Distribution transformer lightning protection range determination method and device based on split-phase differential protection, equipment and medium

Abstract

The invention discloses a distribution transformer lightning protection range determination method and device based on split-phase differential protection, equipment and a medium, and belongs to the technical field of lightning overvoltage protection of a power distribution network. The method comprises the following steps: determining the maximum arrangement distance between lightning protection points on the distribution transformer according to multiple chopping voltage withstanding values of the distribution transformer in a lightning stroke point overvoltage wave propagation range; based on the maximum arrangement distance, lightning protection points are arranged on each phase of wire of the distribution transformer, and the lightning protection points comprise lightning arresters installed on the A-phase wire and the C-phase wire and insulators installed on the B-phase wire. The insulation level is configured in a split-phase differentiation mode, lightning stroke overvoltage is actively guided to be discharged along a preset path, the line voltage is reduced to zero, and therefore the protection range when the line is struck by lightning is expanded. The lightning arresters are only installed in the A phase and the C phase, the insulator string is adopted in the B phase, the maximum arrangement distance is determined based on the line condition, and under the condition that insulation safety is guaranteed, the equipment investment and the operation and maintenance cost are reduced as much as possible.

Description

Technical Field

[0001] This invention relates to the field of lightning overvoltage protection technology for distribution networks, and in particular to a method, device, equipment and medium for determining the lightning protection range of distribution transformers based on phase-differentiated protection. Background Technology

[0002] As the core equipment of the distribution network, the stable operation of distribution transformers directly affects the reliability of power supply. Lightning overvoltage is a major threat causing insulation damage and power outages. The most common and direct lightning protection measure currently is to install metal oxide surge arresters on all three phases of the transmission line. These arresters utilize their excellent nonlinear characteristics to clamp overvoltages to a low residual voltage level, thus protecting the equipment insulation. However, this traditional approach has significant theoretical limitations and economic shortcomings. Its protection range is derived from traveling wave theory, and the protection distance of the arrester is strictly limited by the difference between the equipment insulation level and the arrester's residual voltage. Since the residual voltage is a non-negligible value, the protection radius of a single arrester is very limited. To effectively protect the entire line, especially the terminal distribution transformers, surge arresters must be installed at a high density along the line, resulting in high equipment procurement and long-term maintenance costs. Summary of the Invention

[0003] Therefore, it is necessary to propose a method for determining the lightning protection range of distribution transformers based on phase-differentiated protection to address the above problems. This method aims to enable differentiated configuration of protective devices for different phases, suppress more dangerous phase-to-phase flashover faults, determine the maximum spacing based on line conditions, and minimize equipment investment and operation and maintenance costs while ensuring insulation safety.

[0004] To achieve the above objectives, the first aspect of this application provides a method for determining the lightning protection range of a distribution transformer based on phase-differential protection, the method comprising: The maximum spacing between lightning protection points on the distribution transformer is determined based on the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point. Based on the maximum arrangement spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer. The lightning protection points include: surge arresters installed on phase A and phase C conductors and insulators installed on phase B conductors.

[0005] Furthermore, determining the maximum spacing between lightning protection points on the distribution transformer based on the multiple truncated withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point specifically includes: Obtain the steepness of lightning current and the propagation speed of lightning overvoltage waves; The maximum spacing between lightning protection points on the distribution transformer is obtained by calculating the length based on the steepness of the lightning current, the propagation velocity of the overvoltage wave at the lightning strike point, and the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0006] Furthermore, the maximum spacing between the lightning protection points on the distribution transformer is determined by the following formula:

[0007] In the formula, For maximum spacing, For the steepness of the lightning current, v The propagation speed of lightning overvoltage waves. The withstand voltage value of the distribution transformer under multiple cut-off waves within the propagation range of the overvoltage wave at the lightning strike point.

[0008] Furthermore, the withstand voltage value of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point is determined by the following formula:

[0009] In the formula, This refers to the withstand voltage values ​​of the distribution transformer at multiple cutoff points within the propagation range of the overvoltage wave at the lightning strike point. The voltage is the voltage of the three chopped wave impact tests of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0010] Furthermore, based on the maximum arrangement spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer, specifically including: The minimum layout spacing is determined based on the preset layout cost; Within the range formed by the minimum arrangement spacing and the maximum arrangement spacing, the target arrangement spacing is determined; On each phase conductor of the distribution transformer, a lightning protection point is arranged at each interval of the target arrangement to determine the lightning protection range of the distribution transformer.

[0011] Furthermore, the insulator is an external flashover insulator, and the 50% lightning impulse discharge voltage of the external flashover insulator is less than the starting operating voltage of the surge arrester. This is so that when a lightning overvoltage enters the line, the external flashover insulator of phase B will be the first to experience a flashover to ground due to its lower impulse discharge voltage, thus clamping the potential of phase B to zero and preventing phase-to-phase flashover.

[0012] Furthermore, the external flash insulator has a self-extinguishing arc capability, so that the distribution network can operate with the fault after a single-phase ground fault formed after phase B grounding. After the lightning current passes, the insulation performance of the phase B external flash insulator will automatically recover, realizing the self-clearing of the fault.

[0013] To achieve the above objectives, a second aspect of this application provides a device for determining the lightning protection range of a distribution transformer based on phase-differential protection, the device comprising: The arrangement spacing determination unit is used to determine the maximum arrangement spacing between the lightning protection points on the distribution transformer based on the multiple truncated withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point. A lightning protection point arrangement unit is used to arrange lightning protection points on each phase conductor of the distribution transformer based on the maximum arrangement spacing, so as to determine the lightning protection range of the distribution transformer. The lightning protection points include: surge arresters installed on phase A and phase C conductors and insulators installed on phase B conductors.

[0014] To achieve the above objectives, a third aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method described in the first aspect.

[0015] To achieve the above objectives, a fourth aspect of this application provides a computer device including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described in the first aspect.

[0016] The embodiments of the present invention have the following beneficial effects: This invention proposes a method for determining the lightning protection range of a distribution transformer based on phase-differentiated protection. The method includes: determining the maximum spacing between lightning protection points on the distribution transformer based on the multiple truncated withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point; and arranging lightning protection points on each phase conductor of the distribution transformer based on the maximum spacing to determine the lightning protection range of the distribution transformer. The lightning protection points include surge arresters installed on phase A and phase C conductors and insulators installed on phase B conductors. This invention, by configuring insulation levels differently for each phase, actively guides the discharge of lightning overvoltage along a preset path, reducing the line voltage to zero, thereby increasing the protection range when the line is struck by lightning. Furthermore, compared to the traditional three-phase fully equipped surge arrester scheme, this invention only installs surge arresters on phases A and C, uses insulator strings on phase B, and determines the maximum spacing based on line conditions, minimizing equipment investment and maintenance costs while ensuring insulation safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] in: Figure 1 This is a flowchart illustrating the method for determining the lightning protection range of a distribution transformer based on phase-differentiated protection in an embodiment of the present invention. Figure 2 This is a schematic diagram of the arrangement of surge arresters and insulator strings based on phase-differentiated protection in an embodiment of the present invention. Figure 3 This is a structural block diagram of the distribution transformer lightning protection range determination device based on phase-differentiated protection in an embodiment of the present invention; Figure 4 Internal structure diagram of a computer device in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The most common and direct lightning protection measure currently is to install metal oxide surge arresters on all three phases of the transmission line. These arresters utilize their excellent nonlinear characteristics to clamp overvoltages to a low residual voltage level, thus protecting equipment insulation. However, this traditional approach has significant theoretical limitations and economic shortcomings. Its protection range is derived from traveling wave theory, and the protection distance of the arrester is strictly limited by the difference between the equipment insulation level and the arrester's residual voltage. Since the residual voltage is a non-negligible value, the protection radius of a single arrester is very limited. To effectively protect the entire line, especially the terminal distribution transformers, surge arresters must be installed at a high density along the line, resulting in high equipment procurement and long-term maintenance costs. Furthermore, although this method protects equipment to some extent, it does not fully utilize the system characteristics of the distribution network itself.

[0021] my country's 10kV distribution network widely adopts a neutral-point ineffective grounding method. This system has a unique advantage: when a single-phase ground fault occurs, the grounding current is very small, allowing the system to continue operating under fault conditions for a period of time without immediate tripping. This provides a valuable time window for fault handling and automatic recovery. Existing schemes that install surge arresters on all three phases fail to cleverly utilize this characteristic to achieve more economical and efficient protection. Therefore, the industry urgently needs a new protection strategy and design method that can overcome the limitations of traditional protection range calculation models and effectively reduce the overall cost of lightning protection measures.

[0022] To address the aforementioned problems, this invention proposes a method, device, equipment, and medium for determining the lightning protection range of distribution transformers based on phase-differentiated protection. By configuring the insulation level differently for each phase, the method actively guides lightning overvoltages to discharge along a preset path, consciously controlling the fault mode within the acceptable range of "single-phase grounding," thereby reducing the line voltage to zero. This increases the protection range when a line is struck by lightning and fully utilizes the characteristics of a distribution network with a non-effectively grounded neutral point operating under single-phase grounding faults, thus improving power supply reliability. Furthermore, this method only installs surge arresters on phases A and C, while phase B uses insulator strings. Compared to the traditional three-phase full-installation surge arrester scheme, this significantly reduces equipment investment and maintenance costs, enhancing the economic efficiency of distribution network operation while improving lightning protection reliability.

[0023] One embodiment of the present invention proposes a method for determining the lightning protection range of distribution transformers based on phase-differentiated protection, which can be referred to. Figure 1 , Figure 1 This is a flowchart illustrating the method for determining the lightning protection range of a distribution transformer based on phase-differential protection in an embodiment of the present invention. The method includes: S100. Based on the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point, determine the maximum spacing between lightning protection points on the distribution transformer.

[0024] In this embodiment, lightning waves experience time delays and spatial attenuation during propagation, making it impossible for surge arresters to protect all equipment instantly. When a lightning wave propagates from the lightning strike point to the transformer, if the transformer is too far from the surge arrester, the lightning wave may damage the transformer insulation before or during the arrester's operation. Therefore, insulation safety must be considered when setting up lightning protection points to ensure that the locations of the lightning protection points meet the expected insulation requirements.

[0025] In this embodiment, multiple interception lines are set up based on the "propagation law of overvoltage waves." By covering the "range where lightning strikes may occur" and the "paths along which overvoltage waves may propagate," it ensures that core equipment (such as distribution transformers) can be protected by lightning protection points regardless of the location of the lightning strike. Specifically, based on the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point, the maximum spacing between lightning protection points on the distribution transformer is determined to ensure the safety of all lines when arranging lightning protection points.

[0026] S200. Based on the maximum arrangement spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer. The lightning protection points include: surge arresters installed on the A-phase and C-phase conductors and insulators installed on the B-phase conductor.

[0027] In this embodiment, after determining the maximum arrangement spacing, lightning protection points are arranged on each phase conductor of the distribution transformer according to the maximum arrangement spacing to determine the lightning protection range of the distribution transformer.

[0028] Specifically, the lightning protection setup involves installing surge arresters on the A-phase and C-phase conductors of the distribution transformer, and insulators on the B-phase conductor. When lightning directly strikes any phase conductor, the B-phase insulator, with the lowest insulation level, will break down first, forming a ground flashover and clamping the lightning strike potential to near zero. By installing surge arresters only on phases A and C, and using insulator strings on phase B, compared to the traditional three-phase surge arrester setup, equipment investment and maintenance costs are significantly reduced. This improves lightning protection reliability while enhancing the economic efficiency of the distribution network operation.

[0029] The method for determining the lightning protection range of distribution transformers based on phase-differentiated protection proposed in this invention actively guides lightning overvoltages to discharge along a preset path by configuring insulation levels differently for each phase. This consciously controls the fault mode within the acceptable range of "single-phase grounding," reducing the line voltage to zero and thus increasing the protection range when a lightning strikes the line. It also fully utilizes the characteristics of a distribution network with a non-effectively grounded neutral point operating under single-phase grounding faults, thereby improving power supply reliability. Furthermore, by installing surge arresters only on phases A and C, and using insulator strings on phase B, with the maximum spacing determined based on line conditions, equipment investment and maintenance costs are minimized while ensuring insulation safety.

[0030] In one embodiment of the present invention, S100, based on the multiple truncated withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point, determines the maximum spacing between the lightning protection points on the distribution transformer, specifically including: S110, obtain the lightning current steepness and the lightning overvoltage wave propagation speed.

[0031] In this embodiment, the formula for calculating the lightning current steepness is as follows:

[0032] In the formula, For the steepness of the lightning current, I This represents the amplitude of the lightning current, in kA.

[0033] Understandably, the amplitude of lightning current I This is a preset "protection threshold" determined based on national / industry standards, regional lightning parameters, and equipment insulation levels. For example, the preset lightning current amplitude for 10kV overhead lines is typically designed at 50kA or 100kA. If the area where the transmission line is located is a low-lightning zone, a smaller parameter can be selected for the lightning current amplitude; if the area is a high-lightning zone, a larger parameter can be selected. Furthermore, the selected lightning current amplitude must meet insulation coordination requirements; for example, lightning overvoltage < equipment insulation level × safety margin (usually 0.85).

[0034] In a feasible embodiment, the maximum lightning current amplitude can also be determined by the insulator string U. 50 The value is obtained by reverse calculation of the discharge voltage, and the magnitude of the lightning current is set within the requirement of not exceeding the maximum lightning current amplitude.

[0035] In this embodiment, the propagation velocity of the lightning overvoltage wave is calculated using the following formula:

[0036] In the formula, v The propagation speed of lightning overvoltage waves. Let be the free permeability, and its value is . ; Let be the vacuum permittivity, and its value is . .

[0037] S120. Based on the steepness of the lightning current, the propagation velocity of the overvoltage wave at the lightning strike point, and the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point, the maximum spacing between the lightning protection points on the distribution transformer is calculated.

[0038] In this embodiment, for lightning protection of distribution transformers, the maximum spacing between lightning protection points on the distribution transformer is determined based on the multiple cutoff withstand voltage values, lightning current steepness, and lightning wave propagation speed. The determination of the lightning protection point location is primarily based on identifying high-risk areas according to the "lightning strike susceptibility pattern" and setting up multiple interception lines based on the "overvoltage wave propagation pattern." By covering both the "range where lightning strikes may occur" and the "paths along which overvoltage waves may propagate," it ensures that the distribution transformer can be protected by lightning protection points regardless of the location of the lightning strike.

[0039] In one embodiment, the maximum spacing between lightning protection points on the distribution transformer is determined by the following formula:

[0040] In the formula, For maximum spacing, For the steepness of the lightning current, v The propagation speed of lightning overvoltage waves. This refers to the withstand voltage value of the distribution transformer under multiple cut-off waves within the propagation range of the overvoltage wave at the lightning strike point.

[0041] In one embodiment, the withstand voltage value of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point is determined by the following formula:

[0042] In the formula, This refers to the withstand voltage values ​​of the distribution transformer under multiple chopped waveforms within the propagation range of the overvoltage wave at the lightning strike point. This refers to the three-wave intercept test voltage of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0043] In one embodiment of the present invention, S200, based on the maximum arrangement spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer, specifically including: S210. Determine the minimum layout spacing based on the preset layout cost.

[0044] In this embodiment, the minimum arrangement spacing is determined based on investment cost. It is understood that any cost-based "minimum distance" optimization must be performed while meeting safety regulations. The following methods aim to optimize the configuration scheme, not lower safety standards.

[0045] S220. Within the range formed by the minimum and maximum arrangement spacing, determine the target arrangement spacing.

[0046] In this embodiment, either the minimum arrangement spacing or the maximum arrangement spacing can be selected as the target arrangement spacing.

[0047] S230. On each phase conductor of the distribution transformer, a lightning protection point shall be arranged at each interval of the target arrangement to determine the lightning protection range of the distribution transformer.

[0048] In this embodiment, a lightning protection point is arranged on each phase conductor of the distribution transformer at intervals between targets.

[0049] Specifically, insulators are installed at intervals along the B-phase conductor, and surge arresters are installed at intervals along the A-phase and C-phase conductors. The surge arresters are installed below the suspension points (or at the crossarms of the tower) of the A-phase and C-phase conductors, at the same height and horizontal distance from the connection points of their respective phase conductors. (Refer to [reference needed]). Figure 2 , Figure 2 This is a schematic diagram of the arrangement of surge arresters and insulator strings based on phase-differentiated protection in an embodiment of the present invention. The grounding terminals of the surge arresters must share the same tower grounding electrode. The length of the grounding down conductor should be as short as possible, and the three-phase down conductor paths should be symmetrical (to avoid time lag due to impedance differences in the down conductors). If the tower has a triangular conductor arrangement (such as the common triangular arrangement in 10kV overhead lines), the installation position of the surge arrester must correspond to the conductor arrangement angle to ensure that the "connection distance" between each phase surge arrester and the conductor is consistent, avoiding excessively long connecting conductors for one phase that would increase the wavefront steepness. For example, in a 10kV triangular overhead line tower, phase A is symmetrically distributed at the top and phases B / C at the bottom. The surge arresters are fixed at corresponding positions on the crossarms and connected to the conductors via flexible connections (copper stranded wire), with a connection length of 0.3m for each. The grounding down conductors are all vertically downwards along the main structure of the tower and connected to the grounding electrode.

[0050] In one embodiment, the insulators arranged on phase B are external flashover insulators, and the 50% lightning impulse discharge voltage of the external flashover insulators is less than the starting operating voltage of the surge arrester. So that when lightning overvoltage enters the line, the external flashover insulators on phase B will be the first to flash over to ground due to the lower impulse discharge voltage, clamping the potential of phase B to zero potential and avoiding phase-to-phase flashover.

[0051] In one embodiment, the external flash insulator has a self-extinguishing arc capability, so that the distribution network can operate with the fault after a single-phase ground fault formed after phase B grounding. After the lightning current passes, the insulation performance of the phase B external flash insulator is automatically restored, realizing the self-clearing of the fault.

[0052] In one embodiment of the present invention, the method for determining the lightning protection range of a distribution transformer based on phase-differentiated protection specifically includes: Third chopped impulse voltage of a 10kV distribution transformer U j3 85kV, withstand voltage value after multiple cutoff waves .

[0053] Take the amplitude of lightning current I =10kA, then the lightning current steepness is:

[0054] Wave propagation speed:

[0055] The maximum spacing is:

[0056] Lightning protection points are arranged along the power distribution line at intervals less than the maximum spacing L. The lightning protection points are: surge arresters installed on the A-phase and C-phase conductors of the power distribution line, and external flashover insulators installed on the B-phase conductor, with the external flashover insulators having a voltage rating of 50% of the lightning impulse discharge voltage. The voltage is less than the starting operating voltage of the surge arrester, ensuring that when lightning overvoltage occurs, the external flashover insulator of phase B will break down and flash over first, clamping the potential of phase B to near zero potential, reducing the potential difference between phases AB and BC, and avoiding phase-to-phase insulation flashover.

[0057] In this embodiment of the invention, taking advantage of the characteristics of a 10kV distribution network with a non-effectively grounded neutral point, a single-phase ground fault formed after phase B is grounded allows the system to operate with the fault; after the lightning current passes, the insulation performance of the phase B external flash insulator automatically recovers, realizing fault self-clearing, and the system continues to operate normally.

[0058] In one embodiment of the present invention, a device for determining the lightning protection range of a distribution transformer based on phase-differentiated protection is also proposed, which can be referred to. Figure 3 , Figure 3 This is a structural block diagram of the distribution transformer lightning protection range determination device based on phase-differential protection in an embodiment of the present invention. The device includes: The spacing determination unit 301 is used to determine the maximum spacing between lightning protection points on the distribution transformer based on the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0059] Lightning protection point arrangement unit 302 is used to arrange lightning protection points on each phase conductor of the distribution transformer based on the maximum arrangement spacing to determine the lightning protection range of the distribution transformer. The lightning protection points include: surge arresters installed on phase A and phase C conductors and insulators installed on phase B conductors.

[0060] The distribution transformer lightning protection range determination device based on phase-differentiated protection proposed in this embodiment actively guides lightning overvoltages to discharge along a preset path by configuring insulation levels differently for each phase. It consciously controls the fault mode within the acceptable range of "single-phase grounding," reducing the line voltage to zero and thus increasing the protection range when a lightning strikes the line. It also fully utilizes the characteristics of a distribution network with a non-effectively grounded neutral point operating under single-phase grounding faults, thereby improving power supply reliability. Simultaneously, surge arresters are installed only on phases A and C, while insulator strings are used on phase B. The maximum spacing is determined based on line conditions, minimizing equipment investment and maintenance costs while ensuring insulation safety.

[0061] Figure 4 An internal structural diagram of a computer device according to one embodiment of the present invention is shown. This computer device can specifically be a terminal or a system. Figure 4As shown, the computer device includes a processor, memory, and network interface connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and may also store a computer program. When executed by the processor, this computer program causes the processor to perform the steps in the above-described method embodiments. The internal memory may also store a computer program, which, when executed by the processor, causes the processor to perform the steps in the above-described method embodiments. Those skilled in the art will understand that... Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0062] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, which, when executed by the processor, causes the processor to perform the following steps: A method for determining the lightning protection range of a distribution transformer based on phase-differential protection, the method comprising: Based on the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point, determine the maximum spacing between lightning protection points on the distribution transformer. Based on the maximum spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer. The lightning protection points include: surge arresters installed on the A-phase and C-phase conductors and insulators installed on the B-phase conductor.

[0063] Furthermore, based on the multiple truncated withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point, the maximum spacing between lightning protection points on the distribution transformer is determined, specifically including: Obtain the steepness of lightning current and the propagation speed of lightning overvoltage waves; The maximum spacing between lightning protection points on the distribution transformer is obtained by calculating the length based on the steepness of the lightning current, the propagation velocity of the overvoltage wave at the lightning strike point, and the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0064] Furthermore, the maximum spacing between lightning protection points on the distribution transformer is determined by the following formula:

[0065] In the formula, For maximum spacing, For the steepness of the lightning current, v The propagation speed of lightning overvoltage waves. This refers to the withstand voltage value of the distribution transformer under multiple cut-off waves within the propagation range of the overvoltage wave at the lightning strike point.

[0066] Furthermore, the withstand voltage value of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point is determined by the following formula:

[0067] In the formula, This refers to the withstand voltage values ​​of the distribution transformer under multiple chopped waveforms within the propagation range of the overvoltage wave at the lightning strike point. This refers to the three-wave intercept test voltage of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0068] Furthermore, based on the maximum spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer, specifically including: The minimum layout spacing is determined based on the preset layout cost; Within the range defined by the minimum and maximum arrangement spacing, determine the target arrangement spacing; One lightning protection point is installed on each phase conductor of the distribution transformer at each target spacing to determine the lightning protection range of the distribution transformer.

[0069] Furthermore, the insulator is an external flashover insulator, and the 50% lightning impulse discharge voltage of the external flashover insulator is less than the starting operating voltage of the surge arrester. This ensures that when a lightning overvoltage enters the line, the external flashover insulator of phase B will be the first to experience a ground flashover due to its lower impulse discharge voltage, thus clamping the potential of phase B to zero and preventing phase-to-phase flashover.

[0070] Furthermore, the external flash insulator has self-extinguishing arc capability, allowing the distribution network to operate with the fault after a single-phase ground fault formed after phase B grounding. After the lightning current passes, the insulation performance of the phase B external flash insulator automatically recovers, realizing fault self-clearing.

[0071] In one embodiment, a computer-readable storage medium is provided, storing a computer program that, when executed by a processor, causes the processor to perform the following steps: a method for determining the lightning protection range of a distribution transformer based on phase-differentiated protection, the method comprising: Based on the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point, determine the maximum spacing between lightning protection points on the distribution transformer. Based on the maximum spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer. The lightning protection points include: surge arresters installed on the A-phase and C-phase conductors and insulators installed on the B-phase conductor.

[0072] Furthermore, based on the multiple truncated withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave from the lightning strike point, the maximum spacing between lightning protection points on the distribution transformer is determined, specifically including: Obtain the steepness of lightning current and the propagation speed of lightning overvoltage waves; The maximum spacing between lightning protection points on the distribution transformer is obtained by calculating the length based on the steepness of the lightning current, the propagation velocity of the overvoltage wave at the lightning strike point, and the multiple cut-off withstand voltage values ​​of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0073] Furthermore, the maximum spacing between lightning protection points on the distribution transformer is determined by the following formula:

[0074] In the formula, For maximum spacing, For the steepness of the lightning current, v The propagation speed of lightning overvoltage waves. This refers to the withstand voltage value of the distribution transformer under multiple cut-off waves within the propagation range of the overvoltage wave at the lightning strike point.

[0075] Furthermore, the withstand voltage value of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point is determined by the following formula:

[0076] In the formula, This refers to the withstand voltage values ​​of the distribution transformer under multiple chopped waveforms within the propagation range of the overvoltage wave at the lightning strike point. This refers to the three-wave intercept test voltage of the distribution transformer within the propagation range of the overvoltage wave at the lightning strike point.

[0077] Furthermore, based on the maximum spacing, lightning protection points are arranged on each phase conductor of the distribution transformer to determine the lightning protection range of the distribution transformer, specifically including: The minimum layout spacing is determined based on the preset layout cost; Within the range defined by the minimum and maximum arrangement spacing, determine the target arrangement spacing; One lightning protection point is installed on each phase conductor of the distribution transformer at each target spacing to determine the lightning protection range of the distribution transformer.

[0078] Furthermore, the insulator is an external flashover insulator, and the 50% lightning impulse discharge voltage of the external flashover insulator is less than the starting operating voltage of the surge arrester. This ensures that when a lightning overvoltage enters the line, the external flashover insulator of phase B will be the first to experience a ground flashover due to its lower impulse discharge voltage, thus clamping the potential of phase B to zero and preventing phase-to-phase flashover.

[0079] Furthermore, the external flash insulator has self-extinguishing arc capability, allowing the distribution network to operate with the fault after a single-phase ground fault formed after phase B grounding. After the lightning current passes, the insulation performance of the phase B external flash insulator automatically recovers, realizing fault self-clearing.

[0080] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0081] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for determining the lightning protection range of a distribution transformer based on phase differentiation protection, characterized in that, The method comprises: determining the maximum arrangement interval between lightning protection points on the distribution transformer according to the multi-impulse withstand voltage value of the distribution transformer within the lightning stroke point overvoltage wave propagation range; arranging lightning protection points on each phase conductor of the distribution transformer based on the maximum arrangement interval to determine the lightning protection protection range of the distribution transformer, wherein the lightning protection points comprise: arrester installed on A-phase and C-phase conductors and insulator installed on B-phase conductor.

2. The method of claim 1, wherein, The maximum arrangement interval between lightning protection points on the distribution transformer is determined according to the multi-impulse withstand voltage value of the distribution transformer within the lightning stroke point overvoltage wave propagation range, and specifically comprises: obtaining the lightning current steepness and the lightning overvoltage wave propagation speed; performing length calculation according to the lightning current steepness, the lightning stroke point overvoltage wave propagation speed and the multi-impulse withstand voltage value of the distribution transformer within the lightning stroke point overvoltage wave propagation range to obtain the maximum arrangement interval between lightning protection points on the distribution transformer.

3. The method of claim 2, wherein, The maximum arrangement interval between lightning protection points on the distribution transformer is determined by the following formula: In the formula, is the maximum arrangement distance, is the lightning current steepness, v is the lightning overvoltage wave propagation speed, is the multiple-wave withstand voltage value of the distribution transformer within the lightning strike point overvoltage wave propagation range.

4. The method of claim 2, wherein, The multi-impulse withstand voltage value of the distribution transformer within the lightning stroke point overvoltage wave propagation range is determined by the following formula: In the formula, is the multiple-wave withstand voltage value of the distribution transformer in the wave propagation range of the lightning stroke point overvoltage, is the three-wave chopped impulse test voltage of the distribution transformer in the wave propagation range of the lightning stroke point overvoltage.

5. The method of claim 1, wherein, The lightning protection points are arranged on each phase conductor of the distribution transformer based on the maximum arrangement interval to determine the lightning protection protection range of the distribution transformer, and specifically comprises: determining the minimum arrangement interval based on the preset arrangement cost; determining the target arrangement interval within the range constituted by the minimum arrangement interval and the maximum arrangement interval; arranging a lightning protection point on each phase conductor of the distribution transformer every interval of the target arrangement interval to determine the lightning protection protection range of the distribution transformer.

6. The method of claim 1, wherein, The insulator is an external flash insulator, and the 50% lightning impulse discharge voltage of the external flash insulator is less than the initial operating voltage of the arrester, so that when the lightning overvoltage invades the line, the B-phase external flash insulator initiates flashover to ground due to the low impulse discharge voltage, clamps the B-phase potential to zero potential, and avoids inter-phase flashover.

7. The method of claim 1, wherein, The external flash insulator has self-arc extinguishing capability, so that the single-phase grounding fault formed after the B-phase grounding allows the distribution network to operate with fault, and after the lightning current passes, the insulation performance of the B-phase external flash insulator is automatically restored, realizing fault self-clearing.

8. A device for determining a lightning protection range of a distribution transformer based on phase differentiation protection, characterized in that, The device comprises: an arrangement interval determination unit configured to determine the maximum arrangement interval between lightning protection points on the distribution transformer according to the multi-impulse withstand voltage value of the distribution transformer within the lightning stroke point overvoltage wave propagation range; a lightning protection point arrangement unit configured to arrange lightning protection points on each phase conductor of the distribution transformer based on the maximum arrangement interval to determine the lightning protection protection range of the distribution transformer, wherein the lightning protection points comprise: arrester installed on A-phase and C-phase conductors and insulator installed on B-phase conductor.

9. A computer readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to make the processor execute the steps of the method according to any one of claims 1 to 7. 10.A computer device, comprising a memory and a processor, and characterized in that, The memory stores a computer program, and the computer program is executed by the processor to make the processor execute the steps of the method according to any one of claims 1 to 7.

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