Prediction method of the impact of power cables laid in the same trench on communication signal cables

Abstract

The present invention provides a method for predicting the influence of power cables laid in the same trench on communication signal cables, which belongs to the technical field of power cables. Firstly, the interference influence factor is calculated with distance as the maximum reference basis, and the expected interference calculation is performed in a simulation manner. The obtained primary interference result represents the interference degree of the corresponding position under the premise of metal sheath failure. Then, the primary interference result is screened to obtain the primary interference section as the range of fault detection. Compared with the detection of full line traversal, this method can remove the area with small interference possibility through early calculation, greatly reduce the fault detection range, and improve work efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of power cables, and in particular to a method for predicting the influence of power cables laid in the same trench on communication signal cables. Background Art

[0002] Due to the limitation of space corridor and construction cost, it is sometimes necessary to lay 10kV power supply cables and communication signal cables in the same trench during railway construction. These cables are close to each other, and the electrical cables in the same electromagnetic environment are closely connected to each other through various electromagnetic coupling methods.

[0003] According to the technical conditions for the operation of power cables, for three-core power cables, ideally, the vector sum of the three-phase currents flowing through the three conductive cores during normal symmetrical operation is zero. At this time, no induced voltage is generated on the metal sheath of the cable, and no induced current is generated after both ends of the cable are grounded. However, when a core-to-sheath short circuit occurs in the power cable, the short-circuit current will generate electrostatic induction components and electromagnetic induction components on the communication signal cable through mutual capacitance and mutual inductance, and the induced voltage value may endanger the safe operation of the communication signal cable.

[0004] Therefore, whether interference occurs is closely related to whether the metal sheath is faulty or damaged. In the large-scale hidden danger inspection process, the traversal inspection efficiency is low. Therefore, a targeted and selective method is needed to improve the efficiency of interference prediction. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for predicting the impact of power cables laid in the same trench on communication signal cables. Through relatively easy-to-obtain information and data, multiple rounds of classification and screening are performed to accurately control the inspection scope, reduce the inspection targets, and thereby improve the efficiency of impact prediction.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for predicting the impact of power cables laid in the same trench on communication signal cables, comprising the following steps:

[0007] S1: Obtain the layout information of the cable laying line segment to be analyzed and calculate the interference impact factor;

[0008] S2: Calculate the expected interference according to the interference impact factor to obtain a primary interference result;

[0009] S3: Screening according to the primary interference results to obtain primary interference sections;

[0010] S4: Perform fault detection on the metal sheath of the primary interference section, and obtain interference prediction results based on analysis of the detection results.

[0011] In a preferred solution, in step S1, the interference influence factor is calculated based on the center distance between the power cable and the communication signal cable and the metal sheath diameter of the communication signal cable, and the expression is:

[0012] K= ;

[0013] Among them, K is the interference influence factor, m represents the center distance between the power cable and the communication signal cable, and D is the metal sheath diameter of the communication signal cable.

[0014] In a preferred solution, in step S2, the primary interference result is obtained by performing expected interference calculation based on the interference impact factor and actual data of cable laying, and the expression is:

[0015] ;

[0016] Among them, G is the primary interference result, g is the adjustment coefficient, and K is the interference impact factor.

[0017] In a preferred solution, the calculation expression of the adjustment coefficient is:

[0018] ;

[0019] Where g is the adjustment coefficient, s is the environmental weight, ω is the power angular frequency, represents the magnetic permeability of air, which is 4π×10 -7 H / m.

[0020] In the preferred scheme, the process of obtaining the environmental weight includes: collecting the current temperature and current humidity in the cable laying environment, and presetting the temperature standard range and humidity standard range respectively. If the current temperature and the current humidity are both within the standard range, the environmental weight s is set to 1; if at least one of the current temperature and the current humidity is not within the standard range, the environmental weight s is set to be greater than 1.

[0021] In a preferred solution, in step S3, the screening process of the primary interference sections includes:

[0022] Pre-screening is performed according to the primary interference results, and the corresponding paragraphs whose primary interference results are greater than the threshold are used as the first screening results, and the remaining paragraphs are used as the second screening results;

[0023] Determine the daily working current of the power cable corresponding to the second screening result, and if it is greater than a preset value, mark the paragraph corresponding to the second screening result;

[0024] The first screening results and the marked second screening results are aggregated to generate primary interference paragraphs as screening result outputs.

[0025] In a preferred solution, in step S4, the analysis process of the interference prediction result includes:

[0026] Classifying the detection results of the primary interference paragraphs into damaged paragraphs and undamaged paragraphs;

[0027] For the damaged segment, it is determined that interference already exists, and the existing interference is output as the interference prediction result;

[0028] For the undamaged sections, they are graded according to the primary interference results to obtain different interference risk levels, and the interference risk level of each undamaged section is output as the interference prediction result.

[0029] The present invention provides a method for predicting the impact of power cables laid in the same trench on communication signal cables, which has the following beneficial effects:

[0030] 1. The interference influence factor is calculated based on the distance as the maximum reference, and the expected interference calculation is performed in a simulated manner. The primary interference result obtained represents the interference degree of the corresponding position under the premise of metal sheath failure. Then, according to the primary interference result, the primary interference section is screened as the range of fault detection. Compared with the detection of the entire line traversal, this method can remove areas with low interference possibility through preliminary calculations, greatly reduce the fault detection range, and improve work efficiency.

[0031] 2. Step S1 of the present invention provides basic data for subsequent interference prediction by obtaining accurate cable laying line segment arrangement information. By calculating the interference impact factor, the potential interference between the power cable and the communication signal cable can be quantitatively evaluated, making the subsequent expected interference calculation more accurate and targeted.

[0032] 2. Step S2 of the present invention uses the interference influence factor to calculate the expected interference, which can predict the interference degree of each position when the metal sheath fails. This simulation calculation method can estimate the potential interference without actual detection, providing an important reference for subsequent fault detection.

[0033] 3. Step S3 of the present invention can determine the sections where interference may exist, i.e., the primary interference sections, by screening the primary interference results. This step can significantly reduce the scope of subsequent fault detection, avoid the detection method of traversing the entire line, and thus improve work efficiency. At the same time, by judging by the preset threshold and the daily working current of the power cable, the sections where interference may exist can be further accurately screened.

[0034] 4. Step S4 of the present invention performs actual fault detection on the metal sheath of the primary interference section. By combining the detection results and the primary interference results, the sections where interference exists and the interference risk level of each section can be accurately determined. This not only provides a clear goal for subsequent maintenance work, but also provides important reference information for preventing potential interference. In this way, potential interference problems can be discovered and dealt with in a timely manner to ensure the normal operation of the communication signal cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0036] Figure 1 is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution will be clearly and completely described below in combination with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be understood that in various embodiments of the present invention, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0039] It should be understood that in the present invention, "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0040] It should be understood that in the present invention, "plurality" refers to two or more than two. "And / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "Contains A, B and C", "Contains A, B, C" means that A, B, and C are all included, "Contains A, B or C" means that one of A, B, and C is included, and "Contains A, B and / or C" means that any one, any two, or any three of A, B, and C are included.

[0041] The technical solution of the present invention is described in detail below with specific embodiments. The embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0042] Combination Figure 1 The specific embodiments of the present invention are described in further detail.

[0043] A method for predicting the impact of power cables laid in the same trench on communication signal cables comprises the following steps:

[0044] S1: Obtain the cable laying line segment arrangement information to be analyzed, and calculate the interference impact factor according to the center distance between the power cable and the communication signal cable in the cable laying line segment arrangement information.

[0045] The interference influence factor is calculated based on the center distance between the power cable and the communication signal cable and the metal sheath diameter of the communication signal cable. The expression is as follows:

[0046] K= ;

[0047] Among them, K is the interference factor, m Indicates the center distance between the power cable and the communication signal cable. D It is the diameter of the metal sheath of the communication signal cable.

[0048] The interference factor represents the relationship between the center distance and the metal sheath diameter, where the center distance m Relative to the metal sheath diameter D The smaller it is, the greater the interference factor K is.

[0049] S2: Calculate the expected interference according to the interference impact factor to obtain a primary interference result.

[0050] The primary interference result is obtained by calculating the expected interference based on the interference impact factor and the actual data of cable laying, and the expression is as follows:

[0051] ;

[0052] Among them, G is the primary interference result, g is the adjustment coefficient, and K is the interference influence factor. This formula is simplified based on the calculation formula of longitudinal induced electromotive force. Since the original calculation formula of longitudinal induced electromotive force needs to involve multiple physical parameters, and the short-circuit fault current may not exist before the interference occurs, it cannot be directly calculated. This formula can be used as a reference for distinction without considering factors such as current. The larger G is, the greater the possibility or intensity of interference.

[0053] The calculation expression of the adjustment coefficient is as follows:

[0054] ;

[0055] Where g is the adjustment coefficient, s is the environmental weight, ω is the power angular frequency, represents the magnetic permeability of air, which is 4π×10 -7 H / m. All parameters except the environmental weight can be accurately determined according to the actual situation, ensuring the objectivity of the calculation results.

[0056] The process of obtaining the environmental weight includes: collecting the current temperature and current humidity in the cable laying environment, presetting the temperature standard range and the humidity standard range respectively, if the current temperature and the current humidity are both within the standard range, the environmental weight s is set to 1, if at least one of the current temperature and the current humidity is not within the standard range, the environmental weight s is set to be greater than 1.

[0057] In most cases, the value of the environmental weight is 1, which means that it does not affect the result of the entire adjustment coefficient. However, in extreme environments, the original adjustment coefficient cannot objectively reflect its impact on the possibility of interference (harsh environment will inevitably increase the probability of metal sheath damage). Therefore, the existence of environmental weight can affect the result of the adjustment coefficient when the environment is relatively extreme, making it more in line with changes in interference factors.

[0058] S3: Screening is performed according to the primary interference results to obtain primary interference sections.

[0059] The screening process of the primary interference paragraphs includes:

[0060] Pre-screening is performed based on the primary interference results, and the corresponding paragraphs with primary interference results greater than the threshold are used as the first screening results, and the remaining paragraphs are used as the second screening results. The threshold can be the average value of the primary interference results that have interference problems in the past or a specific value above the average level as the threshold. A suitable threshold can also be determined through experiments or simulations, which can effectively screen out paragraphs that may have interference.

[0061] The daily working current of the corresponding power cable in the second screening result is judged. If it is greater than a preset value, the paragraph corresponding to the second screening result is marked. The preset value can be set based on factors such as the rated current of the cable, historical operating data, and safety margin. For example, if the rated current of the power cable is 1000A, the preset value can be set to a certain percentage of the rated current, such as 80% or 90%, that is, 800A or 900A.

[0062] The first screening results and the marked second screening results are aggregated to generate primary interference paragraphs as screening result outputs.

[0063] The part with larger current will inevitably have more obvious interference ability after the metal sheath fails.

[0064] S4: Perform fault detection on the metal sheath of the primary interference section, and obtain interference prediction results based on analysis of the detection results.

[0065] The analysis process of the interference prediction result includes:

[0066] Classifying the detection results of the primary interference paragraphs into damaged paragraphs and undamaged paragraphs;

[0067] For the damaged segment, it is determined that interference already exists, and the existing interference is output as the interference prediction result;

[0068] For the undamaged sections, they are graded according to the primary interference results to obtain different interference risk levels, and the interference risk level of each undamaged section is output as the interference prediction result.

[0069] Since the interference risk and degree of the cable line have been estimated, the damaged section can be regarded as having interference in the detection results of the primary interference section. For the undamaged section, the value of the primary interference result is a very good reference data. It can be used as a basis for grading. Without adding extra calculation, the interference risk level can be divided to objectively show the interference prediction results.

[0070] The present invention first calculates the interference influence factor based on the distance as the maximum reference basis, and performs the expected interference calculation in a simulation manner. The primary interference result obtained represents the interference degree of the corresponding position under the premise of metal sheath failure, and then screens according to the primary interference result to obtain the primary interference section as the range of fault detection. Compared with the detection of full line traversal, this method can remove areas with very small interference possibility through preliminary calculations, greatly reduce the fault detection range, and improve work efficiency.

[0071] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for predicting the impact of power cables laid in the same trench on communication signal cables, characterized in that: The following steps are involved: S1: Obtain the layout information of the cable laying line segment to be analyzed and calculate the interference impact factor; The interference influence factor is calculated based on the center distance between the power cable and the communication signal cable and the metal sheath diameter of the communication signal cable, and the expression is: K= ； Where K is the interference factor, m represents the center distance between the power cable and the communication signal cable, and D is the metal sheath diameter of the communication signal cable; S2: Calculate the expected interference according to the interference impact factor to obtain a primary interference result; S3: Screening according to the primary interference results to obtain primary interference sections; S4: Perform fault detection on the metal sheath of the primary interference section, and obtain interference prediction results based on analysis of the detection results.

2. The method for predicting the impact of power cables laid in the same trench on communication signal cables according to claim 1, characterized in that: In step S2, the primary interference result is obtained by performing expected interference calculation based on the interference impact factor and the actual data of cable laying, and the expression is: ； Among them, G is the primary interference result, g is the adjustment coefficient, and K is the interference impact factor.

3. The method for predicting the impact of power cables laid in the same trench on communication signal cables according to claim 2, characterized in that: The calculation expression of the adjustment coefficient is: ； Where g is the adjustment coefficient, s is the environmental weight, ω is the power angular frequency, represents the magnetic permeability of air, which is 4π×10 -7 H / m.

4. The method for predicting the impact of power cables laid in the same trench on communication signal cables according to claim 3, characterized in that: The process of obtaining the environmental weight includes: collecting the current temperature and current humidity in the cable laying environment, presetting the temperature standard range and the humidity standard range respectively, if the current temperature and the current humidity are both within the standard range, the environmental weight s is set to 1, if at least one of the current temperature and the current humidity is not within the standard range, the environmental weight s is set to be greater than 1.

5. The method for predicting the impact of power cables laid in the same trench on communication signal cables according to claim 1, characterized in that: In step S3, the screening process of the primary interference sections includes: Pre-screening is performed according to the primary interference results, and the corresponding paragraphs whose primary interference results are greater than the threshold are used as the first screening results, and the remaining paragraphs are used as the second screening results; Determine the daily working current of the power cable corresponding to the second screening result, and if it is greater than a preset value, mark the paragraph corresponding to the second screening result; The first screening results and the marked second screening results are aggregated to generate primary interference paragraphs as screening result outputs.

6. The method for predicting the impact of power cables laid in the same trench on communication signal cables according to claim 1, characterized in that: In step S4, the analysis process of the interference prediction result includes: Classifying the detection results of the primary interference paragraphs into damaged paragraphs and undamaged paragraphs; For the damaged segment, it is determined that interference already exists, and the existing interference is output as the interference prediction result; For the undamaged sections, they are graded according to the primary interference results to obtain different interference risk levels, and the interference risk level of each undamaged section is output as the interference prediction result.

Images