Cable conductor temperature detection method and device, and storage medium

Abstract

The invention discloses a cable conductor temperature detection method and device, and a storage medium. The method comprises the following steps: constructing a transient thermal circuit model for a cable; the multi-layer structure in the transient thermal circuit model sequentially comprises a conductor, an insulating layer, a lining layer and an outer sheath from inside to outside; under the condition that the multi-layer structure in the transient thermal circuit model is not coaxial, the thermal resistance value and the thermal capacitance value of the multi-layer structure in the transient thermal circuit model are detected; correcting the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion; if the correction is completed, constructing a target function according to the temperature value, the thermal resistance value and the thermal capacitance value of the multilayer structure distribution in the transient thermal circuit model; and detecting the temperature value of the conductor according to the objective function. According to the embodiment, the thermal resistance value of the lining layer is corrected by considering the expansion condition of the insulating layer, so that the temperature of the conductor is solved, the influence of dynamic load on conductor temperature detection in actual operation is reduced, and the accuracy is high.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and in particular to a temperature detection method, device and storage medium for a cable conductor. Background Art

[0002] Some cables will leave a gap of a certain thickness between the inner lining and the aluminum sheath to prevent damage to the internal structure of the cable due to cable bending during construction or laying.

[0003] In the actual operation of the cable, the cable insulation layer expands radially as the temperature of the cable increases, and the gas gap in the lining layer changes. Therefore, the thermal resistance value of the lining layer changes with the temperature of the conductor.

[0004] In order to detect the temperature of the conductor and thus evaluate the operating status of the cable, there are three main methods currently used: 1) The first method uses distributed optical fiber to measure the cable surface temperature and combines it with a thermal circuit model to detect the temperature of the conductor; 2) The second method is based on Fourier's heat transfer law and the structural parameters of each layer of the cable. It uses standard specifications to calculate the thermal resistance of each layer of the cable, establishes a steady-state thermal circuit model of the cable, and uses a temperature sensor to measure the outer surface temperature of the cable to indirectly measure the temperature of the conductor; 3) The third method is to use infrared probes or infrared thermal imagers and other detection instruments to measure the conductor temperature.

[0005] However, the cost of optical fiber temperature measurement in the first method is too high and the accuracy is low, which leads to errors in the parameters in the thermal circuit model and low accuracy of conductor temperature detection; the second method uses fixed parameters, which deviate from the actual parameters, resulting in large errors in conductor temperature; the third method is affected by the detection instrument itself and the external infrared radiation, and the measurement accuracy is low. Summary of the invention

[0006] In view of this, the present invention provides a method, device and storage medium for detecting the temperature of a cable conductor, so as to improve the accuracy of detecting the temperature of the cable conductor.

[0007] A first aspect of the present invention provides a method for detecting the temperature of a cable conductor, comprising:

[0008] A transient thermal circuit model is constructed for the cable; the multi-layer structure in the transient thermal circuit model includes a conductor, an insulating layer, an inner lining layer and an outer sheath from the inside to the outside;

[0009] Under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial, detecting the thermal resistance value and the thermal capacity value of the multi-layer structure in the transient thermal circuit model;

[0010] Correcting the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion;

[0011] If the correction is completed, an objective function is constructed according to the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model;

[0012] The temperature value of the conductor is detected according to the objective function.

[0013] A second aspect of the present invention provides a temperature detection device for a cable conductor, comprising:

[0014] A cable modeling module is used to construct a transient thermal circuit model for the cable; the multi-layer structure in the transient thermal circuit model includes a conductor, an insulating layer, an inner lining layer and an outer sheath from the inside to the outside;

[0015] A thermal parameter calculation module, used to detect the thermal resistance and thermal capacity of the multi-layer structure in the transient thermal circuit model under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial;

[0016] A lining layer thermal resistance correction module, used to correct the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion;

[0017] An objective function construction module, for constructing an objective function according to the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model if the correction is completed;

[0018] The conductor temperature detection module is used to detect the temperature value of the conductor according to the objective function.

[0019] A third aspect of the present invention provides an electronic device, the electronic device comprising:

[0020] at least one processor; and

[0021] a memory communicatively connected to the at least one processor; wherein,

[0022] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the temperature detection method of the cable conductor as described in the first aspect above.

[0023] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the temperature detection method for a cable conductor as described in the first aspect above.

[0024] A fifth aspect of the present invention provides a computer program product, the computer program product comprising a computer program, and when the computer program is executed by a processor, the temperature detection method of the cable conductor as described in the first aspect above is implemented.

[0025] In this embodiment, a transient thermal circuit model is constructed for the cable; the multi-layer structure in the transient thermal circuit model includes a conductor, an insulating layer, an inner lining layer and an outer sheath from the inside to the outside; under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial, the thermal resistance and thermal capacity of the multi-layer structure in the transient thermal circuit model are detected; the thermal resistance of the inner lining layer is corrected according to the temperature distribution information of the insulating layer before expansion; if the correction is completed, the objective function is constructed according to the temperature value, thermal resistance and thermal capacity of the multi-layer structure distribution in the transient thermal circuit model; the temperature value of the conductor is detected according to the objective function. This embodiment corrects the thermal resistance of the inner lining layer in consideration of the expansion of the insulating layer, thereby solving the temperature of the conductor, reducing the influence of the dynamic load on the conductor temperature detection in actual operation, and has high accuracy. This process mainly relies on basic sensors such as temperature sensors to collect data, which is low in cost and realizes non-destructive detection of the conductor temperature.

[0026] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a flow chart of a method for detecting the temperature of a cable conductor provided in Embodiment 1 of the present invention.

[0029] Figure 2 It is a structural schematic diagram of a transient thermal circuit model provided in Example 1 of the present invention.

[0030] Figure 3 It is a schematic diagram of a non-coaxial structure of a multi-layer structure of a transient thermal circuit model provided in Example 1 of the present invention.

[0031] Figure 4 It is a structural schematic diagram of a temperature detection device for a cable conductor provided in Embodiment 2 of the present invention.

[0032] Figure 5 It is a structural schematic diagram of an electronic device provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can cover sequential implementations other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] Embodiment 1

[0036] See also Figure 1 , shows a flow chart of a cable conductor temperature detection method provided by the first embodiment of the present invention, the method can be performed by a cable conductor temperature detection device, the cable conductor temperature detection device can be implemented in the form of hardware and / or software, and the cable conductor temperature detection device can be configured in an electronic device. Figure 1 As shown, the method includes:

[0037] Step 101: construct a transient thermal circuit model for the cable.

[0038] like Figure 2 As shown, in view of the fact that the size of the air gap in the lining layer changes with the thermal expansion of the insulation layer, a transient thermal circuit model considering thermal expansion is established for the cable based on Fourier's heat transfer law and combined with the parameters of each layer structure of the cable.

[0039] Among them, the multi-layer structure in the transient thermal circuit model includes a conductor, an insulating layer, an inner lining layer and an outer sheath from the inside to the outside.

[0040] T1 is the thermal resistance of the insulation layer, T2 is the thermal resistance of the inner lining layer, T3 is the thermal resistance of the outer sheath, θ0 is the temperature of the outer surface of the outer sheath, θ1 is the temperature of the conductor, θ2 is the outer temperature of the insulation layer, θ3 is the temperature of the outer sheath, C1 is the heat capacity of the insulation layer, C2 is the heat capacity of the inner lining layer, C3 is the heat capacity of the outer sheath, and Q1 is the heat flow of the entire line.

[0041] Step 102: Under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial, the thermal resistance value and the thermal capacity value of the multi-layer structure in the transient thermal circuit model are detected.

[0042] Due to the existence of air gaps, the multi-layer structure of the cable body in the transient thermal circuit model is non-coaxial, and part of the structure may be offset by gravity. At this time, the thermal resistance and thermal capacity of the multi-layer structure in the transient thermal circuit model can be detected according to the parameters of the multi-layer structure in the transient thermal circuit model in accordance with standard specifications. In this process, the process of calculating the thermal resistance and / or thermal capacity of some structures is corrected by considering the non-coaxial factor.

[0043] For the insulation layer, on the one hand, the thermal resistance of the insulation layer is expressed as:

[0044]

[0045] Where T1 is the thermal resistance of the insulation layer, ρ T is the thermal resistance coefficient of the insulating material (in Km / W), t1 is the insulation thickness between the conductor and the metal sheath (in mm), d c is the diameter of the conductor (in mm).

[0046] On the other hand, the heat capacity of the insulating layer is expressed as:

[0047]

[0048] Where C2 is the heat capacity of the insulation layer, δ pm is the volume heat capacity of the insulating layer (in J / (K·m)), d2 is the outer diameter of the insulating layer, and d1 is the inner diameter of the insulating layer.

[0049] For the lining layer, under the condition that the multi-layer structure is non-coaxial in the transient thermal circuit model, the shape factor of the lining layer can be calculated, where the shape factor represents the state quantity of the deformation of the lining layer.

[0050] Exemplarily, the shape factor is expressed as:

[0051]

[0052] Among them, Figure 3 As shown, S is the shape factor, r1 is the equivalent radius corresponding to the outer surface of the insulation layer, r2 is the equivalent radius corresponding to the inner surface of the outer sheath, e is the eccentricity of the cable under the action of gravity in the presence of non-central symmetry, and arcosh is the inverse hyperbolic cosine function.

[0053] The thermal resistance value of the lining layer is obtained by taking the inverse of the product of the thermal conductivity and the shape factor of the lining layer.

[0054] At this time, the thermal resistance value of the lining layer is expressed as:

[0055]

[0056] Wherein, T2 is the thermal resistance value of the lining layer, λ2 is the thermal conductivity of the lining layer, and S is the shape factor.

[0057] For the outer sheath, on the one hand, the thermal resistance value of the outer sheath is expressed as:

[0058]

[0059] Where T3 is the thermal resistance of the outer sheath, ρ T is the thermal resistance coefficient of the insulating material, D OC D is the diameter of an imaginary concentric cylinder tangent to the outer side of the corrugated metal sleeve crest (in mm), it is the diameter of an imaginary concentric cylinder tangent to the inner side of the corrugated metal sheath trough (in mm), t3 is the thickness of the outer sheath, t s is the thickness of the metal sleeve.

[0060] On the other hand, the thermal capacity of the outer sheath is expressed as:

[0061]

[0062] Where, C3 is the heat capacity of the outer sheath (in J / K), δ o is the volume heat capacity of the outer sheath (in J / (K·m)), d4 is the outer diameter of the outer sheath, and d3 is the inner diameter of the outer sheath.

[0063] Step 103: Correct the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion.

[0064] In this embodiment, since the insulation layer of the cable expands radially as the temperature of the cable increases, the gas gap between the inner lining layer and the aluminum sheath will change. Therefore, the radial temperature distribution information of each layer structure of the cable before the insulation layer expands can be calculated by combining the initial thermal parameter value, heat flow value and cable surface temperature and other parameters, and the Matlab program can be used to calculate the radial temperature distribution information of each layer structure of the cable before the insulation layer expands, so as to correct the thermal resistance value of the inner lining layer based on the temperature distribution information before the insulation layer expands.

[0065] In a specific implementation, the expansion amount of the insulation layer is calculated based on the temperature distribution information of the insulation layer before expansion by using integration or other methods, so that the thermal resistance value of the lining layer is corrected based on the expansion amount of the insulation layer.

[0066] Exemplarily, the expansion amount of the insulating layer is expressed as:

[0067]

[0068] Where ΔL is the expansion of the insulation layer, r c is the outer diameter of the conductor, r x is the outer diameter of the insulating layer, a is the expansion coefficient of the insulating layer, and θ(r) is the temperature distribution information of the insulating layer before expansion.

[0069] Then, the corrected thermal resistance value of the lining layer is expressed as:

[0070]

[0071] Among them, T'2 is the corrected thermal resistance value of the lining layer, S' is the modified shape factor, ΔL is the expansion of the insulation layer, r1 is the equivalent radius corresponding to the outer surface of the insulation layer, r2 is the equivalent radius corresponding to the inner surface of the outer sheath, λ2 is the thermal conductivity of the lining layer, and arcosh is the inverse hyperbolic cosine function.

[0072] Step 104: If the correction is completed, an objective function is constructed according to the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model.

[0073] If the thermal resistance value of the lining layer is corrected, the target function can be constructed by modeling the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model.

[0074] In one embodiment of the present invention, step 104 may include the following steps:

[0075] Step 1041: Derivative the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model to construct a first temperature matrix.

[0076] In this embodiment, the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model may be derived, and a first temperature matrix may be constructed according to the inverse of each temperature value.

[0077] It should be pointed out that the temperature values ​​of the multilayer structure distribution in the transient thermal circuit model include the temperature values ​​of the conductors, and the temperature values ​​of the conductors are unknown quantities to be solved, that is, the first temperature matrix includes the temperature values ​​of the conductors.

[0078] In a specific implementation, the conductor, insulation layer and outer sheath in the transient thermal circuit model can be selected to derive the temperature values ​​of the conductor, the insulation layer and the outer sheath to construct a first temperature matrix. In this case, the first temperature matrix It is expressed as:

[0079]

[0080] Among them, θ1 is the temperature value of the conductor, θ2 is the temperature value of the insulation layer, and θ3 is the temperature value of the outer sheath.

[0081] Step 1042: construct a second temperature matrix using the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model.

[0082] In this embodiment, the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model may be used to construct a second temperature matrix.

[0083] It should be pointed out that the temperature values ​​of the multilayer structure distribution in the transient thermal circuit model include the temperature values ​​of the conductors, and the temperature values ​​of the conductors are waiting to be solved as unknown quantities, that is, the second temperature matrix includes the temperature values ​​of the conductors.

[0084] Generally, the multi-layer structure of the transient heat circuit model involved in the first temperature matrix is ​​the same as the multi-layer structure of the transient heat circuit model involved in the second temperature matrix.

[0085] In a specific implementation, the conductor, the insulation layer and the outer sheath in the transient thermal circuit model can be selected, and the temperature values ​​of the conductor, the insulation layer and the outer sheath can be used to construct the second temperature matrix. In this case, the second temperature matrix θ is expressed as:

[0086] θ=[θ1 θ2 θ3] T

[0087] Among them, θ1 is the temperature value of the conductor, θ2 is the temperature value of the insulation layer, and θ3 is the temperature value of the outer sheath.

[0088] Step 1043: construct a first coefficient matrix according to the thermal resistance and thermal capacity values ​​of the multi-layer structure distribution in the transient thermal circuit model.

[0089] In this embodiment, a first coefficient matrix may be constructed according to the thermal resistance and thermal capacity values ​​of the multi-layer structure distribution in the transient thermal circuit model.

[0090] In a specific implementation, the conductor, insulation layer, inner lining layer and outer sheath in the transient thermal circuit model can be selected, and the thermal resistance value of the insulation layer, the thermal resistance value of the inner lining layer, the thermal resistance value of the outer sheath, and the thermal capacitance value of the conductor, the thermal capacitance value of the insulation layer, and the thermal capacitance value of the outer sheath are processed according to the standard specifications to construct a first coefficient matrix. Insufficient elements in the first coefficient matrix are filled with 0. At this time, the first coefficient matrix A is expressed as:

[0091]

[0092] Among them, T1 is the thermal resistance of the insulation layer, T2 is the thermal resistance of the lining layer, T3 is the thermal resistance of the outer sheath, C1 is the thermal capacitance of the conductor, C2 is the thermal capacitance of the insulation layer, and C3 is the thermal capacitance of the outer sheath.

[0093] Step 1044: construct a second coefficient matrix according to the heat capacity values ​​of the multi-layer structure distribution in the transient heat circuit model.

[0094] In this embodiment, the second coefficient matrix may be constructed according to the heat capacity values ​​of the multi-layer structure distribution in the transient heat circuit model.

[0095] In a specific implementation, the conductor, the insulation layer and the outer sheath in the transient thermal circuit model can be selected, and the heat capacity of the conductor, the heat capacity of the insulation layer and the heat capacity of the outer sheath can be processed according to the standard specifications to construct the second coefficient matrix. The insufficient elements in the second coefficient matrix are filled with 0. At this time, the second coefficient matrix B is expressed as:

[0096]

[0097] Among them, C1 is the heat capacity of the conductor, C2 is the heat capacity of the insulation layer, and C3 is the heat capacity of the outer sheath.

[0098] Step 1045: Detect the heat flow value of the entire line based on the temperature value and thermal resistance value of the multi-layer structure distribution in the transient heat circuit model.

[0099] In this embodiment, the heat flow value of the entire line can be detected based on the temperature value and thermal resistance value of the multi-layer structure distribution in the transient heat circuit model.

[0100] In a specific implementation, the temperature value of the outer surface of the transient heat circuit model, the temperature value of the outer sheath and the thermal resistance value of the outer sheath can be selected. The difference between the temperature value of the outer sheath and the temperature value of the outer surface of the transient heat circuit model is divided by the thermal resistance value of the outer sheath to obtain the full-line heat flow value. At this time, the full-line heat flow value can be expressed as:

[0101]

[0102] Among them, θ0 is the temperature value of the outer surface of the transient thermal circuit model, θ3 is the temperature value of the outer sheath, and T3 is the thermal resistance value of the outer sheath.

[0103] Step 1046: construct a heat flow matrix based on the heat flow values ​​of the entire line.

[0104] In this embodiment, the heat flow matrix can be constructed using the heat flow values ​​of the entire line, and the insufficient elements in the heat flow matrix are filled with 0.

[0105] In the specific implementation, the heat flow matrix Φ is expressed as:

[0106] Φ=[Q1 0 0]

[0107] Among them, Q1 is the heat flow value of the entire line.

[0108] Step 1047: Determine the objective function.

[0109] In this embodiment, the objective function may be obtained by modeling based on the first temperature matrix, the second temperature matrix, the first coefficient matrix, the second coefficient matrix, and the heat flow matrix.

[0110] Among them, the objective function is expressed as the first temperature matrix is ​​equal to the product of the first coefficient matrix and the second temperature matrix plus the product of the second coefficient matrix and the heat flow matrix. At this time, the objective function represents the thermodynamic relationship of the multilayer structure of the transient thermal circuit model under the conditions of thermal expansion and non-coaxiality.

[0111] In the specific implementation, the objective function is expressed as:

[0112]

[0113] in, is the first temperature matrix, θ is the second temperature matrix, A is the first coefficient matrix, B is the second coefficient matrix, and Φ is the flow matrix.

[0114] Step 105: Detect the temperature value of the conductor according to the objective function.

[0115] In this embodiment, the objective function contains the temperature value of the conductor. The temperature value, thermal resistance value and thermal capacity value of the multilayer structure distribution in the transient thermal circuit model can be substituted into the objective function, and the objective function is iteratively solved to obtain the temperature value of the conductor.

[0116] Furthermore, in scenarios such as failures and power switching maintenance, the state of the cable fluctuates, causing the temperature values ​​of the multi-layer structure distribution in each transient thermal circuit model to fluctuate. Therefore, the temperature value of the conductor can be continuously monitored until the cable is in a stable state to obtain the final temperature value of the conductor.

[0117] In this embodiment, a transient thermal circuit model is constructed for the cable; the multi-layer structure in the transient thermal circuit model includes a conductor, an insulating layer, an inner lining layer and an outer sheath from the inside to the outside; under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial, the thermal resistance and thermal capacity of the multi-layer structure in the transient thermal circuit model are detected; the thermal resistance of the inner lining layer is corrected according to the temperature distribution information of the insulating layer before expansion; if the correction is completed, the objective function is constructed according to the temperature value, thermal resistance and thermal capacity of the multi-layer structure distribution in the transient thermal circuit model; the temperature value of the conductor is detected according to the objective function. This embodiment corrects the thermal resistance of the inner lining layer in consideration of the expansion of the insulating layer, thereby solving the temperature of the conductor, reducing the influence of the dynamic load on the conductor temperature detection in actual operation, and has high accuracy. This process mainly relies on basic sensors such as temperature sensors to collect data, which is low in cost and realizes non-destructive detection of the conductor temperature.

[0118] Embodiment 2

[0119] See also Figure 4 , shows a schematic diagram of the structure of a temperature detection device for a cable conductor provided in Embodiment 2 of the present invention. Figure 4 As shown, the device comprises:

[0120] The cable modeling module 401 is used to construct a transient thermal circuit model for the cable; the multi-layer structure in the transient thermal circuit model includes a conductor, an insulating layer, an inner lining layer and an outer sheath from the inside to the outside;

[0121] The thermal parameter calculation module 402 is used to detect the thermal resistance and thermal capacity of the multi-layer structure in the transient thermal circuit model under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial;

[0122] The lining layer thermal resistance correction module 403 is used to correct the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion;

[0123] The objective function construction module 404 is used to construct the objective function according to the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model if the correction is completed;

[0124] The conductor temperature detection module 405 is used to detect the temperature value of the conductor according to the objective function.

[0125] In one embodiment of the present invention, the thermal resistance value of the insulating layer is expressed as:

[0126]

[0127] Wherein, T1 is the thermal resistance of the insulating layer, ρ T is the thermal resistance coefficient of the insulating material, t1 is the insulation thickness between the conductor and the metal sleeve, d c is the diameter of the conductor;

[0128] The thermal resistance value of the outer sheath is expressed as:

[0129]

[0130] Wherein, T3 is the thermal resistance of the outer sheath, ρ T is the thermal resistance coefficient of the insulating material, D OC D is the diameter of an imaginary concentric cylinder tangent to the outer side of the corrugated metal sleeve wave crest. it is the diameter of an imaginary concentric cylinder tangent to the inner side of the corrugated metal sheath trough, t3 is the thickness of the outer sheath, t s is the thickness of the metal sleeve;

[0131] The heat capacity of the insulating layer is expressed as:

[0132]

[0133] Wherein, C2 is the heat capacity of the insulating layer, δ pmis the volume heat capacity of the insulating layer, d2 is the outer diameter of the insulating layer, and d1 is the inner diameter of the insulating layer;

[0134] The heat capacity of the outer sheath is expressed as:

[0135]

[0136] Wherein, C3 is the heat capacity of the outer sheath, δ o is the volume heat capacity of the outer sheath, d4 is the outer diameter of the outer sheath, and d3 is the inner diameter of the outer sheath.

[0137] In one embodiment of the present invention, the thermal parameter calculation module 402 includes:

[0138] A shape factor calculation module, used to calculate the shape factor of the lining layer under the condition that the multi-layer structure is non-coaxial in the transient thermal circuit model;

[0139] The lining thermal resistance calculation module is used to take the inverse of the product between the thermal conductivity of the lining layer and the shape factor to obtain the thermal resistance value of the lining layer.

[0140] In one embodiment of the present invention, the shape factor is expressed as:

[0141]

[0142] Among them, S is the shape factor, r1 is the equivalent radius corresponding to the outer surface of the insulating layer, r2 is the equivalent radius corresponding to the inner surface of the outer sheath, and e is the eccentricity of the cable under the action of gravity in the presence of non-central symmetry.

[0143] In one embodiment of the present invention, the liner thermal resistance correction module comprises:

[0144] An expansion amount calculation module, used to calculate the expansion amount of the insulation layer according to the temperature distribution information of the insulation layer before expansion;

[0145] The expansion correction module is used to correct the thermal resistance value of the lining layer according to the expansion of the insulating layer.

[0146] In one embodiment of the present invention, the expansion amount of the insulating layer is expressed as:

[0147]

[0148] Wherein, ΔL is the expansion amount of the insulating layer, r c is the outer diameter of the conductor, r x is the outer diameter of the insulating layer, a is the expansion coefficient of the insulating layer, and θ(r) is the temperature distribution information of the insulating layer before expansion;

[0149] The corrected thermal resistance value of the lining layer is expressed as:

[0150]

[0151] Wherein, T'2 is the corrected thermal resistance value of the inner lining layer, ΔL is the expansion amount of the insulating layer, r1 is the equivalent radius corresponding to the outer surface of the insulating layer, r2 is the equivalent radius corresponding to the inner surface of the outer sheath, and λ2 is the thermal conductivity of the inner lining layer.

[0152] In one embodiment of the present invention, the objective function construction module 404 includes:

[0153] A first temperature matrix construction module, used to derive the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model to construct a first temperature matrix;

[0154] A second temperature matrix building module, used to build a second temperature matrix with the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model;

[0155] A first coefficient matrix construction module, used to construct a first coefficient matrix according to the thermal resistance and thermal capacity values ​​of the multi-layer structure distribution in the transient thermal circuit model;

[0156] A second coefficient matrix construction module, used to construct a second coefficient matrix according to the heat capacity value of the multi-layer structure distribution in the transient heat circuit model;

[0157] A full-line heat flow value calculation module is used to detect the full-line heat flow value according to the temperature value and thermal resistance value of the multi-layer structure distribution in the transient heat circuit model;

[0158] A heat flow matrix construction module, used to construct a heat flow matrix according to the full-line heat flow value;

[0159] The objective function determination module is used to determine the objective function; the objective function is expressed as the first temperature matrix is ​​equal to the product of the first coefficient matrix and the second temperature matrix plus the product of the second coefficient matrix and the heat flow matrix.

[0160] In one embodiment of the present invention, the objective function is expressed as:

[0161]

[0162] in, is the first temperature matrix, θ is the second temperature matrix, A is the first coefficient matrix, B is the second coefficient matrix, and Φ is the heat flow matrix;

[0163] The first temperature matrix It is expressed as:

[0164]

[0165] The second temperature matrix θ is expressed as:

[0166] θ=[θ1 θ2 θ3] T

[0167] The first coefficient matrix A is expressed as:

[0168]

[0169] The second coefficient matrix B is expressed as:

[0170]

[0171] The heat flow matrix Φ is expressed as:

[0172] Φ=[Q1 0 0

[0173]

[0174] Among them, θ0 is the temperature value of the outer surface of the transient thermal circuit model, θ1 is the temperature value of the conductor, θ2 is the temperature value of the insulation layer, θ3 is the temperature value of the outer sheath, T1 is the thermal resistance value of the insulation layer, T2 is the thermal resistance value of the lining layer, T3 is the thermal resistance value of the outer sheath, C1 is the heat capacitance value of the conductor, C2 is the heat capacitance value of the insulation layer, C3 is the heat capacitance value of the outer sheath, and Q1 is the heat flow value of the entire line.

[0175] The temperature detection device for a cable conductor provided in an embodiment of the present invention can execute the temperature detection method for a cable conductor provided in any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the temperature detection method for a cable conductor.

[0176] Embodiment 3

[0177] See also Figure 5 , showing a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0178] like Figure 5As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0179] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0180] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the temperature detection method of the cable conductor.

[0181] In some embodiments, the temperature detection method of the cable conductor can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the temperature detection method of the cable conductor described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to perform the temperature detection method of the cable conductor in any other appropriate manner (for example, by means of firmware).

[0182] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0183] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0184] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0185] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0186] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0187] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0188] Embodiment 4

[0189] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the temperature detection method of the cable conductor provided by any embodiment of the present invention is implemented.

[0190] In the process of implementation, the computer program product can be written in one or more programming languages ​​or a combination thereof to perform the computer program code of the present invention, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0191] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0192] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the temperature of a cable conductor, characterized in that: include: Construct transient thermal circuit model for cables; The multilayer structure in the transient heat circuit model includes, from inside to outside, a conductor, an insulating layer, an inner lining layer and an outer sheath; Under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial, detecting the thermal resistance value and the thermal capacity value of the multi-layer structure in the transient thermal circuit model; Correcting the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion; If the correction is completed, an objective function is constructed according to the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model; The temperature value of the conductor is detected according to the objective function.

2. The method according to claim 1, characterized in that The thermal resistance of the insulating layer is expressed as: Wherein, T1 is the thermal resistance of the insulating layer, ρ T is the thermal resistance coefficient of the insulating material, t1 is the insulation thickness between the conductor and the metal sleeve, d c is the diameter of the conductor; The thermal resistance value of the outer sheath is expressed as: Wherein, T3 is the thermal resistance of the outer sheath, ρ T is the thermal resistance coefficient of the insulating material, D OC D is the diameter of an imaginary concentric cylinder tangent to the outer side of the corrugated metal sleeve wave crest. it is the diameter of an imaginary concentric cylinder tangent to the inner side of the corrugated metal sheath trough, t3 is the thickness of the outer sheath, t s is the thickness of the metal sleeve; The heat capacity of the insulating layer is expressed as: Wherein, C2 is the heat capacity of the insulating layer, δ pm is the volume heat capacity of the insulating layer, d2 is the outer diameter of the insulating layer, and d1 is the inner diameter of the insulating layer; The heat capacity of the outer sheath is expressed as: Wherein, C3 is the heat capacity of the outer sheath, δ o is the volume heat capacity of the outer sheath, d4 is the outer diameter of the outer sheath, and d3 is the inner diameter of the outer sheath.

3. The method according to claim 1, characterized in that: Under the condition that the multi-layer structure in the transient thermal circuit model is non-coaxial, detecting the thermal resistance value and the thermal capacity value of the multi-layer structure in the transient thermal circuit model includes: Under the condition that the multilayer structure is non-coaxial in the transient thermal circuit model, calculating the shape factor of the lining layer; The reciprocal of the product of the thermal conductivity of the lining layer and the shape factor is taken to obtain the thermal resistance value of the lining layer.

4. The method according to claim 3, characterized in that The shape factor is expressed as: Among them, S is the shape factor, r1 is the equivalent radius corresponding to the outer surface of the insulating layer, r2 is the equivalent radius corresponding to the inner surface of the outer sheath, and e is the eccentricity of the cable under the action of gravity in the presence of non-central symmetry.

5. The method according to claim 1, characterized in that The step of correcting the thermal resistance value of the lining layer according to the temperature distribution information of the insulating layer before expansion includes: Calculating the expansion amount of the insulating layer according to the temperature distribution information of the insulating layer before expansion; The thermal resistance value of the lining layer is corrected according to the expansion amount of the insulating layer.

6. The method according to claim 5, characterized in that The expansion amount of the insulating layer is expressed as: Wherein, ΔL is the expansion amount of the insulating layer, r c is the outer diameter of the conductor, r x is the outer diameter of the insulating layer, a is the expansion coefficient of the insulating layer, and θ(r) is the temperature distribution information of the insulating layer before expansion; The corrected thermal resistance value of the lining layer is expressed as: Wherein, T'2 is the corrected thermal resistance value of the inner lining layer, ΔL is the expansion amount of the insulating layer, r1 is the equivalent radius corresponding to the outer surface of the insulating layer, r2 is the equivalent radius corresponding to the inner surface of the outer sheath, and λ2 is the thermal conductivity of the inner lining layer.

7. The method according to any one of claims 1 to 6, characterized in that The objective function is constructed based on the temperature value, thermal resistance value and thermal capacity value of the multi-layer structure distribution in the transient thermal circuit model, including: Derivatively determining the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model to construct a first temperature matrix; Constructing a second temperature matrix using the temperature values ​​of the multi-layer structure distribution in the transient heat circuit model; Constructing a first coefficient matrix according to the thermal resistance and thermal capacity values ​​of the multi-layer structure distribution in the transient thermal circuit model; Constructing a second coefficient matrix according to the heat capacity values ​​of the multi-layer structure distribution in the transient heat circuit model; Detect the heat flow value of the entire line according to the temperature value and thermal resistance value of the multi-layer structure distribution in the transient heat circuit model; Constructing a heat flow matrix according to the full-line heat flow values; Determine an objective function; the objective function is expressed as the first temperature matrix is ​​equal to the product between the first coefficient matrix and the second temperature matrix plus the product between the second coefficient matrix and the heat flow matrix.

8. The method according to claim 7, characterized in that The objective function is expressed as: in, is the first temperature matrix, θ is the second temperature matrix, A is the first coefficient matrix, B is the second coefficient matrix, and Φ is the heat flow matrix; The first temperature matrix It is expressed as: The second temperature matrix θ is expressed as: θ=[θ1 θ2 θ3] T The first coefficient matrix A is expressed as: The second coefficient matrix B is expressed as: The heat flow matrix Φ is expressed as: Φ=[Q1 0 0] Among them, θ0 is the temperature value of the outer surface of the transient thermal circuit model, θ1 is the temperature value of the conductor, θ2 is the temperature value of the insulation layer, θ3 is the temperature value of the outer sheath, T1 is the thermal resistance value of the insulation layer, T2 is the thermal resistance value of the lining layer, T3 is the thermal resistance value of the outer sheath, C1 is the heat capacitance value of the conductor, C2 is the heat capacitance value of the insulation layer, C3 is the heat capacitance value of the outer sheath, and Q1 is the heat flow value of the entire line.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the temperature detection method for a cable conductor according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the temperature detection method of a cable conductor according to any one of claims 1 to 8 is implemented.

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