Safety monitoring method and system for steel structure of booster station of offshore wind plant

Abstract

The invention discloses an offshore wind plant booster station steel structure safety monitoring method, and relates to the technical field of offshore booster station steel structure safety monitoring, and the method comprises the steps: obtaining the safety monitoring data of an offshore booster station steel structure; performing strong vibration response data analysis and safety evaluation on the offshore booster station steel structure; analyzing the change condition of the inherent frequency after the strong vibration event; analyzing the inclination change condition of the offshore booster station steel structure after the strong vibration event; analyzing the differential settlement change condition of the offshore booster station after the strong vibration event; analyzing the stress-strain change condition of the key part of the offshore booster station steel structure after the strong vibration event; and analyzing the correlation of the safety monitoring data of the offshore booster station steel structure. Online analysis of safety monitoring data of the offshore booster station steel structure is facilitated, and stable operation of the offshore booster station is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of safety monitoring of offshore booster stations, and in particular relates to a method for safety monitoring of steel structures of offshore wind farm booster stations. Background Art

[0002] The offshore wind farm booster station is an important part of the offshore wind farm, responsible for the collection, boosting and transmission of offshore wind farm electricity. As it is far away from the land and in a harsh marine environment, its safety and stability are of vital importance.

[0003] At present, the safety monitoring of offshore substation steel structures usually focuses on vibration monitoring, tilt monitoring, stress-strain monitoring and uneven settlement monitoring, and each special safety monitoring is usually evaluated independently, failing to deeply explore the relationship between the special safety monitoring data. Summary of the invention

[0004] The purpose of the present invention is to solve the defects in the prior art and to propose a method and system for safety monitoring of steel structures of offshore wind farm booster stations, so as to realize comprehensive analysis of safety monitoring of steel structures of offshore booster stations.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A method for safety monitoring of steel structures of offshore wind farm booster stations comprises the following steps: Step 1: Obtain safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress and strain monitoring data, and uneven settlement monitoring data; Step 2: Based on the safety monitoring data of the offshore substation steel structure, conduct strong vibration response data analysis and safety assessment of the offshore substation steel structure; Step 3: Analysis of the change of natural frequency of steel structure after strong vibration event; Analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Analysis of uneven settlement changes of offshore booster stations after strong vibration events; And the analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

[0006] A further improvement of the present invention is that in step 2, based on the safety monitoring data of the offshore booster station steel structure, a strong vibration response data analysis and safety assessment of the offshore booster station steel structure are performed, including: setting the severe vibration response of the offshore booster station steel structure caused by earthquakes, typhoons, ship collisions, and construction, when the maximum peak values ​​of more than half of the vibration monitoring points simultaneously exceed 1m / s 2 When , it is considered that a strong vibration event occurs.

[0007] A further improvement of the present invention is that, in step 2, based on the safety monitoring data of the offshore substation steel structure, strong vibration response data analysis and safety assessment of the offshore substation steel structure are performed, and the specific method is as follows: Step 2.1: Read the vibration raw data file of the strong vibration event and intercept the strong vibration event data; Step 2.2: Preprocess the strong vibration data, perform 0.2-20 Hz bandpass filtering, and perform initial value calibration; Step 2.3: Perform digital integration calculation on the pre-processed data to obtain strong vibration velocity and strong vibration displacement data respectively; Step 2.4: Calculate the vibration intensity value of each monitoring point using the strong vibration acceleration and velocity data; Step 2.5: Calculate the vibration response spectrum of each monitoring point using the strong vibration acceleration data; Step 2.6: Calculate the vibration acceleration response peak value, vibration velocity response peak value, and vibration displacement response peak value of each monitoring point; Step 2.7: Safety and rapid assessment. According to the relationship between the average vibration intensity value of each monitoring point and the seismic fortification intensity value of the offshore booster station steel structure, the assessment results are divided into: severe damage, existing damage and special assessment.

[0008] A further improvement of the present invention is that, when the maximum intensity of the strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is performed - an analysis of the change in the natural frequency of the steel structure after the strong vibration event; the natural frequency of the steel structure can reflect the change in the stiffness of the entire structure; When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted - analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted - analysis of the changes in uneven settlement of the offshore booster station after the strong vibration event; When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted to analyze the stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

[0009] A further improvement of the present invention is that in step 3, the analysis process of the change of the natural frequency of the steel structure after the strong vibration event is as follows: Step 3.1: Collect structural micro-vibration data 1 hour before and after the strong vibration event; Step 3.2: Perform EFDD structural modal analysis; Step 3.3: Automatically pick up the 1st, 2nd and 3rd order natural frequency values ​​of the structure; Step 3.4: Taking the 1st, 2nd and 3rd order natural frequency values ​​before the strong vibration event as the reference value, calculate the decrease ratio of the 1st, 2nd and 3rd order natural frequency values ​​after the strong vibration event; Step 3.5: Safety assessment: according to the median value of the decrease ratio of the third-order natural frequency, the assessment results are divided into: severe damage, existing damage and minor damage.

[0010] A further improvement of the present invention is that, in step 3, the analysis process of the inclination change of the offshore booster station steel structure after the strong vibration event is as follows: Step 4.1: Read the average characteristic value of each tilt monitoring point 1 hour before the strong vibration, and the average characteristic value of each tilt monitoring point more than 1 hour after the strong vibration; Step 4.2: Taking the hourly average of the mean characteristic value of each tilt monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the hourly average of the mean characteristic value of each tilt monitoring point after the strong vibration; Step 4.3: Tilt safety assessment. According to the change value, the assessment results are divided into: permanent tilt deformation, large tilt deformation and slight tilt deformation.

[0011] A further improvement of the present invention is that, in step 3, the process of analyzing the uneven settlement changes of the offshore booster station after the strong vibration event is as follows: Step 5.1: Read the average characteristic value of each uneven settlement monitoring point one day before the strong vibration and the average characteristic value of each uneven settlement monitoring point more than one day after the strong vibration; Step 5.2: Taking the daily average of the mean characteristic values ​​of each monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the daily average of the mean characteristic values ​​of each monitoring point after the strong vibration; Step 5.3: Safety assessment of foundation uneven settlement. According to the change value, the assessment results are divided into: severe uneven settlement deformation, large uneven settlement deformation and slight uneven settlement deformation.

[0012] A further improvement of the present invention is that, in step 3, the analysis process of stress and strain changes in key parts of the offshore booster station steel structure after a strong vibration event is as follows: Step 6.1: Read the mean characteristic value of each stress monitoring point one day before the strong vibration, and the mean characteristic value of each stress monitoring point more than one day after the strong vibration; Step 6.2: Taking the daily average of the mean characteristic values ​​of each monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the daily average of the mean characteristic values ​​of each monitoring point after the strong vibration; Step 6.3: Safety assessment of stress in key parts. According to whether the change value exceeds the design allowable value and the amplitude of the change value, the assessment results are divided into: severe stress-strain deformation, large stress-strain deformation and slight stress-strain deformation.

[0013] A safety monitoring system for steel structures of offshore wind farm booster stations, comprising: Data acquisition module, which acquires safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress and strain monitoring data, and uneven settlement monitoring data; The data analysis module conducts strong vibration response data analysis and safety assessment of offshore booster station steel structures based on offshore booster station steel structure safety monitoring data; Situation analysis module: analysis of the change of natural frequency of steel structure after strong vibration events; Analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Analysis of uneven settlement changes of offshore booster stations after strong vibration events; And the analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

[0014] A further improvement of the present invention is that, in the data analysis module, based on the safety monitoring data of the offshore substation steel structure, the strong vibration response data analysis and safety assessment of the offshore substation steel structure are carried out, including: setting the severe vibration response of the offshore substation steel structure caused by earthquakes, typhoons, ship collisions, and construction, when the maximum peak values ​​of more than half of the vibration monitoring points simultaneously exceed 1m / s 2 When , it is considered that a strong vibration event occurs.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides a method and system for monitoring the safety of steel structures of offshore wind farm substations, which ensures the comprehensiveness of monitoring by acquiring a variety of monitoring data (vibration, tilt, stress-strain, and uneven settlement), and can reflect the safety status of steel structures from multiple angles. The acquisition and analysis of real-time monitoring data can promptly discover potential problems in steel structures, which helps to take preventive measures and avoid accidents. In particular, after a strong vibration event, timely analysis of changes in the natural frequency, tilt, uneven settlement, and stress-strain in key parts of the steel structure can quickly assess the degree of damage and safety of the structure, providing a basis for subsequent maintenance and reinforcement. Through data analysis and safety assessment, the health status of the steel structure can be scientifically and accurately judged, reducing the subjectivity and uncertainty of human judgment. The analysis results of the present invention can provide clear guidance for the maintenance and management of offshore substation steel structures, and help to formulate targeted maintenance plans and measures.

[0016] In summary, the present invention adopts a multi-source data fusion analysis method to solve the problem that in the traditional offshore wind farm substation steel structure safety monitoring, each special safety monitoring is evaluated in isolation and the relationship between the monitoring data is not fully explored. By fusing and analyzing the various monitoring data, the relationship between the monitoring data is further explored, the data island is broken, and the comprehensive analysis of the offshore substation steel structure safety monitoring is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of the safety monitoring method for the steel structure of an offshore wind farm booster station; Figure 2 This is a schematic diagram of the strong vibration response data analysis and safety assessment of the offshore booster station steel structure; Figure 3 This is a schematic diagram of the safety analysis of the natural frequency change of the steel structure after a strong vibration event; Figure 4 This is a schematic diagram of the analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Figure 5 This is a schematic diagram of the analysis of the uneven settlement changes of the offshore booster station after the strong vibration event; Figure 6 Schematic diagram of the analysis of stress and strain changes in key parts of the offshore booster station steel structure after a strong vibration event. Figure 7 This is the structural block diagram of the steel structure safety monitoring system for the offshore wind farm booster station. DETAILED DESCRIPTION

[0018] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0019] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0020] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0021] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0022] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0023] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] Example 1 The present invention provides a method for safety monitoring of steel structures of offshore wind farm booster stations, comprising the following steps: Step 1: Obtain safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress and strain monitoring data, and uneven settlement monitoring data; Step 2: Based on the safety monitoring data of the offshore substation steel structure, conduct strong vibration response data analysis and safety assessment of the offshore substation steel structure; Step 3: Analysis of the change of natural frequency of steel structure after strong vibration event; Analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Analysis of uneven settlement changes of offshore booster stations after strong vibration events; And the analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

[0025] Example 2 Reference Figure 1-6 The present invention provides a method for safety monitoring of steel structures of offshore wind farm booster stations, comprising: Step 1: Obtain safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress-strain monitoring data and uneven settlement monitoring data; Step 2: Based on the acquired safety monitoring data of the offshore substation steel structure, conduct strong vibration response data analysis and safety assessment of the offshore substation steel structure; Step 2.1: Read the vibration raw data file of the strong vibration event and intercept the strong vibration event data; Step 2.2: Preprocess the strong vibration data, perform 0.2-20 Hz bandpass filtering, and perform initial value calibration; Step 2.3: Perform digital integration calculation on the pre-processed data to obtain strong vibration velocity and strong vibration displacement data respectively; Step 2.4: Calculate the vibration intensity value of each monitoring point using the strong vibration acceleration and velocity data; Step 2.5: Calculate the vibration response spectrum of each monitoring point using the strong vibration acceleration data; Step 2.6: Calculate the vibration acceleration response peak value, vibration velocity response peak value, and vibration displacement response peak value of each monitoring point; Step 2.7: Rapid safety assessment. According to the relationship between the average vibration intensity value of each monitoring point and the seismic fortification intensity value of the offshore booster station steel structure, the assessment results are divided into: If the average vibration intensity value of each monitoring point exceeds the seismic fortification intensity value of the offshore booster station steel structure (usually 8 degrees fortification), it is assessed that the structure is severely damaged, a safety warning is issued, and a safety emergency response is initiated. If only the vibration intensity value of the vibration monitoring point at the top of the upper module of the offshore booster station exceeds the seismic fortification intensity value, it is assessed that the structure is damaged, and it is recommended to conduct a detailed inspection as soon as possible. If the maximum vibration intensity value exceeds 6 degrees, a rapid analysis and safety assessment after strong vibration should be carried out on other monitoring special parameters.

[0026] When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted - analysis of the change in the natural frequency of the steel structure after the strong vibration event; the natural frequency of the steel structure can reflect the change in the stiffness of the entire structure. For example, after the strong vibration, the steel structure of the offshore substation is severely damaged, and its stiffness will decrease to a certain extent, which will cause the natural frequency of the structure to decrease accordingly. Therefore, by analyzing the change in the natural frequency of the structure after the strong vibration event, the decrease in stiffness and bearing capacity of the offshore substation steel structure after the strong vibration event can be evaluated.

[0027] When the maximum intensity of the strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis should be conducted - analysis of the changes in the inclination of the offshore booster station steel structure after the strong vibration event; after the strong vibration, if the offshore booster station is permanently tilted, it will seriously affect the structural safety, so it is necessary to quickly evaluate its permanent tilt after another strong vibration.

[0028] When the maximum intensity of the strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis should be conducted - analysis of the uneven settlement changes of the offshore booster station after the strong vibration event; after the strong vibration, if the offshore booster station has uneven foundation settlement changes, it will seriously affect the structural safety, so it is necessary to quickly evaluate its uneven settlement changes after the strong vibration.

[0029] When the maximum intensity of the strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis should be conducted - analysis of the stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event; after the strong vibration, if the structural stress of the offshore booster station exceeds the standard, it will seriously affect the safety of key structural components, so it is necessary to quickly evaluate the changes in its stress monitoring points after the strong vibration.

[0030] Step 3: Analysis of the change of natural frequency of steel structure after strong vibration event; Step 3.1: Collect structural micro-vibration data 1 hour before and after the strong vibration event; Step 3.2: Perform EFDD structural modal analysis; Step 3.3: Automatically pick up the 1st, 2nd and 3rd order natural frequency values ​​of the structure; Step 3.4: Taking the 1st, 2nd and 3rd order natural frequency values ​​before the strong vibration event as the reference value, calculate the decrease ratio of the 1st, 2nd and 3rd order natural frequency values ​​after the strong vibration event; Step 3.5: Safety assessment. According to the median value of the decrease amplitude ratio of the 3rd order natural frequency, the assessment results are divided into: 2. If the median value of the decrease amplitude ratio of the 3rd order natural frequency exceeds 20%, it is directly assessed that the offshore substation steel structure may suffer serious structural damage after the strong vibration event, and a safety warning message is issued, and it is recommended to initiate a safety emergency response; if the median value of the decrease amplitude ratio of the 3rd order natural frequency is between 5% and 20%, it is assessed that the structure may be damaged, and it is recommended to conduct a detailed safety inspection afterwards; if the median value of the decrease amplitude ratio of the 3rd order natural frequency is less than 5%, it is assessed that the overall stiffness of the structure has changed slightly.

[0031] Step 4: Analysis of the inclination change of the offshore booster station steel structure after the strong vibration event; Step 4.1: Read the average characteristic value of each tilt monitoring point 1 hour before the strong vibration, and the average characteristic value of each tilt monitoring point more than 1 hour after the strong vibration; Step 4.2: Taking the hourly average of the mean characteristic value of each tilt monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the hourly average of the mean characteristic value of each tilt monitoring point after the strong vibration; Step 4.3: Tilt safety assessment. According to the change value, the assessment results are divided into: if the change value is 0.1°-0.3°, it is assessed that some positions of the offshore booster station have undergone permanent tilt deformation after the strong vibration, and a safety warning message is issued, and it is recommended to conduct detailed inspection as soon as possible; if the change value is greater than 0.3°, it is assessed that some positions of the offshore booster station have undergone large permanent tilt deformation after the strong vibration, and a safety warning message is issued, and a safety emergency response is recommended; if the change value is less than 0.1°, but there is a more obvious change trend, it is assessed that the structure of the booster station may have an unstable trend after the strong vibration, and a safety warning message is issued, and it is recommended to closely monitor the trend development.

[0032] Step 5: Analysis of the uneven settlement changes of the offshore booster station after the strong vibration event; Step 5.1: Read the average characteristic value of each uneven settlement monitoring point one day before the strong vibration and the average characteristic value of each uneven settlement monitoring point more than one day after the strong vibration; Step 5.2: Taking the daily average of the mean characteristic values ​​of each monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the daily average of the mean characteristic values ​​of each monitoring point after the strong vibration; Step 5.3: Safety assessment of uneven foundation settlement. According to the change value, the assessment results are divided into: if the change value is 5mm-20mm, it is assessed that the foundation of the offshore booster station has undergone uneven settlement and deformation after the strong vibration, and a safety warning message is issued, and it is recommended to conduct detailed inspection as soon as possible; if the change value is greater than 20mm, it is assessed that the foundation of the booster station has undergone large uneven settlement and deformation after the strong vibration, and a safety warning message is issued, and a safety emergency response is recommended; if the change value is less than 5mm, but there is a more obvious change trend, it is assessed that the foundation of the booster station may have an unstable trend after the strong vibration, and a safety warning message is issued, and it is recommended to closely monitor the trend development.

[0033] Step 6: Analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event; Step 6.1: Read the mean characteristic value of each stress monitoring point one day before the strong vibration, and the mean characteristic value of each stress monitoring point more than one day after the strong vibration; Step 6.2: Taking the daily average of the mean characteristic values ​​of each monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the daily average of the mean characteristic values ​​of each monitoring point after the strong vibration; Step 6.3: Safety assessment of stress at key parts. According to whether the change value exceeds the design allowable value and the amplitude of the change value, the assessment results are divided into the following: If there is no monitoring point exceeding the design allowable value, but the change value exceeds 50% of the design allowable value, it is assessed that the stress at key parts of the offshore booster station has undergone a significant change after the strong vibration, and a safety attention message is issued, and it is recommended to conduct detailed inspection as soon as possible; if there is a monitoring point greater than the design allowable value, it is assessed that the key parts of the offshore booster station have exceeded the design allowable value after the strong vibration, and a safety warning message is issued, and a safety emergency response is recommended; if the change value is less than 50% and the current value does not exceed the design allowable value, but there is a more obvious change trend, it is assessed that the key parts of the booster station have a stress-strain change trend after the strong vibration, and a safety attention message is issued, and it is recommended to closely monitor the trend development.

[0034] Example 3 Reference Figure 7 The present invention provides a steel structure safety monitoring system for an offshore wind farm booster station, comprising: Data acquisition module, which acquires safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress and strain monitoring data, and uneven settlement monitoring data; The data analysis module conducts strong vibration response data analysis and safety assessment of offshore booster station steel structures based on offshore booster station steel structure safety monitoring data; Situation analysis module: analysis of the change of natural frequency of steel structure after strong vibration events; Analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Analysis of uneven settlement changes of offshore booster stations after strong vibration events; And the analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

[0035] In this embodiment, in the data analysis module, based on the safety monitoring data of the offshore substation steel structure, the strong vibration response data analysis and safety assessment of the offshore substation steel structure are carried out, including: setting the severe vibration response of the offshore substation steel structure caused by earthquakes, typhoons, ship collisions, and construction, when the maximum peak value of more than half of the vibration monitoring points exceeds 1m / s at the same time 2 When , it is considered that a strong vibration event occurs.

[0036] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0037] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for safety monitoring of steel structures of offshore wind farm booster stations, characterized in that: The following steps are involved: Step 1: Obtain safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress and strain monitoring data, and uneven settlement monitoring data; Step 2: Based on the safety monitoring data of the offshore substation steel structure, conduct strong vibration response data analysis and safety assessment of the offshore substation steel structure; Step 3: Analysis of the change of natural frequency of steel structure after strong vibration event; Analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Analysis of uneven settlement changes of offshore booster stations after strong vibration events; And the analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

2. A method for safety monitoring of steel structure of offshore wind farm booster station according to claim 1, characterized in that: In step 2, based on the safety monitoring data of the offshore substation steel structure, the strong vibration response data analysis and safety assessment of the offshore substation steel structure are carried out, including: setting the severe vibration response of the offshore substation steel structure caused by earthquakes, typhoons, ship collisions, and construction, when the maximum peak value of more than half of the vibration monitoring points exceeds 1m / s at the same time 2 When , it is considered that a strong vibration event occurs.

3. A method for safety monitoring of steel structure of offshore wind farm booster station according to claim 2, characterized in that: In step 2, based on the safety monitoring data of the offshore substation steel structure, the strong vibration response data and safety assessment of the offshore substation steel structure are analyzed. The specific method is as follows: Step 2.1: Read the vibration raw data file of the strong vibration event and intercept the strong vibration event data; Step 2.2: Preprocess the strong vibration data, perform 0.2-20 Hz bandpass filtering, and perform initial value calibration; Step 2.3: Perform digital integration calculation on the pre-processed data to obtain strong vibration velocity and strong vibration displacement data respectively; Step 2.4: Calculate the vibration intensity value of each monitoring point using the strong vibration acceleration and velocity data; Step 2.5: Calculate the vibration response spectrum of each monitoring point using the strong vibration acceleration data; Step 2.6: Calculate the vibration acceleration response peak value, vibration velocity response peak value, and vibration displacement response peak value of each monitoring point; Step 2.7: Safety and rapid assessment. According to the relationship between the average vibration intensity value of each monitoring point and the seismic fortification intensity value of the offshore booster station steel structure, the assessment results are divided into: severe damage, existing damage and special assessment.

4. A method for safety monitoring of steel structure of offshore wind farm booster station according to claim 3, characterized in that: When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted - analysis of the change in the natural frequency of the steel structure after the strong vibration event; the natural frequency of the steel structure can reflect the change in the stiffness of the entire structure; When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted - analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted - analysis of the changes in uneven settlement of the offshore booster station after the strong vibration event; When the maximum intensity of strong vibration in step 2.7 exceeds 6 degrees, a special safety analysis is conducted to analyze the stress and strain changes in key parts of the steel structure of the offshore booster station after the strong vibration event.

5. The offshore wind farm booster station steel structure safety monitoring method according to claim 1 is characterized in that: In step 3, the analysis process of the change of the natural frequency of the steel structure after the strong vibration event is as follows: Step 3.1: Collect structural micro-vibration data 1 hour before and after the strong vibration event; Step 3.2: Perform EFDD structural modal analysis; Step 3.3: Automatically pick up the 1st, 2nd and 3rd order natural frequency values ​​of the structure; Step 3.4: Taking the 1st, 2nd and 3rd order natural frequency values ​​before the strong vibration event as the reference value, calculate the decrease ratio of the 1st, 2nd and 3rd order natural frequency values ​​after the strong vibration event; Step 3.5: Safety assessment: according to the median value of the decrease ratio of the third-order natural frequency, the assessment results are divided into: severe damage, existing damage and minor damage.

6. A method for safety monitoring of steel structure of offshore wind farm booster station according to claim 1, characterized in that: In step 3, the analysis process of the inclination change of the offshore booster station steel structure after the strong vibration event is as follows: Step 4.1: Read the average characteristic value of each tilt monitoring point 1 hour before the strong vibration, and the average characteristic value of each tilt monitoring point more than 1 hour after the strong vibration; Step 4.2: Taking the hourly average of the mean characteristic value of each tilt monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the hourly average of the mean characteristic value of each tilt monitoring point after the strong vibration; Step 4.3: Tilt safety assessment. According to the change value, the assessment results are divided into: permanent tilt deformation, large tilt deformation and slight tilt deformation.

7. A method for safety monitoring of steel structure of offshore wind farm booster station according to claim 1, characterized in that: In step 3, the analysis process of the uneven settlement changes of the offshore booster station after the strong vibration event is as follows: Step 5.1: Read the average characteristic value of each uneven settlement monitoring point one day before the strong vibration and the average characteristic value of each uneven settlement monitoring point more than one day after the strong vibration; Step 5.2: Taking the daily average of the mean characteristic values ​​of each monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the daily average of the mean characteristic values ​​of each monitoring point after the strong vibration; Step 5.3: Safety assessment of foundation uneven settlement. According to the change value, the assessment results are divided into: severe uneven settlement deformation, large uneven settlement deformation and slight uneven settlement deformation.

8. The offshore wind farm booster station steel structure safety monitoring method according to claim 1 is characterized in that: In step 3, the analysis process of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event is as follows: Step 6.1: Read the mean characteristic value of each stress monitoring point one day before the strong vibration, and the mean characteristic value of each stress monitoring point more than one day after the strong vibration; Step 6.2: Taking the daily average of the mean characteristic values ​​of each monitoring point before the strong vibration as the benchmark, calculate the change value and change trend of the daily average of the mean characteristic values ​​of each monitoring point after the strong vibration; Step 6.3: Safety assessment of stress in key parts. According to whether the change value exceeds the design allowable value and the amplitude of the change value, the assessment results are divided into: severe stress-strain deformation, large stress-strain deformation and slight stress-strain deformation.

9. A steel structure safety monitoring system for an offshore wind farm booster station, characterized in that: include: Data acquisition module, which acquires safety monitoring data of offshore booster station steel structure, including vibration monitoring data, tilt monitoring data, stress and strain monitoring data, and uneven settlement monitoring data; The data analysis module conducts strong vibration response data analysis and safety assessment of offshore booster station steel structures based on offshore booster station steel structure safety monitoring data; Situation analysis module: analysis of the change of natural frequency of steel structure after strong vibration events; Analysis of the inclination change of the steel structure of the offshore booster station after the strong vibration event; Analysis of uneven settlement changes of offshore booster stations after strong vibration events; And the analysis of stress and strain changes in key parts of the offshore booster station steel structure after the strong vibration event.

10. The offshore wind farm booster station steel structure safety monitoring system according to claim 9, characterized in that: In the data analysis module, based on the safety monitoring data of the offshore substation steel structure, the strong vibration response data analysis and safety assessment of the offshore substation steel structure are carried out, including: setting the severe vibration response of the offshore substation steel structure caused by earthquakes, typhoons, ship collisions, and construction, when the maximum peak value of more than half of the vibration monitoring points exceeds 1m / s at the same time 2 When , it is considered that a strong vibration event occurs.

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