A configuration method of vertical arrangement conductor strain insulator string in extra heavy ice area

Abstract

The present application relates to the technical field of the arrangement of tension string of extra-high voltage transmission line, and particularly discloses a configuration method of vertically arranged conductor tension string in heavy icing area, which specifically comprises the following steps: step S1: determining the mechanical strength of the tension string; step S2: determining the number of the tension string, which is at least six; step S3: determining the arrangement type of the tension string, which is vertically layered arrangement; step S4: determining the number of hanging points of the tension string, which is at least two groups; and step S5: determining the optimal inter-string distance of the multi-string tension string by calculating the electrical distance, offset distance and ice shedding jump distance of the multi-string tension string. The present application effectively solves the problem of excessively wide inter-string distance of horizontal arrangement of multi-bundle large cross-section conductor, improves the stress of the iron tower and the tension string structure, improves the safety and stability of the tension string in heavy icing area, and takes into account the structure of the appearance of the hardware string.

Description

Technical Field

[0001] This invention relates to the field of tension string arrangement technology for ultra-high voltage transmission lines, and more specifically, to a method for configuring vertically arranged tension strings for conductors in areas with severe icing. Background Technology

[0002] With the rapid development of ultra-high voltage (UHV) power transmission projects in my country, these projects have extended to areas with severe icing. UHV transmission lines in these areas often traverse high-altitude regions with significant elevation differences, making the terrain even more challenging than before.

[0003] Due to factors such as transmission capacity, icing intensity, and high-altitude electromagnetic environment, multi-split large-section conductors are typically used, with the total cross-section of a single phase (pole) often exceeding 5000 mm². The longitudinal tensile force and load on the conductors are excessive, requiring a six-strand insulator structure. The previously used four-strand horizontally arranged tension strings are insufficient in strength and cannot be used. However, due to the large number of six-strand insulators, if all six are arranged horizontally, the width of the tension strings becomes too large, causing problems such as uneven distribution of tower mounting points, tension string width, and stress. With the increasing number of ultra-high voltage transmission lines in recent years, this phenomenon has become increasingly significant.

[0004] Therefore, an improved conductor tension string is needed to effectively solve problems such as excessively wide horizontal spacing and uneven structural stress when using multi-split large-section conductors, improve the safety and stability of the tension string in extremely heavy ice areas, and also take into account the aesthetics of the hardware string structure. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a configuration method for vertically arranged conductor tension strings in areas with severe icing, which effectively solves the problem of excessively wide horizontal spacing when multiple split large cross-section conductors are arranged, improves the stress on the tower and tension string structure, enhances the safety and stability of the tension string in areas with severe icing, and also takes into account the aesthetics of the hardware string structure.

[0006] The solution adopted by this invention to solve the technical problem is:

[0007] A method for configuring vertically arranged conductor tension strings in areas with severe ice conditions includes the following steps:

[0008] Step S1: Determine the mechanical strength of the tension string;

[0009] Step S2: Determine the number of tension strings, wherein the number of strings is at least six;

[0010] Step S3: Determine the arrangement of the tension strings, wherein the arrangement is a vertical layered arrangement;

[0011] Step S4: Determine the number of hanging points for the tension string, wherein the number of hanging points is at least two sets;

[0012] Step S5: Determine the optimal spacing between the multiple tension strings by calculating the electrical distance, offset distance, and de-icing jump distance of the multiple tension strings.

[0013] In some possible implementations, when the number of links is six, a two-layer vertical arrangement with three links on each layer is adopted.

[0014] In some possible implementations, the optimal connection distance includes the optimal connection spacing in the horizontal direction and the optimal connection spacing in the vertical direction.

[0015] In some possible implementations, the electrical distance of the multiple tension strings in step S5 is calculated as follows:

[0016] L1≥max(a,b);

[0017] Where L1 represents the electrical distance between multiple tension strings;

[0018] 'a' represents the minimum net space distance required for independent development during the discharge process when multiple tension series are arranged in parallel.

[0019] b represents the minimum net space distance when multiple tension strings are arranged in parallel and when the flashover voltage of a single tension string is the same.

[0020] In some possible implementations, the offset distance of the multiple tension strings in step S5 is calculated as follows:

[0021] L2≥fsin(atan(G4 / G1))+n;

[0022] Where L2 represents the offset distance of the multi-tension string;

[0023] f represents the sag value of the multi-strand tension string under the approximate catenary line;

[0024] G4 indicates the horizontal load of the multi-tension string under high wind conditions;

[0025] G1 represents the vertical load of the multi-tension string under high wind conditions;

[0026] n represents the maximum diameter of the insulator.

[0027] In some possible implementations, the ice-breaking jump distance of the multi-tension string in step S5 is calculated as follows:

[0028] L3≥max(c,d,e);

[0029] Wherein, L3 represents the ice-breaking jump distance of the multi-tension string;

[0030] c represents the jumping distance caused by the multi-strand tension string itself de-icing;

[0031] d represents the jump distance of a multi-tension string caused by the ice breaking of the conductor;

[0032] e represents the combined jumping distance caused by the simultaneous ice breakage and jumping of the multi-tension string itself and the conductor.

[0033] In some possible implementations, the optimal spacing between the multiple tension strings in the vertical direction is:

[0034] H≥max(a,b);

[0035] H≥fi+n;

[0036] H≥max(c,d,e);

[0037] Wherein, H represents the vertical spacing between the multiple tension strings;

[0038] 'a' represents the minimum net space distance required for independent development during discharge when multiple tension series are connected in parallel.

[0039] b represents the minimum net space distance when multiple tension strings are arranged in parallel and when the flashover voltage of a single tension string is equal;

[0040] n represents the maximum diameter of the disc insulator;

[0041] c represents the jump distance caused by the tension string itself de-icing;

[0042] d represents the jump distance of the tension string caused by the ice breaking and jumping of the conductor;

[0043] e represents the combined jump distance caused by the tension string jumping due to both itself and the conductor simultaneously breaking ice and jumping;

[0044] fi represents the maximum sag value of the tension string under icing conditions.

[0045] In some possible implementations, the optimal spacing between the multiple tension strings in the horizontal direction is:

[0046] L≥max(a,b);

[0047] L≥fsin(atan(G4 / G1))+n;

[0048] L≥max(c,d,e);

[0049] Where L represents the optimal spacing between tension strings in the horizontal direction.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] This invention can effectively solve the problem of excessively wide horizontal spacing between multiple split large cross-section conductors, improve the stress on the tower and tension string structure, enhance the safety and stability of the tension string in extremely heavy ice areas, and also take into account the aesthetics of the hardware string structure.

[0052] This invention avoids uneven stress that can easily occur when hardware movement is restricted, leading to overload of individual hardware and insulators, by using multiple tension strings in heavy icing areas and a vertically layered arrangement. It also avoids the problems of large equipotential rings causing installation difficulties and deformation. Furthermore, it avoids the issues of requiring longer tower crossarms due to wider horizontal dimensions, increasing tower weight, and making it difficult to control the gap between the crossarm and the tower body or crossarm. This results in a narrower tension string width, simpler hardware assembly compared to horizontal arrangements, reduced crossarm length, and easier connection between the tension string and the conductor.

[0053] This invention calculates and designs the optimal spacing between tension strings by considering the electrical performance, offset distance, and de-icing jump distance of the tension strings; ensuring that the distance between multiple tension strings does not contact or collide with the field strength distribution of the tension strings and the insulators between the strings under operating conditions. Attached Figure Description

[0054] Figure 1 This is a flowchart of the present invention;

[0055] Figure 2 This is a top view schematic diagram of the vertically arranged conductor tension string in this invention;

[0056] Figure 3 This is a front view schematic diagram of the vertically arranged conductor tension string in this invention; Detailed Implementation

[0057] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] The present invention will now be described in detail.

[0059] like Figures 1-3 As shown,

[0060] A method for configuring vertically arranged conductor tension strings in areas with severe ice conditions includes the following steps:

[0061] Step S1: Determine the mechanical strength of the tension string. The mechanical strength of the tension string must meet the requirements of the safety factor specified in the regulations, wear resistance of the hardware connection points, maximum rotation angle of the tension tower, rationality of the insulator and hardware connection, and compatibility with the jumper current drainage.

[0062] Specifically, the mechanical strength of tension strings must meet the safety factors specified in the regulations: for general lines, the safety factor for disc insulators should be no less than 2.7, for constant load no less than 4.0, for broken wire load no less than 1.8, for disconnected load no less than 1.5, and for rare load no less than 1.5. For general lines, the safety factor for hardware should be no less than 2.5, for broken wire load no less than 1.5, for disconnected load no less than 1.5, and for rare load no less than 1.5.

[0063] When the conductor experiences dynamic conditions such as jumping or galloping, all connection points (including those on the tower) should be wear-resistant and fatigue-resistant.

[0064] When there are errors or changes in the length of the conductor or insulator, there is a possibility of adjustment or self-recovery in the difference in tension distribution between the sections;

[0065] According to strength requirements, the tension strings of UHV lines need to adopt a multi-connection design. From the perspective of the reliability of the hanging point, it is most reliable to fix each section of the tension string to the tower separately. In addition, the tension string itself has a simple structure and can reduce the cost of the string itself.

[0066] The spacing between tension series insulators varies with the angle of the line's turning point. The spacing between tension series insulators should take into account the maximum possible turning point on the tension tower, ensuring sufficient distance between insulators of different series that are close to each other to avoid the possibility of partial discharge and collision between them. Based on this consideration, according to the tower's turning angle and electrical distance requirements, and according to the spacing between multiple tension series insulators, and on the side of the multiple tension series insulators closest to the tower, connecting hardware is added for adjustment to ensure that the spacing between series is above the safe value.

[0067] To prevent one or more conductors from falling off due to the breakage of a section of the tension string, the tension strings are connected together near the conductor side using a star-shaped connecting plate. The number of its branches is the same as the number of sub-conductors in a phase, serving as a transition between the conductor and the tension string.

[0068] When the jumper is drawn from the tension string, it satisfies the cylindrical shape of multiple splits and corresponding split spacing.

[0069] Step S2: Determine the number of tension strings. For extra-heavy ice areas, the number of tension strings should be at least six.

[0070] Depending on the type of conductor used and the safety factor, multiple combination string types are formed by combining tension strings of different tonnages and numbers of connections; common combinations are shown in the table below.

[0071]

[0072] A technical and economic comparison was conducted on different tonnages and number of connections based on factors such as the number of insulator discs, the weight of hardware, and ease of construction, to determine the optimal combination of number of connections and tonnage.

[0073] For areas with 40mm or more of extremely heavy ice, considering the impact of the weight of the UHV tension string, a six-unit tension string is required.

[0074] Step S3: Determine the arrangement of the tension strings, wherein the arrangement is a vertical layered arrangement;

[0075] For multi-tension strings, if a conventional horizontal arrangement is used, the entire tension string is widely distributed. On the one hand, multiple combined connecting plates are required, and when the movement of the hardware is restricted, uneven stress is likely to occur, leading to overload of individual hardware and insulators. On the other hand, the equalizing ring is large in size, which is not conducive to installation and is also prone to deformation. Due to the wide horizontal dimension, the tower head crossarm needs to be lengthened accordingly, increasing the tower weight, and it is also difficult to control the gap with the tower body or crossarm. Therefore, this invention adopts a vertically layered arrangement for multi-tension strings.

[0076] Specifically, when the number of tension strings is six, a two-layer vertical arrangement with three strings in each layer is adopted. The advantages of this arrangement are that the tension string width is smaller, the hardware assembly is simpler than that of the horizontal arrangement, the crossarm length can be reduced, and the connection between the tension string and the conductor is easier, effectively solving the problems existing in the horizontal arrangement.

[0077] Step S4: Determine the number of hanging points for the tension string;

[0078] From the perspective of the reliability of the hanging points, it is most reliable to fix each section of the tension string to the tower separately. Moreover, the tension string itself has a simple structure and can reduce the cost of the string itself. However, it will inevitably increase the weight of the tower material. Therefore, under the premise of ensuring safety and economy, it is necessary to simplify the hanging points as much as possible to shorten the distance between the hanging points and reduce the size of the crossarm.

[0079] For tension string type, if only one hanging point is used, when the hardware connected to the tower fails, it means that the conductor of the faulty phase will fall directly to the ground, which will cause a major accident. Considering the importance of UHV lines and combined with the design and operation experience of domestic UHV lines, it is recommended to use double hanging point or multi-hanging point type for tension strings.

[0080] For a six-string tension string, considering the average distribution of its stress and stability, a three-point hanging arrangement is recommended.

[0081] Step S5: Determine the optimal spacing between the multiple tension strings by calculating the electrical distance, offset distance, and de-icing jump distance of the multiple tension strings.

[0082] The distance between multiple tension strings is determined on the premise that the field strength distribution of the tension strings and the insulators between the strings do not contact or collide under operating conditions. In other words, the distance between the strings is mainly determined by the electrical performance, offset distance and ice-removal jump distance of the multiple tension strings.

[0083] Electrical performance requirements regarding spacing, specifically: electrical distance requirements for multiple tension strings:

[0084] Through pollution withstand voltage tests on multi-tension strings in heavily icy areas, under certain salt-dense conditions, when the net spacing (spacing minus insulator disc diameter) of multiple parallel strings is greater than a certain value 'a', the discharge process can develop independently. Simultaneously, comparing the pollution flashover voltages of multiple parallel strings and single strings, when the net spacing (spacing minus insulator disc diameter) of multiple parallel strings is greater than a certain value 'b', their pollution flashover voltages are comparable. Therefore, when the net spacing of multiple parallel strings is greater than both 'a' and 'b', the spacing is considered to meet the electrical clearance requirement; that is, the electrical clearance of a multi-tension string is calculated as follows:

[0085] L1≥max(a,b);

[0086] Where L1 represents the electrical distance between multiple tension strings;

[0087] 'a' represents the minimum net space distance required for independent development during the discharge process when multiple tension series are arranged in parallel.

[0088] b represents the minimum net space distance when multiple tension strings are arranged in parallel and when the flashover voltage of a single tension string is the same.

[0089] Offset distance requirements for couplet spacing:

[0090] A significant characteristic of ultra-high voltage tension strings is their long length. In addition to considering the insulator disc diameter, the increased wind load on the string causes the tension string to deviate in a sag-like manner, which can lead to insulators approaching or colliding. Therefore, the spacing between the strings must be greater than the maximum deviation of the tension string.

[0091] That is: the offset distance of the multi-tension string is calculated as follows:

[0092] L2≥fsin(atan(G4 / G1))+n;

[0093] Where L2 represents the offset distance of the multi-tension string;

[0094] f represents the sag value of the multi-strand tension string under the approximate catenary line;

[0095] G4 indicates the horizontal load of the multi-tension string under high wind conditions;

[0096] G1 represents the vertical load of the multi-tension string under high wind conditions;

[0097] n represents the maximum diameter of the insulator.

[0098] Requirements for spacing between couplets during ice-breaking jumps:

[0099] In sections with heavy icing, ice breakage jumps are prone to occur, and the jump amplitude increases with the increase of ice thickness. Ice breakage jumps are divided into ice breakage jumps of the tension string itself and ice breakage jumps of the conductor. After an ice breakage jump occurs, it causes the tension string to shake violently. Because the tension string of the UHV line is too long, the swing amplitude of the insulator is large.

[0100] That is: the calculation of the multi-tension string de-icing jump distance is as follows:

[0101] L3≥max(c,d,e);

[0102] Wherein, L3 represents the ice-breaking jump distance of the multi-tension string;

[0103] c represents the jumping distance caused by the multi-strand tension string itself de-icing;

[0104] d represents the jump distance of a multi-tension string caused by the ice breaking of the conductor;

[0105] e represents the combined jumping distance caused by the simultaneous ice breakage and jumping of the multi-tension string itself and the conductor.

[0106] The optimal spacing between links includes the optimal spacing in the horizontal direction and the optimal spacing in the vertical direction;

[0107] Specifically, such as Figure 3 As shown, the optimal spacing between multiple tension strings in the vertical direction is:

[0108] H≥max(a,b);

[0109] H≥fi+n;

[0110] H≥max(c,d,e);

[0111] Wherein, H represents the vertical spacing between the multiple tension strings;

[0112] 'a' represents the minimum net space distance required for independent development during discharge when multiple tension series are connected in parallel.

[0113] b represents the minimum net space distance when multiple tension strings are arranged in parallel and when the flashover voltage of a single tension string is equal;

[0114] n represents the maximum diameter of the disc insulator;

[0115] c represents the jump distance caused by the tension string itself de-icing;

[0116] d represents the jump distance of the tension string caused by the ice breaking and jumping of the conductor;

[0117] e represents the combined jump distance caused by the tension string jumping due to both itself and the conductor simultaneously breaking ice and jumping;

[0118] fi represents the maximum sag value of the tension string under icing conditions.

[0119] Specifically, such as Figure 2 As shown, the optimal spacing between multiple tension strings in the horizontal direction is:

[0120] L≥max(a,b);

[0121] L≥fsin(atan(G4 / G1))+n;

[0122] L≥max(c,d,e);

[0123] Where L represents the optimal spacing between tension strings in the horizontal direction.

[0124] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for configuring vertically arranged tension strings of conductors in areas with severe ice conditions, characterized in that, Specifically, the following steps are included: Step S1: Determine the mechanical strength of the tension string; Step S2: Determine the number of tension strings, wherein the number of strings is at least six; Step S3: Determine the arrangement of the tension strings, wherein the arrangement is a vertical layered arrangement; Step S4: Determine the number of hanging points for the tension string, wherein the number of hanging points is at least two sets; Step S5: Determine the optimal spacing between multiple tension strings by calculating the electrical distance, offset distance, and ice-removal jump distance of the multiple tension strings; The optimal spacing between links includes the optimal spacing between links in the horizontal direction and the optimal spacing between links in the vertical direction; The electrical distance calculation for the multi-tension string in step S5 is as follows: ； Where L1 represents the electrical distance between multiple tension strings; 'a' represents the minimum net space distance required for independent development during the discharge process when multiple tension series are connected in parallel. b represents the minimum net space distance when multiple tension strings are arranged in parallel and when the flashover voltage of a single tension string is equal; The offset distance of the multi-tension string in step S5 is calculated as follows: ； Where L2 represents the offset distance of the multi-tension string; f represents the sag value of the multi-strand tension string under the approximate catenary line; G4 indicates the horizontal load of a multi-tension string under high wind conditions; G1 represents the vertical load of the multi-tension string under high wind conditions; n Indicates the maximum diameter of the insulator; The calculation of the ice-breaking jump distance of the multi-tension string in step S5 is as follows: ； Where L3 represents the ice-breaking jump distance of the multi-tension string; c represents the jump distance caused by the multi-strand tension string itself de-icing; d represents the jump distance of a multi-tension string caused by ice breakage and jumping of the conductor; e represents the combined jump distance caused by the simultaneous ice-breaking jump of the multi-tension string and the conductor; the optimal spacing between the multi-tension strings in the vertical direction is: ； ； ； Wherein, H represents the vertical spacing between the multiple tension strings; 'a' represents the minimum net space required for independent development during discharge when multiple tension series are connected in parallel; b represents the minimum net space distance when multiple tension strings are arranged in parallel and when the flashover voltage of a single tension string is equal; n represents the maximum diameter of the disc insulator; c represents the jump distance caused by the tension string itself de-icing; d represents the jump distance of the tension string caused by the ice breaking and jumping of the conductor; e represents the combined jump distance caused by the tension string jumping due to both itself and the conductor simultaneously breaking ice and jumping; fi represents the maximum sag value of the tension string under icing conditions; The optimal spacing between the multiple tension strings in the horizontal direction is: ； ； ； Where L represents the optimal spacing between tension strings in the horizontal direction.

2. The method for configuring vertically arranged tension strings of conductors in extremely icy areas according to claim 1, characterized in that, When there are six sections, a two-layer vertical arrangement with three sections on each layer is adopted.

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