A method and system for calculating the safe sag of a conductor of a power transmission tower

Abstract

The application discloses a safety sag calculation method and system for a conductor of a power transmission tower, and the method comprises the following steps: constructing a conductor stress change relationship according to the elastic deformation of the conductor under each control condition and the original length of the conductor; wherein each control condition is set according to preset environmental parameters; determining the conductor tension characteristic under an actual working condition based on the conductor stress change relationship and a preset nonlinear stress change relationship; obtaining a safety sag meeting a predetermined conductor safety requirement according to the conductor tension characteristic, and adjusting the sag of the conductor under the actual working condition according to the safety sag. The application considers the nonlinear characteristics of the conductor when calculating the tension characteristics of the conductor of the power transmission tower under different environments, so that the calculated conductor sag is more accurate and meets the safety requirements of the overhead transmission line, and sufficient data support is provided for effectively evaluating and ensuring the safety of the transmission line.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of safety evaluation of power transmission line conductors, and particularly relates to a safety sag calculation method and system for power transmission tower conductors. BACKGROUND

[0002] The conductors erected at both ends of the power transmission tower need to withstand severe natural environments such as ice, wind and low temperature. Due to the weight of the conductor itself and the external force acting on the conductor in the above natural environment, the conductor will bear a certain tension. How to ensure that the stress of the conductor under different working conditions meets certain safety requirements needs to determine the sag of the conductor under the above natural environment, and the calculation of the sag involves the research on the tension characteristics of the conductor.

[0003] The research on the "stress-strain" relationship of the conductor is the key point of solving the tension characteristics of the conductor, and the linear and nonlinear characteristics of the conductor material have a significant impact on the tension characteristics of the conductor. The existing conductor tension characteristic calculation process only considers the linear characteristics of the conductor material, which leads to the lack of nonlinear influencing factors in the calculation of the "stress-strain" relationship of the conductor, resulting in a large error in the calculation result, and the sag of the conductor during the laying of the conductor may not meet the safety requirements. SUMMARY

[0004] The application provides a safety sag calculation method and system for power transmission tower conductors, which considers the nonlinear characteristics of the conductor when calculating the tension characteristics of the power transmission tower conductor under different environments, so that the calculated conductor sag is more accurate and meets the safety requirements of the power transmission line, and provides sufficient data support for effectively evaluating and ensuring the safety of the power transmission line.

[0005] The first aspect of the application provides a safety sag calculation method for power transmission tower conductors, the method comprising:

[0006] According to the elastic deformation of the conductor under each control condition and the original length of the conductor, a conductor stress change relationship is constructed; wherein each control condition is set according to a preset environmental parameter;

[0007] Based on the conductor stress change relationship and a preset nonlinear stress change relationship, the tension characteristics of the conductor under actual working conditions are determined;

[0008] According to the tension characteristics of the conductor, a safety sag meeting the predetermined safety requirements of the conductor is obtained, and the sag of the conductor under the actual working conditions is adjusted according to the safety sag.

[0009] The above scheme first sets different control conditions suitable for actual situations, and provides background support for subsequent research on the tension characteristics of the conductor. Then, according to the elastic deformation of the conductor under each control condition and the original length of the conductor, the relationship between the stress and the deformation of the conductor under different control conditions is researched, the stress change relationship of the conductor is constructed, and then according to the nonlinear stress change formula, the tension characteristics of the conductor under different working conditions are determined, so that according to the deformation of the conductor in the actual working condition, the stress of the conductor in the working condition can be determined, and the sag range in the working condition is further determined to ensure that the conductor is in a safe operating state, and prevent the phenomenon of power tower collapse due to excessive stress on the conductor.

[0010] In a possible implementation method of the first aspect, each control condition is set according to a preset environmental parameter, specifically:

[0011] A plurality of control conditions are selected, and the environmental parameter of each control condition is determined; wherein the environmental parameter includes specific load, tension and temperature;

[0012] According to the environmental parameter, a first curve and a first ratio corresponding to each control condition are set; wherein the first ratio is the ratio of specific load to tension; and the first curve is a function related to the environmental parameter;

[0013] All first curves and all first ratios are compared respectively, and the critical span of each control condition is determined according to the comparison result.

[0014] According to the critical span, the control conditions are screened to determine the control conditions.

[0015] The above scheme first determines the environmental parameter corresponding to each condition according to the provided control condition, and then sets the first curve and the first ratio according to the environmental parameter to measure the rationality of each condition, determines the more appropriate control condition as the control condition, so that the obtained conductor tension characteristics under the control condition are more accurate. Moreover, by means of the critical span, the control conditions under different conductor spans are screened to obtain the control conditions more suitable for the actual working condition.

[0016] In a possible implementation method of the first aspect, all first curves and all first ratios are compared respectively, and the critical span of each control condition is determined according to the comparison result, specifically:

[0017] All first curves are compared, and the first ratio is screened according to the comparison result to obtain a first screening result;

[0018] All first ratios are compared, and the first curve is screened according to the comparison result to obtain a second screening result;

[0019] According to the first screening result and the second screening result, a plurality of second curves are selected from the first curve;

[0020] According to the intersection of any two second curves, a critical span of the control condition corresponding to the second curve is determined.

[0021] In a possible implementation method of the first aspect, the first curve is specifically:

[0022] The specific expression of the first curve is:

[0023] ;

[0024] In the formula, F kx is the first curve, E is the elastic modulus of the conductor, r k is the specific load of the control condition, l is the span of the control condition, is the conductor tension under the control condition, is the thermal expansion coefficient of the conductor, t is the temperature of the to-be-solved condition, t k is the temperature of the control condition, F okx is the initial component of the first curve F kx , t kx is the temperature of the xth control condition.

[0025] In a possible implementation method of the first aspect, according to the critical span, the control conditions are screened to determine the control condition, which is specifically:

[0026] If the actual span of the control condition is less than the critical span of the control condition, the control condition with the minimum first ratio is selected as the control condition;

[0027] If the actual span of the control condition is greater than the critical span of the control condition, the control condition with the maximum first ratio is selected as the control condition.

[0028] In a possible implementation method of the first aspect, according to the elastic deformation of the conductor under each control condition and the original line length of the conductor, a conductor stress change relationship is constructed, which is specifically:

[0029] According to the difference between the elastic deformation of the conductor under each control condition and the control condition, an original line length derivation formula of each control condition is constructed;

[0030] Based on the fact that the original line length is equal under different control conditions, the conductor stress change relationship corresponding to each control condition is obtained according to the original line length derivation formula.

[0031] The above scheme derives the original wire length of the wire according to the elastic deformation of the wire under each control condition, and because the original wire length is the same regardless of the deformation of the wire, the original wire length derivation formula is also equal, so the corresponding wire stress change relationship of each control condition can be obtained, which provides data support for subsequent research on the influence of different control conditions on stress change.

[0032] In a possible implementation method of the first aspect, based on the wire stress change relationship and a preset nonlinear stress change relationship, the wire tension characteristic under the actual working condition is determined, specifically:

[0033] According to the wire stress change relationship and the actual working condition, the elastic deformation under the actual working condition is obtained;

[0034] According to the elastic deformation under the actual working condition and the nonlinear stress change relationship, the wire tension characteristic under the actual working condition is determined.

[0035] The above scheme studies the relationship between the elastic deformation and the stress of the wire in the actual working condition according to the obtained wire stress change relationship, and then determines the wire tension characteristic under the actual working condition according to the nonlinear stress change relationship describing the nonlinear "stress-strain" relationship of the wire, which provides data support for subsequent calculation of the sag that can ensure that the wire is always in a safe operating state under the actual working condition.

[0036] In a possible implementation method of the first aspect, a safe sag meeting a predetermined wire safety requirement is obtained according to the wire tension characteristic, and the sag of the wire under the actual working condition is adjusted according to the safe sag, specifically:

[0037] According to the wire tension characteristic, the stress of the wire under the actual working condition is determined;

[0038] According to the stress and the predetermined wire safety requirement, a safe sag meeting the wire safety requirement under the actual working condition is obtained;

[0039] According to the safe sag, the sag of the wire under the actual working condition is adjusted.

[0040] The above scheme can accurately determine the stress of the wire under the actual working condition according to the wire tension characteristic under the actual working condition, and then ensure that the wire does not have excessive elastic deformation and thus does not have safety problems by adjusting the sag of the wire according to the stress and the predetermined wire safety requirement.

[0041] The second aspect of the present application provides a safety sag calculation system for a wire of a power transmission tower, and the system comprises a wire stress change relationship construction module, a wire tension characteristic calculation module, and a sag adjustment module.

[0042] The conductor stress change relationship construction module is configured to construct a conductor stress change relationship according to the elastic deformation of the conductor under each control condition and the original length of the conductor; and each control condition is set according to a preset environmental parameter.

[0043] The conductor tension characteristic calculation module is configured to determine the conductor tension characteristic under the actual working condition based on the conductor stress change relationship and a preset nonlinear stress change relationship.

[0044] The sag adjustment module is configured to obtain a safe sag that meets a predetermined conductor safety requirement according to the conductor tension characteristic, and adjust the sag of the conductor under the actual working condition according to the safe sag.

[0045] The third aspect of the present application provides a storage medium storing computer readable program code, when the computer readable program code is executed, the steps of the power transmission tower conductor safe sag calculation method in any of the embodiments of the present application are implemented. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0047] Figure 1 is a specific flowchart of a power transmission tower conductor safe sag calculation method provided by an embodiment of the present application;

[0048] Figure 2 is a stress-strain relationship diagram of a power transmission tower conductor safe sag calculation method provided by an embodiment of the present application;

[0049] Figure 3 is a structure diagram of a terminal device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0051] It should be understood that the step numbers used herein are only for the convenience of description, and are not limited to the execution sequence of the steps.

[0052] First Embodiment

[0053] Changes in the natural environment exert varying degrees of external force on the conductors suspended from transmission towers. Combined with the conductors' own weight, excessive tension on the conductors can place an undue burden on both the conductors and the poles. Therefore, a certain degree of sag is typically maintained within a controllable range to ensure the stability of the transmission towers and thus improve the safety of the transmission lines. Sag, in this context, refers to the vertical distance between the lowest point of the conductor and the line connecting the two suspension points on adjacent poles at the same height on flat ground.

[0054] The study of sag is essentially a study of conductor tension characteristics. The relationship between stress and conductor elastic deformation under different environments is not simply a purely linear change, but a complex nonlinear change. Only by clearly defining the conductor tension characteristics under nonlinear stress-strain conditions can we obtain accurate conductor sag that ensures the stable operation of the transmission tower-line.

[0055] like Figure 1 As shown, Figure 1 This application provides a schematic flowchart of a method for calculating the safe sag of a transmission tower conductor according to a certain embodiment. The method for calculating the safe sag of a transmission tower conductor in this embodiment includes steps S1 to S3, which are detailed below:

[0056] Step S1: Based on the elastic deformation of the conductor under each control condition and the original length of the conductor, construct the stress variation relationship of the conductor.

[0057] In this embodiment, to simulate the influence of different environmental factors on conductor tension characteristics, suitable and representative control conditions need to be selected as background conditions for studying conductor tension characteristics. Furthermore, according to the design requirements of transmission lines, conductors need to meet specific stress requirements under characteristic meteorological conditions, and these specific meteorological conditions are the control conditions in this embodiment. Therefore, several control conditions are first selected to determine the environmental parameters for each control condition.

[0058] The control conditions include low-temperature conditions, icing conditions, high-wind conditions, and average annual conditions. The environmental parameters for these conditions are given by the design requirements of the transmission line and are known quantities. The environmental parameters include specific load, tension, and temperature.

[0059] To facilitate the selection of control conditions, two intermediate variables are designed in this embodiment to compare the suitability of each control condition. These two intermediate variables are the first curve and the first ratio. Based on the environmental parameters of each control condition, a first curve and a first ratio are set for each control condition. The first ratio is the ratio of specific load to tension.

[0060] Furthermore, the specific expression for the first curve is as follows:

[0061] ;

[0062] In the formula, F kx Let E be the elastic modulus of the conductor, and r be the first curve. k To control the specific load under the operating condition, l represents the span of the control operating condition. To control the conductor tension under operating conditions, The coefficient of thermal expansion of the conductor is expressed in ×10⁻⁶. -6 / ℃, where t is the temperature of the operating condition to be determined. k To control the operating temperature, F okx For the first curve F kx The initial components, t kx Let x be the temperature for the xth control condition, and let a, b, c, and d be the four control conditions mentioned above. The span is the horizontal distance between the suspension points of the conductors on two adjacent towers in an overhead line.

[0063] In addition, F kx and F okx The following relationship exists between them:

[0064] ;

[0065] Then, by comparing the first curve and the first ratio, the comparison results of each control condition are obtained.

[0066] For example, the comparison results of the first curve and the first ratio in the embodiments of this application are sorted according to the following formula:

[0067] ;

[0068] The first row of formulas represents the first ratio of the four control conditions a, b, c, and d. and The specific loads are for four control conditions: a, b, c, and d. and For the tension of four control conditions a, b, c, and d, F oka F okb F okc and F okd The first curve represents the four control conditions a, b, c, and d.

[0069] According to the above formula, if If they are the same, then F okx Smaller control conditions are discarded; if F okx If they are the same, then... The smaller control conditions are discarded, and the first curve of the remaining control conditions is called the second curve. The intersection point of each second curve is calculated in pairs.

[0070] Specifically, in determining the second curve After the intersection, adjust the distance l at the intersection. ij The critical gap between the i-th and j-th control conditions is called the critical distance between them. Therefore, the following formulas can be obtained for the i-th and j-th control conditions:

[0071] ;

[0072] In the formula, These are the tensions for the i-th and j-th control conditions, respectively, in N / mm. 2 , These are the specific loads for the i-th and j-th control conditions, respectively, in N / mm². 2 , t ki t kj The temperatures for the i-th and j-th control conditions are respectively, in °C.

[0073] Calculating the above formula yields the formula for calculating the critical gear gap, as follows:

[0074] ;

[0075] In the formula, (m) represents the critical gap distance in meters (m).

[0076] After determining the critical span for each control condition, the actual span for the corresponding control condition is judged based on the critical span, thereby completing the screening of the control conditions and determining control conditions that better meet the design requirements of the transmission line.

[0077] For example, in this embodiment of the application, if the actual gear distance of the i-th control condition is less than l ij Then, the control condition with the smallest first ratio between the i-th and j-th control conditions is selected as the control condition; if the actual gear distance of the i-th control condition is greater than l ij Then, the control condition with the largest first ratio between the i-th and j-th control conditions is selected as the control condition.

[0078] Then, the stress-deformation relationship of the conductor under each control condition was studied in conjunction with the control conditions.

[0079] First, after clarifying the elastic deformation of the conductor under each control condition, the original conductor length derivation formula for each control condition can be calculated based on the differences in the control conditions.

[0080] Because the original length of the conductor is its length when it first left the factory, and it has not been deformed by weather or other environmental factors, the original length is known and remains consistent under any controlled conditions. Based on this principle, the following formula exists:

[0081] ;

[0082] In the formula, l represents any span in meters, and t0 represents the initial temperature. Let be the coefficient of thermal expansion of the conductor, E be the elastic modulus of the conductor, and r be the coefficient of thermal expansion of the conductor. k For the k-th control condition, the specific load is... Let t be the stress under the k-th control condition. k Let be the temperature under the k-th control condition, and r be the specific load of the operating condition to be determined. Let t be the stress under the desired working condition, and t be the temperature under the desired working condition.

[0083] Simplifying the above formulas yields a cubic equation for the stress σ under the desired operating condition. This equation represents the stress variation relationship of the conductor under the desired operating condition. Based on this, the stress variation relationship of the conductor corresponding to each of the aforementioned control conditions can be obtained, as shown in the following expressions:

[0084] ;

[0085] Because the control conditions are set by default, r k , and t k Since all parameters are known, the stress under the desired working condition can be solved by controlling the environmental parameters of the conditions, thus obtaining the conductor tension characteristics under the desired working condition.

[0086] Step S2: Based on the conductor stress variation relationship and the preset nonlinear stress variation relationship, determine the conductor tension characteristics under actual working conditions.

[0087] In this embodiment of the application, in order to improve the accuracy of the data, a preset nonlinear stress change relationship is introduced to express the nonlinear stress-strain relationship of the conductor in actual situation.

[0088] Due to the nonlinear characteristics of the conductor material, the stress-strain relationship of the conductor is nonlinear, and the specific formula is as follows:

[0089] ;

[0090] In the formula, This represents the conductor stress, expressed in N / mm². 2 a1, a2, a3, and a4 are stress coefficients, which are generally constants. The value represents conductor deformation, expressed as a percentage.

[0091] In general, the stress-strain relationship of conductors is often assumed to be linear, under which conductor deformation is also linear, and the elongation of the conductor increases linearly with increasing stress. However, in reality, if the conductor is made of materials such as rubber, polymers, or biological soft tissue, these materials will exhibit nonlinear characteristics in the stress-strain relationship. This is because stress distribution is affected by the inherent properties of the material; in some special materials, stress is not uniformly distributed, leading to nonlinear length changes in the conductor due to uneven stress. Moreover, stress distribution is not only affected by the type of material but also by changes in the conductor's geometry, which is also nonlinear. Therefore, when calculating the relationship between conductor length and stress, it cannot be simply regarded as a linear relationship; more complex nonlinear factors need to be considered to ensure the accuracy and practicality of the obtained conductor tension characteristics. It is also worth mentioning that in the analysis of transmission conductors, the relationship between conductor sag, length, and stress reflects this nonlinear relationship. Therefore, by studying the tension characteristics of conductors, a more accurate conductor sag can be obtained, ensuring the safety of transmission towers.

[0092] To better represent the deformation of a conductor under both linear and nonlinear stress-strain relationships, Figure 2 A stress-strain graph is provided. As shown in the figure, the graph above represents a linear stress-strain relationship. As the stress increases, the elongation of the conductor also gradually increases at a fixed ratio, as indicated by the formula. E is the elastic modulus of the conductor. The figure below shows a nonlinear stress-strain relationship. As stress increases, the change in conductor length is not uniform, but rather the elongation gradually decreases with increasing stress.

[0093] Therefore, in this embodiment, a preset nonlinear stress variation relationship is introduced to calculate the tension characteristics of conductors in real life more accurately, so as to obtain a more accurate conductor sag.

[0094] Because the stress obtained in step 1 regarding the working condition to be determined A cubic equation in one variable is actually an assumption Since the relationship between the stress and the conductor is linear, this embodiment of the application needs to introduce the nonlinear stress variation relationship to express it. This highlights the nonlinear characteristics of the conductor.

[0095] First, obtain specific information about the actual working conditions, and then analyze the relationship between the actual working conditions and the conductor stress variation obtained in step 1. Because , In fact, it is stress and stress The resulting elastic deformation can be addressed by combining the aforementioned nonlinear stress variation relationship with... and Replace these elastic deformations, and then substitute the replaced parameters into the stress values ​​obtained in step 1 for the desired working condition. The cubic equation in one variable is used to obtain the stress under actual working conditions. The cubic equation in one variable is expressed as follows:

[0096] ;

[0097] Then, the nonlinear stress variation relationship and the stress under actual working conditions are compared. Combining the cubic equation in one variable, we obtain the following formula:

[0098] ;

[0099] To simplify the calculation, let:

[0100] ;

[0101] Therefore, the following formula is obtained:

[0102] ;

[0103] The formula can be rewritten by replacing b with 0. By determining the coefficients, a univariate polynomial equation concerning elastic deformation under actual working conditions can be obtained, the specific expression of which is:

[0104] ;

[0105] By combining the environmental parameters of the actual working conditions, this univariate polynomial equation can be solved to obtain the stress under the actual working conditions.

[0106] Based on the stress under actual working conditions, the tension characteristics of the conductor under actual working conditions can be obtained, and the relationship between the conductor length and stress under actual working conditions can be determined.

[0107] Step S3: Obtain the safety sag that meets the predetermined safety requirements of the conductor based on the conductor tension characteristics, and adjust the conductor sag under actual working conditions based on the safety sag.

[0108] In this step, after determining the conductor tension characteristics under actual working conditions, the relationship between conductor length and stress under actual working conditions can be determined. Combined with the predetermined conductor safety requirements, the safe sag that meets the conductor safety requirements under actual working conditions can be obtained.

[0109] The safety sag refers to the maximum sag of the conductor within a controllable range. When the stress on the conductor is high, the sag of the conductor decreases, and the sag increases due to rising temperature or icing. Therefore, by adjusting the conductor's sag under actual operating conditions using the safety sag, it is possible to ensure that the stress on the conductor always meets the safety requirements of the transmission line, and also to ensure that the conductor has a certain safety reserve under extreme weather conditions, enabling the transmission line to operate stably.

[0110] Implementing the embodiments of this application has the following beneficial effects:

[0111] This application first establishes control conditions that reflect actual conditions and represent different weather conditions, providing data support for studying the nonlinear conductor tension characteristics. Then, based on the elastic deformation of the conductor and its original length under each control condition, the stress-strain relationship under linear conditions is first calculated. Next, a nonlinear stress variation formula is introduced, and the nonlinearly varying elastic deformation of the conductor is used to calculate the stress under actual operating conditions, obtaining the nonlinear stress-strain relationship and accurate stress under actual operating conditions. Finally, based on the stress under actual operating conditions, the safe sag of the conductor under these conditions is obtained, and the conductor sag is adjusted accordingly. This ensures that the stress on the conductor remains within the normal range under most weather conditions, providing data support for ensuring the safe operation of transmission lines. Furthermore, the nonlinear stress-strain relationship of the conductor can also provide data support for real-time assessment of transmission line safety.

[0112] Second Embodiment

[0113] Furthermore, in order to implement the safety sag calculation system for transmission tower conductors corresponding to the above method embodiments, and to achieve the corresponding functional and technical effects, Figure 3 A structural diagram of a safety sag calculation system for transmission tower conductors is provided. For ease of explanation, only the parts relevant to this embodiment are shown. The safety sag calculation system for transmission tower conductors provided in this embodiment includes:

[0114] The conductor stress variation relationship construction module 201 is used to construct the conductor stress variation relationship based on the elastic deformation of the conductor under each control condition and the original length of the conductor; wherein each control condition is set according to preset environmental parameters.

[0115] In this embodiment, suitable control conditions are first selected. The specific process is as follows: several control conditions are selected, and the environmental parameters for each control condition are determined; wherein, the environmental parameters include specific load, tension, and temperature; based on the environmental parameters, a first curve and a first ratio corresponding to each control condition are set; wherein, the first ratio is the ratio of specific load to tension; the first curve is a function related to the environmental parameters; all first curves and all first ratios are compared respectively, and the critical span for each control condition is determined based on the comparison results; based on the critical span, the control conditions are screened to determine the control conditions.

[0116] Then, based on the elastic deformation of the conductor under each control condition and the differences in the control conditions, a derivation formula for the original conductor length under each control condition is constructed. Since the original conductor length is equal under different control conditions, the conductor stress variation relationship corresponding to each control condition is obtained based on the original conductor length derivation formula.

[0117] The conductor tension characteristic calculation module 202 is used to determine the conductor tension characteristics under actual working conditions based on the conductor stress change relationship and the preset nonlinear stress change relationship.

[0118] In this embodiment, the elastic deformation under the actual working conditions is obtained based on the conductor stress variation relationship and the actual working conditions. The conductor tension characteristics under the actual working conditions are then determined based on the elastic deformation under the actual working conditions and the nonlinear stress variation relationship.

[0119] The sag adjustment module 203 is used to obtain a safe sag that meets the predetermined safety requirements of the conductor based on the conductor tension characteristics, and to adjust the sag of the conductor under actual working conditions based on the safe sag.

[0120] In this embodiment, after determining the conductor tension characteristics under actual operating conditions, the relationship between conductor length and stress under actual operating conditions can be determined. Combined with predetermined conductor safety requirements, a safe sag that meets these requirements under actual operating conditions can be obtained. Because the conductor sag decreases when the stress on the conductor is high, and increases in temperature or icing on the conductor will increase the sag, adjusting the conductor sag under actual operating conditions using the safe sag ensures that the stress on the conductor consistently meets the safety requirements of the transmission line. Furthermore, it ensures that the conductor has a certain safety reserve even in extreme weather conditions, enabling the transmission line to operate stably.

[0121] In some embodiments, the conductor stress variation relationship construction module 201 further includes:

[0122] According to the design requirements of transmission lines, conductors need to meet specific stress requirements under characteristic meteorological conditions. These specific meteorological conditions are the control conditions in this embodiment. Therefore, several control conditions are selected first to determine the environmental parameters for each control condition. These control conditions include low-temperature conditions, icing conditions, high-wind conditions, and average annual conditions. The environmental parameters for these conditions are given by the design requirements of the transmission line and are known quantities. The environmental parameters include specific load, tension, and temperature.

[0123] To facilitate the selection of control conditions, two intermediate variables are designed in this embodiment to compare the suitability of each control condition. These two intermediate variables are the first curve and the first ratio. Based on the environmental parameters of each control condition, a first curve and a first ratio are set for each control condition. The first ratio is the ratio of specific load to tension.

[0124] Furthermore, the specific expression for the first curve is as follows:

[0125] ;

[0126] In the formula, F kx Let E be the elastic modulus of the conductor, and r be the first curve. k To control the specific load under the operating condition, l represents the span of the control operating condition. To control the conductor tension under operating conditions, The coefficient of thermal expansion of the conductor is expressed in ×10⁻⁶. -6 / ℃, where t is the temperature of the operating condition to be determined, in ℃ and t. k To control the operating temperature, F okx For the first curve F kx The initial components, t kx Let x be the temperature for the xth control condition, and let a, b, c, and d be the four control conditions mentioned above. The span is the horizontal distance between the suspension points of the conductors on two adjacent towers in an overhead line.

[0127] In addition, F kx and F okx The following relationship exists between them:

[0128] ;

[0129] Then, by comparing the first curve and the first ratio, the comparison results for each control condition are obtained. Based on the comparison results, several second curves are selected from the first curves. Then, based on the intersection of any two second curves, the critical span of the control condition corresponding to the second curve is determined. After determining the critical span of each control condition, the actual span of the corresponding control condition is judged based on the critical span, thus completing the screening of the control conditions and determining the control conditions that better meet the design requirements of the transmission line.

[0130] For example, in this embodiment of the application, if the actual gear distance of the i-th control condition is less than l ij Then, the control condition with the smallest first ratio between the i-th and j-th control conditions is selected as the control condition; if the actual gear distance of the i-th control condition is greater than l ij Then, the control condition with the largest first ratio between the i-th and j-th control conditions is selected as the control condition.

[0131] Then, the stress-deformation relationship of the conductor under each control condition was studied in conjunction with the control conditions.

[0132] First, after clarifying the elastic deformation of the conductor under each control condition, the original conductor length derivation formula for each control condition can be calculated based on the differences in the control conditions.

[0133] Because the original length of the conductor is its length when it first left the factory, and it has not been deformed by weather or other environmental factors, the original length is known and remains consistent under any controlled conditions. Based on this principle, the following formula exists:

[0134] ;

[0135] In the formula, l represents any span in meters, and t0 represents the initial temperature. Let be the coefficient of thermal expansion of the conductor, E be the elastic modulus of the conductor, and r be the coefficient of thermal expansion of the conductor. k For the k-th control condition, the specific load is... Let t be the stress under the k-th control condition. k Let be the temperature under the k-th control condition, and r be the specific load of the operating condition to be determined. Let t be the stress under the desired working condition, and t be the temperature under the desired working condition.

[0136] Simplifying the above formulas, we can obtain a stress related to the desired working condition. The cubic equation in one variable represents the stress variation relationship of the conductor under the desired operating condition. Based on this, the stress variation relationship of the conductor under each of the control conditions can be obtained, as shown in the following specific expression:

[0137] ;

[0138] Because the control conditions are set by default, r k , and t k Since all parameters are known, the stress under the desired working condition can be solved by controlling the environmental parameters of the conditions, thus obtaining the conductor tension characteristics under the desired working condition.

[0139] In some embodiments, the conductor tension characteristic calculation module 202 further includes:

[0140] In this embodiment, to improve data accuracy, a preset nonlinear stress variation relationship is introduced to express the nonlinear stress-strain relationship of the conductor in actual conditions. The specific expression of the nonlinear stress variation relationship is as follows:

[0141] ;

[0142] In the formula, This represents the conductor stress, expressed in N / mm². 2 a1, a2, a3, and a4 are stress coefficients, which are generally constants. The value represents conductor deformation, expressed as a percentage.

[0143] Because the stress for the desired working condition was obtained in the conductor tension characteristic calculation module 201. A cubic equation in one variable is actually an assumption Since the relationship between the stress and the conductor is linear, this embodiment of the application needs to introduce the nonlinear stress variation relationship to express it. This highlights the nonlinear characteristics of the conductor.

[0144] First, obtain specific information about the actual working conditions, and then analyze the relationship between the actual working conditions and the conductor stress variation obtained in step 1. Because , In fact, it is stress and stress The resulting elastic deformation can be addressed by combining the aforementioned nonlinear stress variation relationship with... and These elastic deformations are replaced, and then the replaced parameters are substituted into the stress obtained from the conductor tension characteristic calculation module 201 for the desired working condition. The cubic equation in one variable is used to obtain the stress under actual working conditions. The cubic equation in one variable is expressed as follows:

[0145] ;

[0146] Then, the nonlinear stress variation relationship and the stress under actual working conditions are compared. Combining the cubic equation in one variable, we obtain the following formula:

[0147] ;

[0148] To simplify the calculation, let:

[0149] ;

[0150] Therefore, the following formula is obtained:

[0151] ;

[0152] The formula can be rewritten by replacing b with 0. By determining the coefficients, a univariate polynomial equation concerning elastic deformation under actual working conditions can be obtained, the specific expression of which is:

[0153] ;

[0154] By combining the environmental parameters of the actual working conditions, this univariate polynomial equation can be solved to obtain the stress under the actual working conditions.

[0155] Based on the stress under actual working conditions, the tension characteristics of the conductor under actual working conditions can be obtained, and the relationship between the conductor length and stress under actual working conditions can be determined.

[0156] Implementing the embodiments of this application has the following beneficial effects:

[0157] This application first establishes different control conditions suitable for actual conditions to provide background support for subsequent research on conductor tension characteristics. Then, based on the elastic deformation of the conductor and the original length of the conductor under each control condition, the relationship between stress and deformation of the conductor under different control conditions is studied to construct the conductor stress variation relationship. Then, based on the nonlinear stress variation formula, the conductor tension characteristics under different operating conditions are determined. This allows the conductor stress under actual operating conditions to be determined based on the conductor deformation, and further determines the sag range under that operating condition to ensure the conductor is in a safe operating state, providing sufficient data support for effectively assessing and ensuring the safety of transmission lines.

[0158] This application embodiment also provides a storage medium that stores computer-readable program code, which, when executed, implements the steps of the above-described method for calculating the safe sag of a transmission tower conductor.

[0159] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for calculating the safe sag of a transmission tower conductor, characterized in that, include: Based on the elastic deformation of the conductor and its original length under each control condition, a stress variation relationship for the conductor is constructed. Each control condition is set according to preset environmental parameters, specifically: several control conditions are selected, and the environmental parameters for each control condition are determined; these environmental parameters include specific load, tension, and temperature; based on the environmental parameters, a first curve and a first ratio are set for each control condition; the first ratio is the ratio of specific load to tension; the first curve is a function related to the environmental parameters; all first curves and all first ratios are compared, and the critical span for each control condition is determined based on the comparison results; based on the critical span, the control conditions are screened to determine the control criteria. Specifically, the construction of the conductor stress variation relationship involves: constructing an original line length derivation formula for each control condition based on the elastic deformation of the conductor under each control condition and the difference in the control conditions; and obtaining the conductor stress variation relationship corresponding to each control condition based on the fact that the original line length is equal under different control conditions, according to the original line length derivation formula. Based on the conductor stress variation relationship and the preset nonlinear stress variation relationship, the conductor tension characteristics under actual working conditions are determined. Specifically, the elastic deformation under the actual working conditions is obtained according to the conductor stress variation relationship and the actual working conditions; the conductor tension characteristics under the actual working conditions are determined according to the elastic deformation under the actual working conditions and the nonlinear stress variation relationship. The safety sag that meets the predetermined safety requirements of the conductor is obtained based on the conductor tension characteristics, and the conductor sag is adjusted according to the safety sag under actual working conditions.

2. The method for calculating the safe sag of transmission tower conductors according to claim 1, characterized in that, The process involves comparing all the first curves and all the first ratios respectively, and determining the critical range for each control condition based on the comparison results. Specifically: Compare all the first curves, and filter the first ratios based on the comparison results to obtain the first filtering results; Compare all the first ratios, and filter the first curves according to the comparison results to obtain the second filtering results; Based on the first and second screening results, select several second curves from the first curve; Based on the intersection of any two second curves, determine the critical gear of the control condition corresponding to the second curve.

3. The method for calculating the safe sag of transmission tower conductors according to claim 1, characterized in that, The first curve is specifically: The specific expression for the first curve is: ； In the formula, F kx Let E be the elastic modulus of the conductor, and r be the first curve. k To control the specific load under the operating condition, l represents the span of the control operating condition. To control the conductor tension under operating conditions, Let t be the coefficient of thermal expansion of the conductor, and t be the temperature of the operating condition to be determined. k To control the operating temperature, F okx For the first curve F kx The initial components, t kx Let be the temperature for the xth control condition.

4. The method for calculating the safe sag of transmission tower conductors according to claim 1, characterized in that, The step of screening the control conditions based on the critical gear distance to determine the control conditions specifically involves: If the actual gear ratio of the control condition is less than the critical gear ratio of the control condition, then the control condition with the smallest first ratio is selected as the control condition. If the actual gear ratio of the control condition is greater than the critical gear ratio of the control condition, then the control condition with the largest first ratio is selected as the control condition.

5. The method for calculating the safe sag of transmission tower conductors according to claim 1, characterized in that, The process of obtaining a safety sag that meets predetermined safety requirements based on the conductor tension characteristics, and adjusting the conductor sag under actual operating conditions based on the safety sag, specifically involves: Determine the stress of the conductor under actual working conditions based on the conductor tension characteristics; Based on the stress and the predetermined conductor safety requirements, a safe sag that meets the conductor safety requirements under actual working conditions is obtained; Adjust the sag of the conductor under actual working conditions according to the aforementioned safety sag.

6. A safety sag calculation system for transmission tower conductors, characterized in that, include: The module includes a conductor stress variation relationship construction module, a conductor tension characteristic calculation module, and a sag adjustment module. The conductor stress variation relationship construction module is used to construct the conductor stress variation relationship based on the elastic deformation of the conductor and the original length of the conductor under each control condition. Each control condition is set according to preset environmental parameters, specifically: selecting several control conditions and determining the environmental parameters for each control condition; the environmental parameters include specific load, tension, and temperature; setting a first curve and a first ratio corresponding to each control condition based on the environmental parameters; the first ratio is the ratio of specific load to tension; the first curve is a function related to the environmental parameters; comparing all first curves and all first ratios respectively, and determining the critical span for each control condition based on the comparison results; and filtering the control conditions based on the critical span to determine the control conditions. Specifically, the construction of the conductor stress variation relationship involves: constructing an original line length derivation formula for each control condition based on the elastic deformation of the conductor under each control condition and the difference in the control conditions; and obtaining the conductor stress variation relationship corresponding to each control condition based on the fact that the original line length is equal under different control conditions, according to the original line length derivation formula. The conductor tension characteristic calculation module is used to determine the conductor tension characteristics under actual working conditions based on the conductor stress change relationship and the preset nonlinear stress change relationship. Specifically, it obtains the elastic deformation under the actual working conditions based on the conductor stress change relationship and the actual working conditions; and determines the conductor tension characteristics under the actual working conditions based on the elastic deformation under the actual working conditions and the nonlinear stress change relationship. The sag adjustment module is used to obtain a safe sag that meets the predetermined safety requirements of the conductor based on the conductor tension characteristics, and to adjust the sag of the conductor under actual working conditions based on the safe sag.

7. A storage medium, characterized in that, The storage medium stores computer-readable program code, which, when executed, implements the steps of the method for calculating the safe sag of a transmission tower conductor according to any one of claims 1 to 5.

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