Mooring system for floating offshore wind power platform, monitoring system, and monitoring method

Abstract

A mooring system for a floating offshore wind power platform, a monitoring system, and a monitoring method. The mooring system comprises a static mooring system and a dynamic mooring system. The static mooring system comprises three mooring cable bundles. Upright columns (1) are consistent with the centers of the mooring cable bundles. The dynamic mooring system comprises a power unit, propeller units (4), and a control unit. A group of propeller units (4) is installed below each upright column (1) of the platform, and each group of propeller units (4) comprises one to four propeller units (4). The monitoring system monitors the platform in real time, obtains the real-time motion level and mooring tension of the platform, and on the basis of offset and inclination requirements and mooring tension requirements of the platform in a real-time motion state, calculates the power required by the propeller units (4) for execution. A conventional mooring method is combined with a power positioning system to reduce the load on the mooring cables and reduce the maximum offset and the inclination angle of the platform foundation, benefiting both the efficiency and service life of dynamic cables and wind turbines.

Description

A mooring system, monitoring system and monitoring method for a floating offshore wind power platform

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number: 202310951328.0 and application date of July 31, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the technical field of mooring systems for offshore wind power platforms, and in particular to a mooring system, a monitoring system, and a monitoring method for a floating offshore wind power platform. Background Art

[0004] Traditional single-point mooring systems include tower soft-rigid arms, catenary buoys, single-leg buoys, internal turrets, and external turrets. Conventional multi-point mooring systems typically have layouts such as 3*3, 3*2, 6*1, and 8*1. Due to the harsh marine environment, offshore floating wind turbines are often subject to large wind, wave, and current loads. Existing mooring systems are unable to meet the requirements of resisting large loads. That is, as wind and waves affect the mooring system, the load on the mooring system increases, and the resistance structure is static, which cannot increase the safety and reliability of the mooring system as the load increases. In addition, there is a lack of effective monitoring of the static load of the mooring system, making it impossible to effectively reduce and manage the load when the mooring system is subjected to critical loads.

[0005] In the prior art, application number 2023103264852, a floating offshore wind turbine foundation and its installation method, proposes a floating offshore wind turbine foundation that lowers the center of gravity of the floating foundation by suspending a ballasted caisson, increasing the swaying motion damping of the floating foundation, thereby reducing the overall size. However, there is a lack of countermeasures for the drastic load changes, and the method still relies on static load resistance.

[0006] Application No. 2023103161930, a mooring cable tension monitoring device and monitoring method for marine floating structures, proposes a method to address the high installation precision and high cost requirements for the undocking operation of permanent fixed mooring systems and aging platform mooring systems in the existing technology during installation and maintenance. It mainly evaluates the load situation by comprehensively monitoring the tension size and posture movement changes of the mooring anchor chain of the floating structure. The mooring anchor chain tension of the monitored object is measured by sensors. The object of attention is the main body of the floating object that bears the tension load. The load is observed to predict whether there is overload and the risk of fracture and deformation. It assesses safety by observing and predicting risks, but has no response measures for the drastic changes in load it faces. Moreover, the load it measures is an imminent reality and cannot cope with larger-scale load changes in the future, such as load changes after an hour or half a day. It is also difficult to overcome the hidden dangers of imminent drastic changes in load.

[0007] Application No. CN2023105274986, a real-time monitoring system and method for the mooring force of a deepwater turret single-point mooring system, proposes a real-time monitoring system and method for the mooring force of a deepwater turret single-point mooring system. This system not only enables real-time and accurate monitoring of the mooring force of a deepwater turret single-point mooring system, but also establishes a model and performs verification. This solution is suitable for floating production storage and offloading vessels, but not for floating offshore wind power platforms. Moreover, it targets deepwater turret single-point mooring systems, which face drastic load changes and lack countermeasures, and still rely on static load resistance.

[0008] Therefore, a mooring system, a monitoring system and a monitoring method for a floating offshore wind power platform are needed to overcome the above problems.

[0009] Summary of the Invention

[0010] In view of this, facing the shortcomings of the existing technology, the purpose of this application is to provide a mooring system and a monitoring system and a monitoring method for a floating offshore wind power platform, which have low load on the mooring cable.

[0011] The present application aims to solve one of the problems in the background technology by combining the existing multi-point mooring system with the dynamic positioning system. The platform's motion state and the mooring system tension are monitored in real time through the platform monitoring system. When the platform's motion reaches a certain critical point, the dynamic positioning system is started, and the thruster unit equipment under the platform is turned on. By reading the real-time data of the current platform motion state and the mooring system tension, the corresponding thrust load required to confine the platform to a certain motion range and meet the mooring tension requirements is calculated. Finally, the thruster unit power is calculated and fed back to the three groups of thruster units under the platform for real-time operation.

[0012] The technical solutions adopted in this application are to provide the following technical solutions to achieve the above-mentioned objectives and other related objectives:

[0013] A mooring system for a floating offshore wind power platform, comprising a static mooring system and a dynamic mooring system;

[0014] The static mooring system includes three mooring bundles connected to the platform's columns. The mooring bundles are composed of 1-3 mooring cables and are in the shape of a catenary. The columns and mooring bundles are aligned in center.

[0015] The dynamic mooring system includes a power unit, a thruster unit and a control unit;

[0016] The power unit includes the prime mover, generator set, switchboard and cables;

[0017] The propeller unit includes a supporting shaft, a propeller, a rotating motor and a universal joint;

[0018] The control unit includes a positioning system, a sensor, a computer system, a control interface, a control strategy module, and a power management module;

[0019] A group of thruster units is installed under the columns of the platform, and each group of thruster units includes 1-4 thruster units.

[0020] The technical solution of a mooring system for a floating offshore wind power platform provided in this application also includes the following technical features:

[0021] Preferably, the columns of the platform are arranged in a circular array, and the center of the array is the center of the platform or the center of all the columns.

[0022] Preferably, the mooring bundles are arranged in a circular array, with the center of the array being the center of the platform or the center of all columns.

[0023] Preferably, the angle between the mooring bundles is 120°.

[0024] Preferably, each group of thruster units consists of one thruster unit, and the thruster unit is installed directly below the column.

[0025] Preferably, each group of thruster units consists of two thruster units, and the two thruster units are symmetrically installed on both sides below the column.

[0026] Preferably, each group of propeller units consists of three propeller units, and the three propeller units are evenly distributed below the column in the form of an equilateral triangle and are equidistant from the central axis of the column.

[0027] Preferably, each group of propeller units consists of four propeller units, and the four propeller units are respectively installed under the four corners of the column and are equidistant from the central axis of the column.

[0028] Preferably, each group of propeller units has the freedom of 360-degree rotation in the horizontal direction and 90-degree rotation in the vertical direction.

[0029] A platform monitoring system for a mooring system of a floating offshore wind power platform, comprising a positioning monitoring system and an environmental measurement system;

[0030] Positioning and monitoring system, which includes a satellite positioning system, a laser positioning system, and an underwater ultra-short baseline acoustic positioning device. The positioning system calculates the actual direction and position of the platform by measuring the deviation of the direction and distance between the platform and a reference point;

[0031] The environmental measurement system includes a platform motion measurement system, anemometers, a gyrocompass, a mooring system tension monitoring system, and an offshore hydrological and meteorological observation platform. The environmental measurement system is used to measure the platform's motion parameters in the six degrees of freedom, the mooring system tension value, the wind speed and direction parameters at the wind turbine, and the wave and current parameters of the platform's environment, thereby estimating the external force loads on the platform.

[0032] A platform monitoring method for a mooring system of a floating offshore wind power platform. The platform monitoring system monitors the platform, obtains the platform's real-time motion level and mooring tension, and calculates the power required by the thruster unit based on the platform's offset tilt and mooring tension requirements in the real-time motion state. The thruster unit then executes the calculation.

[0033] The first step is to use the environmental measurement system to read the external environmental conditions: wind, waves, and currents, and calculate the external environmental loads on the platform; the positioning monitoring system to read the real-time tension of the mooring system; the wind turbine platform positioning monitoring system to read the relative position and direction of the wind turbine foundation platform; and the wind turbine platform motion monitoring system to read the acceleration and velocity of the platform's six degrees of freedom.

[0034] The second step is to import the data obtained from the above analysis into a computer system. Based on the design and positioning requirements of the wind turbine platform itself and the platform's own characteristics (including weight, center, center of buoyancy, hydrostatic stiffness, and damping parameters), the computer system calculates the force required to maintain the platform's displacement and direction. This force is the resultant force that the entire thrust system should generate.

[0035] The technical solution of a platform monitoring method for a mooring system of a floating offshore wind power platform provided in this application also includes the following technical features:

[0036] Preferably, the wind tilting moment caused by the aerodynamic load of the wind turbine is evaluated using the blade element momentum theory method, and the calculation formula is as follows:

[0037] Where: ρ is the air density; CT is the thrust coefficient; A rotor A is the swept area of ​​the wind wheel, rotor =πR 2 , R is the radius of the wind wheel; U 10min is the 10-minute average wind speed at hub height;

[0038] The wave load on the wind turbine foundation can be calculated using the measured wave spectrum using the following formula:

[0039] Where, is the average wave force numerator; β is the wave direction relative to the longitudinal axis of the platform; is the wave drift coefficient relative to the wave direction; S(ω) is the wave spectrum;

[0040] The average wind load on the wind turbine foundation can be calculated using the measured wind speed using the following formula:

[0041] Where, is the wind force coefficient in all directions of the wind turbine foundation; β is the wind direction relative to the longitudinal axis of the platform; is the average wind speed; the flow load on the fan foundation can be calculated using the measured flow velocity, as follows:

[0042] Where, is the primary flow coefficient in all directions of the fan foundation; is the secondary flow coefficient in all directions of the fan foundation; is the horizontal component of the velocity; v1, v2 are the longitudinal and lateral velocities of the platform;

[0043] The static balance calculation formula for the fan platform is as follows:

[0044] F mo (x)+F hs (x)+F th (x)+F cu (x)+F wi (x)+F wd (x)+F wa (x) = 0

[0045] Where, F mo (x) is the mooring tension; F hs (x) is the hydrostatic force of the platform foundation; F th (x) is the total force of the propeller unit; F cu (x) is the flow load on the platform foundation; F wi (x) is the wind load on the platform foundation; Fwd (x) is the wind load on the wind turbine; F wa (x) is the wave load on the platform foundation.

[0046] Preferably, the method comprises a group thruster unit control method for controlling at least two groups of thruster units;

[0047] The propulsion force can be controlled by real-time monitoring of the platform motion variables, and the calculation formula is as follows:

[0048] F th (x) = -G P Δx-G V v+F 0

[0049] Where G P is the displacement coefficient matrix; G V is the velocity coefficient matrix; Δx is the platform displacement matrix; v is the platform velocity matrix; F 0 is the thrust constant;

[0050] The total thrust is the combined thrust generated by each thruster unit and is calculated as follows:

[0051] F th (x) = AT

[0052] Where A is the thruster unit matrix, which consists of the position and direction of each thruster unit, and its expression is as follows:

[0053] Where x1 is the longitudinal coordinate of the propeller unit relative to the platform center; y1 is the transverse coordinate of the propeller unit relative to the platform center; z1 is the vertical coordinate of the propeller unit relative to the platform center; α1 is the horizontal direction angle of the propeller unit relative to the platform center; β1 is the vertical inclination angle of the propeller unit relative to the platform center;

[0054] T is the thrust matrix of the propeller unit, which is expressed as follows:

[0055] Where T is the thrust generated by each thruster unit.

[0056] The thrust required by each thruster unit is allocated according to the position and direction of the thruster unit. According to the direction and position of each thruster unit, the proportion of each thruster unit is combined. The total thrust and the total power of the thruster unit are minimized as the optimization goal to meet the requirements of the total thrust size and direction.

[0057] This application has the following beneficial effects:

[0058] 1. Combining traditional mooring methods with dynamic positioning systems can not only reduce the tension on traditional mooring lines, but also reduce the maximum deflection and inclination of the platform foundation. Therefore, this solution has a beneficial effect on the selection and service life of mooring lines, dynamic cables, and wind turbine units.

[0059] 2. The thruster unit is installed under the foundation of a traditional semi-submersible platform, with one set of thruster units installed under each of the three columns;

[0060] 3. Control the thruster unit and calculate the corresponding thrust load required to limit the platform to a certain range of motion and meet the mooring tension requirements, and finally calculate the thruster unit power;

[0061] This application combines traditional mooring methods with dynamic positioning systems to reduce the load on the mooring cables and at the same time reduce the maximum offset and inclination of the platform foundation, which has certain benefits for dynamic cables, wind turbine efficiency and service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] FIG1 is a schematic diagram of the overall structure of a mooring system of a floating offshore wind power platform of the present application;

[0063] FIG2 is a structural diagram of a dynamic positioning system of a mooring system of a floating offshore wind power platform of the present application;

[0064] FIG3 is a structural diagram of a propeller unit of a mooring system of a floating offshore wind power platform of the present application;

[0065] FIG4 is a schematic diagram of a mooring system of a floating offshore wind power platform of the present application;

[0066] FIG5 is a schematic diagram of a mooring system of a floating offshore wind power platform of the present application;

[0067] FIG6 is a flow chart of a mooring system for a floating offshore wind power platform of the present application.

[0068] In the picture:

[0069] 1. Column; 2. Buoy; 3. Mooring line; 4. Thruster unit; 5. Support shaft; 6. Propeller; 7. Rotating motor; 8. Universal joint; 9. Platform. DETAILED DESCRIPTION

[0070] The following further describes the specific embodiments of the present application in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present application and are not intended to limit the present application.

[0071] In the description of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0072] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0073] Furthermore, in the description of the present application, unless otherwise specified, “plurality” means two or more.

[0074] As shown in Figures 1 to 3, a mooring system for a floating offshore wind power platform includes a static mooring system and a dynamic mooring system;

[0075] As shown in Figure 1, the static mooring system includes three mooring bundles, which are connected to the platform column 1. The mooring bundles are composed of 1-3 mooring cables 3 and are in the shape of a catenary. The centers of the column 1 and the mooring bundles are aligned.

[0076] As shown in Figures 2 and 3 , the dynamic mooring system includes a power unit, a thruster unit 4 and a control unit;

[0077] The power unit includes the prime mover, generator set, switchboard and cables;

[0078] The propeller unit 4 includes a support shaft 5, a propeller 6, a rotating motor 7 and a universal joint 8;

[0079] The control unit includes a positioning system, a sensor, a computer system, a control interface, a control strategy module, and a power management module;

[0080] As shown in Figures 2, 4 and 5, a group of thruster units 4 is installed under the column 1 of the platform 9. Each group of thruster units includes 1-4 thruster units 4. The selection and specific number of thruster units 4 are determined by the actual design. The thruster units 4 generate longitudinal, lateral and vertical thrust and rotational torque, and cooperate with the mooring system to keep the wind turbine platform safely and stably positioned within the target range.

[0081] Specifically, the columns 1 of the platform 9 are arranged in a circular array, and the center of the array is the center of the platform or the center of all the columns.

[0082] Specifically, the mooring bundles are arranged in a circular array, with the center of the array being the center of the platform or the center of all columns.

[0083] Specifically, the angle between the mooring bundles is 120°.

[0084] Specifically, each group of thruster units consists of one thruster unit, and the thruster unit is installed directly below the column.

[0085] Specifically, each group of thruster units consists of two thruster units, and the two thruster units are symmetrically installed on both sides below the column.

[0086] Specifically, each group of thruster units consists of three thruster units, and the three thruster units are evenly distributed below the column in the form of an equilateral triangle and are equidistant from the central axis of the column.

[0087] Specifically, each group of thruster units consists of four thruster units, and the four thruster units are respectively installed under the four corners of the column and are equidistant from the central axis of the column.

[0088] Specifically, each group of thruster units has the freedom of 360-degree horizontal rotation and 90-degree vertical rotation.

[0089] As shown in Figure 6, a platform monitoring method for a mooring system of a floating offshore wind power platform is shown. The platform monitoring system monitors the platform, obtains the real-time motion level of the platform and the mooring tension, and calculates the power required by the thruster unit based on the platform's offset tilt and mooring tension requirements under the real-time motion state. The thruster unit then executes the calculation. During implementation, the platform is monitored by the platform monitoring system, and the real-time motion level of the platform and the mooring tension are fed back. The power of the thruster unit is calculated based on the platform's offset tilt and mooring tension requirements under the real-time motion state.

[0090] As shown in Figure 6, a platform monitoring system for a mooring system of a floating offshore wind power platform includes a positioning monitoring system and an environmental measurement system;

[0091] Positioning and monitoring system, which includes a satellite positioning system, a laser positioning system, and an underwater ultra-short baseline acoustic positioning device. The positioning system calculates the actual direction and position of the platform by measuring the deviation of the direction and distance between the platform and a reference point;

[0092] The environmental measurement system includes a platform motion measurement system, anemometers, a gyrocompass, a mooring system tension monitoring system, and an offshore hydrological and meteorological observation platform. The environmental measurement system is used to measure the platform's motion parameters in the six degrees of freedom, the mooring system tension value, the wind speed and direction parameters at the wind turbine, and the wave and current parameters of the platform's environment, thereby estimating the external force loads on the platform.

[0093] A platform monitoring method for a mooring system of a floating offshore wind power platform comprises the following steps: first, reading external environmental conditions such as wind, waves, and currents through an environmental measurement system to calculate the external environmental loads on the platform; reading the real-time tension of the mooring system through a positioning monitoring system; reading the relative position and direction of the wind turbine foundation platform through a wind turbine platform positioning monitoring system; and reading the acceleration and velocity of the platform's six degrees of freedom through a wind turbine platform motion monitoring system;

[0094] The second step is to import the data obtained from the above analysis into a computer system. Based on the design and positioning requirements of the wind turbine platform itself and the platform's own characteristics (including weight, center, center of buoyancy, hydrostatic stiffness, and damping parameters), the computer system calculates the force required to maintain the platform's displacement and direction. This force is the resultant force that the entire thrust system should generate.

[0095] Specifically, the wind tilting moment caused by the aerodynamic load of the wind turbine is evaluated using the blade element momentum theory method, and the calculation formula is as follows:

[0096] Where: ρ is the air density; C T is the thrust coefficient; A rotor is the swept area of ​​the wind wheel, A rotor =πR 2 , R is the radius of the wind wheel; U 10min is the 10-minute average wind speed at hub height;

[0097] The wave load on the wind turbine foundation can be calculated using the measured wave spectrum using the following formula:

[0098] Where, is the average wave force numerator; β is the wave direction relative to the longitudinal axis of the platform; is the wave drift coefficient relative to the wave direction; S(ω) is the wave spectrum.

[0099] The average wind load on the wind turbine foundation can be calculated using the measured wind speed using the following formula:

[0100] Where, is the wind force coefficient in all directions of the wind turbine foundation; β is the wind direction relative to the longitudinal axis of the platform; is the average wind speed

[0101] The flow load on the fan foundation can be calculated using the measured flow velocity. The calculation formula is as follows:

[0102] Where, is the primary flow coefficient in all directions of the fan foundation; is the secondary flow coefficient in all directions of the fan foundation; is the horizontal component of the flow velocity; v1 and v2 are the longitudinal and lateral velocities of the platform.

[0103] The static balance calculation formula for the fan platform is as follows:

[0104] F mo (x)+F hs (x)+F th (x)+F cu (x)+F wi (x)+F wd (x)+F wa (x) = 0

[0105] Where, F mo (x) is the mooring tension; F hs (x) is the hydrostatic force of the platform foundation; F th (x) is the total force of the propeller unit; F cu (x) is the flow load on the platform foundation; F wi (x) is the wind load on the platform foundation; F wd (x) is the wind load on the wind turbine; F wa (x) is the wave load on the platform foundation.

[0106] Specifically, as shown in FIG6 , a group thruster unit control method is included for controlling at least two groups of thruster units;

[0107] The propulsion force can be controlled by real-time monitoring of the platform motion variables, and the calculation formula is as follows:

[0108] F th (x) = -G P Δx-G V v+F 0

[0109] Where G P is the displacement coefficient matrix; G V is the velocity coefficient matrix; Δx is the platform displacement matrix; v is the platform velocity matrix; F 0 is the thrust constant;

[0110] The total thrust is the combined thrust generated by each thruster unit and is calculated as follows:

[0111] F th (x) = AT

[0112] Where A is the thruster unit matrix, which consists of the position and direction of each thruster unit, and its expression is as follows:

[0113] Where x1 is the longitudinal coordinate of the propeller unit relative to the platform center; y1 is the transverse coordinate of the propeller unit relative to the platform center; z1 is the vertical coordinate of the propeller unit relative to the platform center; α1 is the horizontal direction angle of the propeller unit relative to the platform center; β1 is the vertical inclination angle of the propeller unit relative to the platform center;

[0114] T is the thrust matrix of the propeller unit, which is expressed as follows:

[0115] Where T is the thrust generated by each thruster unit;

[0116] The thrust required by each thruster unit is allocated according to the position and direction of the thruster unit. According to the direction and position of each thruster unit, the proportion of each thruster unit is combined. The total thrust and the total power of the thruster unit are minimized as the optimization goal to meet the requirements of the total thrust size and direction.

[0117] Specifically, the propulsion force can be controlled by real-time monitoring of the platform motion variables, and its calculation formula is as follows:

[0118] F th (x) = -G P Δx-G V v+F 0

[0119] Considering an extreme operating condition with Hs = 14.1m, Tp = 17.8s, wind speed = 38.2m / s, and flow velocity Vc = 1.2m / s, the platform is subject to a total environmental load of 5000kN. Three sets of single 100-ton thrusters are used, placed directly below each column. The thruster displacement coefficient is 20kN / m, the speed coefficient is 1200kN / (m / s); the platform longitudinal displacement is 22.6m, the lateral displacement is 2.7m; the platform longitudinal speed is 0.72m / s, the platform lateral speed is 0.06m / s; the thrust constant is 1500kN. After calculation, the total thrust of the thruster is 2500kN, so the thrust can resist 50% of the total environmental load on the platform, thereby greatly reducing the load on the mooring cable. Therefore, when offshore floating wind turbines are subject to large wind, wave and current loads, the method of combining thrusters and mooring cables can make the existing mooring system meet the needs of resisting large loads and improve the safety of the entire mooring system.

[0120] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present application. These improvements and replacements should also be regarded as the scope of protection of the present application.

Claims

1. A mooring system for a floating offshore wind power platform, characterized in that: Includes static mooring system and dynamic mooring system; The static mooring system includes three mooring cable bundles, which are connected to the platform columns. The mooring cable bundles are composed of 1-3 mooring cables and are in the shape of a catenary. The centers of the columns and the mooring cable bundles are consistent. The dynamic mooring system includes a power unit, a thruster unit and a control unit; The power unit includes the prime mover, generator set, switchboard and cables; The propeller unit includes a supporting shaft, a propeller, a rotating motor and a universal joint; The control unit includes a positioning system, a sensor, a computer system, a control interface, a control strategy module, and a power management module; A group of thruster units is installed under the columns of the platform, and each group of thruster units includes 1 to 4 thruster units.

2. A mooring system for a floating offshore wind power platform according to claim 1, characterized in that: The platform's columns are arranged in a circular array, with the array center being the center of the platform or the center of all the columns; the mooring cable bundles are arranged in a circular array, with the array center being the center of the platform or the center of all the columns.

3. A mooring system for a floating offshore wind power platform according to claim 1, characterized in that: Each set of thruster units has the freedom of 360-degree horizontal rotation and 90-degree vertical rotation.

4. A mooring system for a floating offshore wind power platform according to claim 1, characterized in that: The angle between the mooring lines is 120°.

5. A mooring system for a floating offshore wind power platform according to claim 1, characterized in that: Each set of thruster units consists of a thruster unit, which is installed just below the column; Alternatively, each set of thruster units is composed of two thruster units, and the two thruster units are symmetrically installed on both sides below the column; Alternatively, each group of thruster units is composed of three thruster units, and the three thruster units are evenly distributed below the column in an equilateral triangle and are equidistant from the central axis of the column; Alternatively, each group of thruster units is composed of four thruster units, and the four thruster units are respectively installed under the four corners of the column and are equidistant from the central axis of the column.

6. A platform monitoring system for a mooring system of a floating offshore wind power platform, characterized in that: Including positioning monitoring system and environmental measurement system; Positioning monitoring system, which includes satellite positioning system, laser positioning system, underwater ultra-short baseline acoustic positioning device. The positioning system measures the deviation of the direction and distance between the platform and the reference point to calculate the actual direction and position of the platform; The environmental measurement system includes the platform motion measurement system, anemometer, gyrocompass, mooring system tension monitoring system and offshore hydrological and meteorological observation platform; the environmental measurement system is used to measure the platform's motion parameters in six degrees of freedom, the mooring system tension value, the wind speed and direction parameters at the wind turbine and the wave and current parameters of the platform's environment, so as to estimate the platform's influence. external force load.

7. A platform monitoring method for a mooring system of a floating offshore wind power platform, characterized in that: The steps include: The first step is to read the external environmental conditions: wind, waves, and currents through the environmental measurement system, and calculate the external environmental loads on the platform; read the real-time tension of the mooring system through the positioning monitoring system; read the relative position and direction of the wind turbine foundation platform through the wind turbine platform positioning monitoring system; and read the acceleration and speed of the platform's six degrees of freedom through the wind turbine platform motion monitoring system; The second step is to import the data obtained from the above analysis into the computer system. Based on the design and positioning requirements of the wind turbine platform itself and the platform's own characteristics, including weight, center, center of buoyancy, hydrostatic stiffness, and damping parameters, the computer system can calculate the force required to maintain the platform's displacement and direction. This force is the resultant force that the entire thrust system should generate.

8. The platform monitoring method of a mooring system of a floating offshore wind power platform according to claim 7, characterized in that: The wind tilting moment caused by the aerodynamic load of the wind turbine is evaluated by the blade element momentum theory, and the calculation formula is as follows: Where: ρ is the air density; C T is the thrust coefficient; A rotor A is the swept area of ​​the wind wheel, rotor =πR 2 , R is the radius of the wind wheel; U 10min is the 10-minute average wind speed at hub height; The wave load on the wind turbine foundation can be calculated using the measured wave spectrum as follows: In the formula, is the average wave force numerator; β is the wave direction relative to the longitudinal axis of the platform; is the wave drift coefficient relative to the wave direction; S(ω) is the wave spectrum; The average wind load on the wind turbine foundation can be calculated using the measured wind speed. The calculation formula is as follows: In the formula, is the wind force coefficient in all directions of the wind turbine foundation; β is the wind direction relative to the longitudinal axis of the platform; is the average wind speed; The flow load on the fan foundation can be calculated using the measured flow velocity. The calculation formula is as follows: In the formula, is the primary flow coefficient in all directions of the fan foundation; is the secondary flow coefficient in all directions of the fan foundation; is the velocity of the horizontal component; v1, v2 are the longitudinal and lateral velocities of the platform; The static balance calculation formula for the fan platform is as follows: F mo (x)+F hs (x)+F th (x)+F cu (x)+F wi (x)+F wd (x)+F wa (x)=0 In the formula, F mo (x) is the mooring tension; F hs (x) is the hydrostatic force of the platform foundation; F th (x) is the total force of the thruster unit; F cu (x) is the flow load on the platform foundation; F wi (x) is the wind load on the platform foundation; F wd (x) is the wind speed received by the wind turbine Load; F wa (x) is the wave load on the platform foundation.

9. The platform monitoring method of a mooring system of a floating offshore wind power platform according to claim 7, characterized in that: The invention comprises a method for controlling a group of thruster units, which is used for controlling at least two groups of thruster units; the method comprises the following steps: allocating the thrusts required by each thruster unit according to the position and direction of the thruster unit, combining the proportions of each thruster unit according to the direction and position of each thruster unit, and taking the total thrust and the total power of the thruster units as the minimum as the optimization target to meet the requirements of the total thrust size and direction.

10. The platform monitoring method of a mooring system of a floating offshore wind power platform according to claim 9, characterized in that: The propulsion force can be controlled by real-time monitoring of the platform motion variables, and the calculation formula is as follows: F th (x) = -G P Δx-G V v+F 0 In the formula, G P is the displacement coefficient matrix; G V is the velocity coefficient matrix; Δx is the platform displacement matrix; v is the platform velocity matrix; F 0 is the thrust constant; The total thrust is the combination of the thrusts generated by each thruster unit, and is calculated as follows: F th (x)=AT Where A is the thruster unit matrix, which consists of the position and direction of each thruster unit, and its expression is as follows: Wherein, x1 is the longitudinal coordinate of the thruster unit relative to the platform center; y1 is the transverse coordinate of the thruster unit relative to the platform center; z1 is the vertical coordinate of the thruster unit relative to the platform center; α1 is the horizontal direction angle of the thruster unit relative to the platform center; β1 is the vertical inclination angle of the thruster unit relative to the platform center; T is the thrust matrix of the thruster unit, and its expression is as follows: Where T is the thrust generated by each thruster unit.

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