faulty cables;

S2', obtaining the reference volume of a plurality of the faulty cables;

S3', calculating the ratio of the total air volume of the plurality of faulty cables to the reference volume, to obtain the air ratio of the plurality of faulty cables;

S4', selecting the minimum value among the air ratios of the plurality of faulty cables as the defect ratio threshold.

In one embodiment, the defects existing in the cable may be defects including ablation defects of the buffer layer and insufficient holding force of the corrugated sheath to the insulated wire core, then, the defect ratio threshold may include the buffer layer ablation defect ratio threshold, correspondingly Alternatively, the faulty cable may include a faulty cable with buffer layer ablation, and the buffer layer ablation defect ratio threshold may be obtained by selecting the minimum value among the air ratios of a plurality of faulty cables with buffer layer ablation.

In another embodiment, the defect existing in the cable may also be a defect including insufficient cohesion force of the corrugated sheath to the insulated wire core, then, the defect ratio threshold may be a defect ratio threshold including the cohesion force, and accordingly, the faulty cable may is the faulty cable including the wrinkled sheath with insufficient holding force to the insulated core, then the holding force defect ratio threshold can be obtained by selecting the minimum value among the air ratios of multiple faulty cables with insufficient holding force.

It should be noted that, in steps S1' to S3', the specific calculation method and principle of the total air volume, the reference volume and the ratio of the total air volume to the reference volume of each faulty cable can be referred to the step S1 of the foregoing embodiment. The related descriptions in S3 will not be repeated here.

As an optional embodiment, the method further includes:

S5. When it is determined that the cable to be detected is defective, add the cable to be detected to the risk list;

S6. When it is determined that the risk list output condition is satisfied, output the risk list to the setting terminal.

The risk list output condition may be set according to actual needs, for example, set to determine that the number of detections reaches a set number, or set to receive a request for obtaining a risk list from a user, and the like.

In a specific implementation, the risk list may include information about a plurality of cables to be inspected with defective buffer layers.

In this embodiment, when it is determined that the cable to be detected is defective, the risk list is output to the setting terminal, so that the relevant personnel can receive the defect feedback in time and deal with the defect in time.

The method for detecting a defect of a cable provided in this embodiment is described below with three specific embodiments.

Specific embodiment one:

A1', obtain the total air volume between the corrugated sheath and the buffer layer of multiple faulty cables with buffer layer ablation (hereinafter referred to as faulty cables), specifically including steps A11' to A15':

A11', obtain the total length of multiple faulty cables and the specification parameters within a single wrinkle pitch, as shown in Table 1;

Table 1 Basic data of each faulty cable

A12', obtain the approximate function expression of the contact surface between the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z , and the specific steps include A121' to A122':

区间上平均分布得到插值基点

，k = 1, … , 4，对全部k = 1, … , 4，在各故障电缆上，在不同皱纹内插值基点

位置多点测量皱纹内侧Z方向坐标，取平均值之后可得到插值数据点的坐标

，测量后得到插值数据点坐标如表2所示：A121', because the cubic polynomial interpolation method is used, 4 interpolation data points are required in this embodiment, based on the cylindrical coordinate system ρ-θ-Z , in

Average distribution on the interval to get the interpolation base point

, k = 1, … , 4, for all k = 1, … , 4, on each faulty cable, interpolated base points in different wrinkles

Measure the coordinates of the inner side of the wrinkle in Z direction at multiple points. After taking the average value, the coordinates of the interpolated data points can be obtained.

, the coordinates of the interpolated data points are obtained after measurement, as shown in Table 2:

Table 2 Interpolated data point coordinates for each faulty cable

Interpolated data points Interpolate data point 1 Interpolate data point 2 Interpolate data point 3 Interpolate data point 4 Fault A Section (0.0650, 0, 0) (0.0671, 0, 0.0060) (0.0691, 0, 0.0089) (0.0712, 0, 0.0160) Fault B (0.0606, 0, 0) (0.0627, 0, 0.0061) (0.0649, 0, 0.0089) (0.0670, 0, 0.0140) Fault C section (0.0590, 0, 0) (0.0611, 0, 0.0060) (0.0631, 0, 0.0092) (0.0652, 0, 0.0150)

，k=1,…,4，进行插值计算，得到各故障电缆的接触曲面在柱坐标系ρ-θ-Z下的近似函数表达式

；其中，各故障电缆的近似函数表达式的系数如表3所示。A122', based on interpolated data points

, k =1,...,4, perform interpolation calculation to obtain the approximate function expression of the contact surface of each faulty cable in the cylindrical coordinate system ρ-θ-Z

; Among them, the coefficient of the approximate function expression of each faulty cable is shown in Table 3.

Table 3 Coefficients of approximate function expressions for each faulty cable

A13', according to the thickness of the thinnest point of the buffer layer of each faulty cable, the radius of the insulating core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the critical point of contact between the corrugated sheath and the buffer layer of each faulty cable angle, specifically including steps A131' to A133'.

计算两圆心间距离d _OO’ ，并判断d _BB’ + d _O‘B + d _O’C ≤ 2d _OA 是否成立。A131', for each faulty cable, the formula

Calculate the distance d _OO' between the centers of the two circles, and judge whether d _BB' + d _O'B + d _O'C ≤ 2 d _OA is established.

；A132', if true, the corrugated sheath above the cable is not in contact with the buffer layer, and the critical point angle of the contact between the corrugated sheath and the buffer layer

;

。A133', if not established, the corrugated sheath above the cable is in effective contact with the buffer layer,

.

Among them, the calculation results of each faulty cable are shown in Table 4.

Table 4 Calculation results of the contact critical point angle of each faulty cable

A14', for each faulty cable, calculate the corrugated sheath within a single corrugated pitch according to the air volume calculation formula, the approximate function expression, the angle of the contact critical point, and one or more of the specification parameters The air volume between the buffer layer and the air volume is simplified by the double integral of the following air volume calculation formula V _U , and then the numerical integration method is applied to calculate V _U .

计算得到皱纹护套与缓冲层之间总空气体积V _total 。A15', for each faulty cable, based on air volume, overall length and wrinkle pitch, according to formula

The total air volume V _total between the corrugated sheath and the buffer layer is calculated.

A2', obtain the reference volume of multiple faulty cables, specifically:

计算基准体积，得到

。For all i = 1, …, 3, according to the formula

Calculate the base volume to get

.

A3', calculate the ratio of the total air volume of multiple faulty cables to the reference volume, and obtain the air ratio of multiple faulty cables, specifically:

进行空气比率计算，得到w(l _i )。According to the formula

Perform an air ratio calculation to obtain w ( l _i ).

The calculation results of the above steps A14', A15', A2' and A3' are shown in Table 5.

Table 5 Calculation results of steps A14', A15', A2' and A3'

，依据公式

选取多条故障电缆的空气比率中的最小值作为缺陷比率阈值t。在本具体实施例中，计算可得，t=7.5476%。A4', the aggregate calculation to obtain the air ratio set of the faulty cable section

, according to the formula

The minimum value among the air ratios of multiple faulty cables is selected as the defect ratio threshold t . In this specific embodiment, the calculation can be obtained, t =7.5476%.

，对全部j = 1, …, 4，获取每一待检测电缆的皱纹护套与缓冲层之间的总空气体积，具体包括步骤A11至A15：A1, collection of cables to be tested for 220kV voltage level

, for all j = 1, ..., 4, obtain the total air volume between the corrugated sheath and the buffer layer of each cable to be tested, specifically including steps A11 to A15:

A11, obtain the total length of multiple cables to be tested and the specification parameters within a single wrinkle pitch, as shown in Table 6;

Table 6 Basic data of each cable to be tested

A12, obtain the approximate function expressions of the contact surfaces of the corrugated sheath and the buffer layer of the plurality of cables to be tested under the cylindrical coordinate system ρ-θ-Z , and the specific steps include A121 to A122:

区间上平均分布得到插值基点

，k = 1, … , 4，对全部k = 1, … , 4，在各待检测电缆上，在不同皱纹内插值基点

位置多点测量皱纹内侧Z方向坐标，取平均值之后可得到插值数据点的坐标

，测量后得到插值数据点坐标如表7所示：A121, since the cubic polynomial interpolation method is used, 4 interpolation data points are required in this embodiment, based on the cylindrical coordinate system ρ-θ-Z , in

Average distribution on the interval to get the interpolation base point

, k = 1, … , 4, for all k = 1, … , 4, on each cable to be tested, interpolate base points in different wrinkles

Measure the coordinates of the inner side of the wrinkle in Z direction at multiple points. After taking the average value, the coordinates of the interpolated data points can be obtained.

, the coordinates of the interpolated data points are obtained after measurement, as shown in Table 7:

Table 7 Interpolated data point coordinates of each cable to be tested

Interpolated data points Interpolate data point 1 Interpolate data point 2 Interpolate data point 3 Interpolate data point 4 in the transport section (0.0608, 0, 0) (0.0628, 0, 0.0060) (0.0648, 0, 0.0090) (0.0668, 0, 0.0150) In transport section B (0.0562, 0, 0) (0.0580, 0, 0.0060) (0.0599, 0, 0.0090) (0.0617, 0, 0.0145) in section C (0.0590, 0, 0) (0.0609, 0, 0.0061) (0.0627, 0, 0.0093) (0.0646, 0, 0.0160) in the Ding section (0.0600, 0, 0) (0.0619, 0, 0.0059) (0.0637, 0, 0.0089) (0.0656, 0, 0.0140)

，k=1,…,4，进行插值计算，得到各待检测电缆的接触曲面在柱坐标系ρ-θ-Z下的近似函数表达式

；其中，各待检测电缆的近似函数表达式的系数如表8所示。A122, based on interpolated data points

, k =1,...,4, perform interpolation calculation, and obtain the approximate function expression of the contact surface of each cable to be tested in the cylindrical coordinate system ρ-θ-Z

; Among them, the coefficients of the approximate function expressions of the cables to be detected are shown in Table 8.

Table 8 Coefficients of approximate function expressions of cables to be tested

A13, according to the thickness of the thinnest point of the buffer layer of each cable to be tested, the radius of the insulating core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the critical contact between the corrugated sheath and the buffer layer of each cable to be tested The angle of the point specifically includes steps A131 to A133.

计算两圆心间距离d _OO’ ，并判断d _BB’ + d _O‘B + d _O’C ≤ 2d _OA 是否成立。A131, for each cable to be tested, the formula

Calculate the distance d _OO' between the centers of the two circles, and judge whether d _BB' + d _O'B + d _O'C ≤ 2 d _OA is established.

；A132, if established, the corrugated sheath above the cable is not in contact with the buffer layer, and the contact critical point angle between the corrugated sheath and the buffer layer

;

。A133, if not established, the corrugated sheath above the cable is in effective contact with the buffer layer,

.

Among them, the calculation results of each cable to be tested are shown in Table 9.

Table 9 The calculation results of the contact critical point angle of each cable to be tested

A14, for each cable to be tested, according to one or more parameters in the air volume calculation formula, approximate function expression, angle of contact critical point and specification parameters, calculate the wrinkle sheath and buffer within a single wrinkle pitch For the air volume between the layers, simplify the double integral of the following air volume calculation formula V _U , and then apply the numerical integration method to calculate V _U .

计算得到皱纹护套与缓冲层之间总空气体积V _total 。A15, for each cable to be tested, based on air volume, total length and wrinkle pitch, according to the formula

The total air volume V _total between the corrugated sheath and the buffer layer is calculated.

A2, obtain the reference volume of multiple cables to be tested, specifically:

计算基准体积，得到

。For all j = 1, …, 4, according to the formula

Calculate the base volume to get

.

A3, calculate the ratio of the total air volume of the multiple cables to be tested to the reference volume, and obtain the air ratio of the multiple cables to be tested, specifically:

进行空气比率计算，得到w(q _j )。For all j = 1, …, 4, according to the formula

Perform an air ratio calculation to obtain w ( q _j ).

The calculation results of the above steps A14, A15, A2 and A3 are shown in Table 10.

Table 10 Calculation results of steps A14, A15, A2 and A3

，对全部j = 1, …,4，进行以下判断：若

，则判定q _j 存在缓冲层烧蚀缺陷，否则，则判定q _j 不存在缓冲层烧蚀缺陷；A4, aggregate calculation to obtain the set of air ratios of the cable segment to be screened

, for all j = 1, ..., 4, make the following judgments: if

, then it is determined that q _j has buffer layer ablation defects, otherwise, it is determined that q _j does not have buffer layer ablation defects;

A5, for all j = 1, ..., 4, when it is determined that q _j has buffer layer ablation defects, q _j is added to the risk list, and the risk list is obtained as: {in section A, in section B};

A6, when it is determined that the risk list output condition is satisfied, output the risk list to the setting terminal.

Specific embodiment two:

A1', obtain the total air volume between the corrugated sheath and the buffer layer of multiple faulty cables with buffer layer ablation (hereinafter referred to as faulty cables), specifically including steps A11' to A15':

A11', obtain the total length of multiple faulty cables and the specification parameters within a single wrinkle pitch, as shown in Table 11.

Table 11 Basic data of each faulty cable

。A12', obtain the approximate function expression of the contact surface between the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z

.

A13', according to the thickness of the thinnest point of the buffer layer of each faulty cable, the radius of the insulating core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the critical point of contact between the corrugated sheath and the buffer layer of each faulty cable angle, specifically including steps A131' to A133'.

计算两圆心间距离d _OO’ ，并判断d _BB’ + d _O‘B + d _O’C ≤ 2d _OA 是否成立。A131', for each faulty cable, the formula

Calculate the distance d _OO' between the centers of the two circles, and judge whether d _BB' + d _O'B + d _O'C ≤ 2 d _OA is established.

；A132', if true, the corrugated sheath above the cable is not in contact with the buffer layer, and the critical point angle of the contact between the corrugated sheath and the buffer layer

;

。A133', if not established, the corrugated sheath above the cable is in effective contact with the buffer layer,

.

Among them, the calculation results of each faulty cable are shown in Table 12.

Table 12 Calculation results of contact critical point angle of each faulty cable

A14', for each faulty cable, calculate the corrugated sheath within a single corrugated pitch according to the air volume calculation formula, the approximate function expression, the angle of the contact critical point, and one or more of the specification parameters The air volume between the buffer layer and the air volume is simplified by the double integral of the following air volume calculation formula V _U , and then the numerical integration method is applied to calculate V _U .

计算得到皱纹护套与缓冲层之间总空气体积V _total 。A15', for each faulty cable, based on air volume, overall length and wrinkle pitch, according to formula

The total air volume V _total between the corrugated sheath and the buffer layer is calculated.

A2', obtain the reference volume of multiple faulty cables, specifically:

计算基准体积，得到

。For all i = 1, …, 3, according to the formula

Calculate the base volume to get

.

计算多条故障电缆的总空气体积与基准体积的比率，得到多条所述故障电缆的空气比率w(l _i )。A3', according to the formula

Calculate the ratio of the total air volume of the plurality of faulty cables to the reference volume, and obtain the air ratio w ( li ₎ of the plurality of faulty cables.

The calculation results of the above steps A14', A15', A2' and A3' are shown in Table 13.

Table 13 Calculation results of steps A14', A15', A2' and A3'

，依据公式

选取多条故障电缆的空气比率中的最小值作为缺陷比率阈值t。在本具体实施例中，计算可得，t=7.5114%。A4', the aggregate calculation to obtain the air ratio set of the faulty cable section

, according to the formula

The minimum value among the air ratios of multiple faulty cables is selected as the defect ratio threshold t . In this specific embodiment, the calculation can be obtained, t =7.5114%.

，对全部j = 1, …, 4，获取每一待检测电缆的皱纹护套与缓冲层之间的总空气体积。A1, collection of cables to be tested for 220kV voltage level

, for all j = 1, …, 4, obtain the total air volume between the corrugated jacket and the buffer layer of each cable to be tested.

A11, obtain the total length of multiple cables to be tested and the specification parameters within a single wrinkle pitch, as shown in Table 14;

Table 14 Basic data of each cable to be tested

。A12, obtain the approximate function expression of the contact surfaces of the corrugated sheath and the buffer layer of the plurality of cables to be tested in the cylindrical coordinate system ρ-θ-Z

.

A13, according to the thickness of the thinnest point of the buffer layer of each cable to be tested, the radius of the insulating core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the critical contact between the corrugated sheath and the buffer layer of each cable to be tested The angle of the point specifically includes steps A131 to A133.

计算两圆心间距离d _OO’ ，并判断d _BB’ + d _O‘B + d _O’C ≤ 2d _OA 是否成立。A131, for each cable to be tested, the formula

Calculate the distance d _OO' between the centers of the two circles, and judge whether d _BB' + d _O'B + d _O'C ≤ 2 d _OA is established.

；A132, if established, the corrugated sheath above the cable is not in contact with the buffer layer, and the contact critical point angle between the corrugated sheath and the buffer layer

;

。A133, if not established, the corrugated sheath above the cable is in effective contact with the buffer layer,

.

Among them, the calculation results of each cable to be tested are shown in Table 15.

Table 15 Calculation results of the contact critical point angle of each cable to be tested

A14, for each cable to be tested, according to one or more parameters in the air volume calculation formula, approximate function expression, angle of contact critical point and specification parameters, calculate the wrinkle sheath and buffer within a single wrinkle pitch For the air volume between the layers, simplify the double integral of the following air volume calculation formula V _U , and then apply the numerical integration method to calculate V _U .

计算得到皱纹护套与缓冲层之间总空气体积V _total 。A15, for each cable to be tested, based on air volume, total length and wrinkle pitch, according to the formula

The total air volume V _total between the corrugated sheath and the buffer layer is calculated.

A2, obtain the reference volume of multiple cables to be tested, specifically:

计算基准体积，得到

。For all j = 1, …, 4, according to the formula

Calculate the base volume to get

.

A3, calculate the ratio of the total air volume of the multiple cables to be tested to the reference volume, and obtain the air ratio of the multiple cables to be tested, specifically:

进行空气比率计算，得到w(q _j )。For all j = 1, …, 4, according to the formula

Perform an air ratio calculation to obtain w ( q _j ).

The calculation results of the above steps A14, A15, A2 and A3 are shown in Table 16.

Table 16 Calculation results of steps A14, A15, A2 and A3

，对全部j = 1, …,4，进行以下判断：若

，则判定q _j 存在缓冲层烧蚀缺陷，否则，则判定q _j 不存在缓冲层烧蚀缺陷；A4, aggregate calculation to obtain the set of air ratios of the cable segment to be screened

, for all j = 1, ..., 4, make the following judgments: if

, then it is determined that q _j has buffer layer ablation defects, otherwise, it is determined that q _j does not have buffer layer ablation defects;

A5, for all j = 1, ..., 4, when it is determined that q _j has buffer layer ablation defects, q _j is added to the risk list, and the risk list is obtained as: {in section A, in section B};

A6, when it is determined that the risk list output condition is satisfied, output the risk list to the setting terminal.

Specific embodiment three:

_A10 ', obtain the total length of the faulty cable li and the specification parameters within a single wrinkle pitch, as shown in Table 17;

Table 17 Basic data for each faulty cable

A11', for all i = 1 , _. record, and the basic data obtained in step A10' is the same as the historical data, then directly obtain the calculation result record of the faulty cable as the air ratio, if there is no air ratio calculation result record, or the basic data obtained in step A10' If the data is not the same as the historical data, execute A12' to A3' to obtain the air ratio of the faulty cable. After obtaining the air ratio of all faulty cables, go to step A4'.

。A12', obtain the approximate function expression of the contact surface between the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ-Z

.

A13', according to the thickness of the thinnest point of the buffer layer of the faulty cable, the radius of the insulating core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the angle of the critical point of contact between the corrugated sheath of the faulty cable and the buffer layer , specifically including steps A131' to A133'.

计算两圆心间距离d _OO’ ，并判断d _BB’ + d _O‘B +d _O’C ≤ 2d _OA 是否成立。A131', with the formula

Calculate the distance d _OO' between the centers of the two circles, and judge whether d _BB' + d _O'B + d _O'C ≤ 2 d _OA is established.

；A132', if true, the corrugated sheath above the faulty cable is not in contact with the buffer layer, and the contact critical point angle between the corrugated sheath and the buffer layer

;

。A133', if not established, the corrugated sheath above the faulty cable is in effective contact with the buffer layer,

.

Among them, the calculation results of each faulty cable are shown in Table 18.

Table 18 Calculation results of contact critical point angle of each faulty cable

A14', according to the air volume calculation formula, the approximate function expression, the angle of the contact critical point, and one or more parameters in the specification parameters, calculate the air volume between the wrinkle sheath and the buffer layer within a single wrinkle pitch Air volume, simplify the double integral of the following air volume calculation formula V _U , and then apply the numerical integration method to calculate V _U .

计算得到皱纹护套与缓冲层之间总空气体积V _total 。A15', based on air volume, overall length and wrinkle pitch, according to formula

The total air volume V _total between the corrugated sheath and the buffer layer is calculated.

A2', obtain the reference volume of the faulty cable, specifically:

计算基准体积，得到

。According to the formula

Calculate the base volume to get

.

计算故障电缆的总空气体积与基准体积的比率，得到故障电缆的空气比率w(l _i )。A3', according to the formula

Calculate the ratio of the total air volume of the faulty cable to the reference volume to obtain the air ratio w ( l _i ) of the faulty cable.

The calculation results of the above steps A14', A15', A2' and A3' are shown in Table 19.

Table 19 Calculation results of steps A14', A15', A2' and A3'

，依据公式

选取多条故障电缆的空气比率中的最小值作为缺陷比率阈值t。在本具体实施例中，计算可得，t=7.0258%。A4', the aggregate calculation to obtain the air ratio set of the faulty cable section

, according to the formula

The minimum value among the air ratios of multiple faulty cables is selected as the defect ratio threshold t . In this specific embodiment, it can be calculated that t =7.0258%.

，对全部j = 1, …, 3，获取多条待检测电缆的总长度和在单个皱纹节距内的规格参数，如表20所示；A10, for 220kV voltage level cable collection to be tested

, for all j = 1, …, 3, obtain the total length of multiple cables to be tested and the specification parameters within a single wrinkle pitch, as shown in Table 20;

Table 20 Basic data of each cable to be tested

_A11 , for all j = 1, . Record, and the basic data obtained in step A10' is the same as the historical data, then directly obtain the calculation result record of the cable to be detected as the air ratio, if there is no calculation result record of the air ratio, or the basis obtained in step A10 If the data is not the same as the historical data, execute A12 to A3 to obtain the air ratio of the cable to be detected; after obtaining the air ratio of all cables to be detected, go to step A4. In this embodiment, for j = 1, . . . , 3, the air ratio has saved results and the data required by the air volume calculation method is no different from the historical data, so w ( q _j ) can be directly obtained, and step A4 is entered.

。A12, obtain the approximate function expression of the contact surface between the corrugated sheath and the buffer layer of the cable to be tested in the cylindrical coordinate system ρ-θ-Z

.

A13, according to the thickness of the thinnest point of the buffer layer of each cable to be tested, the radius of the insulating core, the outer radius of the buffer layer and the inner radius of the corrugated sheath, determine the critical contact between the corrugated sheath and the buffer layer of each cable to be tested The angle of the point specifically includes steps A131 to A133.

计算两圆心间距离d _OO’ ，并判断d _BB’ + d _O‘B + d _O’C ≤ 2d _OA 是否成立。A131, for each cable to be tested, the formula

Calculate the distance d _OO' between the centers of the two circles, and judge whether d _BB' + d _O'B + d _O'C ≤ 2 d _OA is established.

；A132, if established, the corrugated sheath above the cable is not in contact with the buffer layer, and the contact critical point angle between the corrugated sheath and the buffer layer

;

。A133, if not established, the corrugated sheath above the cable is in effective contact with the buffer layer,

.

A14, for each cable to be tested, according to one or more parameters in the air volume calculation formula, approximate function expression, angle of contact critical point and specification parameters, calculate the wrinkle sheath and buffer within a single wrinkle pitch For the air volume between the layers, simplify the double integral of the following air volume calculation formula V _U , and then apply the numerical integration method to calculate V _U .

计算得到皱纹护套与缓冲层之间总空气体积V _total 。A15, for each cable to be tested, based on air volume, total length and wrinkle pitch, according to the formula

The total air volume V _total between the corrugated sheath and the buffer layer is calculated.

A2, obtain the reference volume of the cable to be tested, specifically:

计算基准体积，得到

。According to the formula

Calculate the base volume to get

.

A3, calculate the ratio of the total air volume of the cable to be detected to the reference volume, and obtain the air ratio of the cable to be detected, specifically:

进行空气比率计算，得到w(q _j )。According to the formula

Perform an air ratio calculation to obtain w ( q _j ).

，各待检测电缆的空气比率如表21所示。对全部j = 1, …, 3，进行以下判断：若

，则判定q _j 存在缓冲层烧蚀缺陷，否则，则判定q _j 不存在缓冲层烧蚀缺陷。A4, aggregate calculation to obtain the set of air ratios of the cable segment to be screened

, the air ratio of each cable to be tested is shown in Table 21. For all j = 1, …, 3, make the following judgments: if

, then it is determined that q _j has a buffer layer ablation defect, otherwise, it is determined that q _j does not have a buffer layer ablation defect.

Table 21 Air ratio of the cable to be tested

Cable segment name Air ratio w (%) In transport section B 19.6336 in section C 6.2844 in the Ding section 1.7596

A5, for all j = 1, ..., 3, when it is determined that q _j has buffer layer ablation defects, q _j is added to the risk list, and the risk list is obtained as: {in this paragraph B}.

A6, when it is determined that the risk list output condition is satisfied, output the risk list to the setting terminal.

It should be noted that the specific embodiment 3 is aimed at the scene that when a defect in the buffer layer of the cable in Section A is detected, after the actual measurement and update of data are performed on the faulty section in Section A, the buffer layer needs to be ablated again. Conditions for screening of risky cable segments.

Referring to FIG. 7 , FIG. 7 is a structural block diagram of a cable defect detection device provided by an embodiment of the present invention.

The cable defect detection device provided by this embodiment includes:

an air volume acquisition module 21 for acquiring the total air volume between the corrugated sheath and the buffer layer of the cable to be tested;

The reference volume acquisition module 22 is used to acquire the reference volume of the cable to be detected; wherein, the reference volume is the total volume of the insulated wire core not wrapped with the buffer layer, the insulated wire wrapped with the buffer layer the total volume of the core or the total internal volume of the corrugated sheath;

The air ratio calculation module 23 is used to calculate the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected;

Defect judgment module 24, for judging whether the air ratio of the cable to be detected is greater than or equal to the defect ratio threshold, if yes, then it is determined that the cable to be detected is defective, if not, it is determined that the cable to be detected is not defective; The defect ratio threshold is configured according to the ratio of the total air volume between the corrugated jacket and the buffer layer of the at least one faulty cable to the reference volume.

As an optional embodiment, the air volume acquisition module specifically includes:

A parameter acquisition unit, used to acquire the total length of the cable to be tested and the specification parameters within a single wrinkle pitch; wherein, the specification parameters include the inner radius of the corrugated sheath, the outer radius of the buffer layer, and the unwrapped buffer the radius of the insulated core of the layer, the wrinkle pitch, the wrinkle depth and the thinnest point thickness of the buffer layer;

The function acquisition unit is used to acquire the approximate function expression of the contact surface of the corrugated sheath and the buffer layer in the cylindrical coordinate system ρ-θ- Z ; wherein, the pole of the cylindrical coordinate system is the corrugated sheath The center of the sleeve, the polar axis is any radial direction of the center of the corrugated sheath, and the Z-axis direction is the axial direction of the cable;

An angle obtaining unit, configured to determine the relationship between the corrugated sheath and the corrugated sheath according to the thickness of the thinnest point of the buffer layer, the radius of the insulated wire core, the outer radius of the buffer layer and the inner radius of the corrugated sheath the angle of the contact critical point of the buffer layer;

The first volume acquisition unit is configured to calculate the single wrinkle pitch according to one or more parameters in the air volume calculation formula, the approximate function expression, the angle of the contact critical point and the specification parameters. The air volume between the corrugated sheath and the buffer layer; wherein, the air volume calculation formula is based on the air volume between the corrugated sheath and the buffer layer, the volume of the corrugated sheath determined by the corresponding relationship between the internal volume, the volume of the insulated wire core wrapped with the buffer layer and the volume of the force-deformed portion of the buffer layer;

The second volume obtaining unit is configured to calculate the total air volume between the corrugated sheath and the buffer layer according to the air volume, the total length and the corrugated pitch.

Further, the function acquisition unit is specifically used for:

，k=1，…，n；Based on the cylindrical coordinate system ρ-θ-Z , n interpolation data points are selected from the contact surface between the corrugated sheath and the buffer layer; wherein, the coordinates of the k-th interpolation data point are

, k=1,...,n;

The interpolation calculation is performed according to the n interpolation data points to obtain an approximate function expression of the contact surface in the cylindrical coordinate system ρ-θ-Z .

Further, the air volume calculation formula is:

；

;

；d _OA 表示所述皱纹护套的内侧半径；d _O’C 表示所述缓冲层的外侧半径；d _O’B 表示所述绝缘线芯的半径；d _dep 表示所述皱纹深度；d _len 表示所述皱纹节距；d _BB’ 表示所述缓冲层的最薄点厚度；f(ρ)表示所述近似函数表达式；θ _A 表示所述接触临界点的角度。in,

; d _OA represents the inner radius of the corrugated sheath; d _O'C represents the outer radius of the buffer layer; d _O'B represents the radius of the insulated wire core; d _dep represents the depth of the corrugation; d _len represents the The corrugation pitch; d _BB' represents the thickness of the thinnest point of the buffer layer; f(ρ) represents the approximate function expression; θ _A represents the angle of the contact critical point.

Further, the approximate function expression is:

；

;

Among them, T ₃ , T ₂ , T ₁ and T ₀ are polynomial coefficients.

Optionally, the approximate function expression is:

；

;

Wherein, d _OA represents the inner radius of the wrinkle sheath; d _dep represents the wrinkle depth; d _len represents the wrinkle pitch.

Further, the specification parameters also include, on the radial plane, the maximum distance from the center of the corrugated sheath to the outside of the buffer layer;

时，所述空气体积计算公式为：When the approximate function expression is

, the air volume calculation formula is:

；

;

Wherein, d _O'C represents the outer radius of the buffer layer; d _OC represents the maximum distance from the center of the corrugated sheath to the outer side of the buffer layer; θ _A represents the angle of the contact critical point.

Further, the angle obtaining unit is specifically used for:

Determine whether the sum of the thickness of the thinnest point of the buffer layer, the radius of the insulating wire core and the outer radius of the buffer layer is less than or equal to twice the inner radius of the corrugated sheath;

If yes, then according to the calculation formula of the inner radius of the corrugated sheath, the outer radius of the buffer layer, the radius of the insulating wire core, the thickness of the thinnest point of the buffer layer and the angle of the contact critical point, the the angle of the critical point of contact between the corrugated sheath and the buffer layer;

If not, determining that the angle of the critical point of contact between the corrugated sheath and the buffer layer is equal to π;

Wherein, the calculation formula of the contact critical point angle is:

；

;

；d _BB’ 表示所述缓冲层的最薄点厚度；d _O’B 表示所述绝缘线芯的半径；d _O’C 表示所述缓冲层的外侧半径；d _OA 表示所述皱纹护套的内侧半径。Among them, θ _A represents the angle of the contact critical point;

; d _BB' represents the thickness of the thinnest point of the buffer layer; d _O'B represents the radius of the insulated wire core; d _O'C represents the outer radius of the buffer layer; d _OA represents the corrugated sheath's radius Inside radius.

Further, the specification parameters also include the inner maximum radius and inner minimum radius of the corrugated sheath;

When the reference volume is the total internal volume of the corrugated sheath, the reference volume acquisition module is specifically used for:

According to the corrugation pitch, the inner maximum radius of the corrugated sheath, the inner minimum radius of the corrugated sheath, the approximate function expression and the calculation of the The calculation formula of the first volume of the insulated wire core of the buffer layer is used to calculate the first volume corresponding to the cable to be detected;

According to the corresponding first volume of the cable to be detected, the total length and the corrugated pitch, the total internal volume of the corrugated sheath is calculated to be used as the reference volume of the cable to be detected;

Wherein, the calculation formula of the first volume VA is _:

；

;

_Wherein , VA represents the first volume; d _len represents the wrinkle pitch; d _OK represents the inner maximum radius of the corrugated sheath; d _OD represents the inner minimum radius of the corrugated sheath; f(ρ) represents the approximate function expression.

Further, when the reference volume is the total volume of the insulated wire core wrapped with the buffer layer, the reference volume acquisition module is specifically used for:

According to the outer radius of the buffer layer, the corrugation pitch and the calculation formula for calculating the second volume of the insulated wire core wrapped with the buffer layer within a single corrugation pitch, the calculation is obtained. the second volume corresponding to the cable to be detected;

According to the second volume corresponding to the cable to be detected, the total length and the wrinkle pitch, the total volume of the insulated wire core wrapped with the buffer layer is calculated and obtained as the total volume of the cable to be detected. base volume;

Wherein, the calculation formula of the second volume is:

；

;

Wherein, VB represents the second volume; d _len represents the wrinkle pitch; d _O'C represents the outer radius _of the buffer layer.

As an optional embodiment, the apparatus further includes a threshold acquisition module, which is specifically used for:

obtaining the total air volume between the corrugated jacket and the buffer layer of the plurality of said faulty cables;

obtaining the reference volume of a plurality of the faulty cables;

Calculate the ratio of the total air volume of the plurality of faulty cables to the reference volume to obtain the air ratio of the plurality of faulty cables;

The minimum value among the air ratios of the plurality of faulty cables is selected as the defect ratio threshold.

As an optional embodiment, the device further includes a risk list output module, which is specifically used for:

When it is determined that the cable to be inspected is defective, adding the cable to be inspected to the risk list;

When it is determined that the risk list output condition is satisfied, the risk list is output to the setting terminal.

The cable defect detection device disclosed in the embodiment of the present invention obtains the total air volume between the corrugated sheath and the buffer layer of the cable to be detected and the reference volume of the cable to be detected, and calculates the total air volume and reference volume of the cable to be detected. ratio to obtain the air ratio of the cable to be tested, and then compare the air ratio of the cable to be tested to the defect ratio configured according to the ratio of the total air volume between the corrugated jacket and the buffer layer of at least one faulty cable and the reference volume The magnitude relationship between the thresholds is used to determine whether the cable to be tested has defects, so that the defect of the cable can be accurately detected.

Referring to FIG. 8 , it is a schematic structural diagram of a terminal device provided by an embodiment of the present invention.

A terminal device provided by an embodiment of the present invention includes a processor 310, a memory 320, and a computer program stored in the memory 320 and configured to be executed by the processor 310, where the processor 310 executes the computer In the program, the method for detecting the defect of the cable as described in any of the above embodiments is realized.

When the processor 310 executes the computer program, the steps in the above embodiments of the cable defect detection method are implemented, for example, all steps of the cable defect detection method shown in FIG. 1 . Alternatively, when the processor 310 executes the computer program, the functions of each module/unit in the above-mentioned embodiment of the cable defect detection apparatus, for example, the functions of each module of the cable defect detection apparatus shown in FIG. 7 are realized.

Exemplarily, the computer program may be divided into one or more modules, and the one or more modules are stored in the memory 320 and executed by the processor 310 to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal device. For example, the computer program can be divided into an air volume acquisition module, a reference volume acquisition module, an air ratio calculation module and a defect judgment module, and the specific functions of each module are as follows: an air volume acquisition module for acquiring the corrugated sheath of the cable to be tested The total air volume between the buffer layer and the buffer layer; the reference volume acquisition module is used to obtain the reference volume of the cable to be detected; wherein, the reference volume is the total volume of the insulated wire core not wrapped around the buffer layer, and the surrounding The total volume of the insulated wire core covered with the buffer layer or the internal total volume of the corrugated sheath; the air ratio calculation module is used to calculate the ratio of the total air volume of the cable to be tested to the reference volume to obtain the The air ratio of the cable to be tested; the defect judgment module is used to judge whether the air ratio of the cable to be tested is greater than or equal to the defect ratio threshold, if so, it is determined that the cable to be tested is defective, if not, it is determined that the cable to be tested is defective The detection cable is free of defects; wherein the defect ratio threshold is configured according to the ratio of the total air volume and the reference volume between the corrugated jacket and the buffer layer of the at least one faulty cable.

The terminal device may be a computing device such as a desktop computer, a notebook, a palmtop computer, and a cloud server. The terminal device may include, but is not limited to, the processor 310 and the memory 320 . Those skilled in the art can understand that the schematic diagram is only an example of a terminal device, and does not constitute a limitation to the terminal device, and may include more or less components than the one shown in the figure, or combine some components, or different components, For example, the terminal device may further include an input and output device, a network access device, a bus, and the like.

The so-called processor 310 may be a central processing unit (Central Processing Unit, CPU), and may also be other general-purpose processors, digital signal processors (Digital Signal Processors, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), Field-Programmable Gate Array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The processor 310 is the control center of the terminal device, and uses various interfaces and lines to connect various parts of the entire terminal device.

The memory 320 can be used to store the computer program and/or module, and the processor 310 can call the data stored in the memory 320 by running or executing the computer program and/or module stored in the memory 320, Various functions of the terminal device are realized. The memory 320 may mainly include a stored program area and a stored data area, wherein the stored program area may store an operating system, an application program required for at least one function (such as a sound playback function, an image playback function, etc.), and the like; the storage data area may Stores data created according to the use of the terminal device (such as audio data, phone book, etc.), etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory such as hard disk, internal memory, plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, at least one magnetic disk storage device, flash memory device, or other volatile solid state storage device.

Wherein, if the modules/units integrated in the terminal device are implemented in the form of software functional units and sold or used as independent products, they may be stored in a computer-readable storage medium. Based on this understanding, the present invention can implement all or part of the processes in the methods of the above embodiments, and can also be completed by instructing relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the program is executed by the processor, the steps of the foregoing method embodiments can be implemented. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form, and the like. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, removable hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory) , Random Access Memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc.

It should be noted that the device embodiments described above are only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical unit, that is, it can be located in one place, or it can be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution in this embodiment. In addition, in the drawings of the apparatus embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art can understand and implement it without creative effort.

The above are the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made, and these improvements and modifications may also be regarded as It is the protection scope of the present invention.

Claims (15)

1. A method of detecting defects in a cable, comprising:

acquiring the total air volume between a corrugated sheath and a buffer layer of a cable to be detected;

acquiring the reference volume of the cable to be detected; the reference volume is the total volume of the insulated wire core which is not wrapped with the buffer layer, the total volume of the insulated wire core wrapped with the buffer layer or the total volume of the inside of the corrugated sheath;

calculating the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected;

judging whether the air ratio of the cable to be detected is greater than or equal to a defect ratio threshold value, if so, judging that the cable to be detected has defects, and if not, judging that the cable to be detected does not have defects; wherein the defect ratio threshold is configured according to a ratio of a total air volume between the corrugated sheath and the buffer layer of the at least one faulty cable to a baseline volume.

2. The method of claim 1, wherein said obtaining a total air volume between a corrugated sheath and a buffer layer of a cable to be tested comprises:

acquiring the total length of a cable to be detected and specification parameters within a single wrinkle pitch; wherein the specification parameters comprise an inside radius of the corrugated sheath, an outside radius of the buffer layer, a radius of the insulated wire core not wrapped around the buffer layer, the corrugated pitch, the corrugated depth and the thinnest point thickness of the buffer layer;

obtaining the contact curved surface of the wrinkle sheath and the buffer layer in a cylindrical coordinate systemρ-θ-ZAn approximate function expression of; the polar point of the cylindrical coordinate system is the center of the corrugated sheath, the polar axis is any radial direction of the center of the corrugated sheath, and the Z-axis direction is the axial direction of the cable;

determining the angle of the contact critical point of the corrugated sheath and the buffer layer according to the thinnest point thickness of the buffer layer, the radius of the insulated wire core, the outer radius of the buffer layer and the inner radius of the corrugated sheath;

calculating an air volume between the crepe sheath and the breaker ply within a single crepe pitch according to one or more of an air volume calculation formula, the approximate functional expression, the angle of the contact critical point, and the specification parameters; wherein the air volume calculation formula is determined according to the corresponding relation between the air volume between the corrugated sheath and the buffer layer, the internal volume of the corrugated sheath, the volume of the insulated wire core wrapped with the buffer layer and the volume of the stressed deformation part of the buffer layer;

calculating the total air volume between the corrugated sheath and the cushioning layer according to the air volume, the total length and the corrugated pitch.

3. The method for detecting defects in an electrical cable of claim 2, wherein said obtaining a curved contact surface of said corrugated sheath and said buffer layer is performed in a cylindrical coordinate systemρ-θ-ZThe following approximate functional expression, comprising:

based on cylindrical coordinate systemρ-θ-ZSelecting n interpolation data points from the contact curved surface of the wrinkle sheath and the buffer layer; wherein the coordinates of the kth interpolated data point is

，k=1，…，n；

Carrying out interpolation calculation according to the n interpolation data points to obtain the contact curved surface in the cylindrical coordinate systemρ-θ-ZThe following approximate function expression.

4. The method for detecting defects in an electrical cable according to claim 3, wherein said air volume calculation formula is:

；

wherein,

；

representing a volume of air between the corrugated sheath and the cushion layer within a single one of the corrugated pitches;d _OA represents the inside radius of the corrugated sheath;d _O’C represents an outside radius of the buffer layer;d _O’B represents a radius of the insulated wire core;d _dep representing the wrinkle depth;d _len representing the wrinkle pitch;d _BB’ represents the thinnest point thickness of the buffer layer;f(ρ)representing the approximate function expression;θ _A representing the angle of the critical point of contact.

5. The method for detecting defects in an electrical cable according to claim 3, wherein said approximation function expression is:

；

wherein,T ₃ 、T ₂ 、T ₁ andT ₀ is a polynomial coefficient.

6. The method for detecting defects in an electrical cable according to claim 2, wherein said approximation function expression is:

；

wherein,d _OA represents the inside radius of the corrugated sheath;d _dep representing the wrinkle depth;d _len the corrugation pitch is indicated.

7. The method of defect detection of cable of claim 6, wherein said gauge parameters further include a maximum distance, in a radial plane, from a center of said corrugated jacket to an outer side of said buffer layer;

when the approximate function expression is

The air volume calculation formula is as follows:

；

wherein,

representing a volume of air between the corrugated sheath and the cushion layer within a single one of the corrugated pitches;d _O’C represents an outside radius of the buffer layer;d _OC represents the maximum distance from the center of the corrugated sheath to the outside of the cushioning layer;θ _A representing the angle of the critical point of contact.

8. The method of detecting defects in an electrical cable according to claim 2, wherein said determining an angle of a critical point of contact of said corrugated jacket with said buffer layer based on a thinnest point thickness of said buffer layer, a radius of said insulated wire core, an outside radius of said buffer layer, and an inside radius of said corrugated jacket comprises:

judging whether the thickness of the thinnest point of the buffer layer, the sum of the radius of the insulated wire core and the outer radius of the buffer layer are smaller than or equal to two times of the inner radius of the corrugated sheath or not;

if so, calculating to obtain the angle of the contact critical point of the corrugated sheath and the buffer layer according to the calculation formula of the inner radius of the corrugated sheath, the outer radius of the buffer layer, the radius of the insulated wire core, the thinnest point thickness of the buffer layer and the angle of the contact critical point;

if not, determining that the angle of the contact critical point of the wrinkle sheath and the buffer layer is equal to pi;

wherein, the contact critical point angle calculation formula is as follows:

；

wherein,θ _A represents the angle of the critical point of contact;

；d _BB’ represents the thinnest point thickness of the buffer layer;d _O’B represents a radius of the insulated wire core;d _O’C represents an outside radius of the buffer layer;d _OA representing the inside radius of the corrugated sheath.

9. The method of defect detection of cable of claim 2, wherein said gauge parameters further comprise an inside maximum radius and an inside minimum radius of said corrugated sheath;

when the reference volume is the total internal volume of the corrugated sheath, the obtaining of the reference volume of the cable to be detected includes:

calculating to obtain a first volume corresponding to the cable to be detected according to the wrinkle pitch, the maximum radius of the inner side of the wrinkle sheath, the minimum radius of the inner side of the wrinkle sheath, the approximate function expression and a calculation formula for calculating the first volume of the insulated wire cores which are not wrapped with the buffer layer in the single wrinkle pitch;

calculating to obtain the total internal volume of the corrugated sheath according to the first volume, the total length and the corrugated pitch corresponding to the cable to be detected, and taking the total internal volume as the reference volume of the cable to be detected;

wherein the calculation formula of the first volume is as follows:

；

wherein,V _A representing the first volume;d _len representing the wrinkle pitch;d _OK represents the inside maximum radius of the corrugated sheath;d _OD represents an inside minimum radius of the corrugated sheath;f(ρ)representing the approximate function expression.

10. The method for detecting the defects of the cable according to claim 2, wherein when the reference volume is the total volume of the insulated wire core wrapped with the buffer layer, the obtaining of the reference volume of the cable to be detected comprises:

calculating to obtain a second volume corresponding to the cable to be detected according to the outside radius of the buffer layer, the wrinkle pitch and a calculation formula for calculating the second volume of the insulated wire core wrapped with the buffer layer in the single wrinkle pitch;

calculating to obtain the total volume of the insulated wire core wrapped with the buffer layer according to the second volume corresponding to the cable to be detected, the total length and the wrinkle pitch, and taking the total volume as the reference volume of the cable to be detected;

wherein the calculation formula of the second volume is:

；

wherein,V _B representing the second volume;d _len representing the wrinkle pitch;d _O’C representing the outside radius of the buffer layer.

11. The method of defect detection of a cable according to claim 1, further comprising:

obtaining a total air volume between a corrugated sheath and a buffer layer of a plurality of the faulty cables;

acquiring reference volumes of a plurality of fault cables;

calculating the ratio of the total air volume of the fault cables to a reference volume to obtain the air ratio of the fault cables;

selecting the minimum value of the air ratios of the fault cables as the defect ratio threshold value.

12. The method of defect detection of a cable according to claim 1, further comprising:

when the cable to be detected is judged to have defects, adding the cable to be detected into a risk list;

and outputting the risk list to a set terminal when the condition for outputting the risk list is determined to be met.

13. A defect detection apparatus for a cable, comprising:

the air volume acquisition module is used for acquiring the total air volume between the corrugated sheath and the buffer layer of the cable to be detected;

the reference volume acquisition module is used for acquiring the reference volume of the cable to be detected; the reference volume is the total volume of the insulated wire core which is not wrapped with the buffer layer, the total volume of the insulated wire core wrapped with the buffer layer or the total volume of the inside of the corrugated sheath;

the air ratio calculation module is used for calculating the ratio of the total air volume of the cable to be detected to the reference volume to obtain the air ratio of the cable to be detected;

the defect judging module is used for judging whether the air ratio of the cable to be detected is greater than or equal to a defect ratio threshold value, if so, judging that the cable to be detected has defects, and if not, judging that the cable to be detected does not have defects; wherein the defect ratio threshold is configured according to a ratio of a total air volume between the corrugated sheath and the buffer layer of the at least one faulty cable to a baseline volume.

14. A terminal device comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, the processor implementing a method of defect detection of a cable according to any one of claims 1 to 12 when executing the computer program.

15. A computer-readable storage medium, comprising a stored computer program, wherein the computer program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform a method for defect detection of a cable according to any one of claims 1 to 12.

Images