Cable assembly strong electromagnetic pulse shielding effectiveness evaluation method

Abstract

The invention provides a strong electromagnetic pulse shielding effectiveness evaluation method for a cable assembly, and the method comprises the following steps: 1), carrying out the induction and classification of influence factors which affect the strong electromagnetic pulse shielding effectiveness of the cable assembly through an electromagnetic topological structure according to an analytic hierarchy process (AHP); 2) carrying out weight proportion distribution on the related influence factors according to an index weight ANP algorithm; (3) the strong electromagnetic pulse shielding effectiveness under all the influence factors is predicted and calculated through an evaluation method; 4) calculating the total shielding effectiveness of the strong electromagnetic pulse of the cable assembly under the condition of multiple influence factors through the weight proportion distributed by the algorithm; according to the method, the strong electromagnetic pulse shielding effectiveness of the cable assembly can be evaluated, and the method can be applied to strong electromagnetic pulse shielding design of common cable assemblies. The field blank of the cable assembly strong electromagnetic pulse shielding effectiveness evaluation method is filled. The evaluation method provided by the invention comprises a plurality of influence factors, and the evaluation result has extremely high accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic compatibility shielding effectiveness evaluation, and in particular relates to a strong electromagnetic pulse shielding effectiveness evaluation method. Background Art

[0002] Due to the development of high-power integrated equipment and the requirements of strong electromagnetic pulses such as nuclear electromagnetic pulses, lightning, static electricity and high-power microwaves, the shielding design of cable assemblies has become the development direction of electromagnetic compatibility technology. Cable assemblies are the general term for multi-core cables and connectors. Figure 2 As shown. In order to improve the shielding effectiveness of cable assemblies, the requirements for the braiding parameters of the shielding layer, the shielding effectiveness of the connector and the grounding method are getting higher and higher; other factors such as height from the ground, cable length and installation method also have a great impact on the shielding performance. Therefore, it is particularly important to obtain the shielding effectiveness of multi-core cable assemblies under the influence of multiple factors. Therefore, the shielding effectiveness must be evaluated through evaluation technology to obtain the expected shielding design effect of the equipment. There are many shielding effectiveness evaluations for existing cable assemblies, such as DC impedance, shielding attenuation, peak shielding effectiveness and transfer impedance, but they are all evaluation methods evolved from test methods, lacking shielding effectiveness evaluation under multiple factors; and there is a lack of shielding effectiveness evaluation methods for cable assemblies under the influence of multiple factors under strong electromagnetic pulse conditions. Because the braiding parameters of the shielding layer, the shielding effectiveness of the connector, the grounding method, the height from the ground, the cable length, the internal cable distribution and the installation method have obvious effects on multi-core cable assemblies, and the above evaluation methods do not uniformly consider the above factors. Although the shielding performance has been considered in the design stage before the equipment is put into use, for example, the cables used in outdoor equipment can all use shielded cables, and the connectors use metal connectors with good shielding performance. However, the cable shielding effectiveness evaluated under single or several factors cannot fully reflect the shielding performance of the material under strong electromagnetic pulse conditions.

[0003] Therefore, in view of the above problems, it is necessary to provide a method for evaluating the strong electromagnetic pulse shielding effectiveness of multi-core cable assemblies. Summary of the invention

[0004] In order to evaluate the strong electromagnetic pulse shielding effectiveness of a cable assembly, the present invention proposes a strong electromagnetic pulse shielding effectiveness evaluation method for a cable assembly.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] Step 1, using electromagnetic topology structure and analytic hierarchy process (AHP) to classify the factors affecting the strong electromagnetic pulse shielding effectiveness of the cable assembly;

[0007] Step 2: Allocate weight proportions of these relevant influencing factors according to the indicator weight ANP algorithm;

[0008] Step 3, predicting and calculating the strong electromagnetic pulse shielding effectiveness under various influencing factors respectively through evaluation methods;

[0009] Step 4, calculating the total shielding effectiveness of the cable assembly against strong electromagnetic pulses under multiple influencing factors through the weight ratio assigned by the algorithm.

[0010] Furthermore, the influencing factors of the strong electromagnetic pulse shielding effectiveness evaluation method in step one include cable height from the ground, shielding layer weaving parameters, cable harness distribution, cable length, distance from the interference source, source impedance, load impedance and shielding layer overlap resistance.

[0011] Furthermore, the weight ratios of the influencing factors in step 2 are distributed as follows: λ1-cable height from the ground 10%-15%, λ2-shielding layer preparation parameters 35%-50%, λ3-cable harness distribution 5%-10%, λ4-cable length 10%-15%, λ5-distance from the interference source 15%-20%, λ6-source impedance 5%-10%, λ7-load impedance 5%-10%, λ8-shielding layer overlap resistance 15%-25%, and the sum of the weight ratios of the influencing factors must be 100%.

[0012] Furthermore, the evaluation method of step three is as follows: the cable height from the ground is compared with a height of 50 mm; the shielding braiding parameters are compared with a braiding density of 90%; the cable bundle distribution is compared with the number of cables 3, the cable length is compared with a length of 1 m, the distance from the interference source is compared with 1 m, the source impedance is compared with a 50 Ω resistor, the load impedance is compared with a 50 Ω resistor, and the shielding layer overlap resistance is compared with 2 mΩ.

[0013] Furthermore, the strong electromagnetic pulse shielding effectiveness of the cable assembly in step 4 is added to the above comparison value by 100 dB through the assigned weight ratio. Strong electromagnetic pulses include one or any combination of narrowband high-power microwaves, ultra-wideband electromagnetic pulses, nuclear electromagnetic pulses, lightning electromagnetic pulses and electrostatic electromagnetic pulses.

[0014] The beneficial effect of the present invention is that it can evaluate the shielding effectiveness of cable assemblies under strong electromagnetic pulses, including narrowband high-power microwaves, ultra-wideband electromagnetic pulses, nuclear electromagnetic pulses, lightning electromagnetic pulses and electrostatic electromagnetic pulses. The technical solution of the present invention is to utilize the multi-factor coupling characteristics of strong electromagnetic pulses on multi-core cable assemblies to evaluate the time domain shielding effectiveness of cable assemblies under various strong electromagnetic pulses. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Flow chart of cable assembly shielding effectiveness evaluation method.

[0016] Figure 2 Schematic diagram of the cable assembly.

[0017] Figure 3 Schematic diagram of cable cross section.

[0018] Among them: 1. Plug connector; 2. Multi-core cable; 3. Shielding layer; 4. Core wire. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and preferred embodiments of the present invention.

[0020] The present invention proposes a method for testing the strong electromagnetic pulse shielding effectiveness of a cable assembly, and the preferred implementation process includes:

[0021] Step 1: The influencing factors of the strong electromagnetic pulse shielding effectiveness of the multi-core cable assembly are summarized and classified using the electromagnetic topology structure according to the hierarchical analysis method (AHP). These influencing factors include the height of the cable from the ground, the shielding layer preparation parameters, the cable harness distribution, the cable length, the distance from the interference source, the source impedance, the load impedance and the shielding layer overlap resistance. From the hierarchical analysis method, it can be seen that the shielding layer preparation parameters, the height of the cable from the ground, the cable length, the distance from the interference source and the shielding layer overlap resistance are strong influencing factors;

[0022] Step 2: These relevant influencing factors are weighted according to the indicator weight ANP algorithm. The weight ratios of the influencing factors are as follows: cable height from the ground 10%, shielding layer preparation parameters 35%, cable harness distribution 5%, cable length 10%, distance from the interference source 15%, source impedance 5%, load impedance 5%, and shielding layer overlap resistance 15%.

[0023] Step 3, predict and calculate the strong electromagnetic pulse shielding effectiveness under each influencing factor through the evaluation method, compare the cable height from the ground with the height of 50mm; compare the shielding braiding parameters with the braiding density of 90%; compare the cable bundle distribution with the number of cables 3, the cable length with the length of 1m, the distance from the interference source with 1m, the source impedance with the resistance of 50Ω, the load impedance with the resistance of 50Ω, and the shielding layer overlap resistance with 2mΩ. The specific formula is as follows:

[0024] SE 离地高度 =20lg(50 / H)

[0025] SE 编制参数 =20lg(90 / F)

[0026] SE 线缆线束 =20lg(3 / N)

[0027] SE 线缆长度 =20lg(1 / L)

[0028] SE 干扰源距离 =20lg(1 / D)

[0029] SE 源阻抗 =20lg(50 / R1)

[0030] SE 负载阻抗 =20lg(50 / R2)

[0031] SE 屏蔽层搭接电阻 =20lg(2 / R3)

[0032] Where: H - height from the ground, mm; F ​​- braiding density, %; N - number of cables; L - cable length, m;

[0033] D——distance from interference source, m; R1——source impedance, Ω; R2——load impedance, Ω;

[0034] R3——Shielding layer overlap resistance, mΩ;

[0035] Step 4, calculate the total shielding effectiveness of the strong electromagnetic pulse of the multi-core cable assembly under multiple influencing factors through the weight ratio assigned by the algorithm. Electromagnetic pulses include one or any combination of narrowband high-power microwaves, ultra-wideband electromagnetic pulses, nuclear electromagnetic pulses, lightning electromagnetic pulses and electrostatic electromagnetic pulses; the ideal shielding effectiveness of any combination of strong electromagnetic pulses is 100dB, and the total shielding effectiveness formula is as follows:

[0036] SE = 100 + 0.1 SE 离地高度 +0.35SE 编制参数 +0.05SE 线缆线束 +0.1SE 线缆长度

[0037] +0.1SE 干扰源距离 +0.05SE 源阻抗 +0.05SE 负载阻抗 +0.15SE 屏蔽层搭接电阻

[0038] The ideal shielding effectiveness of any two combinations of strong electromagnetic pulses is 90dB, and the total shielding effectiveness formula is as follows:

[0039] SE = 90 + 0.1 SE 离地高度 +0.35SE 编制参数 +0.05SE 线缆线束 +0.1SE 线缆长度

[0040] +0.1SE 干扰源距离 +0.05SE源阻抗 +0.05SE 负载阻抗 +0.15SE 屏蔽层搭接电阻

[0041] The ideal shielding effectiveness of any three combinations of strong electromagnetic pulses is 80dB, and the total shielding effectiveness formula is as follows:

[0042] SE = 80 + 0.1 SE 离地高度 +0.35SE 编制参数 +0.05SE 线缆线束 +0.1SE 线缆长度

[0043] +0.1SE 干扰源距离 +0.05SE 源阻抗 +0.05SE 负载阻抗 +0.15SE 屏蔽层搭接电阻

[0044] The ideal shielding effectiveness of any four combinations of strong electromagnetic pulses is 70dB, and the total shielding effectiveness formula is as follows:

[0045] SE = 70 + 0.1 SE 离地高度 +0.35SE 编制参数 +0.05SE 线缆线束 +0.1SE 线缆长度

[0046] +0.1SE 干扰源距离 +0.05SE 源阻抗 +0.05SE 负载阻抗 +0.15SE 屏蔽层搭接电阻

[0047] The ideal shielding effectiveness of five combined strong electromagnetic pulses is 60dB, and the total shielding effectiveness formula is as follows:

[0048] SE = 60 + 0.1 SE 离地高度 +0.35SE 编制参数 +0.05SE 线缆线束 +0.1SE 线缆长度

[0049] +0.1SE 干扰源距离 +0.05SE 源阻抗 +0.05SE 负载阻抗 +0.15SE 屏蔽层搭接电阻

[0050] The above formula can be used to calculate the strong electromagnetic pulse shielding effectiveness of multi-core cable assemblies. The shielding effectiveness of multi-core cable assemblies under different influencing factors is significantly different when evaluated according to this method. This evaluation method is effective and feasible, and the data error is within an acceptable range.

Claims

1. A method for evaluating the strong electromagnetic pulse shielding effectiveness of a cable assembly, characterized in that: Step 1: Use electromagnetic topology structure and hierarchical analysis method to classify the factors affecting the strong electromagnetic pulse shielding effectiveness of cable assemblies; Step 2: Allocate weight proportions of these relevant influencing factors according to the indicator weight ANP algorithm; Step 3: Use the evaluation method to predict and calculate the strong electromagnetic pulse shielding effectiveness under each influencing factor; Step 4: Calculate the total shielding effectiveness of the cable assembly against strong electromagnetic pulses under multiple influencing factors through the weight ratio assigned by the algorithm.

2. The method for evaluating the strong electromagnetic pulse shielding effectiveness of a cable assembly according to claim 1, characterized in that: The factors affecting the strong electromagnetic pulse shielding effectiveness of the cable assembly in step one include the cable height from the ground, shielding layer weaving parameters, cable harness distribution, cable length, distance from the interference source, source impedance, load impedance and shielding layer overlap resistance.

3. According to the cable assembly strong electromagnetic pulse shielding effectiveness evaluation method described in claim 1, its characteristic is that: the weight ratio of the influencing factors of the strong electromagnetic pulse shielding effectiveness of the cable assembly in the step 2 is distributed as follows: λ1-cable height from the ground 10%-15%, λ2-shielding layer compilation parameters 35%-50%, λ3-cable harness distribution 5%-10%, λ4-cable length 10%-15%, λ5-distance from the interference source 15%-20%, λ6-source impedance 5%-10%, λ7-load impedance 5%-10%, λ8-shielding layer overlap resistance 15%-25%, and the sum of the weight ratios of the influencing factors must be 100%.

4. The method for evaluating the strong electromagnetic pulse shielding effectiveness of a cable assembly according to claim 1, characterized in that: The evaluation method of step three is as follows: the cable height from the ground is compared with a height of 50 mm; the shielding braiding parameters are compared with a braiding density of 90%; the cable bundle distribution is compared with the number of cables 3, the cable length is compared with a length of 1 m, the distance to the interference source is compared with 1 m, the source impedance is compared with a 50 Ω resistor, the load impedance is compared with a 50 Ω resistor, and the shielding layer overlap resistance is compared with 2 mΩ.

5. The method for evaluating the strong electromagnetic pulse shielding effectiveness of a cable assembly according to claim 1, characterized in that: The strong electromagnetic pulse shielding effectiveness of the cable assembly in step four is obtained by adding the ideal shielding effectiveness value under different strong electromagnetic pulses and the above-mentioned comparison value through the assigned weight ratio; at the same time, the strong electromagnetic pulse includes one or any combination of narrowband high-power microwave, ultra-wideband electromagnetic pulse, nuclear electromagnetic pulse, lightning electromagnetic pulse and electrostatic electromagnetic pulse.

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