A method for estimating low voltage cable cross-section and bridge using regression analysis

Abstract

The present invention provides a method for estimating the cross-section of a low-voltage cable and a bridge using regression analysis deduction, and relates to the technical field of low-voltage cable selection and laying design. The method comprises: determining a target laying length and a target total low-voltage power consumption of a low-voltage cable; when the target laying length is lower than a first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable; based on the first regression curve, determining a first estimation factor according to the power of an electrical equipment; determining an equivalent cross-section of the low-voltage cable according to the first estimation factor and the target total low-voltage power consumption; and determining a cable laying strategy according to the equivalent cross-section, wherein the laying strategy comprises the number of bridges and the laying rate, and is used to improve the accuracy of the low-voltage cable laying design.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage cable selection and laying design, and in particular to a method for estimating a low-voltage cable cross section and a bridge frame by using regression analysis deduction. Background Art

[0002] In electrical design, cable selection and bridge laying account for a considerable proportion. In the early stage of a project, how to accurately estimate the overall cross-section size of all low-voltage cables and the number of bridges required, while ensuring that the laying coefficient of each cable is as reasonable as possible and reducing the actual cable cost, and timely propose conditions to the budget and civil engineering professionals to ensure the project progress; and control the difference between the budget and the actual cost within an acceptable range, are issues that must be considered in the early stages of each project.

[0003] In the existing technical solutions, most of them still rely on design and construction experience, or simple formula derivation and very little data support. The estimated cables and bridges in this way not only have large deviations, but also large margins, which increase a lot of costs; and the traditional estimation method is more inclined to evaluate the power consumption (cable current carrying capacity), while ignoring the actual proportion of cable voltage drop. Once the cable selection is too small, the number of bridges is too small, and the bridge filling rate is too large in the later stage of the project, it will not only increase the cost of transformation, but also it will be difficult to provide a theoretical basis for the project or the owner at the time of project settlement. Experience alone is difficult to be convincing. Therefore, it is urgent to create an estimation method to provide a reliable theoretical basis and real data reference for the estimation of the overall low-voltage cable and the selection of bridges in the early stage of the project. Summary of the invention

[0004] The problem solved by the present invention is how to estimate the magnitude of the overall low-voltage cables of the project and predict the number and size of the overall bridges at the beginning of the project, so as to provide a theoretical basis for project scheme design and improve the accuracy of electrical professional budget in actual projects.

[0005] To solve the above problems, the present invention provides a method for estimating the cross-section of low-voltage cables and bridges using regression analysis, comprising:

[0006] Determine the target laying length of low-voltage cables and the target total low-voltage power consumption;

[0007] When the target laying length is less than the first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable;

[0008] Based on the first regression curve, determining a first estimation factor according to the power of the electric device, wherein the power of the electric device is obtained by the target total low-voltage power consumption;

[0009] Determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment;

[0010] The cable laying strategy is determined according to the equivalent cross-section, wherein the laying strategy includes the number of cable trays and the laying rate.

[0011] Optionally, when the target laying length is less than the first laying length, constructing a first regression curve according to the acquired cable cross-section and maximum carrying power of the low-voltage cable includes:

[0012] Obtaining the current carrying capacity of the low-voltage cable;

[0013] Based on the current carrying capacity, at a preset power factor and a preset temperature, determining the maximum carrying power of the low-voltage cable;

[0014] Based on the regression analysis method, the first regression curve between the cable cross section and the maximum carrying power is constructed.

[0015] Optionally, determining the first estimation factor according to the power of the electrical equipment based on the first regression curve includes:

[0016] In the first regression curve, extracting the interval of the rate of change of the cable cross section with the maximum carrying power;

[0017] According to a preset first mapping relationship, a change rate corresponding to the power of the electrical device is determined from the change rate interval as the first estimation factor.

[0018] Optionally, the preset first mapping relationship includes:

[0019] When the power of the electric device is in the first interval, the change rate is determined as the first change rate interval;

[0020] When the power of the electric device is in the second interval, the change rate is determined to be in the second change rate interval;

[0021] When the power of the electrical equipment is in the third interval, the change rate is determined as the third change rate interval, wherein the upper limit of the first interval is less than or equal to the lower limit of the second interval, and the upper limit of the second interval is less than or equal to the lower limit of the third interval; the upper limit of the first change rate interval is less than or equal to the lower limit of the second change rate interval, and the upper limit of the second change rate interval is less than or equal to the lower limit of the third change rate interval.

[0022] Optionally, determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment includes:

[0023] Obtaining the number of cable cores of the low-voltage cable;

[0024] When the number of cable cores is a first number, adding a first weight to the first estimation factor;

[0025] When the number of cable cores is a second number, adding a second weight to the first estimation factor, wherein the first number is smaller than the second number, and the first weight is smaller than the second weight;

[0026] The first estimation factor after adding weight is multiplied by the power of the electrical equipment to obtain the equivalent cross-section.

[0027] Optionally, after determining the target laying length of the low-voltage cable and the target total low-voltage power consumption, the method further includes:

[0028] When the target laying length is longer than the first laying length, constructing a second regression curve between the cable conductor cross section and the line voltage drop based on a regression analysis method;

[0029] determining a second estimation factor according to the second regression curve and the determined target pressure drop;

[0030] Determining the equivalent cross-section of the low-voltage cable according to the second estimation factor, the target laying length and the target total low-voltage power consumption;

[0031] The cable laying strategy is determined according to the equivalent cross-section.

[0032] Optionally, determining the second estimation factor according to the second regression curve and the determined target pressure drop includes:

[0033] Combining the second regression curve with a preset voltage drop formula to obtain a second mapping relationship between the cable conductor cross-section and the cable design parameters, wherein the cable design parameters include at least one of a cable laying length, a cable voltage drop, and a laying coefficient;

[0034] The second estimation factor is determined based on the second mapping relationship and according to the target voltage drop.

[0035] Optionally, the determining the second estimation factor based on the second mapping relationship and according to the target voltage drop includes:

[0036] Based on the regression analysis method, construct a third regression curve, wherein the third regression curve is used to characterize the mapping relationship between the cable conductor cross-section and the equivalent cross-section;

[0037] The second mapping relationship and the target pressure drop are substituted into the third regression curve to obtain the second estimation factor.

[0038] Optionally, determining the equivalent cross-section of the low-voltage cable according to the second estimation factor, the target laying length and the target total low-voltage power consumption includes:

[0039] Acquiring a cable temperature, and determining a temperature weight based on the cable temperature, wherein the temperature weight is used to correct the second estimation factor, and the temperature weight is negatively correlated with the cable temperature;

[0040] The modified second estimation factor, the target laying length and the target total low-voltage power consumption determine the equivalent cross-section of the low-voltage cable.

[0041] Optionally, before determining the cable laying strategy according to the equivalent cross-section, the method further includes:

[0042] Modifying the first estimation factor or the second estimation factor according to distribution characteristics of the electrical equipment, wherein the distribution characteristics include at least one of power distribution of the electrical equipment and the number of the electrical equipment;

[0043] When the distribution feature is the number of electrical equipment, obtaining an average cross-sectional area of ​​the control cables, determining the number of control cables according to the number of electrical equipment and the average cross-sectional area; and correcting the second estimation factor according to the number of cables;

[0044] When the distribution feature is the power distribution of the electrical equipment, it is determined whether the power distribution of the electrical equipment meets the preset distribution condition. If the preset distribution condition is met, a preset distribution weight is added to the first estimation factor or the second estimation factor to obtain a modified first estimation factor or a modified second estimation factor. The method for estimating the cross section of a low-voltage cable and a bridge frame using regression analysis deduction of the present invention has the following beneficial effects:

[0045] The estimation strategy is determined by the known target laying length. When the target laying length is lower than the first laying length, the laying strategy of the cable is affected by the maximum carrying power. A first regression curve is constructed according to the cable cross-section and the maximum carrying power. The first regression curve characterizes the variation characteristics of the cable cross-section with the maximum carrying power. The first estimation factor for estimating the equivalent cross-section is determined according to the variation characteristics and the power of the electrical equipment. The factor is used to convert the nonlinear relationship characterized by the first regression curve into a linear relationship to reduce the estimation error. The estimated equivalent cross-section is determined according to the first estimation factor and the target total low-voltage power consumption so that the estimated equivalent cross-section matches the target total low-voltage power consumption. The number of bridges and the laying rate are determined according to the equivalent cross-section to realize the laying strategy estimation based on limited information while ensuring the accuracy of the low-voltage cable laying design. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1A schematic flow chart of a method for estimating a low-voltage cable cross section and a bridge frame using regression analysis in an embodiment of the present invention;

[0047] Figure 2 This is an example diagram of a first regression curve of a method for estimating a low-voltage cable cross section and a bridge frame using regression analysis deduction according to an embodiment of the present invention;

[0048] Figure 3 This is a flow chart of the method for estimating the cross section of a low-voltage cable and a bridge frame by using regression analysis and deduction after step S100 according to an embodiment of the present invention;

[0049] Figure 4 This is an example diagram of the second regression curve of the method for estimating the cross section of a low-voltage cable and a bridge frame using regression analysis deduction according to an embodiment of the present invention;

[0050] Figure 5 This is an example diagram of the third regression curve of the method for estimating the cross section of a low-voltage cable and a bridge frame by using regression analysis deduction according to an embodiment of the present invention;

[0051] Figure 6 An exemplary diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0053] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0054] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0055] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0056] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0057] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a method for estimating the cross-section of low-voltage cables and bridges by using regression analysis.

[0058] like Figure 1 As shown, an embodiment of the present invention provides a method for estimating a low-voltage cable cross-section and a bridge frame by using regression analysis deduction, comprising:

[0059] Step S100, determining the target laying length of the low-voltage cable and the target total low-voltage power consumption.

[0060] In cable-based electrical design, there is a lack of data support in the early stages of the design, and one can only determine the estimated total power consumption of the overall system of electrical equipment and the length of cables to be laid, and estimate the cable cross-section, number of bridges and laying rate based on the cable parameters. Therefore, in an embodiment of the present invention, the method for estimating low-voltage cable cross-sections and bridges using regression analysis is mainly intended to more accurately estimate the laying strategy based on the estimated total power consumption of the overall system of electrical equipment and the length of cables to be laid.

[0061] Specifically, before making an estimate, the estimated total power consumption of the entire system of electrical equipment is obtained, that is, the target total low-voltage power consumption, and the length of the cable to be laid, that is, the target laying length, is obtained.

[0062] Step S101: when the target laying length is shorter than the first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable.

[0063] In one embodiment, cables with the same parameters are seriously affected by the target laying length. When the target laying length is lower than the first laying length, the laying strategy is mainly affected by the current carrying capacity; when the target laying length is higher than the first preset length, due to the longer length, the target voltage drop of the cable is too large, and the laying strategy is mainly affected by the voltage drop.

[0064] When the target laying length is lower than the first laying length, the current carrying capacity is used as an estimation basis, and a first regression curve for characterizing the quantitative relationship between the cable cross-section and the maximum carrying power of the cable at a preset temperature is constructed by calculating the cable cross-section and the maximum carrying power of the cable at a preset temperature.

[0065] Step S102: determining a first estimation factor based on the first regression curve and according to the power of the electric equipment, wherein the power of the electric equipment is obtained by the target total low-voltage power consumption.

[0066] In one embodiment, in the first regression curve, although there is a nonlinear relationship between the maximum carrying power and the cable cross section, that is, the rate of change of the cable cross section increases with the increase of the maximum carrying power, in actual projects, the system composed of all electrical devices has multiple electrical devices as a whole. Due to the nonlinear relationship between power and cross section, when multiple electrical devices are used as independent power output devices, the relationship between the power of the electrical device and the cable cross section is different from the relationship between the system as a whole and the cable cross section. Only by summing up the power of the system as a whole to determine the equivalent cable cross section will produce errors. Therefore, through the idea of ​​differentiation, the first regression curve is divided into countless straight lines, the slope range of the straight line is calculated, and the slope corresponding to the power of the electrical device is selected from the slope range, and then the equivalent cross section is estimated according to the slope, that is, the power of each electrical device in the system as a whole is determined, and the first estimation factor for estimating the cable cross section is determined according to the power of the electrical device.

[0067] Step S103: determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment.

[0068] In one embodiment, after determining the first estimation factor, that is, after determining the slope corresponding to the equivalent cross-section of the power of the electrical equipment in the first regression curve, the equivalent cross-section of the cable is re-determined by the first estimation factor and the target total low-voltage power consumption.

[0069] Step S104, determining a cable laying strategy according to the equivalent cross-section, wherein the laying strategy includes the number of cable trays and the laying rate.

[0070] In one embodiment, after the equivalent cross section is determined, the number of bridges to be laid and the laying rate are determined according to the total area of ​​the equivalent cross section. Since the target laying length of the cable has been determined, the equivalent cross section has been determined, and the type and working performance of the cable (parameters such as the number of cable cores, cable conductor cross section, outer diameter, cable carrying power and current carrying capacity) have also been determined, when the specifications of the bridge are known, the number of bridges and the laying rate can be calculated to achieve the laying strategy estimation based on the target laying length and the target total low-voltage power consumption.

[0071] In this embodiment, the estimation strategy is determined by the known target laying length. When the target laying length is lower than the first laying length, the laying strategy of the cable is affected by the maximum carrying power. A first regression curve is constructed according to the cable cross-section and the maximum carrying power. The first regression curve characterizes the change characteristics of the cable cross-section with the maximum carrying power. The first estimation factor for estimating the equivalent cross-section is determined according to the change characteristics and the power of the electrical equipment. The factor is used to convert the nonlinear relationship characterized by the first regression curve into a linear relationship to reduce the estimation error. The estimated equivalent cross-section is determined according to the first estimation factor and the target total low-voltage power consumption so that the estimated equivalent cross-section matches the target total low-voltage power consumption. The number of bridges and the laying rate are determined according to the equivalent cross-section to achieve laying strategy estimation based on limited information while ensuring the accuracy of the low-voltage cable laying design.

[0072] Optionally, when the target laying length is less than the first laying length, constructing a first regression curve according to the acquired cable cross-section and maximum carrying power of the low-voltage cable includes:

[0073] The current carrying capacity of the low-voltage cable is obtained.

[0074] Based on the current carrying capacity, the maximum carrying power of the low-voltage cable is determined at a preset power factor and a preset temperature.

[0075] Based on the regression analysis method, the first regression curve between the cable cross section and the maximum carrying power is constructed.

[0076] In one embodiment, the calculation of the maximum carrying power can be expressed as:

[0077]

[0078] Among them, P z35℃ represents the maximum power that the cable can carry at 35°C, U represents the operating voltage, cosφ represents the power factor. In this embodiment, the power factor is 0.8, and I z35℃ Indicates the current carrying capacity of the cable at 35°C.

[0079] The cable cross section can be expressed as:

[0080]

[0081] Where S represents the cable cross section and D represents the outer diameter of the cable.

[0082] like Figure 2 As shown in the figure, the curve represents the first regression curve between the cable cross section and the maximum carrying power of a specific cable, wherein the horizontal axis x represents the maximum carrying power in kW, and the vertical axis y represents the cable cross section in mm 2 , R 2 (R-squared) is an indicator for evaluating the fit of the first regression curve.

[0083] Optionally, determining the first estimation factor according to the power of the electrical equipment based on the first regression curve includes:

[0084] In the first regression curve, the interval of the rate of change of the cable cross-section with respect to the maximum carrying power is extracted.

[0085] According to a preset first mapping relationship, a change rate corresponding to the power of the electrical device is determined from the change rate interval as the first estimation factor.

[0086] by Figure 2 For example, the image simulates the first regression curve of the power carried by the cable with an outer diameter of 2.5 to 300 mm between 16.32 and 313.28 kW. In this regression curve, the change rate of the maximum carrying power is in the interval of [8.89, 21.59]. Since there is a nonlinear relationship between the change rate of the maximum carrying power and the cable cross section, the power of each part of the electrical equipment in the overall system is determined, and then the equivalent cross section corresponding to the electrical equipment is determined to reduce the estimation error caused by nonlinear changes.

[0087] In one embodiment, the estimation of the equivalent cross section can be expressed as:

[0088]

[0089] Among them, 0.0139, 5.323 and 83.857 in the formula respectively represent the parameters in the first regression curve, P represents the power of the electrical equipment, and k represents the target laying coefficient.

[0090] Then, the change rate interval is brought into the estimation formula of the equivalent cross section, which is expressed as:

[0091] S eq =KP(8.89≤K≤21.59),

[0092] Wherein, K represents the first estimation factor, and P represents the power of the electrical equipment.

[0093] Optionally, the preset first mapping relationship includes:

[0094] When the power of the electric device is in the first interval, the change rate is determined as the first change rate interval.

[0095] When the power of the electric device is in the second interval, the change rate is determined as the second change rate interval.

[0096] When the power of the electrical equipment is in the third interval, the change rate is determined as the third change rate interval, wherein the upper limit of the first interval is less than or equal to the lower limit of the second interval, and the upper limit of the second interval is less than or equal to the lower limit of the third interval; the upper limit of the first change rate interval is less than or equal to the lower limit of the second change rate interval, and the upper limit of the second change rate interval is less than or equal to the lower limit of the third change rate interval.

[0097] The range of the change rate is determined according to the power range of the electrical equipment. Taking the above embodiment as an example, the value of K is [8.89, 21.59]. When the power of the electrical equipment P<100kW, the value range of K is [8.89, 14.7]. When the power of the electrical equipment is 100kW≤P≤200kW, the value range of K is (14.7, 20). When the power of the electrical equipment P>200kW, the value range of K is [20, 21.59].

[0098] Optionally, when the power of the electrical equipment cannot be determined, the mean of the change rate is determined and the mean is used as the first estimation factor.

[0099] When the power distribution and characteristics of a single electrical device cannot be determined, the mean value of the rate of change is used as the first estimation factor to make the first regression curve represent a linear relationship, thereby minimizing errors and obtaining higher estimation expectations.

[0100] Optionally, determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment includes:

[0101] The number of cable cores of the low-voltage cable is obtained.

[0102] When the number of the cable cores is a first number, a first weight is added to the first estimation factor.

[0103] When the number of cable cores is a second number, a second weight is added to the first estimation factor, wherein the first number is smaller than the second number, and the first weight is smaller than the second weight.

[0104] The first estimation factor after adding weight is multiplied by the power of the electrical equipment to obtain the equivalent cross-section.

[0105] In one embodiment, in addition to the commonly used 4-core cable, there may be a feeder load in the power-consuming device system, and the feeder load uses a 5-core cable. In this case, a second weight is added to the first estimation factor to estimate the impact of the feeder load. In this embodiment, the second weight is set to 1.

[0106] In actual cable selection, the current carrying capacity cannot be exactly equal to the calculated current. Therefore, if the equivalent cross-sectional area is estimated only according to the current carrying capacity, the result is still slightly smaller. Therefore, in this embodiment, after calculating and determining the value of K, the K value is increased by 0.5 as the first weight to leave a certain error margin.

[0107] Alternatively, if Figure 3 As shown, after determining the target laying length of the low-voltage cable and the target total low-voltage power consumption, it also includes:

[0108] Step S110: when the target laying length is longer than the first laying length, constructing a second regression curve between the cable conductor cross-section and the line voltage drop based on a regression analysis method.

[0109] Step S111: determining a second estimation factor according to the second regression curve and the determined target pressure drop.

[0110] Step S112, determining the equivalent cross-section of the low-voltage cable according to the second estimation factor, the target laying length and the target total low-voltage power consumption.

[0111] Step S113, determining the cable laying strategy according to the equivalent cross-section.

[0112] When the target laying length is long, the voltage drop of the cable has a significant impact. The equivalent cross-section is estimated using the voltage drop as an influencing factor, and the cable laying strategy is determined based on the estimated equivalent cross-section.

[0113] like Figure 4 As shown, in one embodiment, the first laying length is set to 100 meters. When the target laying length is greater than 100 meters, a second regression curve between the cable conductor cross section and the line voltage drop is constructed based on the regression analysis method. In the figure, the horizontal axis x represents the cable conductor cross section, in units of mm 2 , the vertical axis y represents the line voltage drop, the unit is % / (A·km).

[0114] The second regression curve characterizes the relationship between the cable conductor cross-section and the line voltage drop. Based on this correspondence, the second estimation factor affecting the equivalent cross-section can be further determined according to the target voltage drop. The second estimation factor is used to characterize the mapping relationship between the line voltage drop and the equivalent cross-section under the unit laying length and the unit low-voltage power consumption. Therefore, the equivalent cross-section of the low-voltage cable can be determined by the target laying length and the target total low-voltage power consumption, and the cable laying strategy can be determined according to the equivalent cross-section.

[0115] Optionally, determining the second estimation factor according to the second regression curve and the determined target pressure drop includes:

[0116] The second regression curve is combined with a preset voltage drop formula to obtain a second mapping relationship between the cable conductor cross-section and the cable design parameters, wherein the cable design parameters include at least one of the cable laying length, the cable voltage drop and the laying coefficient.

[0117] The second estimation factor is determined based on the second mapping relationship and according to the target voltage drop.

[0118] In one embodiment, the second regression curve is substituted into a preset voltage drop formula to obtain a second mapping relationship, and the voltage drop formula is expressed as:

[0119]

[0120] The voltage drop formula after substitution is expressed as:

[0121]

[0122] Wherein, L represents the cable length, ΔU% represents the voltage drop percentage, P represents the power of the electrical appliance, U represents the working voltage, k represents the laying coefficient, s represents the cable conductor cross section, and y represents the line voltage drop in the second regression curve. Wherein, 6.2797 and -0.885 represent the parameters in the second regression curve.

[0123] Let U be 0.38kW, and simplify it to:

[0124] Right now

[0125]

[0126] The second estimation factor includes parameters other than k in the formula, which are used to affect the estimation of the equivalent cross section.

[0127] Optionally, the determining the second estimation factor based on the second mapping relationship and according to the target voltage drop includes:

[0128] Based on the regression analysis method, a third regression curve is constructed, wherein the third regression curve is used to characterize the mapping relationship between the cable conductor cross-section and the equivalent cross-section.

[0129] The second mapping relationship and the target pressure drop are substituted into the third regression curve to obtain the second estimation factor.

[0130] In one embodiment, according to the cable parameters, a mapping relationship between the cable conductor cross-section and the equivalent cross-section is constructed based on the regression analysis method, such as Figure 5 As shown, the abscissa x represents the cable conductor cross-section, and the ordinate y represents the equivalent cross-section.

[0131] After substituting the second mapping relationship into the third regression curve and determining the target pressure drop, the second estimation factor is obtained, wherein the third regression curve is expressed as:

[0132] S eq =as+b,

[0133] Among them, S eq represents the equivalent cross section, s represents the cable conductor cross section, a and b represent the slope and y-axis endpoint of the regression curve respectively. Figure 5 In the illustrated embodiment, the third regression curve is expressed as:

[0134] S eq =9.8s+220.11,

[0135] Then the equivalent cross-section estimation formula after substitution is:

[0136]

[0137] If the pressure drop is further set to 3.5% and the laying coefficient is set to 0.65, the equivalent cross-section estimation formula is simplified to:

[0138]

[0139] S eq ≥49.51(PL) 1.13 +220.11,

[0140] Therefore, according to this formula, after taking the target laying length L and the power P of the electrical equipment, the estimated equivalent cross-section S can be obtained: eq , determine the laying strategy based on the equivalent cross-section.

[0141] Optionally, determining the equivalent cross-section of the low-voltage cable according to the second estimation factor, the target laying length and the target total low-voltage power consumption includes:

[0142] The cable temperature is obtained, and a temperature weight is determined based on the cable temperature, wherein the temperature weight is used to correct the second estimation factor, and the temperature weight is negatively correlated with the cable temperature.

[0143] The modified second estimation factor, the target laying length and the target total low-voltage power consumption determine the equivalent cross-section of the low-voltage cable.

[0144] Furthermore, after determining the second estimation factor, temperature can be further introduced to increase the estimation accuracy. For example, a preset temperature and temperature weight mapping relationship is constructed. At each temperature, there is a corresponding temperature weight. The second estimation factor is corrected by the temperature weight to obtain the equivalent cross-section after considering the temperature.

[0145] In one embodiment, the mapping relationship includes that when the temperature is 30°C, the temperature weight is 1, that is, it does not affect the second estimation factor, and when the temperature is 35°C, the temperature weight is 1.05. By multiplying the temperature weight with the laying coefficient, the modified second estimation factor is obtained. Figure 5 Taking the corresponding embodiment as an example, the equivalent cross-section estimation formula established is:

[0146]

[0147] When the temperature is 35°C, k = 0.65 and then multiplied by the temperature weight, that is, k = 1.05 × 0.65 = 0.6825, the pressure drop is still 3.5%, and the estimation formula is expressed as:

[0148]

[0149] Optionally, before determining the cable laying strategy according to the equivalent cross-section, the method further includes:

[0150] The first estimation factor or the second estimation factor is modified according to distribution characteristics of the electrical devices, wherein the distribution characteristics include at least one of power distribution of the electrical devices and the number of the electrical devices.

[0151] When the distribution characteristic is the number of electrical devices, the average cross-sectional area of ​​the control cables is obtained, and the number of control cables is determined according to the number of electrical devices and the average cross-sectional area; and the second estimation factor is corrected according to the number of cables.

[0152] When the distribution feature is the power distribution of the electrical equipment, determine whether the power distribution of the electrical equipment meets the preset distribution conditions. If the preset distribution conditions are met, add the preset distribution weight to the first estimation factor or the second estimation factor to obtain a corrected first estimation factor or a corrected second estimation factor.

[0153] In one embodiment, the first estimation factor or the second estimation factor may be corrected according to the distribution characteristics of the electrical equipment to make the estimation result more accurate.

[0154] In actual projects, the number of control cables will also affect the cable cross-section. The number of control cables is positively correlated with the number of equipment. When the equivalent cross-section is determined by the second estimation factor, it can be corrected by the number of electrical equipment, including determining the number of control cables based on the average cross-sectional area of ​​the control cables and the number of electrical equipment. Figure 5 For example, the estimation formula is expressed as:

[0155]

[0156] Where N represents the number of electrical equipment, S k Indicates the average cross-sectional area of ​​the control cable.

[0157] On the other hand, when there are many low-power electrical devices in the system composed of electrical equipment, in order to ensure the mechanical strength of the cable when it is laid over a long distance, 2.5mm is generally not used. 2 The minimum cable is only 4mm 2 For cables with a cross-section smaller than that of a standard cable, the equivalent cross-section estimated based on the first estimation factor and the second estimation factor is too small. The distribution weight is introduced to offset the estimation deviation.

[0158] Specifically, the preset distribution condition includes: the number of electrical devices having power less than a preset power is greater than a preset number.

[0159] Optionally, the preset power value is 10 kW, and the preset quantity is determined by actual demand.

[0160] Then the value of the distribution weight is [1.1, 1.3].

[0161] That is, the target laying coefficients in the first estimation factor and the second estimation factor are multiplied by the distribution weight to obtain a modified first estimation factor and a modified second estimation factor.

[0162] like Figure 6 As shown, an electronic device 600 provided by an embodiment of the present invention includes a memory 610 and a processor 620; the memory 610 is used to store a computer program; the processor 620 is used to implement the method of estimating the cross-section of a low-voltage cable and a bridge frame by using regression analysis as described above when executing the computer program.

[0163] In other words, an electronic device 600 includes a memory 610 and a processor 620 coupled to the memory 610; the memory 610 is configured to store a computer program; and the processor 620 is configured to perform the following operations when executing the computer program:

[0164] Determine the target laying length of low-voltage cables and the target total low-voltage power consumption;

[0165] When the target laying length is less than the first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable;

[0166] Based on the first regression curve, determining a first estimation factor according to the power of the electric device, wherein the power of the electric device is obtained by the target total low-voltage power consumption;

[0167] Determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment;

[0168] The cable laying strategy is determined according to the equivalent cross-section, wherein the laying strategy includes the number of cable trays and the laying rate.

[0169] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for estimating the cross-section of a low-voltage cable and a bridge frame using regression analysis as described above is implemented.

[0170] In other words, a non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor performs the following operations:

[0171] Determine the target laying length of low-voltage cables and the target total low-voltage power consumption;

[0172] When the target laying length is less than the first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable;

[0173] Based on the first regression curve, determining a first estimation factor according to the power of the electrical equipment;

[0174] Determine the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electric equipment, wherein the power of the electric equipment is obtained by the target total low-voltage power consumption;

[0175] The cable laying strategy is determined according to the equivalent cross-section, wherein the laying strategy includes the number of cable trays and the laying rate.

[0176] An electronic device 600 that can be used as a server or client of the present invention will now be described, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device 600 is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device 600 can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, 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.

[0177] The electronic device 600 includes a computing unit, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) or a computer program loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for the operation of the device can also be stored. The computing unit, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0178] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc. In the present application, the unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or it may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present invention. In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0179] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for estimating low voltage cable cross section and bridge frame using regression analysis, characterized in that: include: Determine the target laying length of low-voltage cables and the target total low-voltage power consumption; When the target laying length is less than the first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable; Based on the first regression curve, determining a first estimation factor according to the power of the electric device, wherein the power of the electric device is obtained by the target total low-voltage power consumption; Determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment; The cable laying strategy is determined according to the equivalent cross-section, wherein the laying strategy includes the number of cable trays and the laying rate.

2. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 1 is characterized in that: When the target laying length is less than the first laying length, constructing a first regression curve according to the obtained cable cross-section and maximum carrying power of the low-voltage cable comprises: Obtaining the current carrying capacity of the low-voltage cable; Based on the current carrying capacity, at a preset power factor and a preset temperature, determining the maximum carrying power of the low-voltage cable; Based on the regression analysis method, the first regression curve between the cable cross section and the maximum carrying power is constructed.

3. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 1, characterized in that: The determining the first estimation factor according to the power of the electrical equipment based on the first regression curve comprises: In the first regression curve, extracting the interval of the rate of change of the cable cross section with the maximum carrying power; According to a preset first mapping relationship, a change rate corresponding to the power of the electrical device is determined from the change rate interval as the first estimation factor.

4. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 3 is characterized in that: The preset first mapping relationship includes: When the power of the electric device is in the first interval, the change rate is determined as the first change rate interval; When the power of the electric device is in the second interval, the change rate is determined to be in the second change rate interval; When the power of the electrical equipment is in the third interval, the change rate is determined as the third change rate interval, wherein the upper limit of the first interval is less than or equal to the lower limit of the second interval, and the upper limit of the second interval is less than or equal to the lower limit of the third interval; the upper limit of the first change rate interval is less than or equal to the lower limit of the second change rate interval, and the upper limit of the second change rate interval is less than or equal to the lower limit of the third change rate interval.

5. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 1, characterized in that: The step of determining the equivalent cross-section of the low-voltage cable according to the first estimation factor and the power of the electrical equipment comprises: Obtaining the number of cable cores of the low-voltage cable; When the number of cable cores is a first number, adding a first weight to the first estimation factor; When the number of cable cores is a second number, adding a second weight to the first estimation factor, wherein the first number is smaller than the second number, and the first weight is smaller than the second weight; The first estimation factor after adding weight is multiplied by the power of the electrical equipment to obtain the equivalent cross-section.

6. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 1, characterized in that: After determining the target laying length of the low-voltage cable and the target total low-voltage power consumption, the method further includes: When the target laying length is longer than the first laying length, constructing a second regression curve between the cable conductor cross section and the line voltage drop based on a regression analysis method; determining a second estimation factor according to the second regression curve and the determined target pressure drop; Determining the equivalent cross-section of the low-voltage cable according to the second estimation factor, the target laying length and the target total low-voltage power consumption; The cable laying strategy is determined according to the equivalent cross-section.

7. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 6, characterized in that: Determining the second estimation factor according to the second regression curve and the determined target pressure drop comprises: Combining the second regression curve with a preset voltage drop formula to obtain a second mapping relationship between the cable conductor cross-section and the cable design parameters, wherein the cable design parameters include at least one of a cable laying length, a cable voltage drop, and a laying coefficient; The second estimation factor is determined based on the second mapping relationship and according to the target voltage drop.

8. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 6, characterized in that: The determining the second estimation factor based on the second mapping relationship and according to the target voltage drop comprises: Based on the regression analysis method, construct a third regression curve, wherein the third regression curve is used to characterize the mapping relationship between the cable conductor cross-section and the equivalent cross-section; The second mapping relationship and the target pressure drop are substituted into the third regression curve to obtain the second estimation factor.

9. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 6, characterized in that: Determining the equivalent cross-section of the low-voltage cable according to the second estimation factor, the target laying length and the target total low-voltage power consumption includes: Acquiring a cable temperature, and determining a temperature weight based on the cable temperature, wherein the temperature weight is used to correct the second estimation factor, and the temperature weight is negatively correlated with the cable temperature; The modified second estimation factor, the target laying length and the target total low-voltage power consumption determine the equivalent cross-section of the low-voltage cable.

10. The method for estimating the cross section of low-voltage cables and bridges by using regression analysis according to claim 6, characterized in that: Before determining the cable laying strategy according to the equivalent cross-section, the method further includes: Modifying the first estimation factor or the second estimation factor according to distribution characteristics of the electrical equipment, wherein the distribution characteristics include at least one of power distribution of the electrical equipment and the number of the electrical equipment; When the distribution feature is the number of electrical equipment, obtaining an average cross-sectional area of ​​the control cables, determining the number of control cables according to the number of electrical equipment and the average cross-sectional area; and correcting the second estimation factor according to the number of cables; When the distribution feature is the power distribution of the electrical equipment, determine whether the power distribution of the electrical equipment meets the preset distribution conditions. If the preset distribution conditions are met, add the preset distribution weight to the first estimation factor or the second estimation factor to obtain a corrected first estimation factor or a corrected second estimation factor.

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