2332 results about "Offshore wind power" patented technology

The invention relates to an offshore energy platform coordinated scheduling method based on multi-energy complementation and hierarchical optimization, which combines multi-energy complementation characteristic modeling, multi-target opportunity constraint optimization and rolling optimization, and realizes offshore multi-energy coordinated scheduling by constructing a hierarchical decoupling optimization and control system. Based on prediction and historical data of multiple types of energy such as offshore wind power, photovoltaic energy and tidal energy, complementarity and flexibility of the energy are quantified, high-quality data support is provided for scheduling optimization, a day-ahead layered optimization model containing renewable energy priority consumption and flexible standby configuration is constructed, and a medium-and-long-term output strategy is formulated. Output of various energy sources is dynamically adjusted through a rolling optimization mechanism, and flexible response to renewable energy fluctuation is achieved. And finally, second-level frequency and voltage support is realized by using a virtual synchronous machine and droop control, and the self-adaptive capability of the system is enhanced. According to the invention, the cooperative regulation capability and operation stability of the offshore platform multi-energy system can be effectively improved, and the dependence on a traditional standby power supply is reduced.

An offshore wind power plant composite ring current collection system topology planning method based on an N-1 safety criterion comprises the following steps that S1, wind power plant basic data including wind turbine and transformer substation node coordinates, wind turbine rated power, cable electrical parameters and the like are obtained; s2, generating a candidate cable set and a cable cross avoidance constraint pair set based on the basic data; s3, a scene set containing a normal scene and all single cable fault scenes is constructed, an optimization model with the minimum total cost of the whole life cycle as the target is established, and cable construction / operation variables and direct current power flow power balance, node degrees and cable cross avoidance constraints are integrated; s4, solving the model to obtain an initial topology scheme; and S5, carrying out full fault set N-1 security verification on the initial scheme, and bringing a violation scene into a fault set to resolve until the scheme meets an N-1 criterion. According to the method, through non-predefined topological optimization and planning, reliability and economical efficiency are taken into consideration, calculation complexity is reduced, and the method can be expanded to a cross-substation scene.

An offshore wind power plant current collection system optimization method considering cable type selection comprises the following steps: S1, acquiring wind power plant basic data including fan and transformer substation coordinates, fan rated power, multi-specification cable electrical and cost parameters and the like; s2, on the basis of the basic data, generating a candidate cable set by using clustering partitions and a distance threshold value, completing candidate set reduction, and synchronously generating a cable crossing avoidance constraint pair set; s3, an optimization model with the minimum total cost of the whole life cycle is established, the double-side ring path does not need scene variables, and the composite ring path needs to integrate scene driving variables; s4, carrying out path accelerated solution, carrying out hot start on a double-sided ring, carrying out cross constraint simplification, and carrying out additional fault set dimension reduction on a composite ring to obtain an initial scheme; and S5, performing full fault set N-1 verification on the initial scheme, bringing a violation scene into a fault set for resolution until the scheme meets an N-1 criterion, and outputting a final result. According to the method, topology and cable type selection integrated optimization is realized, and the solving quality and efficiency are considered.

The invention discloses a multi-modal offshore wind power ultra-short-term prediction method in the field of offshore wind power plant cluster power prediction, and aims to solve the technical problems of spatial-temporal feature splitting and insufficient dynamic dependency relationship modeling. The method comprises the steps of performing anomaly detection and restoration on fan data, and generating a corrected wind power cluster data set; extracting a mean value, a standard deviation and a latest value of core operation data of each fan through a dynamic time window, and constructing a multi-dimensional node feature; a static geographic similarity matrix is generated based on geographic coordinates, a basic wake effect matrix is generated in combination with real-time wind direction data, correction is carried out through the maximum mutual information quantization time-delay effect, and then a dynamic adjacency matrix is obtained through self-adaptive fusion; and integrating the multi-dimensional node features and the dynamic adjacency matrix into a space-time diagram sequence data architecture, inputting the space-time diagram sequence data architecture into a multi-scale wake flow perception diagram space-time prediction model, and outputting a multi-fan power prediction value. According to the invention, high-precision multi-fan power prediction can be realized.

The invention provides an offshore wind turbine generator fault diagnosis method and system based on multi-source sensor data fusion. The method comprises the steps that a vibration signal from at least one component of a wind turbine generator is acquired through a vibration sensor; performing time-frequency conversion on the vibration signal by applying synchronous compression wavelet transform to obtain time-frequency representation of the vibration signal; when the reconstruction error exceeds a preset threshold value, it is judged that an abnormal event exists in the vibration signal; obtaining the position of a part corresponding to the abnormal event; starting an image sensor and an acoustic sensor according to the position of the component, and acquiring an image signal and a sound signal of the component according to the image sensor and the acoustic sensor; according to the DS evidence theory, the vibration signal, the image signal and the sound signal, obtaining the confidence of the fault type; the fault type of the component is judged according to the maximum confidence allocation principle, high-resolution time-frequency analysis can be achieved through synchronous compression wavelet transform (SST), and the fault feature identification degree is improved in combination with the self-encoding neural network and the D-S evidence theory.

The invention discloses an offshore wind power plant micro-siting optimization method considering regular layout. The method comprises the following steps: firstly, obtaining wind data, wind power plant parameters, fan parameters and wake flow parameters; performing multi-angle rotation on the wind power plant based on an equivalent rotation coordinate method, constructing a gridding mixed integer quadratic programming model, and performing rotation rule layout optimization (RRLO-1) to obtain an initial fan layout; on the basis of the initial layout, a hybrid algorithm (GA-ISSA) of a genetic algorithm and a sparrow search algorithm is adopted, the position of a draught fan and the rotation angle of the wind power plant are finely adjusted, and fine rule layout optimization (RRLO-2) is completed; and finally, the wake flow influence is calculated through a Cosine wake flow model and a quadratic sum superposition model, a fan power curve is processed in a piecewise linearization mode, and the final layout is output by taking the maximization of the total generating capacity as the target. According to the method, a fan position configuration scheme meeting the engineering rule layout requirement is provided for early-stage planning of the offshore wind plant, the wake effect is reduced, the power generation efficiency is improved, and development of the offshore wind power industry and low-carbon target implementation are facilitated.

The invention discloses an offshore wind power fault monitoring method based on a knowledge graph and digital twinning, and aims to solve the problems that multi-source data acquisition is dispersed, the transmission delay is high, and real-time convergence and integration are difficult to realize in the operation state monitoring of offshore wind power equipment. According to the invention, the following modules are provided: a multi-source data acquisition layer is used for solving the problems of dispersed data acquisition and transmission lag and ensuring the real-time performance; the knowledge graph construction module is used for solving the problems of extraction, fusion and storage of equipment entity relationships; the digital twin modeling module realizes visual presentation and accurate simulation of the state of physical equipment; the fault monitoring reasoning module solves the problems of anomaly detection and root cause positioning; the intelligent early warning decision module determines an early warning level and efficiently matches a solution; the visual interaction module solves the problems of scattered information display and poor linkage, supports third-party docking, realizes accurate early warning and root cause positioning, improves the decision-making efficiency, adapts to severe environments, supports large-scale wind power plant monitoring, and reduces the operation and maintenance cost.

The invention discloses a fault ride-through test method for an offshore wind power flexible direct output system, and the method comprises the steps: building a fault equivalent circuit of the offshore wind power flexible direct output system, analyzing the operation characteristics of an AC power grid side under a low-voltage fault, and determining the incidence relation between the DC side excess energy and the power grid voltage drop; establishing a model representing each component in the fault equivalent circuit, wherein the components at least comprise a machine-side converter, a grid-side converter, a direct-current capacitor and an unloading resistor; when a low-voltage fault of an alternating-current power grid side is detected, executing the following cooperative control based on the model: synchronously starting unloading resistance control and reactive power support control, wherein an unloading resistor dissipates excess energy of a direct-current side through a direct-current chopper; the grid-side converter injects a capacitive reactive current which is deeply matched with the voltage drop of the power grid so as to improve the voltage of a grid-connected point; and if the direct-current voltage continuously exceeds the preset threshold value, starting power prompt drop control, and reducing the output power of the unit according to a gradient until the system recovers to be stable.

An offshore wind turbine integral coupling fatigue calculation method based on artificial intelligence belongs to the technical field of offshore wind power engineering, is used for solving the problem of efficient and high-precision evaluation of the fatigue life of an offshore wind turbine, and is characterized in that key environment parameter vectors influencing structural response and a data set of corresponding fatigue damage labels are acquired; training a deep neural network model by using the data set; the deep neural network model outputs corresponding fatigue damage per unit time in response to a central point parameter of an environment working condition block in an input long-term joint probability distribution diagram of the wind power site; according to the method, the defects that a traditional time domain simulation method is high in calculation cost and long in period are overcome, the calculation efficiency is improved by a plurality of orders of magnitude while the precision is guaranteed, and a powerful tool is provided for rapid design and optimization of the offshore wind turbine.

The invention discloses a short-term wind speed prediction method for multiple offshore wind power plants, relates to the technical field of power system intellectualization, and constructs a dynamic graph structure fusing the correlation between geographic distance and wind speed according to the correlation between the geographic position of a target area and the wind speed, namely a multi-wind-plant connected graph, and represents the spatial topological relation of a wind power plant group. A wind power plant group is mapped into a node network by constructing a dynamic graph structure fusing geographic distance and wind speed correlation, spatial dependence intensity between nodes is quantized by using a weighted adjacent matrix, spectral domain convolution operation is carried out by a graph convolution network based on a normalized Laplacian matrix, and the spatial dependence intensity between nodes is quantized by using a normalized Laplacian matrix. Efficient neighborhood feature aggregation is achieved through Chebyshev polynomial approximation, complex spatial association caused by geographic position difference and meteorological condition interaction can be accurately captured, the defect of non-Euclidean spatial relationship modeling in a traditional method is overcome, and the representation capacity of the spatial dependency relationship in the multi-wind-power-plant environment is remarkably improved.

The invention relates to a noise damping control system of an offshore wind turbine generator, and belongs to the technical field of offshore wind power generation. The coupling state evaluation module is used for determining a coupling state evaluation index through a preset deep neural network model based on the platform motion information, the vibration spectrum data and the sound pressure signal; the cooperative control strategy generation module is used for determining target rigidity and target damping according to the coupling state evaluation index and the vibration spectrum data; according to the invention, the coupling state evaluation module processes platform motion information, vibration spectrum data and sound pressure signals acquired by the data acquisition module through a preset deep neural network model; the preset model is endowed with strong nonlinear fitting capability through offline supervised learning of massive historical working condition data; and an accurate and quantitative risk basis which cannot be reached by the prior art is provided for subsequent control decisions.

The invention relates to the technical field of offshore wind power foundation engineering, in particular to an offshore wind turbine pile group structure suitable for complex geology and a mounting method of the offshore wind turbine pile group structure. The offshore wind turbine pile group structure suitable for the complex geology comprises guide assemblies and a pile group system frame, wherein each guide assembly is composed of a steel pipe pile guide sleeve, a jacket guide sleeve and a connecting ring plate, and the pile group system frame integrates the multiple guide assemblies through a connecting frame. The modular overall pile group structure design is achieved through the pile group system frame integrating the multiple guide assemblies and the connecting frame, the fan load is dispersed to the multiple pile foundations through the pile group synergistic effect, and therefore the bearing capacity of the whole foundation is improved, the foundation can adapt to different seabed geological conditions, and the construction efficiency is improved. The development requirement of offshore wind power in a complex environment is met, efficient installation, high bearing capacity and geological adaptability optimization of the offshore wind turbine foundation are achieved, stable support is provided for an offshore wind turbine generator, the construction cost is reduced, and the construction efficiency is improved.

The invention discloses a deep and far sea wind power foundation platform and load integrated system under extreme environment conditions, and belongs to the technical field of offshore wind power platforms. The system comprises a basic platform body, a multi-dimensional monitoring subsystem, an environment-load coupling analysis subsystem, an intelligent regulation and control execution subsystem, a safety early warning decision subsystem and a shore-based collaborative management subsystem. Through synchronous acquisition of extreme marine environment, basic platform structure load and operation state data, distributed multi-type sensor layout and high-frequency sampling, data acquisition comprehensiveness and timeliness are realized, monitoring data are fused, a coupling model is constructed, 24-hour load change is predicted, and the real-time performance of the system is improved. According to the method, the attitude of the platform is dynamically adjusted, bearing configuration is optimized, emergency protection is started, the limitation of traditional separation analysis and fixed regulation and control is broken through, and the risk disposal and operation and maintenance efficiency is improved through risk quantification and grading early warning, remote monitoring and intelligent scheduling of a shore-based collaborative management subsystem and four-level early warning accurate matching coping strategies.

The invention provides a collaborative suppression method for short-circuit current-subsynchronous oscillation of an offshore wind power flexible direct current system, and the method comprises the steps: 1, determining a common parameter for a broadband coupling problem: determining the common parameter through a system topological structure and theoretical analysis of offshore wind power which is directly connected to a receiving-end power grid through flexible direct current for the short-circuit current and subsynchronous oscillation problem; 3, an upper optimization layer based on the DDQN outputs an optimal adjustment instruction for the generality parameters according to the system state, a lower execution layer receives the adjustment instruction of the upper layer, a new generality parameter value is obtained and output to a current inner loop controller, and a current inner loop controller is constructed; the current inner loop controller generates a modulation signal to control the output of the converter. According to the invention, the dynamic damping controller is designed to optimize common parameters, so that collaborative suppression of short-circuit current and subsynchronous oscillation is realized.

The invention discloses an intelligent monitoring method and system for the bearing performance of an offshore wind power pile foundation, and relates to the technical field of offshore wind power pile foundation monitoring, and the intelligent monitoring method comprises two main parts of pile foundation horizontal displacement calculation and early warning and fan structure frequency calculation and early warning. Pile foundation performance degradation induced by scouring is considered, a model algorithm considering the influence of scouring on pile foundation bearing performance and fan structure frequency calculation is established, dynamic prediction and trend analysis are conducted on offshore fan structure performance, and full-chain closed-loop management from data collection and real-time processing to decision output is formed. Therefore, by the adoption of the intelligent monitoring method and system for the bearing performance of the offshore wind power pile foundation, the technical defects that the offshore wind power pile foundation is difficult to monitor, evaluate and early warn are systematically overcome through a logic closed loop of multi-dimensional monitoring, high-precision analysis and intelligent early warning.

The invention relates to an offshore wind power-energy storage-hydrogen production system cooperative control method and device and a medium, and the method comprises the steps: collecting wind power plant operation data, energy storage system data and hydrogen production system data in real time, and obtaining a state vector; the state vector is input into a strategy network, a current action vector is calculated, the strategy network is obtained through training of a double-evaluator reinforcement learning framework, a first evaluator evaluates an economical efficiency target value function, and a second evaluator evaluates a safety target value function; the strategy network outputs a control instruction corresponding to the current action vector, and issues the control instruction to each execution device for adjustment, including adjusting fan operation parameters according to the axial induction factor and the yaw angle; adjusting the electrolytic cell input power according to the electrolytic load power; and controlling the charging and discharging operation of the energy storage system according to the energy storage power. Compared with the prior art, the method has the advantages of high collaboration, high adaptability, safety and the like.

The invention discloses a corrosion-resistant offshore wind power FRP-steel composite tower tube structure multi-objective optimization design method. The method comprises the following steps that a composite tower tube structure in an outer layer GFRP-steel tube-inner layer GFRP composite section form is adopted below the sea level and in a splash zone; mapping the coupling load time history to a parameterized finite element model of the composite tower tube structure; constructing a multi-objective optimization function by taking the minimization of the total manufacturing cost of the composite tower drum structure, the minimization of the total mass of the composite tower drum structure and the maximization of the total volume proportion of the GFRP material of the composite tower drum structure as objectives; and establishing a constraint evaluation system, carrying out iterative optimization on the multi-objective function by adopting a fast non-dominated sorting genetic algorithm with an elitist retention strategy, outputting a Pareto optimal solution set, and selecting a final implementation scheme. The problems that a traditional pure steel tower drum is large in corrosion loss and the design is difficult to balance multiple performance targets in the severe ocean environment can be solved.

The invention discloses a soil constitutive parameter determination system and method based on an in-situ expansion test and numerical inversion, and belongs to the technical field of geotechnical engineering investigation. The system comprises a data interface and preprocessing module, a configurable numerical calculation engine, an intelligent inversion module and a result output module. A pressure-expansion displacement curve of the soil body is obtained in situ through the integrated probe; selecting a target constitutive model and setting a parameter inversion space; an intelligent optimization algorithm is used for driving a numerical calculation engine to conduct iteration forward modeling, and the optimal constitutive parameter set is automatically searched with the purpose of minimizing the difference between a simulation curve and an actual measurement curve. According to the method, in-situ expansion testing and intelligent numerical inversion are deeply fused, in-situ, accurate and automatic calibration of the whole set of parameters of the HSS model is achieved, and dependence on an empirical formula and a disturbed soil sample is abandoned. Reliable technical support is provided for refined design of major projects such as offshore wind power, and the method has great scientific value and engineering application prospects.

The invention discloses a fatigue test method for a cabin structural member of an offshore wind power generator. A test piece is subjected to surface treatment, a multi-sensor array is arranged, the test piece is placed in a combined system of a multi-axis dynamic loading unit and a collaborative environment simulation cabin, an intelligent control and analysis platform synchronously applies a multi-axis alternating load, salt spray corrosion and a circulating temperature and humidity environment, and real marine service conditions are simulated; the state of a test piece is evaluated in real time based on criteria such as a strain concentration coefficient and acoustic emission energy, a strengthening test is started for potential damage risks, a load strategy is adjusted to track crack propagation when microcracks are monitored, and after the test is ended, a fatigue life prediction model is established or calibrated by combining failure test piece analysis data. And outputting a life evaluation result and a structure improvement suggestion. Through the multi-factor collaborative simulation and self-adaptive control technology, the authenticity and efficiency of the test are improved, and technical support is provided for design optimization and reliability guarantee of offshore wind power cabin structural parts.

The invention relates to the technical field of anti-collision systems, in particular to an offshore wind power construction safety pre-warning system based on AIS (automatic identification system) data, which comprises a ship dynamic uncertainty modeling module for acquiring AIS signal updating frequency and positioning precision marks of a target ship and generating a ship future position probability ellipse. According to the invention, the position coordinate, the speed value and the course angle of the ship are obtained in real time based on the AIS data, the reliability and the motion trend of ship position prediction are determined by combining the AIS signal updating frequency and the positioning precision mark, and the future position probability ellipse of the ship is accurately generated; a protection area is dynamically constructed, comprehensive calculation is carried out in combination with the spatial relation between a ship future position probability ellipse and the positions of surrounding fan pile foundations, and a hourly dynamic collision risk index sequence is obtained; and further according to the statistical deviation between the current motion state of the ship and the standard parameter of the function partition, combining with path difference analysis to obtain a navigation abnormity comprehensive index.

The invention relates to an offshore wind power pile foundation anti-scouring structure, and belongs to the technical field of offshore wind power construction, and the offshore wind power pile foundation anti-scouring structure comprises a pile foundation main body, a plurality of spoilers, a protective cylinder, a sand seepage cover and filling stones; the pile foundation main body is columnar, and the pile foundation main body is configured to be inserted into a seabed of a preset area; the pile foundation body is sleeved with the protection barrel, one end of the protection barrel is located on a seabed, the other end of the protection barrel is covered with the sand seepage cover, and a plurality of through holes are formed in the barrel wall of the protection barrel. The multiple spoilers are arranged outside the protective cylinder in the circumferential direction of the protective cylinder and connected with the protective cylinder, each spoiler comprises a spoiler vertical plate and a spoiler side plate, the spoiler vertical plate is parallel to the axis direction of the pile foundation body, and an acute included angle is formed between the spoiler side plate and the spoiler vertical plate; the space between the protective cylinder and the pile foundation body is filled with the filling stone, and the beneficial effect of prolonging the service life of the offshore wind power pile foundation is achieved.

The invention discloses a fault processing method for an offshore wind power direct current parallel sending-out system through a DRU-MMC. The fault processing method comprises the steps that direct current energy consumption devices are arranged at direct current outlets of respective land MMC converter stations of a DRU-HVDC system and an MMC-HVDC system; when the alternating current power grid at the receiving end has an alternating current fault, the direct current energy consumption device is controlled to adopt a direct current voltage suppression strategy; when the DRU-HVDC system and the MMC-HVDC system respectively have direct current faults, different locking and circuit breaker disconnection time sequence control strategies are adopted, and in the direct current fault ride-through period, a direct current suppression strategy and a direct current voltage suppression strategy are controlled to be adopted by a direct current energy consumption device of the DRU-HVDC system. Therefore, the fault ride-through capability of the DRU-MMC direct current parallel sending-out system of the offshore wind power can be effectively improved, and stable operation of the system is ensured.

The invention discloses an offshore wind power collecting and sending-out system and method based on a multi-port multi-frequency alternating current and direct current hybrid integrated platform, and belongs to the field of power transmission and distribution of power systems. The system comprises an intermediate-frequency, power-frequency and low-frequency wind power collection subsystem, an offshore integrated platform, a direct-current sending-out submarine cable, a low-frequency sending-out submarine cable, an onshore converter station and an onshore frequency conversion station. The various wind power collection subsystems respectively collect wind turbine generator group outputs with corresponding frequencies and send the wind turbine generator group outputs to the offshore integrated platform; the offshore integrated platform converts intermediate-frequency, power-frequency and partial low-frequency electric energy into direct current and then transmits the direct current to the onshore converter station through the direct-current sending-out submarine cable, and the converter station converts the direct current into power-frequency alternating current; and after being boosted, the other low-frequency electric energy is sent to a land frequency conversion station through a low-frequency sending-out submarine cable to be converted into power-frequency alternating current, so that efficient collection and grid-connected sending-out of multi-frequency wind power resources are realized. According to the invention, the problem that a plurality of independent platforms need to be built in a complex multi-point grid-connected scene in the prior art can be solved.

The invention discloses an offshore wind power cable line fault early warning method and system, and relates to the technical field of cable line fault early warning, and the method comprises the following steps: laying a three-dimensional distributed optical fiber temperature array along an offshore wind power cable, and monitoring the cable thermal field space distribution in combination with an active acoustic dispersion imaging technology; acquiring initial evolution trajectory data of the edge high-temperature region; and on the basis of the initial evolution trajectory data, constructing a coupling relationship among the ocean current parameter, the sediment disturbance characteristic and the cable heat conduction parameter, forming an ocean current-sediment-heat conduction coupled digital twin model, and dynamically correcting a virtual scene of the cable burial depth in the model through a recursive filtering algorithm. Through combination of thermal field monitoring, digital twin modeling and intelligent intervention, accurate early warning and dynamic response of offshore wind power cable faults are realized, the operation and maintenance efficiency is improved, system self-optimization and cross-scene migration are supported, and the safety and intelligent level of cable operation are significantly enhanced.

The invention provides an offshore wind plant current collection network topology optimization method based on an improved grey wolf optimization algorithm, and the method comprises the steps: S1, obtaining basic data of an offshore wind plant, initializing the grey wolf algorithm, and generating an initial solution set; s2, adopting polar coordinates and a minimum spanning tree to optimize and expand the initial solution set; s3, optimizing a connection mode in each group; s4, executing the optimal connection of each group of fan combination; s5, performing optimal solution set exploration on the grey wolf algorithm by adopting an operator; s6, repeatedly executing until a preset maximum number of iterations is reached, and generating a topology model of the current collection system of the offshore wind plant; the method can improve the initial solution quality and the convergence efficiency, gives consideration to the global search capability and the local optimization precision, and achieves the quick and effective processing of geometric constraints.

The invention discloses a power grid active support control method for an offshore wind power low-frequency power transmission system. Real-time response of low-frequency power grid angular frequency to power-frequency power grid angular frequency is realized by using an onshore M3C converter; the active power response of the low-frequency fan to the angular frequency of the low-frequency power grid is realized by utilizing a low-frequency fan side converter and a grid side converter; through cooperative control of the M3C converter and the low-frequency fan, active support of the offshore wind power low-frequency power transmission system for frequency fluctuation of an onshore power frequency power grid can be realized, the system stability is improved, and the method has a good application prospect.

The invention discloses a hybrid direct current transmission power coordination control device and a control method and equipment thereof, and relates to the technical field of offshore power generation, and the hybrid direct current transmission power coordination control device comprises a diode rectifier unit and a first modular multilevel converter which are connected with an offshore wind plant, the sending-end converter station is used for converting alternating current generated by an offshore wind plant into direct current and outputting the direct current; the second modularized multi-level current converter is connected with the diode rectifier unit and the land power grid and is used for restoring the direct current into the alternating current and transmitting the alternating current to the land power grid; and the control module is connected with the first modular multilevel converter and is used for controlling the DC voltage of the first modular multilevel converter based on the fluctuation power according to the transfer relation between the active power and the DC voltage of the sending end converter station, so that the higher requirement of the rated capacity of the MMC in the related technology is met, and the reliability of the MMC is improved. And the engineering construction cost is increased.

The invention discloses an offshore wind power frequency conversion gathering and sending control method, device and system based on onshore integration, and belongs to the technical field of power transmission and distribution of power systems, and the method comprises the steps: converting first AC electric energy generated by an intermediate-frequency / power-frequency wind power plant into first DC electric energy through an offshore converter station; the first direct-current electric energy is transmitted to a land integration station through a direct-current submarine cable; second alternating-current electric energy generated by the low-frequency wind power plant is transmitted to the land integration station through a low-frequency alternating-current submarine cable; and converting the second alternating-current electric energy into second direct-current electric energy in the land integrated station, carrying out collection and power frequency conversion on the first direct-current electric energy and the second direct-current electric energy, and transmitting power frequency alternating-current electric energy obtained after conversion to a land power grid. Therefore, by implementing the application, the problem that the electric energy cannot be transmitted at low cost due to the fact that it is difficult to directly send the electric energy of different frequencies out of the system for topological combination in the prior art can be solved.

The invention, which relates to the technical field of direct-current power transmission, discloses a co-offshore medium-high-frequency alternating-current offshore wind power full-direct-current collection system comprising: an offshore wind turbine module, which is used for obtaining offshore medium-voltage direct-current electric energy; the multi-port direct-current voltage transformation module is used for converting the offshore medium-voltage direct-current electric energy into offshore high-voltage direct-current electric energy; the direct-current submarine cable module is used for gathering the offshore high-voltage direct-current electric energy, acquiring the gathered offshore high-voltage direct-current electric energy and transmitting the gathered offshore high-voltage direct-current electric energy to the shore converter station module; the shore converter station module is used for acquiring shore high-voltage alternating-current electric energy according to the collected offshore high-voltage direct-current electric energy; the onshore alternating current module is used for receiving the onshore high-voltage alternating current electric energy and achieving full-direct-current collection of offshore wind power. By improving the medium voltage-high voltage direct current transformer topological structure and the control method, efficient and economical electric energy transmission is realized, the construction economy and the engineering application value of an open-sea wind power collection system are improved, and the average price and low price requirements of marketization development are met.

The invention belongs to the technical field of wind turbine generator maintenance, and particularly relates to an offshore wind turbine generator two-stage rolling maintenance method considering subsystem correlation, which comprises the following steps: S1, constructing a comprehensive reliability model; s2, taking the minimization of the total maintenance cost in the operation cycle of the wind turbine generator as a target, and forming a target optimization problem based on the comprehensive reliability model; solving the target optimization problem to form a first-stage long-term maintenance strategy; s3, when an operation window meeting the storm accessibility condition appears, determining a subsystem of which the current reliability is lower than a preventive maintenance threshold value; s4, the opportunity maintenance benefit ratio is calculated, and if the opportunity maintenance benefit ratio is larger than a processing threshold value, advanced maintenance of the subsystem is triggered; and S5, after the advanced maintenance is executed each time, the optimal preventive maintenance time point is solved again so as to dynamically update the subsequent maintenance plan. According to the method, the fault coupling and degradation evolution law between subsystems can be accurately described, and the storm accessibility window is actively utilized to dynamically adjust the maintenance plan.