Design method and arrangement mode of transformer substation under coupling action of earthquake and strong wind

Abstract

The invention discloses a transformer substation design method and an arrangement mode under the earthquake and strong wind coupling effect, relates to the technical field of transformer substation electrical design, and particularly aims at solving the problem that in the background technology, a traditional transformer substation does not consider the working state under the coupling effect of multiple disasters. The transformer substation design method under the earthquake and strong wind coupling effect and the arrangement mode comprise the following steps that transformer substation electric power facility classification and site classification are determined; determining the designed service life; determining a substation system working state requirement; selecting substation electrical facilities such as electrical equipment and communication equipment; determining earthquake and strong wind load parameters; calculating the failure probability of the electrical equipment; calculating each state probability of the substation system; analyzing the state of the electrical equipment under the disaster effect; and verifying the substation system states under different disaster prevention requirements.

Description

Technical Field

[0001] This invention belongs to the field of substation electrical design technology, specifically relating to substation design methods and layout under the coupled effects of earthquakes and strong winds. Background Technology

[0002] In recent years, China's urban economy has developed rapidly, with a dense labor force and numerous high-tech industries, leading to a surge in demand for electricity. The continuous advancement of urban modernization has not only increased the demand for power system infrastructure construction but also placed higher expectations on its earthquake and wind resistance capabilities. As a core component of transmission lines, substations are generally located far from cities, potentially in earthquake zones and strong wind areas. Under the simultaneous impact of multiple disasters, the ability of substations to remain operational becomes even more crucial, but traditional substation designs have not considered the operational status under the coupled effects of various disasters.

[0003] Therefore, it is urgent to design a substation design method and layout for the coupled effects of earthquakes and strong winds to solve the above problems. Summary of the Invention

[0004] To address the problem that existing technologies for traditional substations do not consider the operating conditions under the coupled effects of multiple disasters, the present invention aims to provide a substation design method and layout for the coupled effects of earthquakes and strong winds, comprising the following steps: determining the classification of substation power facilities and site category; determining the design service life; determining the operating condition requirements of the substation system; selecting substation electrical facilities such as electrical equipment and communication equipment; determining earthquake and strong wind load parameters; calculating the failure probability of electrical equipment; calculating the probability of each state of the substation system; analyzing the state of electrical equipment under disaster effects; and verifying the state of the substation system under different disaster prevention requirements.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] Substation design methods under the coupled effects of earthquakes and strong winds include:

[0007] S1. Determine the basic information of the substation site;

[0008] S2. Calculate the seismic load and strong wind load of the substation based on the substation site foundation information;

[0009] S3. Based on seismic load and strong wind load, calculate the failure probability of electrical equipment in substations under the coupled action of earthquake and strong wind.

[0010] S4. Based on the failure probability of electrical equipment in a substation under the coupled effects of earthquake and strong wind, analyze the power system status corresponding to a single electrical device in the substation under the coupled effects of earthquake and strong wind, and determine whether the disaster resistance design conditions of the substation are met based on the power system status results, the voltage level of the substation, and its position in the power system.

[0011] S5. Based on the judgment result of step S4, adjust the layout of electrical equipment in the station.

[0012] Preferably, in step S1, the basic information of the substation site includes: power facility classification and site conditions, design service life, and substation operating system status requirements.

[0013] Preferably, in step S2, the substation seismic load calculation process is as follows: γ, η1, and η2 are obtained based on the seismic fortification parameters, seismic action, and control indicators, and then multiple seismic wave diagrams are drawn based on the results of γ, η1, and η2.

[0014] Preferably,

[0015] The formulas for calculating γ, η1, and η are as follows:

[0016]

[0017] In the formula, α is the earthquake influence coefficient; α max T represents the maximum value of the earthquake influence coefficient. g ξ is the characteristic period; T is the natural period of the structure; ξ is the damping ratio of the structure; γ is the attenuation index; η1 is the adjustment coefficient for the downward slope of the linear descent segment; η2 is the damping adjustment coefficient.

[0018] Preferably, in step S2, the strong wind load of the substation is calculated, which is to determine the equivalent static load of the first mode of the average wind load and the pulsating wind load, and the calculation formulas for the equivalent static load of the first mode of the average wind load and the pulsating wind load are the same.

[0019] Preferably, the formula for calculating the equivalent static load of the first mode of the average wind load and the pulsating wind load is as follows:

[0020]

[0021] In the formula, w k The standard value of the average wind load; μ s For wind load shape coefficient; μ z β is the wind pressure height variation coefficient; w0 is the basic wind pressure; β z Let z be the wind vibration coefficient at height z;

[0022] in,

[0023] In the formula, g is the peak factor; I 10 Turbulence intensity at a height of 10 meters; B z R is the background component factor; R is the resonance component factor.

[0024] Preferably, in step S3, the electrical equipment includes surge arresters and instrument transformers in the substation; the process of calculating the failure probability of the electrical equipment includes: calculating the maximum stress value at the root of the porcelain bushing of the electrical equipment, comparing the maximum stress value with the yield strength of the porcelain bushing of the electrical equipment used by the manufacturer, obtaining the failure state of the electrical equipment under this working condition, and then obtaining a scatter plot of the failure state as a function of earthquake intensity, and then using a smooth curve to fit the failure probability curve of the electrical equipment under this site condition. The failure probability curve corresponds to the failure probability of the electrical equipment in the substation under different earthquakes and strong winds.

[0025] Preferably, in step S5, adjusting the layout of electrical equipment within the station based on the judgment result of step S4 includes:

[0026] When the low-requirement disaster resistance design conditions of a substation are not met, the layout of the electrical equipment within the substation is changed; when the medium-requirement disaster resistance design conditions of a substation are not met, energy-consuming devices such as dampers are added; when the high-requirement disaster resistance design conditions of a substation are not met, measures to improve seismic resistance are adopted.

[0027] The beneficial effects of this invention are: This invention discloses a substation design method and layout scheme under the coupled effects of earthquakes and strong winds. Compared with the prior art, the improvement of this invention lies in:

[0028] This invention proposes a design method for 220kV substations under the coupled effects of earthquakes and strong winds. Based on existing substation design methods, it considers the coupling effect of earthquakes and strong winds, using peak ground acceleration as the control index. By establishing finite element models of individual electrical equipment within the substation and inputting seismic waves and wind loads, dynamic response analysis is performed on the equipment to obtain the operating states of the equipment under different disaster protection requirements, thereby estimating the operating state of the substation system. For substation systems that fail disaster verification, different improvement methods are proposed according to different protection requirements. By changing the layout and adding energy dissipation devices, the overall disaster resistance capability of the substation is improved, ensuring the normal operation of the substation under multiple disasters. Attached Figure Description

[0029] Figure 1 This is a flowchart of the design method for high-voltage substations under the coupled effects of earthquakes and strong winds according to the present invention.

[0030] Figure 2 This is a flowchart of the design method for high-voltage substations under the coupled effects of earthquakes and strong winds, as described in this invention.

[0031] Figure 3 This is a graph showing the earthquake influence coefficient of this invention.

[0032] Figure 4 This invention relates to a common foundation arrangement for surge arresters and instrument transformers.

[0033] Figure 5 This invention relates to a double-busbar wiring arrangement for electrical equipment.

[0034] Figure 6 The Monte Carlo simulation method used in this invention to calculate the failure probability of the system;

[0035] Figure 7 This is a schematic diagram of the simplified system state analysis of the present invention.

[0036] Among them: Figure 3 In the diagram, 1-Voltage transformer; 2-Surge arrester; 3-Horizontal rotary disconnector; 4-Current transformer; 5-Road; 6-Cable trench; 7-Terminal box; 8-Circuit breaker; 9-Vertical retractable disconnector; 10-Vertical retractable disconnector; 11-Substation perimeter wall; 12-Crossing busbar. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but should not be used to limit the scope of the present invention.

[0038] Example:

[0039] See attached document Figure 1-7 The substation design method shown here, under the coupled effects of earthquake and strong wind, specifically includes:

[0040] S1. Determine the basic information of the substation site;

[0041] Basic information about the substation site includes: classification of power facilities and site conditions, design service life, and status requirements of the substation's operating system.

[0042] Specifically, the classification of power facilities includes: substation voltage level and the substation's position in the power system; site conditions include: substation altitude, ambient temperature, average maximum temperature of the hottest month, ground roughness, design wind speed, seismic fortification intensity, design basic seismic acceleration, and site category. The design service life of a substation is determined according to the design service life of substations at different voltage levels as specified in the "Technical Regulations for Substation Building Structure Design" (DL / T5457-2012). The substation operating system status requirements refer to the maximum number of transmission lines that can remain operational.

[0043] S2. Based on the substation site foundation information, calculate the seismic load and strong wind load of the substation;

[0044] The specific contents of the earthquake and strong wind load parameters are as follows: based on the substation site foundation information determined in S1, earthquake load calculation and strong wind load calculation are performed; the specific steps for earthquake load calculation are: determining seismic fortification parameters, determining earthquake action, and determining control indicators; the specific steps for strong wind load calculation are: calculating wind load and determining control indicators.

[0045] The calculation process for substation seismic load is as follows: γ, η1, and η2 are obtained based on seismic design parameters, seismic action, and control indices. Then, multiple seismic wave diagrams are plotted based on the results of γ, η1, and η2, such as... Figure 3 As shown, multiple artificial seismic waves were plotted based on the seismic action;

[0046] The formulas for calculating γ, η1, and η are as follows:

[0047]

[0048] In the formula: α is the earthquake influence coefficient; α max T represents the maximum value of the earthquake influence coefficient. g ξ is the characteristic period; T is the natural period of the structure; ξ is the damping ratio of the structure; γ is the attenuation index; η1 is the adjustment coefficient of the downward slope of the linear descent segment. When the calculated value η1 < 0, η1 should be taken as 0; η2 is the damping adjustment coefficient. When the calculated value η1 < 0.55, η1 should be taken as 0.55.

[0049] The specific method for generating multiple artificial seismic waves is to synthesize more than 30 artificial seismic waves for calculating the response of electrical equipment based on the test spectrum corresponding to the seismic influence coefficient.

[0050] The seismic design parameters are determined as follows: Considering the importance of power facilities and their role in earthquake relief, the current national standard "Code for Seismic Design of Power Facilities" (GB) is used.

[0051] The 50260-2013 (hereinafter referred to as the "Standard") stipulates that the power supply buildings of power transmission and transformation projects in "important power facilities" are "key fortification category (Category B)". Their seismic measures should be determined according to the requirement of being one degree higher than the seismic fortification intensity of the region, but their seismic action should still be determined according to the seismic fortification intensity of the region, which is consistent with the current national standards.

[0052] Determination of seismic action: For electrical facilities, according to the current national standard "Code for Seismic Design of Power Facilities" (GB50260-2013), the amplification factor for horizontal seismic influence is 2.5, that is, the maximum value of the horizontal seismic influence coefficient α. maxIt is 2.5 times the basic design earthquake acceleration corresponding to the corresponding seismic fortification intensity; the standard gives the maximum value of the horizontal seismic influence coefficient corresponding to the basic design earthquake, as shown in Table 1. For electrical facilities, the control indicators are determined according to current national standards.

[0053] Table 1 Maximum values ​​of horizontal earthquake influence coefficient

[0054]

[0055] For cantilever structures such as electrical equipment, it is assumed that only the first mode of vibration plays a decisive role in the analysis process. Therefore, in the analysis process, only the equivalent static load of the first mode of vibration of the average wind load and the pulsating wind load is determined.

[0056] The formula for calculating the average wind load is:

[0057]

[0058] In the formula, z b , z represents the standard reference height and the average wind speed at that location. Let be the average wind speed at any altitude; α is the ground roughness index.

[0059] The formula for calculating pulsating wind load is:

[0060]

[0061] In the formula, ω is the frequency. This is the overall turbulent dimension, taken as 1200. * For ground friction speed, The formulas for calculating the equivalent static load of the first mode of vibration of both average wind load and pulsating wind load are the same, and are as follows:

[0062] Equivalent static wind load calculation

[0063] w k =β z μ s μ z w0

[0064] In the formula, w k The average wind load standard value (kN / m2); μ s For wind load shape coefficient, it is obtained according to the "Code for Design of Building Structures" and is taken as 1.0 for column-type electrical equipment; μ z β is the wind pressure height variation coefficient; w0 is the basic wind pressure; β z Let z be the wind vibration coefficient at height z;

[0065] in,

[0066] In the formula, g is the peak factor, taken as 2.5; I10 is the turbulence intensity at a height of 10 meters; B z R is the background component factor, calculated using modal analysis of the finite element model; R is the resonance component factor, calculated using modal analysis of the finite element model.

[0067]

[0068] In the formula, The wind pressure height variation coefficient is given by the z-height of four types of ground roughness: A, B, C, and D.

[0069] S3. Based on seismic load and strong wind load, calculate the failure probability of electrical equipment in substations under the coupled action of earthquake and strong wind.

[0070] Specifically, electrical equipment refers to individual electrical devices such as surge arresters and instrument transformers within a substation. The approach to calculating the failure probability of electrical equipment is as follows: establish a finite element model of the electrical equipment within the substation and verify its effectiveness. Specifically, the main weak point of the electrical equipment is at the root of the porcelain bushing. Using the stress at the root of the porcelain bushing as a demand indicator, the failure state of the porcelain column-type high-voltage electrical equipment is divided into two levels: failure and no failure. Based on site conditions, the seismic load and wind load calculated in step S2 are input into the finite element model of the electrical equipment to calculate the maximum stress value of the electrical equipment. Comparing this value with the yield strength of the porcelain bushing used by the manufacturer, the failure state of the electrical equipment under this condition can be obtained. Recording all the results under all conditions yields a scatter plot of the failure state as a function of seismic intensity. Using a smooth curve fit, the failure probability curve of the electrical equipment under this site condition can be obtained, corresponding to the failure probability of electrical equipment within the substation under different earthquakes and strong winds.

[0071] S4. Based on the failure probability of electrical equipment in a substation under the coupled effects of earthquake and strong wind, analyze the power system status corresponding to a single electrical device in the substation under the coupled effects of earthquake and strong wind, and determine whether the disaster resistance design conditions of the substation are met based on the system status results, the voltage level of the substation, and its position in the power system.

[0072] like Figure 4 , Figure 5 As shown, the Monte Carlo simulation method is used to evaluate the operational status of a single bay under specific conditions based on the failure probability of individual equipment. Taking a simplified system as the analysis object, and setting the peak ground acceleration (PGA) at 0.5g and the wind speed at 20m, the Monte Carlo simulation method can generate random numbers representing the equipment failure probability under this condition. This failure probability can simultaneously reflect the randomness of ground motion and the randomness of equipment materials.

[0073] like Figure 5As shown, a directed graph model is constructed using a simplified system as the analysis object. In this example, for devices 1 to 7 in the system, a set of random numbers representing the failure probabilities of the devices are generated using the Monte Carlo simulation method. Specifically, these numbers are 0.54, 0.23, 0.64, 0.75, 0.60, 0.64, and 0.88. By comparing these random numbers with the device failure probabilities calculated in S3, the working status of the devices can be determined (the device failure probability is preset to 0.5 here): the random numbers for devices 1, 3, 4, 5, 6, and 7 are all greater than 0.5, so they are determined to be in normal working condition; while the random number for device 2, 0.15, is less than 0.5, so it is determined to be in a failure state.

[0074] The status of a device affects the status of the pathways it is connected to, such as... Figure 5 Device 1 is working normally, and its connected lines are also working normally, which is recorded as 1; device 2 fails, and its connected lines lose their working capacity, which is recorded as 0. For this power system, the failure of only the line connected to device 2 will not cause the entire system to fail, so the system state is 1, that is, it is working normally.

[0075] The above steps can be repeated to calculate the system state and failure probability multiple times, thereby improving accuracy.

[0076] Based on the voltage level and position of a substation within the power system, my country's current standards specify the disaster resistance targets for power facilities and buildings (structures) within the power system, thus determining the substation's voltage level and position. Under low-requirement disaster resistance design conditions, when subjected to disasters less severe than the local design disaster level, the substation's building structure remains undamaged or requires no repair and can continue to be used; the electrical facilities remain undamaged, and the power supply function is unaffected. Under medium-requirement disaster resistance design conditions, when subjected to disasters equivalent to the local design disaster level, the substation's building structure may be damaged, but it can still be used after general repairs; the electrical facilities remain undamaged, and the power supply function is unaffected. Under high-requirement disaster resistance design conditions, when subjected to disasters more severe than the local design disaster level, the substation's building structure will not collapse, the electrical facilities should not be severely damaged, and the power supply function can be quickly restored after repairs.

[0077] Low-requirement disaster resistance design conditions refer to the occurrence of frequent earthquakes below the seismic fortification intensity of the region and strong winds below the basic wind pressure with a 10-year return period; medium-requirement disaster resistance design conditions refer to the occurrence of earthquakes equivalent to the seismic fortification intensity of the region and strong winds equivalent to the basic wind pressure with a 50-year return period; high-requirement disaster resistance design conditions refer to the occurrence of rare earthquakes above the seismic fortification intensity of the region and strong winds equivalent to the basic wind pressure with a 100-year return period.

[0078] The control indicators for earthquakes and strong winds are as follows: the control indicator for earthquake disasters is peak ground acceleration; the control indicator for strong wind disasters is wind speed.

[0079] After determining the protection conditions, the failure probability of electrical equipment can be calculated in step S3. Substituting this into step S4, the substation system status and failure probability under the protection conditions can be obtained. If the failure probability is higher than 5%, the disaster resistance design conditions are considered to have failed.

[0080] S5. Based on the judgment result of step S4, adjust the layout of electrical equipment in the station.

[0081] If the low-requirement disaster resistance design conditions are not met, methods such as changing the layout of electrical equipment within the station can be adopted; if the medium-requirement disaster resistance design conditions are not met, methods such as adding energy-consuming devices such as dampers can be adopted; if the high-requirement disaster resistance design conditions are not met, methods such as improving seismic resistance measures can be adopted.

[0082] The changes include altering the layout of electrical equipment within the station, specifically by reducing the spacing between equipment to minimize the impact of connections between them, placing busbars at lower levels to reduce the risk of busbar damage, and relocating equipment to make it easier to maintain and install.

[0083] like Figure 4 The common base structure for voltage transformers and surge arresters shown includes a common structural support and a flexible connection between the surge arrester and the transformer.

[0084] like Figure 5 As shown, the optimized circuit breaker layout increases the disaster resistance of the bay by adjusting the positions of the circuit breakers, cable trenches, and terminal boxes; this layout can be used for the arrangement of equipment in various levels of substations. The flexible connection of the surge arresters and instrument transformers uses multi-strand expanded diameter aluminum stranded wire. The optimized disconnector layout includes setting the busbar as a vertical telescopic structure and changing the position of the disconnector, ensuring that the disconnector can be maintained without interrupting power to the busbar.

[0085] The basic principles, main features, and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A substation design method under the coupled effects of earthquakes and strong winds, characterized in that, include: S1. Determine the basic information of the substation site; S2. Calculate the seismic load and strong wind load of the substation based on the substation site foundation information; S3. Based on seismic load and strong wind load, calculate the failure probability of electrical equipment in substations under the coupled action of earthquake and strong wind. S4. Based on the failure probability of electrical equipment in a substation under the coupled effects of earthquake and strong wind, analyze the power system status corresponding to a single electrical device in the substation under the coupled effects of earthquake and strong wind, and determine whether the disaster resistance design conditions of the substation are met based on the power system status results, the voltage level of the substation, and its position in the power system. S5. Based on the judgment result of step S4, adjust the layout of electrical equipment in the station.

2. The substation design method under the coupled effects of earthquake and strong wind as described in claim 1, characterized in that, In step S1, the basic information of the substation site includes: classification of power facilities and site conditions, design service life and substation operating system status requirements.

3. The substation design method under the coupled effects of earthquake and strong wind as described in claim 1, characterized in that, In step S2, the substation seismic load calculation process is as follows: γ, η1 and η2 are obtained based on the seismic fortification parameters, seismic action and control indicators, and then multiple seismic wave diagrams are drawn based on the results of γ, η1 and η2.

4. The substation design method under the coupled effects of earthquake and strong wind as described in claim 3, characterized in that, The formulas for calculating γ, η1, and η are as follows: In the formula, α is the earthquake influence coefficient; α max This represents the maximum value of the earthquake influence coefficient. T g ξ is the characteristic period; T is the natural period of the structure; ξ is the damping ratio of the structure; γ is the attenuation index; η1 is the adjustment coefficient for the downward slope of the linear descent segment; η2 is the damping adjustment coefficient.

5. The substation design method under the coupled effects of earthquake and strong wind as described in claim 1, characterized in that, In step S2, the strong wind load of the substation is calculated, which is to determine the equivalent static load of the first mode of the average wind load and the pulsating wind load, and the calculation formulas for the equivalent static load of the first mode of the average wind load and the pulsating wind load are the same.

6. The substation design method under the coupled effects of earthquake and strong wind as described in claim 1, characterized in that, The formulas for calculating the equivalent static load of the first mode of vibration of the average wind load and the pulsating wind load are as follows: w k =b z m s m z w0; In the formula, w k The standard value of the average wind load; μ s For wind load shape coefficient; μ z β is the wind pressure height variation coefficient; w0 is the basic wind pressure; β z Let z be the wind vibration coefficient at height z; in, In the formula, g is the peak factor; I 10 10 meters represents the turbulence intensity; B represents the background component factor; R represents the resonance component factor.

7. The substation design method under the coupled effects of earthquake and strong wind as described in claim 1, characterized in that, In step S3, the electrical equipment includes surge arresters and instrument transformers in the power station; The process of calculating the failure probability of electrical equipment includes: calculating the maximum stress value at the root of the porcelain bushing of the electrical equipment, comparing the maximum stress value with the yield strength of the porcelain bushing used by the manufacturer to obtain the failure state of the electrical equipment under this working condition, and then obtaining a scatter plot of the failure state as a function of earthquake intensity. Finally, a smooth curve is used to fit the failure probability curve of the electrical equipment under the site conditions. The failure probability curve corresponds to the failure probability of electrical equipment in the substation under different earthquakes and strong winds.

8. The substation design method under the coupled effects of earthquake and strong wind as described in claim 1, characterized in that, In step S5, adjusting the layout of electrical equipment within the station based on the judgment result of step S4 includes: When the low-requirement disaster resistance design conditions of a substation are not met, the layout of the electrical equipment within the substation is changed; when the medium-requirement disaster resistance design conditions of a substation are not met, energy-consuming devices such as dampers are added; when the high-requirement disaster resistance design conditions of a substation are not met, measures to improve seismic resistance are adopted.

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