A Method and System for the Ordered Withdrawal and Recovery of Offshore Wind Farm Groups under Typhoon Conditions

Abstract

The present invention provides a method and system for the orderly withdrawal and recovery of an offshore wind farm group under typhoon conditions. The method includes: establishing a wind farm operation control model with the maximization of the total social benefit as the optimization objective; establishing an operation uncertainty set based on the output uncertainty of the wind farm group and the load uncertainty; converting the wind farm operation control model into a corresponding robust linear programming model according to the operation uncertainty set; and solving the robust linear programming model to obtain the withdrawal and recovery strategy of the wind farm during typhoon. The present invention fully considers various uncertainties of typhoon, wind power and load, as well as the power system frequency change rate and quasi-steady state frequency change, and introduces the frequency safety constraint as a safe operation constraint condition to establish a robust linear programming model, which can ensure that the solution result resists the uncertainties of typhoon, wind power and load, provide reliable guidance for the operation control of the wind farm under typhoon conditions, and effectively ensure the safe and stable operation of the power system.

Description

Technical Field

[0001] The present invention relates to the technical field of operation control of wind farms in a power system, and particularly to a method and system for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions based on robustness optimization. Background Art

[0002] Currently, the power system is accelerating towards the process of "dual highs". However, the high proportion of renewable energy in the "dual highs" poses a great challenge to the safe and stable operation of the power system. In particular, the randomness, volatility and uncertainty of wind power will bring a series of new problems to the system. In recent years, extreme weather has been particularly frequent, especially typhoon weather, which has brought great troubles to the development of wind power in the southern coastal areas. When a typhoon approaches, the wind power quickly climbs to the rated power and then maintains for a period of time. When the wind speed reaches the cut-out wind speed, the wind power quickly drops. If the system reserve is insufficient, it will lead to insufficient active power in the system and even a major power outage. When the typhoon leaves the wind farm, the wind speed quickly drops. If the wind farm that has already been taken out of operation resumes operation according to the natural cut-out wind speed, a huge power injection process will occur for the power grid. In short, during a typhoon, the system will face two major disturbance problems of power shortage and power surplus in a short period of time, posing a huge threat. Especially for provinces with a certain scale of offshore wind power installed capacity, it is urgent to study and solve the operation strategy that can ensure the safety of the power system and achieve the optimal economy under typhoon conditions.

[0003] However, in order to ensure the safety of the power grid and minimize the curtailment of wind power as much as possible, the wind farm group needs to withdraw and resume operation orderly during a typhoon. Although the wind turbines of the wind farm can maximize the utilization of wind power according to the natural turbine tripping method, the disturbance to the power grid is the greatest and the operation mode is extremely dangerous. In addition, the existing operation control technologies of the power system under typhoons only involve the design of the anti-typhoon control system for offshore wind power and the method for orderly withdrawal of offshore wind power under typhoon conditions. There is no research on the power control of wind farms under typhoon conditions and the restoration strategy based on typhoon uncertainty or load uncertainty, and it does not really apply to the operation control scenario of wind farms in the power system under typhoon conditions, nor can it effectively ensure the safety and stability of the power system under typhoon conditions. Summary of the Invention

[0004] The object of the present invention is to provide a method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions. By fully considering various uncertainties of typhoons, wind power and loads, as well as the power system frequency change rate and quasi-steady state frequency change, and introducing frequency safety constraints as safety operation constraint conditions to establish a robust linear programming model, the orderly withdrawal and restoration strategy of the offshore wind farm group under typhoon conditions is obtained by solving, so as to solve the application defects of the existing operation control of wind farms under typhoons, ensure that the obtained orderly withdrawal and restoration strategy of the offshore wind farm group can resist the uncertainties of typhoons, wind power and loads, and meet the goal of maximizing the total social benefit, provide reliable guidance for the operation control of wind farms under typhoon conditions, and thus effectively ensure the safe and stable operation of the power system.

[0005] In order to achieve the above object, it is necessary to provide a method and system for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions for the above technical problems.

[0006] In the first aspect, an embodiment of the present invention provides a method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions, and the method includes the following steps:

[0007] Establish a wind farm operation control model with the optimization goal of maximizing the total social benefit;

[0008] Based on the output uncertainty of the wind farm group and the load uncertainty, establish an operation uncertainty set;

[0009] According to the operation uncertainty set, convert the wind farm operation control model into a corresponding robust linear programming model;

[0010] Solve the robust linear programming model to obtain the wind farm withdrawal and restoration strategy during typhoons; the wind farm withdrawal and restoration strategy includes the output of thermal power units, the reserve of thermal power units and the output of the wind farm group at different times.

[0011] Further, the step of establishing a wind farm operation control model with the optimization goal of maximizing the total social benefit includes:

[0012] Establish a total social benefit model according to the wind farm revenue and the thermal power unit generation cost in the power system, and determine the objective function of the wind farm operation control model according to the total social benefit model;

[0013] Determine the safety operation constraint conditions of the wind farm operation control model according to the objective function.

[0014] Further, the objective function is expressed as:

[0015] max{C1 - C2}

[0016] Wherein,

[0017]

[0018]

[0019] Among them, C1 represents the total revenue of the wind farm group during a typhoon; represents the set of wind farms; C2 represents the total power generation cost of thermal power units during a typhoon; C1 - C2 represents the social total revenue model; represents the set of generating units; c W represents the on-grid electricity price of wind power; p w,t represents the actual output of the wind farm at time t, represents the coal consumption cost of thermal power units; p g,t represents the output of the thermal power unit at time t; represents the duration of the typhoon; Δt represents the time interval.

[0020] Further, the safe operation constraint conditions include the wind farm group shutdown constraint, wind power output constraint, power balance constraint, frequency safety constraint, thermal power unit output constraint, thermal power unit ramp rate constraint, and thermal power unit reserve constraint;

[0021] The wind farm group shutdown constraint is expressed as:

[0022]

[0023] Among them, and respectively represent the arrival time and departure time of the 10 - level wind circle of the typhoon;

[0024] The wind power output constraint is expressed as:

[0025]

[0026] Among them, represents the predicted maximum output of the wind farm;

[0027] The power balance constraint is expressed as:

[0028]

[0029] Among them, represents the load power at time t; Δp represents the energy relaxation parameter;

[0030] The frequency safety constraint is expressed as:

[0031]

[0032]

[0033] In the formula,

[0034]

[0035] Among them, H represents the total system inertia; S base is the system power base value; RoCoF max represents the maximum rate of change of the system frequency; D represents the system load damping; K ∑ represents the equivalent power-frequency characteristic coefficient of all thermal power units; represents the limit value of the quasi-steady-state frequency deviation; S g represents the capacity of the thermal power unit; K g represents the additional primary frequency regulation control coefficient of the thermal power unit; R g represents the droop coefficient of the thermal power unit;

[0036] The output constraint of the thermal power unit is expressed as:

[0037]

[0038] Among them, and respectively represent the minimum technical output and the maximum technical output of thermal power unit g;

[0039] The ramping constraint of the thermal power unit is expressed as:

[0040] p g,t -p g,t-1 ≤RU g

[0041] p g,t -p g,t-1 ≥-RD g

[0042] Among them, RU g and RD g respectively represent the up-ramping rate and the down-ramping rate of thermal power unit g; The spare constraint of the thermal power unit is expressed as:

[0043]

[0044]

[0045]

[0046] R g,t ≥0

[0047]

[0048]

[0049] Among them, and R g,t respectively represent the upward reserve and downward reserve of the thermal power unit g at time t; and R total respectively represent the upward reserve and downward reserve of the power system.

[0050] Furthermore, the steps of establishing the operation uncertainty set based on the output uncertainty of the wind farm group and the load uncertainty include:

[0051] Obtain the wind power prediction interval and the load power prediction interval respectively;

[0052] According to the upper bound value and the lower bound value of the wind power prediction interval, combined with the uncertainty budget, construct the wind power output uncertainty set;

[0053] According to the upper bound value and the lower bound value of the load power prediction interval, combined with the uncertainty budget, construct the load uncertainty set.

[0054] Furthermore, the operation uncertainty set is expressed as:

[0055]

[0056] where represents the operation uncertainty set; and respectively represent the upper bound value, the lower bound value and the nominal value of the wind power prediction interval at time t; and respectively represent the upper bound value, the lower bound value and the nominal value of the load power prediction interval at time t; represents the auxiliary variable for adjusting the uncertain parameter at time t; Γ represents the uncertainty budget.

[0057] Furthermore, the steps of converting the wind farm operation control model into the corresponding robust linear programming model according to the operation uncertainty set include:

[0058] Based on the robustness principle, convert the wind farm group shutdown constraint of the wind farm operation control model into the corresponding robust wind farm group shutdown constraint; the robust wind farm group shutdown constraint is expressed as:

[0059]

[0060] where and respectively represent the arrival time of the 10th typhoon wind circle lower bound and the departure time

[0061] Without changing other safe operation constraint conditions of the wind farm operation control model, the operation uncertainty set is incorporated into the safe operation constraint conditions to obtain robust linear constraint conditions;

[0062] The objective function of the wind farm operation control model is used as the objective function of the robust linear programming model, and in combination with the robust linear constraint conditions, the corresponding robust linear programming model is obtained.

[0063] In a second aspect, an embodiment of the present invention provides an orderly exit and restoration system for an offshore wind farm group under typhoon conditions. The system includes:

[0064] A model establishment module, configured to establish a wind farm operation control model with maximizing the total social benefit as the optimization objective;

[0065] An uncertainty analysis module, configured to establish an operation uncertainty set based on the output uncertainty of the wind farm group and the load uncertainty;

[0066] A model conversion module, configured to convert the wind farm operation control model into a corresponding robust linear programming model according to the operation uncertainty set;

[0067] A strategy solving module, configured to solve the robust linear programming model to obtain a wind farm exit and restoration strategy during typhoon; the wind farm exit and restoration strategy includes the output of thermal power units, the reserve of thermal power units, and the output of the wind farm group at different times.

[0068] In a third aspect, an embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0069] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are implemented.

[0070] The present application provides a method and system for the orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions. Through the method, an operation control model of the wind farm is established with the optimization goal of maximizing the total social benefit. Based on the output uncertainty of the wind farm group and the load uncertainty, an operation uncertainty set is established. Then, according to the operation uncertainty set, the operation control model of the wind farm is converted into a corresponding robust linear programming model, and the robust linear programming model is solved to obtain the technical solution of the withdrawal and restoration strategy of the wind farm during typhoons. Compared with the prior art, the method for the orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions fully considers various uncertainties of typhoons, wind power, and loads, as well as the rate of change of the power system frequency and the quasi-steady state frequency change, and introduces frequency safety constraints as safety operation constraint conditions to establish a robust linear programming model, ensuring that the obtained withdrawal and restoration strategy of the offshore wind farm group under typhoon conditions can resist the uncertainties of typhoons, wind power, and loads, and meet the goal of maximizing the total social benefit, providing reliable guidance for the operation control of the wind farm under typhoon conditions, and effectively ensuring the safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 FIG. is a schematic diagram of the application scenario of the method for the orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions in an embodiment of the present invention;

[0072] Figure 2 FIG. is a process framework diagram of the orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions in an embodiment of the present invention;

[0073] Figure 3 FIG. is a process schematic diagram of the method for the orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions in an embodiment of the present invention;

[0074] Figure 4 FIG. is a schematic diagram of the solution result of the robust linear programming model in an embodiment of the present invention;

[0075] Figure 5 FIG. is a schematic diagram of the structure of the system for the orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions in an embodiment of the present invention;

[0076] Figure 6 FIG. is an internal structure diagram of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0077] To make the objectives, technical solutions, and beneficial effects of this application clearer and more understandable, the following further elaborates on the present invention in conjunction with the accompanying drawings and embodiments. Obviously, the following described embodiments are part of the embodiments of the present invention and are only used to illustrate the present invention, but not to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0078] The method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions provided by the present invention can be applied to a terminal or server as shown in Figure 1 . Among them, the terminal can be, but is not limited to, various personal computers, laptop computers, smart phones, tablet computers, and portable wearable devices, and the server can be implemented by an independent server or a server cluster composed of multiple servers. The server can execute the method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions provided by the present invention according to the Figure 2 shown process architecture, obtain the withdrawal and restoration strategy of the wind farm during typhoon, and transmit it to the terminal for the terminal user to perform reliable and effective wind farm operation control; the following embodiments will elaborate in detail on the method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions of the present invention.

[0079] In one embodiment, as shown in Figure 3 , a method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions is provided, including the following steps:

[0080] S11. Establish a wind farm operation control model with maximizing the total social benefit as the optimization objective; among them, maximizing the total social benefit is an optimization objective determined from the perspective of social managers by comprehensively considering the wind farm benefit and the power generation cost of thermal power units in consideration of the insufficient output of the wind farm group during the turbine tripping stage, complete turbine tripping stage, and restoration stage during typhoon, especially the zero output during the complete turbine tripping stage, and the need to use thermal power units in the power system to undertake the corresponding grid load; specifically, the step of establishing a wind farm operation control model with maximizing the total social benefit as the optimization objective includes:

[0081] Establish a total social benefit model based on the wind farm benefit and the power generation cost of thermal power units in the power system, and determine the objective function of the wind farm operation control model according to the total social benefit model; among them, the total social benefit model can be understood as the difference model between the total benefit of the wind farm group and the total power generation cost of thermal power units; correspondingly, the objective function is expressed as:

[0082] max{C1 - C2}

[0083] In the formula,

[0084]

[0085]

[0086] Among them, C1 represents the total revenue of the wind farm group during typhoon periods, which can be understood as the wind power grid-connected price multiplied by the total power generation of the wind farm; represents the set of wind farms; C2 represents the total power generation cost of thermal power units during typhoon periods, which can be understood as the sum of the power generation costs of each thermal power unit; C1 - C2 represents the social total revenue model; represents the set of generating units; c W represents the grid-connected price of wind power; p w,t represents the actual output of the wind farm at time t, represents the coal consumption cost of the thermal power unit; p g,t represents the output of the thermal power unit at time t; represents the duration of the typhoon; Δt represents the time interval.

[0087] According to the objective function, determine the safe operation constraint conditions of the wind farm operation control model; among them, the safe operation constraint conditions include the wind farm group shutdown constraint, wind power output constraint, power balance constraint, frequency safety constraint, thermal power unit output constraint, thermal power unit ramp rate constraint, and thermal power unit reserve constraint; it should be noted that while determining the safe operation constraint conditions, the decision variables of the wind farm operation control model are also determined as the output of the thermal power unit, the reserve of the thermal power unit, and the output of the wind farm group;

[0088] During typhoon periods, if a wind farm is covered by the 10 - level wind circle of the typhoon, that is, the wind speed of the wind farm exceeds the natural cut - out wind speed, the wind farm should be taken out of operation. Based on this principle, determine the wind farm group shutdown constraint, which is expressed as:

[0089]

[0090] Among them, represents the arrival time of the 10 - level wind circle of the typhoon, and more strictly speaking, it refers to the time when the wind speed of the wind farm reaches the natural cut - out wind speed of the fan, which is a random variable; represents the departure time of the 10 - level wind circle of the typhoon, which is a random variable;

[0091] Based on the principle that the output of the wind farm should not exceed its maximum predicted output, determine the wind power output constraint, which is expressed as:

[0092]

[0093] Among them, represents the predicted maximum output of the wind farm, which is a random variable;

[0094] Based on the principle of power balance between the output power and load power of the entire power system, the power balance constraint is determined and expressed as:

[0095]

[0096] Among them, represents the load power at time t and is a random variable; Δp represents the energy relaxation parameter, which should be as small as possible to ensure as much energy balance as possible. However, to ensure the feasibility of the constraint, this parameter should not be less than the length of the load uncertainty interval (the length of the load uncertainty interval is the difference between the upper bound and the lower bound of the load interval prediction), that is and and can be given by relevant load prediction techniques and will not be elaborated here;

[0097] Based on only considering thermal power units as frequency regulation resources and the frequency security constraint is mainly related to primary frequency regulation, the frequency security constraint including the rate of change of frequency constraint and the quasi-steady state frequency constraint is determined; in order to ensure that the corresponding frequency security index does not exceed the specified threshold after a large disturbance occurs in the power system, the rate of change of frequency should not be too large. Based on the principle that the power system disturbance mainly comes from the power change of the wind farm group and the system can return to the equilibrium position within Δt time after the disturbance occurs, the rate of change of frequency constraint is determined as:

[0098]

[0099] Among them, H represents the total inertia of the system; S base is the power base value of the system; RoCoF max represents the maximum rate of change of the system frequency;

[0100] At the same time, considering that the power system will reach a new equilibrium state after being subjected to a large disturbance and returning to equilibrium, and the frequency at this time will increase or decrease compared with the frequency before the disturbance, and the power system requires that the quasi-steady state frequency deviation after the disturbance should not exceed a certain value, the corresponding quasi-steady state frequency constraint is determined as follows:

[0101]

[0102] In the formula,

[0103]

[0104] Among them, D represents the system load damping; K ∑ represents the equivalent power-frequency characteristic coefficient of all thermal power units; represents the limit value of the quasi-steady state frequency deviation; S g represents the capacity of the thermal power unit; K gRepresents the primary frequency regulation additional control coefficient of the thermal power unit; R g Represents the droop coefficient of the thermal power unit;

[0105] Based on the principle that the output of the thermal power unit should be between the maximum technical output and the minimum technical output, determine the output constraint of the thermal power unit, expressed as:

[0106]

[0107] Among them, and respectively represent the minimum technical output and the maximum technical output of the thermal power unit g;

[0108] The ramp rate constraint of the thermal power unit is expressed as:

[0109] p g,t -p g,t-1 ≤RU g

[0110] p g,t -p g,t-1 ≥-RD g

[0111] Among them, RU g and RD g respectively represent the up-ramp rate and the down-ramp rate of the thermal power unit g;

[0112] The reserve constraint of the thermal power unit is expressed as:

[0113]

[0114]

[0115]

[0116] R g,t ≥0

[0117]

[0118]

[0119] Among them, and R g,t respectively represent the up reserve and the down reserve of the thermal power unit g at time t; and R total respectively represent the up reserve and the down reserve of the power system.

[0120] In this embodiment, considering the uncertainty of the typhoon arrival time and departure time, the corresponding shutdown constraint conditions of the wind farm group are determined, making the operation control of the wind farm more in line with the real scenario. At the same time, considering that the withdrawal and restoration of the wind farm will cause large fluctuations in wind power, when establishing the optimization model, the frequency security constraint is particularly considered as a safe operation constraint condition, making the orderly withdrawal and restoration process of the wind farm more reasonable and effectively ensuring the stability of the power system when the wind farm withdraws and restores orderly.

[0121] S12. Based on the output uncertainty of the wind farm group and the load uncertainty, establish an operation uncertainty set; among them, the operation uncertainty set is a box-type uncertainty set constructed to ensure the robustness of the optimization model in dealing with the fluctuations of wind farm output and load; specifically, the steps of establishing the operation uncertainty set based on the output uncertainty of the wind farm group and the load uncertainty include:

[0122] Obtain the wind power prediction interval and the load power prediction interval respectively; among them, the wind power prediction interval and the load power prediction interval can be obtained by using existing relevant wind power prediction and load power prediction technologies, which will not be elaborated here;

[0123] According to the upper bound value and the lower bound value of the wind power prediction interval, combined with the uncertainty budget, construct a wind power output uncertainty set;

[0124] According to the upper bound value and the lower bound value of the load power prediction interval, combined with the uncertainty budget, construct a load uncertainty set;

[0125] Among them, the operation uncertainty set is expressed as:

[0126]

[0127] Among them, represents the operation uncertainty set; and respectively represent the upper bound value, the lower bound value and the nominal value of the wind power prediction interval at time t; and respectively represent the upper bound value, the lower bound value and the nominal value of the load power prediction interval at time t; represents the auxiliary variable for adjusting the uncertain parameter at time t; Γ represents the uncertainty budget, which is generally given by the dispatcher. The larger the parameter, the greater the considered uncertainty and the stronger the robustness of the model solution result.

[0128] S13. Convert the wind farm operation control model into a corresponding robust linear programming model according to the operation uncertainty set. Among them, the wind farm operation control model is a non-linear optimization problem, which is difficult to solve and does not meet the robustness requirements. Based on this, after converting it into a corresponding robust linear programming model, the model is optimized and solved, so as to ensure the efficiency and accuracy of obtaining the optimal solution. Specifically, the steps of converting the wind farm operation control model into a corresponding robust linear programming model according to the operation uncertainty set include:

[0129] Based on the robustness principle, equivalently convert the wind farm group shutdown constraint of the wind farm operation control model into a corresponding robust wind farm group shutdown constraint. The robust wind farm group shutdown constraint is expressed as:

[0130]

[0131] Among them, and respectively represent the lower bound of the arrival time of the 10th-level typhoon wind circle and the upper bound of the departure time ;

[0132] Under the condition of keeping other safe operation constraint conditions of the wind farm operation control model unchanged, supplement the operation uncertainty set into the safe operation constraint conditions to obtain robust linear constraint conditions;

[0133] Take the objective function of the wind farm operation control model as the objective function of the robust linear programming model, and combine the robust linear constraint conditions to obtain a corresponding robust linear programming model.

[0134] In summary, the robust linear programming model is as follows:

[0135] Objective function:

[0136] max{C1 - C2}

[0137]

[0138]

[0139] Constraint conditions:

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146] p g,t -p g,t-1 ≤RU g

[0147] p g,t -p g,t-1 ≥-RD g

[0148]

[0149]

[0150]

[0151] R g,t ≥0

[0152]

[0153]

[0154]

[0155] For the variable interpretations in the robust linear programming model, refer to the relevant descriptions of the above wind farm operation control model, which will not be elaborated here;

[0156] S14. Solve the above robust linear programming model to obtain the wind farm withdrawal and restoration strategy during typhoon; the wind farm withdrawal and restoration strategy includes the thermal power unit output, thermal power unit reserve, and wind farm group output at different times; among them, the robust linear programming model can be understood as a linear programming problem with robustness, and existing optimization solution methods can be used for solving. Preferably, in this embodiment, yalmip+gurobi is used to solve the robust linear programming model simply and efficiently, obtain the decision variable values corresponding to different times in the model, and then obtain the orderly withdrawal and restoration strategy of the wind farm during typhoon; in addition, the thermal power unit output curve, thermal power unit reserve curve, and wind farm group output curve during typhoon can also be drawn based on the decision variable values corresponding to different times in the model. During typhoon, only refer to the output p of wind farm w at each time t in the wind farm group output curve w,t Execute the operation control of withdrawal and restoration for the wind farm group to ensure the safety and stability of the power system.

[0157] In the embodiments of the present application, various uncertainties of typhoons, wind power, and load are fully considered, as well as the rate of change of the power system frequency and the quasi-steady state frequency change. Moreover, a frequency security constraint is introduced as a security operation constraint condition to establish a robust linear programming model for solving the optimal strategy. It can ensure that the obtained orderly withdrawal and restoration strategies of the offshore wind farm group under typhoon conditions can resist the uncertainties of typhoons, wind power, and load, and meet the goal of maximizing the total social benefit, providing reliable guidance for the operation control of wind farms under typhoon conditions, thereby effectively ensuring the safe and stable operation of the power system.

[0158] To verify the effectiveness of the orderly withdrawal and restoration method of the offshore wind farm group under typhoon conditions of the present invention, the present invention selects the Gaolian typhoon in 1993 as an example for the following analysis and verification:

[0159] The maximum wind speed of the Gaolian typhoon is 69 m / s, and it landed in the Yangjiang area around June 28, 1993. The maximum wind speed before landing is 44 m / s. Considering the current offshore wind farms in Guangdong Province, the model solution results are as Figure 4 shown: The wind farm group collectively shuts down the generators at 14:30 on the afternoon of the 27th ( Figure 4 the 250th point in Figure 4 ), but in order to maintain system stability, the wind farm group shuts down the generators in multiple segments in advance, and all generators are shut down at 14:30; during the recovery stage of the wind farm group, that is, when the typhoon leaves the wind farm group ( Figure 4 the 300th point and the 400th point in Figure 4 ), due to the geographical dispersion of the wind farms, the wind farm group generally resumes operation in two major segments, and during the recovery process, it also resumes in multiple segments; it can also be seen from Figure 4 that during the low load period, there is wind curtailment in the wind farms because thermal power units have a minimum technical output requirement. It should be particularly noted that during the process of the typhoon approaching the wind farm group, there is not necessarily a situation of collective generator shutdown, but like in the recovery process, it will shut down in two major segments based on the geographical dispersion. This example is only for facilitating the display of the generator shutdown and recovery processes to illustrate the effectiveness of the orderly withdrawal and restoration, and a situation of collective generator shutdown is specifically set, which does not mean that the situation of collective generator shutdown shown in Figure 4 will necessarily occur when the present invention is applied to the actual operation control of wind farms during typhoons.

[0160] In one embodiment, as Figure 5 shown, there is provided an orderly withdrawal and restoration system for an offshore wind farm group under typhoon conditions, and the system includes:

[0161] A model establishment module 1, configured to establish a wind farm operation control model with the maximization of the total social benefit as the optimization goal;

[0162] An uncertainty analysis module 2, configured to establish an operation uncertainty set based on the output uncertainty of the wind farm group and the load uncertainty;

[0163] A model conversion module 3, configured to convert the wind farm operation control model into a corresponding robust linear programming model according to the operation uncertainty set;

[0164] A strategy solving module 4, configured to solve the robust linear programming model to obtain a wind farm exit and recovery strategy during typhoon; the wind farm exit and recovery strategy includes the output of thermal power units, the standby of thermal power units, and the output of the wind farm group at different times.

[0165] For the specific limitations of an orderly exit and recovery system for an offshore wind farm group under typhoon conditions, reference can be made to the limitations of an orderly exit and recovery method for an offshore wind farm group under typhoon conditions in the above text, which will not be elaborated here. Each module in the above-mentioned orderly exit and recovery system for an offshore wind farm group under typhoon conditions can be implemented in whole or in part by software, hardware, and their combination. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0166] Figure 6 The internal structure diagram of a computer device in an embodiment is shown. The computer device may specifically be a terminal or a server. As Figure 6 shown, the computer device includes a processor, a memory, a network interface, a display, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it realizes an orderly exit and recovery method for an offshore wind farm group under typhoon conditions. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device may be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the outer shell of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0167] Those of ordinary skill in the art can understand, Figure 6The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computing device may include more or fewer components than those shown in the figure, or combine some components, or have the same component arrangement.

[0168] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0169] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are implemented.

[0170] In summary, a method and system for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions provided by an embodiment of the present invention. The method for orderly withdrawal and restoration of an offshore wind farm group under typhoon conditions realizes the optimization goal of maximizing the total social benefit, establishes an operation control model for the wind farm, and based on the uncertainty of the output of the wind farm group and the uncertainty of the load, establishes an operation uncertainty set. Then, according to the operation uncertainty set, the wind farm operation control model is converted into a corresponding robust linear programming model, and the robust linear programming model is solved to obtain the technical solution of the withdrawal and restoration strategy of the wind farm during typhoons. By fully considering various uncertainties of typhoons, wind power and load, as well as the rate of change of the power system frequency and the quasi-steady state frequency change, and introducing frequency safety constraints as safety operation constraint conditions to establish a robust linear programming model, it is ensured that the obtained strategy for orderly withdrawal and restoration of the offshore wind farm group under typhoon conditions can resist the uncertainties of typhoons, wind power and load, and meet the goal of maximizing the total social benefit, providing reliable guidance for the operation control of the wind farm under typhoon conditions, and thus effectively ensuring the safe and stable operation of the power system.

[0171] Each embodiment in this specification is described in a progressive manner. For parts that are the same or similar in each embodiment, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0172] The above-described embodiments merely represent several preferred embodiments of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the protection scope of the claimed rights.

Claims

1. A method for orderly withdrawal and restoration of an offshore wind farm cluster under typhoon conditions, characterized in that, The method includes the following steps: Taking the maximization of the total social benefit as the optimization objective, establish an operating control model for the wind farm; Based on the output uncertainty of the wind farm group and the load uncertainty, establish an operating uncertainty set; According to the operating uncertainty set, convert the wind farm operating control model into a corresponding robust linear programming model; Solve the robust linear programming model to obtain the wind farm withdrawal and recovery strategy during typhoon; the wind farm withdrawal and recovery strategy includes the output of thermal power units, the reserve of thermal power units, and the output of the wind farm group at different times; Among them, the objective function of the wind farm operating control model is expressed as: max{C1-C2} In the formula, Among them, C1 represents the total revenue of the wind farm group during typhoon; represents the set of wind farms; C2 represents the total power generation cost of thermal power units during typhoon; C1 - C2 represents the social total revenue model; represents the set of generating units; c W represents the on-grid electricity price of wind power; p w,t represents the actual output of the wind farm at time t, represents the coal consumption cost of thermal power units; p g,t represents the output of the thermal power unit at time t; represents the duration of the typhoon; Δt represents the time interval.

2. The method for orderly withdrawal and restoration of an offshore wind farm cluster under typhoon conditions according to claim 1, wherein The steps of taking the maximization of the total social benefit as the optimization objective and establishing an operating control model for the wind farm include: Establish a total social benefit model according to the benefits of the wind farms and the power generation costs of thermal power units in the power system, and determine the objective function of the wind farm operating control model according to the total social benefit model; Determine the safe operating constraint conditions of the wind farm operating control model according to the objective function.

3. The method for orderly withdrawal and restoration of an offshore wind farm cluster under typhoon conditions as described in claim 2, characterized in that, The safe operating constraint conditions include the shutdown constraint of the wind farm group, the wind power output constraint, the power balance constraint, the frequency safety constraint, the output constraint of thermal power units, the ramp rate constraint of thermal power units, and the reserve constraint of thermal power units; The shutdown constraint of the wind farm group is expressed as: Among them, and respectively represent the arrival time and departure time of the typhoon's 10th-level wind circle; The wind power output constraint is expressed as: Among them, represents the predicted maximum output of the wind farm; The power balance constraint is expressed as: Among them, represents the load power at time t; Δp represents the energy relaxation parameter; The frequency safety constraint is expressed as: In the formula, Among them, H represents the total system inertia; S base is the system power base value; RoCoF max represents the maximum system frequency change rate; D represents the system load damping; K ∑ represents the equivalent power-frequency characteristic coefficient of all thermal power units; represents the limit value of the quasi-steady-state frequency deviation; S g represents the capacity of the thermal power unit; K g represents the additional primary frequency regulation control coefficient of the thermal power unit; R g represents the regulation difference coefficient of the thermal power unit; The output constraint of thermal power units is expressed as: Among them, and respectively represent the minimum technical output and the maximum technical output of the thermal power unit g; The ramp rate constraint of thermal power units is expressed as: p g,t -p g,t-1 ≤ RU g p g,t -p g,t-1 ≥ -RD g Among them, RU g and RD g respectively represent the up-ramp rate and down-ramp rate of the thermal power unit g; The reserve constraint of thermal power units is expressed as: Among them, and R g,t respectively represent the upward reserve and downward reserve of the thermal power unit g at time t; and R total respectively represent the upward reserve and downward reserve of the power system.

4. The method for orderly withdrawal and recovery of an offshore wind farm group under typhoon conditions according to claim 1, wherein The steps of establishing an operating uncertainty set based on the output uncertainty of the wind farm group and the load uncertainty include: Obtain the wind power prediction interval and the load power prediction interval respectively; According to the upper bound value and the lower bound value of the wind power prediction interval, combined with the uncertainty budget, construct a wind power output uncertainty set; According to the upper bound value and the lower bound value of the load power prediction interval, combined with the uncertainty budget, construct a load uncertainty set.

5. The method for orderly withdrawal and restoration of an offshore wind farm cluster under typhoon conditions as claimed in claim 4, wherein The operating uncertainty set is expressed as: Among them, represents the set of operation uncertainties; and respectively represent the upper bound value, lower bound value and nominal value of the wind power prediction interval at time t; and respectively represent the upper bound value, lower bound value and nominal value of the load power prediction interval at time t; represents the uncertain parameter adjustment auxiliary variable at time t; Γ represents the uncertainty budget.

6. The method for orderly withdrawal and restoration of an offshore wind farm cluster under typhoon conditions according to claim 3, wherein The steps of converting the wind farm operating control model into a corresponding robust linear programming model according to the operating uncertainty set include: Based on the robustness principle, convert the shutdown constraint of the wind farm group in the wind farm operating control model into a corresponding robust shutdown constraint of the wind farm group; the robust shutdown constraint of the wind farm group is expressed as: Among them, and respectively represent the lower bound of the arrival time of the typhoon's 10-level wind circle and the upper bound of the departure time ; Without changing the other safe operating constraint conditions of the wind farm operating control model, supplement the operating uncertainty set into the safe operating constraint conditions to obtain robust linear constraint conditions; Take the objective function of the wind farm operating control model as the objective function of the robust linear programming model, and combine the robust linear constraint conditions to obtain the corresponding robust linear programming model.

7. An orderly withdrawal and restoration system for an offshore wind farm group under typhoon conditions, characterized in that, Applied to the method for orderly withdrawal and recovery of an offshore wind farm group under typhoon conditions as described in claim 1, the system includes: A model establishment module for establishing an operating control model for the wind farm with the maximization of the total social benefit as the optimization objective; An uncertainty analysis module, configured to establish an operation uncertainty set based on the output uncertainty of a wind farm cluster and the load uncertainty; A model conversion module, configured to convert the wind farm operation control model into a corresponding robust linear programming model according to the operation uncertainty set; A strategy solving module, configured to solve the robust linear programming model to obtain a wind farm withdrawal and restoration strategy during a typhoon; the wind farm withdrawal and restoration strategy includes the output of thermal power units, the reserve of thermal power units, and the output of the wind farm cluster at different times.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of any one of the methods recited in claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, the steps of any one of the methods recited in claims 1 to 6 are implemented.

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