A method for improving the resilience of new energy power grids in sandstorm weather

Abstract

The present invention discloses a method for improving the resilience of a new energy power grid under sandstorm weather, which belongs to the field of safe operation of new energy power grids, and includes the following steps: S1, constructing a new energy power grid model; S2, based on the new energy power grid model, constructing a new energy power grid impact model under sandstorm weather; S3, formulating a resilience improvement strategy based on the new energy power grid impact model under sandstorm weather, the objective function of the resilience improvement strategy is to build a model with the maximum load increase and total photovoltaic power generation output as the target, and the constraints are: energy storage equipment constraint, unit output constraint, node power balance constraint, branch flow constraint, maintenance constraint and cleaning constraint. The above-mentioned method for improving the resilience of a new energy power grid under sandstorm weather can effectively reduce the system load reduction under the influence of sandstorms, accelerate the system recovery process, and enhance the ability of the power system to resist sandstorms.

Description

Technical Field

[0001] The present invention relates to the technical field of safe operation of new energy power grids, and in particular to a method for improving the resilience of new energy power grids under sandstorm weather. Background Art

[0002] With the adjustment of the grid energy structure, a large number of new energy power generation equipment have been connected, indicating that the traditional thermal power grid is gradually transforming into a new energy power grid. This transformation not only responds to the call for energy conservation and emission reduction, but also effectively responds to the challenge of global climate change. As a new form of new energy power generation, solar thermal power generation can complement traditional thermal power generation and effectively reduce the consumption of fossil energy. In order to solve the randomness and uncertainty of the output of new energy power generation equipment, energy storage equipment has gradually become an indispensable part of the new energy power grid.

[0003] At the same time, the resilience of the power system refers to the ability of the system to effectively resist the impact of disasters and quickly return to normal operation when faced with extreme disasters with low probability and high risk. Improving the resilience of the power system is the key to ensuring national energy security and social stability.

[0004] At present, relevant research mainly focuses on planning and operation, aiming to reduce the impact of extreme disasters on the power system by formulating corresponding strategies. However, existing research often lacks in-depth discussion of the characteristics of new energy power grids and a comprehensive understanding of the system response mechanism under different disaster types. Specifically, extreme weather events such as sandstorms have a particularly significant impact on the power system. At the system level, sandstorms may cause damage to transmission lines, resulting in a decrease in overall transmission capacity. At the equipment level, the attachments carried by sandstorms will cause the illumination of photovoltaic and solar thermal power stations to weaken, reduce power generation efficiency, and even cause wind turbines to shut down. It can be seen that when a disaster occurs, the power system faces problems such as large-scale power outages, energy supply interruptions, and difficulties in post-disaster recovery. Summary of the invention

[0005] The purpose of the present invention is to provide a method for improving the resilience of a new energy power grid under sandstorm weather to solve the above-mentioned technical problems.

[0006] To achieve the above object, the present invention provides a method for improving the resilience of a new energy power grid in sandstorm weather, comprising the following steps:

[0007] S1. Construct a new energy power grid model, which includes a new energy model, a thermal power unit model and a transmission network model. The new energy model includes a solar thermal power station, a wind-storage combined system and a solar-storage combined system;

[0008] S2. Based on the new energy grid model described in step S1, a new energy grid impact model under sandstorm weather is constructed, wherein the new energy grid impact model includes a transmission line failure rate model and a new energy unit impact model;

[0009] S3. Formulate a resilience enhancement strategy based on the impact model of new energy power grid under sandstorm weather described in step S2. The objective function of the resilience enhancement strategy is to build a model with the maximum load increase and total photovoltaic power generation output as the goal. The constraints are: energy storage equipment constraints, unit output constraints, node power balance constraints, branch flow constraints, maintenance constraints and cleaning constraints.

[0010] Preferably, the solar thermal power station described in step S1 includes a heat collection system, a heat storage system and a power generation system, wherein

[0011] The collector system expression is as follows:

[0012] (1);

[0013] (2);

[0014] In the formula, The effective light energy captured by the mirror field of the CSP power station; Direct solar radiation; is the effective light receiving area of ​​the mirror field; is the total area of ​​heliostats in the field; The heat energy ultimately provided to the mirror field; is the energy loss of the collector system;

[0015] The heat storage system expression is as follows:

[0016] (3);

[0017] (4);

[0018] In the formula, is the heat stored in the thermal storage system; The heat energy provided to the generator through the heat transfer medium; is the heat energy loss of the heat storage system; is the energy storage loss coefficient;

[0019] The power generation system expression is as follows:

[0020] (5);

[0021] In the formula, for The power output of the solar thermal power station at all times; is the thermoelectric conversion efficiency; express The working status of the steam turbine unit of the CSP power station at all times; The energy consumed in starting the steam turbine unit.

[0022] Preferably, the wind-storage combined system expression in step S1 is as follows:

[0023] (6);

[0024] (7);

[0025] (8);

[0026] (9);

[0027] (10);

[0028] (11);

[0029] (12);

[0030] In the formula, for Total output power of wind turbines in the wind-storage combined system at any given moment; is the rated power of the wind turbine; for The actual wind speed in the area where the wind turbine is located at the moment; is the cut-in wind speed; To cut out the wind speed; To start the wind speed; The maximum wind speed that the wind turbine can withstand; The power provided by the wind turbine to the transmission grid model; The electric energy provided by the wind turbine to the energy storage device; Energy storage equipment connected to wind turbines The amount of power stored at any time; Energy storage equipment connected to wind turbines The amount of power stored at any time; and They represent charging efficiency and discharging efficiency respectively; The electrical energy released for the energy storage device; is the time step; for The electric energy provided by the wind-storage combined system to the transmission grid model at each moment; Indicates the energy storage device connected to the wind turbine The maximum storage capacity at the moment.

[0031] Preferably, the expression of the photovoltaic energy storage combined system in step S1 is as follows:

[0032] (13);

[0033] (14);

[0034] (15);

[0035] (16);

[0036] (17);

[0037] (18);

[0038] (19);

[0039] In the formula, The actual output power of the photovoltaic unit in the photovoltaic and energy storage combined system; is the rated output power of the photovoltaic unit under standard conditions; is the solar radiation received by the photovoltaic unit; is the light intensity under standard conditions; is the power temperature coefficient; is the surface temperature of the photovoltaic panel under working conditions; is the surface temperature of the photovoltaic panel under standard conditions; The electrical energy provided by the photovoltaic unit to the energy storage device; Release electrical energy to energy storage devices; Energy storage device connected to photovoltaic units The amount of power stored at any time; Energy storage device connected to photovoltaic units The amount of power stored at any time; The electricity provided by the photovoltaic unit directly to the transmission grid model; for The electricity provided by the photovoltaic and energy storage system to the transmission grid at all times; Energy storage equipment connected to photovoltaic units Maximum power storage at all times.

[0040] Preferably, the transmission line failure rate model expression described in step S2 is as follows:

[0041] (20);

[0042] In the formula, For transmission lines Failure rate at any time; for The instantaneous wind speed on the transmission line at any moment; is the design wind speed of the transmission line; The maximum wind speed that the transmission line can withstand;

[0043] Add constraints to the transmission line failure rate model: sandstorm movement trajectory, which is expressed as follows:

[0044] (twenty one);

[0045] In the formula, express The location of the sandstorm at any given moment; , Respectively represent the horizontal and vertical coordinates of the initial position of the sandstorm; represents the speed at which the sandstorm moves, and ; Indicates the direction of the sandstorm movement and The angle of the axis.

[0046] Preferably, the new energy unit impact model described in step S2 includes a sandstorm impact model of direct solar radiation, a sandstorm impact model of photovoltaic panels, a sandstorm impact model of mirror fields, and a sandstorm impact model of wind turbines;

[0047] Among them, the direct solar radiation model affected by sandstorms is constructed based on the Iqbal parameterized C model and the change of aerosol absorption radiation coefficient under sandstorm weather. Its expression is as follows:

[0048] (twenty two);

[0049] In the formula, is the transmittance of beam radiation in each band; is the solar radiation in the upper atmosphere; is the ozone absorption coefficient; is the Rayleigh molecular scattering coefficient; is the absorption coefficient of uniform mixed gas; is the aerosol absorption radiation coefficient; is the water vapor absorption radiation coefficient;

[0050] The model expression of the impact of sandstorm on photovoltaic panels is as follows:

[0051] (twenty three);

[0052] (twenty four);

[0053] In the formula, is the transmittance of the photovoltaic panel under dust accumulation conditions; is the light transmittance of photovoltaic panel glass under dust accumulation conditions; is the light transmittance of photovoltaic panel glass under clean conditions; is the error function; is the dust accumulation density; , , All represent sandstorm related parameters;

[0054] The model expression of sandstorm affecting mirror field is as follows:

[0055] (25);

[0056] (26);

[0057] In the formula, is the total area blocked by dust, in cm 2 ; is the radius of the dust particle, in units of ; is the number of dust particles per unit area of ​​the mirror field; is the angle between the incident light and the mirror field surface;

[0058] The execution strategy of the sandstorm impact wind turbine model is to perform shutdown operations when the sandstorm speed is not less than 20m / s.

[0059] Preferably, the objective function of the toughness improvement strategy described in step S3 is as follows:

[0060] (27);

[0061] In the formula, for Complete the maintenance of the selected transmission line nodes at any time The load lifting amount; for Total output of photovoltaic power generation at all times; is the total number of load nodes; The end time of the operation;

[0062] And the energy storage device constraint expression is as follows:

[0063] (28);

[0064] (29);

[0065] (30);

[0066] (31);

[0067] (32);

[0068] In the formula, and are the lower and upper limits of the charging power of the energy storage device connected to the wind-storage combined system, respectively; and are the lower and upper limits of the discharge power of the energy storage equipment connected to the wind-storage combined system, respectively; and The lower and upper limits of the charging power of the energy storage devices respectively connected to the photovoltaic and energy storage combined system; and The lower and upper limits of the discharge power of the energy storage devices respectively connected to the photovoltaic and energy storage combined system;

[0069] The unit output constraint expression is as follows:

[0070] (33);

[0071] (34);

[0072] (35);

[0073] (36);

[0074] (37);

[0075] (38);

[0076] (39);

[0077] In the formula, and They are the maximum and minimum output of thermal power units respectively; and They are Moment and The output of thermal power units at the moment; and are the maximum and minimum output of the CSP plant respectively; and They are Moment and The output of the CSP plant at the moment; It is the maximum output of the wind-storage combined system; The maximum output of the photovoltaic and energy storage combined system; It is the climbing ability of thermal power unit; The climbing ability of the CSP station;

[0078] Node power balance constraints

[0079] (40);

[0080] In the formula, , , , and They represent the total number of thermal power units, wind-storage combined systems, solar-thermal power stations, solar-storage combined systems and transmission lines respectively; is the element of the node-generator association matrix; is the element of the association matrix between the node and the wind-storage joint system; is the element of the association matrix between the node and the photovoltaic and energy storage combined system; is the element of the association matrix between the node and the CSP plant; is the element of the association matrix between the node and the branch of the transmission model; for time The load of the node; express Timeline The trend of represents the set of all transmission lines, and , For normal transmission line collection; A collection of faulty transmission lines; express time The load increase of the node;

[0081] The branch power flow constraint expression is as follows:

[0082] (41);

[0083] (42);

[0084] (43);

[0085] (44);

[0086] (45);

[0087] In the formula, and They are Timeline and lines The trend of and Line and lines Reactance; To express Timeline A binary variable for the state in which the line is selected When repairing, is 1, otherwise it is 0; is the maximum capacity of the transmission line; for Time Node The phase angle of and Node Maximum and minimum values ​​of the phase angle; and They are Time Node and nodes The voltage phase angle;

[0088] The maintenance constraint expression is as follows:

[0089] (46);

[0090] In the formula, Under normal circumstances Time Node The load capacity;

[0091] The clean constraint expression is as follows:

[0092] (47);

[0093] (48);

[0094] (49);

[0095] In the formula, It indicates the output of CSP power station in the post-disaster recovery phase; It represents the output of the photovoltaic and storage combined system during the post-disaster recovery phase; Indicates the cleaning work stage The output of the solar thermal power station at all times; Indicates the cleaning work stage The output of the solar-storage combined system at all times; Binary variable representing cleaning work, when cleaning work is performed is 1 if the value is true, otherwise it is 0.

[0096] Therefore, the present invention adopts the above-mentioned method for improving the resilience of the new energy power grid under sandstorm weather, which has the following beneficial effects:

[0097] 1. Reduced failure rate: By optimizing the design and maintenance of transmission lines, the failure rate in sandstorm weather can be reduced, and the risk of power outages can be reduced;

[0098] 2. Output optimization: By modeling the impact of new energy units, optimize their operating strategies and improve the power generation efficiency and reliability of the overall system.

[0099] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 This is a flow chart of a method for improving the resilience of a new energy power grid under sandstorm weather according to the present invention;

[0101] Figure 2 The modified IEEE-30 transmission network system topology diagram described in the simulation example;

[0102] Figure 3 This is a diagram showing the relationship between the geographical boundaries of the system and the movement path of the sandstorm described in the simulation example;

[0103] Figure 4 This is the real-time wind speed diagram of the line described in the simulation example;

[0104] Figure 5 This is a diagram showing the line failure rate results described in the simulation example;

[0105] Figure 6 This is a diagram showing changes in direct solar radiation as described in the simulation example;

[0106] Figure 7 The overall output variation diagram of the wind turbine generator set described in the simulation example;

[0107] Figure 8 Figure 2 is a diagram of load recovery in different scenarios described in the simulation example. DETAILED DESCRIPTION

[0108] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not used to limit the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0109] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0110] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0111] like Figure 1 As shown, a method for improving the resilience of a new energy power grid under sandstorm weather includes the following steps:

[0112] S1. Construct a new energy power grid model. The new energy power grid model includes a new energy model, a thermal power unit model and a transmission network model. The new energy model includes a solar thermal power station, a wind-storage combined system and a solar-storage combined system.

[0113] The solar thermal power station described in step S1 includes a heat collection system, a heat storage system and a power generation system, which correspond to three main types of equipment: a concentrating and collecting mirror field, a heat storage system and a steam turbine generator.

[0114] The collector system expression is as follows:

[0115] (1);

[0116] (2);

[0117] In the formula, The effective light energy captured by the mirror field of the CSP power station; Direct solar radiation; is the effective light receiving area of ​​the mirror field; is the total area of ​​heliostats in the field; The heat energy ultimately provided to the mirror field; is the energy loss of the heat collection system; and in this process, the heat loss of the heat transfer medium in the process of internal transfer of the CSP power station can be ignored;

[0118] The heat storage system expression is as follows:

[0119] (3);

[0120] (4);

[0121] In the formula, is the heat stored in the thermal storage system; The heat energy provided to the generator through the heat transfer medium; is the heat energy loss of the heat storage system; is the energy storage loss coefficient;

[0122] The power generation system expression is as follows:

[0123] (5);

[0124] In the formula, for The power output of the solar thermal power station at all times; is the thermoelectric conversion efficiency; express The working status of the steam turbine unit of the solar thermal power station at all times. is 1, otherwise it is 0; The energy consumed in starting the steam turbine unit.

[0125] As a typical new energy power generation equipment, the wind power generation system converts wind energy into electrical energy by driving the wind turbine generator with the power of wind, but its output has the disadvantages of randomness and uncertainty. The windfarm-battery Energy Storage System (WF-BESS) formed by combining it with energy storage can help reduce the impact of wind power uncertainty on the operation of the power system. The expression of the wind-battery combined system in step S1 is as follows:

[0126] (6);

[0127] (7);

[0128] (8);

[0129] (9);

[0130] (10);

[0131] (11);

[0132] (12);

[0133] In the formula, for Total output power of wind turbines in the wind-storage combined system at any given moment; is the rated power of the wind turbine; for The actual wind speed in the area where the wind turbine is located at the moment; is the cut-in wind speed; To cut out the wind speed; To start the wind speed; The maximum wind speed that the wind turbine can withstand; The power provided by the wind turbine to the transmission grid model; The electric energy provided by the wind turbine to the energy storage device; Energy storage equipment connected to wind turbines The amount of power stored at any time; Energy storage equipment connected to wind turbines The amount of power stored at any time; and They represent charging efficiency and discharging efficiency respectively; The electrical energy released for the energy storage device; is the time step; for The electric energy provided by the wind-storage combined system to the transmission grid model at each moment; Indicates the energy storage device connected to the wind turbine The maximum storage capacity at the moment.

[0134] The photovoltaic storage combined system is used to combine solar photovoltaic power generation equipment with energy storage equipment. While realizing efficient utilization of clean energy, the energy stored in the energy storage equipment can provide reliable power supply for important loads in the power system in an emergency. The photovoltaic storage combined system in step S1 is expressed as follows:

[0135] (13);

[0136] (14);

[0137] (15);

[0138] (16);

[0139] (17);

[0140] (18);

[0141] (19);

[0142] In the formula, The actual output power of the photovoltaic unit in the photovoltaic and energy storage combined system; is the rated output power of the photovoltaic unit under standard conditions; is the solar radiation received by the photovoltaic unit; is the light intensity under standard conditions; is the power temperature coefficient; is the surface temperature of the photovoltaic panel under working conditions; is the surface temperature of the photovoltaic panel under standard conditions; The electrical energy provided by the photovoltaic unit to the energy storage device; Release electrical energy to energy storage devices; Energy storage device connected to photovoltaic units The amount of power stored at any time; Energy storage device connected to photovoltaic units The amount of power stored at any time; The electricity provided by the photovoltaic unit directly to the transmission grid model; for The electricity provided by the photovoltaic and energy storage system to the transmission grid at all times; Energy storage equipment connected to photovoltaic units Maximum power storage at all times.

[0143] S2. Based on the new energy grid model described in step S1, a new energy grid impact model under sandstorm weather is constructed, because the impact of sandstorms on new energy grids can be divided into two levels. First, strong winds during sandstorms can cause the transmission lines in the system to break, directly affecting the power transmission of the system; second, the sand and dust carried by strong winds will significantly reduce solar radiation, accelerate the mechanical wear of wind turbines, and indirectly lead to a decrease in the output of all new energy power generation equipment in the system. Therefore, the new energy grid impact model includes a transmission line failure rate model and a new energy unit impact model;

[0144] The transmission line failure rate model expression described in step S2 is as follows:

[0145] (20);

[0146] In the formula, For transmission lines Failure rate at any time; for The instantaneous wind speed on the transmission line at any moment; is the design wind speed of the transmission line; The maximum wind speed that the transmission line can withstand;

[0147] Add constraints to the transmission line failure rate model: sandstorm movement trajectory, which is expressed as follows:

[0148] (twenty one);

[0149] In the formula, express The location of the sandstorm at any given moment; , Respectively represent the horizontal and vertical coordinates of the initial position of the sandstorm; represents the speed at which the sandstorm moves, and ; Indicates the direction of the sandstorm movement and The angle of the axis.

[0150] In this embodiment, based on the transmission line failure rate model, the Monte Carlo state sampling method is used to sample the failure rate of the transmission network line in each time period, to obtain the change in the operating state of the transmission network line under sandstorm weather, and to establish a basic fault scenario to more accurately simulate and predict the operating state and potential fault conditions of the transmission network under sandstorm weather.

[0151] The new energy generating set impact model described in step S2 includes a sandstorm impact solar direct radiation model, a sandstorm impact photovoltaic panel model, a sandstorm impact mirror field model, and a sandstorm impact wind turbine model;

[0152] It is assumed that the extinction processes encountered by direct sunlight entering the atmosphere include: ozone absorption, Rayleigh molecular scattering, uniform mixed gas absorption, water vapor absorption, and aerosol absorption, and that each extinction layer is separated from each other. The transmittance of beam radiation in each band can be obtained by the simple product of the transmittance of each layer. However, the thickness of atmospheric particles changes dramatically during sandstorms, and the vertical optical thickness and wavelength index changes of aerosol particles will directly affect the light propagation and scattering process in the atmosphere. Therefore, it is necessary to correct them in the modeling process. At this time, the sandstorm-affected direct solar radiation model is constructed based on the Iqbal parameterized C model and the changes in the aerosol absorption radiation coefficient under sandstorm weather. Its expression is as follows:

[0153] (twenty two);

[0154] In the formula, is the transmittance of beam radiation in each band; is the solar radiation in the upper atmosphere; is the ozone absorption coefficient; is the Rayleigh molecular scattering coefficient; is the absorption coefficient of uniform mixed gas; is the aerosol absorption radiation coefficient; is the water vapor absorption radiation coefficient;

[0155] When a sandstorm passes, the pollution layer formed by dust accumulation on the photovoltaic panels will directly absorb or scatter solar radiation, thereby reducing the transmittance of the photovoltaic panels and causing a decrease in the power generation efficiency of the photovoltaic system. Therefore, the expression of the sandstorm affecting the photovoltaic panels model is as follows:

[0156] (twenty three);

[0157] (twenty four);

[0158] In the formula, is the transmittance of the photovoltaic panel under dust accumulation conditions; is the light transmittance of photovoltaic panel glass under dust accumulation conditions; is the light transmittance of photovoltaic panel glass under clean conditions; is the error function; is the dust accumulation density; , , All represent sandstorm related parameters, among which , , ;

[0159] When a sandstorm hits, the dust deposited on the surface of the CSP mirror field will reduce the reflection efficiency of the mirror, weaken the focusing ability of the mirror field on solar radiation and the heat absorption efficiency of the CSP station. The model expression of the effect of sandstorm on the mirror field is as follows:

[0160] (25);

[0161] (26);

[0162] In the formula, is the total area blocked by dust, in cm 2 ; is the radius of the dust particle, in units of ; is the number of dust particles per unit area of ​​the mirror field; is the angle between the incident light and the mirror field surface;

[0163] Sandstorm weather is often accompanied by strong wind speeds. When the wind speed is higher than the maximum wind speed that the wind turbine can withstand, in addition to affecting the production efficiency of the wind turbine, the strong wind also poses a great threat to the structural stability of new energy equipment. The wind turbine blades are subjected to additional stress under the action of strong winds and face the risk of damage and collapse. Therefore, the execution strategy of the sandstorm impact wind turbine model is to perform a shutdown operation when the sandstorm speed is not less than 20m / s.

[0164] S3. Formulate a resilience enhancement strategy based on the impact model of new energy power grid under sandstorm weather described in step S2. The objective function of the resilience enhancement strategy is to build a model with the maximum load increase and total photovoltaic power generation output as the goal. The constraints are: energy storage equipment constraints, unit output constraints, node power balance constraints, branch flow constraints, maintenance constraints and cleaning constraints.

[0165] The objective function of the toughness improvement strategy described in step S3 is as follows:

[0166] (27);

[0167] In the formula, for Complete the maintenance of the selected transmission line nodes at any time The load lifting amount; for Total output of photovoltaic power generation at all times; is the total number of load nodes; The end time of the operation;

[0168] And the energy storage device constraint expression is as follows:

[0169] (28);

[0170] (29);

[0171] (30);

[0172] (31);

[0173] (32);

[0174] In the formula, and are the lower and upper limits of the charging power of the energy storage device connected to the wind-storage combined system, respectively; and are the lower and upper limits of the discharge power of the energy storage equipment connected to the wind-storage combined system, respectively; and The lower and upper limits of the charging power of the energy storage devices respectively connected to the photovoltaic and energy storage combined system; and The lower and upper limits of the discharge power of the energy storage devices respectively connected to the photovoltaic and energy storage combined system;

[0175] The unit output constraint expression is as follows:

[0176] (33);

[0177] (34);

[0178] (35);

[0179] (36);

[0180] (37);

[0181] (38);

[0182] (39);

[0183] In the formula, and They are the maximum and minimum output of thermal power units respectively; and They are Moment and The output of thermal power units at the moment; and are the maximum and minimum output of the CSP plant respectively; and They are Moment and The output of the CSP plant at the moment; It is the maximum output of the wind-storage combined system; The maximum output of the photovoltaic and energy storage combined system; It is the climbing ability of thermal power unit; The climbing ability of the CSP station;

[0184] Node power balance constraints

[0185] (40);

[0186] In the formula, , , , and They represent the total number of thermal power units, wind-storage combined systems, solar-thermal power stations, solar-storage combined systems and transmission lines respectively; is the element of the node-generator association matrix; is the element of the association matrix between the node and the wind-storage joint system; is the element of the association matrix between the node and the photovoltaic and energy storage combined system; is the element of the association matrix between the node and the CSP plant; is the element of the association matrix between the node and the branch of the transmission model; for time The load of the node; express Timeline The trend of represents the set of all transmission lines, and , For normal transmission line collection; A collection of faulty transmission lines; express time The load increase of the node;

[0187] The branch power flow constraint expression is as follows:

[0188] (41);

[0189] (42);

[0190] (43);

[0191] (44);

[0192] (45);

[0193] In the formula, and They are Timeline and lines The trend of and Line and lines Reactance; To express Timeline A binary variable for the state in which the line is selected When repairing, is 1, otherwise it is 0; is the maximum capacity of the transmission line; for Time Node The phase angle of and Node Maximum and minimum values ​​of the phase angle; and They are Time Node and nodes The voltage phase angle;

[0194] The maintenance constraint expression is as follows:

[0195] (46);

[0196] In the formula, Under normal circumstances Time Node The load capacity;

[0197] The clean constraint expression is as follows:

[0198] (47);

[0199] (48);

[0200] (49);

[0201] In the formula, It indicates the output of CSP power station in the post-disaster recovery phase; It represents the output of the photovoltaic and storage combined system during the post-disaster recovery phase; Indicates the cleaning work stage The output of the solar thermal power station at all times; Indicates the cleaning work stage The output of the solar-storage combined system at all times; Binary variable representing cleaning work, when cleaning work is performed is 1 if the value is true, otherwise it is 0.

[0202] Simulation Example

[0203] As Figure 2 The modified IEEE-30 transmission network system shown in the figure is taken as an example for analysis and verification. The specific parameters of each unit are shown in Table 1.

[0204] Table 1 Capacity of each unit in the transmission network

[0205] ;

[0206] The parameters of each energy storage device are shown below.

[0207] Table 2 Energy storage equipment capacity

[0208] ;

[0209] The maximum load in the IEEE-30 transmission network system is 246.4MW, and the installed capacity of new energy generators accounts for 73.5% of the total installed capacity of the system.

[0210] Assume that at 9:00 a.m. on the first day of the sandstorm Figure 3 Starting from (45,60) as shown, it passes through the area where the IEEE-30 transmission network system is located, and moves from southwest to northeast to (310, 150). The moving direction is at an angle of 30° with the horizontal axis, the moving speed is 108km / h, and the maximum impact radius is 30km. During the passage of the sandstorm, it is assumed that the entire area is affected by the sandstorm. The simulation is performed with a time interval of 15 minutes. In order to visualize the impact of the movement direction of the sandstorm on the new energy power grid, first use an arrow to indicate the movement direction of the sandstorm. The arrow points to the propagation path of the sandstorm. The circle area represents an area with higher wind speed. Strong winds in the area will cause power transmission line failures. The wind speed in the area decreases with distance. The wind speed outside the circle is lower, so only the impact of sandstorms on new energy power generation equipment is considered. Combining the above visualization elements together, the result is as follows Figure 4 shown.

[0211] (1) Analysis of the impact of wind speed on transmission lines

[0212] Assuming that the design wind speed of the transmission line is 20m / s, when the wind speed on the line is higher than the design wind speed, the line failure rate increases exponentially. Once the real-time wind speed exceeds 25m / s, the transmission line failure rate reaches 1 when the emergency state is reached. Based on the instantaneous wind speed on each line and the transmission line failure rate calculated by formula (22), the following can be obtained: Figure 5 The change of line failure rate in the system shown in Figure 3. In order to accurately construct the fault set of the transmission line, the Monte Carlo state sampling method is used to sample the failure rate of the transmission line. The disconnection time of the transmission line after the sandstorm is affected is shown in Table 3.

[0213] Table 3 System disconnection situation

[0214] ;

[0215] (2) Analysis of the impact of sandstorms on new energy power generation equipment

[0216] If no cleaning measures are taken under the influence of sandstorms, the changes in solar radiation received by photovoltaic panels and solar thermal power stations in the system in the previous 24 hours are as follows: Figure 6 At the same time, during the sandstorm, the wind turbines in the system need to be shut down for protection to prevent equipment damage or failure. The output changes of wind turbines in the wind-storage combined system in the first 24 hours are shown in the figure below. Figure 7 shown.

[0217] Based on the above analysis, the following resilience enhancement strategy is formulated: According to the spatial and temporal location division of the sandstorm and the new energy power grid, the period after 13:00 on the first day can be understood as the post-disaster recovery stage, and the main tasks of this stage are to repair the damaged lines and clean and restore the new energy power generation equipment. In order to verify the effectiveness of the resilience enhancement strategy described in the present invention, four scenarios are set as shown in Table 4 for analysis and calculation ("×" indicates that the corresponding strategy is not executed, and "√" indicates that the corresponding strategy is executed).

[0218] Table 4 Scenario settings

[0219] ;

[0220] When no corresponding recovery strategy is adopted, the transmission lines are repaired in the order of faults, and the cleaning order selects the new energy units with larger power generation to be cleaned first. When the cleaning strategy is adopted, the cleaning order of the photovoltaic storage system and the solar thermal power station depends on the two generators to provide power generation confirmation during the entire system recovery period. In order to protect the personal safety of the staff, the cleaning and restart of the new energy units needs to be carried out after the disaster is over. During the cleaning work, the cleaned new energy system cannot transmit electricity normally, and the working order of the cleaning team under scenarios 2 and 4 is shown in Table 5.

[0221] Table 5 Cleaning work sequence

[0222] ;

[0223] Assuming that the time for repairing a single transmission line is 6 hours, the transmission line maintenance strategy shown in Table 6 is obtained by using the present invention to obtain the optimal transmission line maintenance sequence.

[0224] Table 6 Transmission line maintenance sequence

[0225] ;

[0226] The degree of system load recovery after a disaster is the most intuitive reflection of the resilience improvement strategy. A reasonable and efficient resilience improvement strategy can help speed up the system recovery process and reduce the impact of disasters on the system. The load recovery conditions corresponding to the four scenarios are as follows: Figure 8 As shown. Figure 8 It can be seen that the system has a slight load reduction phenomenon since the 11th hour, and the load carried by the system at this time is still maintained at 98.15% of the normal load. In the 13th to 24th period, due to the large number of transmission lines to be repaired and the gradual weakening of solar radiation to 0, the system load reduction is the most serious. From the load recovery curve, it can be seen that scenario 1 has the worst resilience level, and the load reduction in this period is as high as 573.31MWh, accounting for 23.1% of the normal load level in this period; at the 19th hour, due to the high load demand and the solar radiation dropped to zero, the load reduction in scenario 1 is the most serious, with a reduction of 71MW. Since the 13th hour, scenario 2, under the condition of only using the cleaning sequence selection strategy, reduces the total load reduction of the system from 741.07MWh to 669.62MWh during the entire post-disaster maintenance process compared with scenario 1. At the 16th hour, the load recovery rate of scenario 2 is 84.9%, which is 8.7% higher than that of scenario 1. The results show that the clean sequence selection strategy can reduce the system load reduction to a certain extent, but both scenarios are repaired in the order of transmission line faults, resulting in a slow system recovery rate and difficulty in restoring the system to a higher load level in a short time. By adopting the transmission line maintenance strategy, scenario 3 can be restored to normal operation at the 37th moment, 24 hours earlier than scenario 1, and the load reduction in the whole process is reduced by 69.88MWh compared with scenario 2.

[0227] Through the resilience enhancement strategy described in the present invention, the system corresponding to scenario 4 has the smallest overall load reduction compared to the first three systems, and the highest resilience level. The total load reduction in the post-disaster stage is 527.9MWh, and the system can still maintain a high load level during the period when the sandstorm is most severely affected. Cleaning the solar power generation equipment in the new energy grid in the correct cleaning order makes the total power generation of the solar power generation equipment in the system in scenario 4 during the entire recovery stage 5506.93MWh, accounting for 30.7% of the output of all units in the system, an increase of 229.31MWh compared to scenario 3.

[0228] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for improving the resilience of a new energy power grid in sandstorm weather, characterized by: The following steps are involved: S1. Construct a new energy power grid model, which includes a new energy model, a thermal power unit model and a transmission network model. The new energy model includes a solar thermal power station, a wind-storage combined system and a solar-storage combined system; S2. Based on the new energy grid model described in step S1, a new energy grid impact model under sandstorm weather is constructed, wherein the new energy grid impact model includes a transmission line failure rate model and a new energy unit impact model; Add constraints to the transmission line failure rate model: sandstorm movement trajectory, which is expressed as follows: (21)； In the formula, express The location of the sandstorm at any given moment; , Respectively represent the horizontal and vertical coordinates of the initial position of the sandstorm; represents the speed at which the sandstorm moves, and ; Indicates the direction of the sandstorm movement and The angle of the axis; The new energy generating set impact model described in step S2 includes a sandstorm impact solar direct radiation model, a sandstorm impact photovoltaic panel model, a sandstorm impact mirror field model, and a sandstorm impact wind turbine model; Among them, the model of sandstorm affecting direct solar radiation is based on The parameterized C model and the change of aerosol absorption radiation coefficient under sandstorm weather are constructed, and its expression is as follows: (22)； In the formula, is the transmittance of beam radiation in each band; is the solar radiation in the upper atmosphere; is the ozone absorption coefficient; is the Rayleigh molecular scattering coefficient; is the absorption coefficient of uniform mixed gas; is the aerosol absorption radiation coefficient; is the water vapor absorption radiation coefficient; The model expression of the impact of sandstorm on photovoltaic panels is as follows: (23)； (24)； In the formula, is the transmittance of the photovoltaic panel under dust accumulation conditions; is the light transmittance of photovoltaic panel glass under dust accumulation conditions; is the light transmittance of photovoltaic panel glass under clean conditions; is the error function; is the dust accumulation density; , , All represent sandstorm related parameters; The model expression of sandstorm affecting mirror field is as follows: (25)； (26)； In the formula, is the effective light receiving area of ​​the mirror field; is the total area of ​​heliostats in the field; is the total area blocked by dust, in cm 2 ; is the radius of the dust particle, in units of ; is the number of dust particles per unit area of ​​the mirror field; is the angle between the incident light and the mirror field surface; The execution strategy of the sandstorm impact wind turbine model is to perform shutdown operations when the sandstorm speed is not less than 20m / s; S3. Formulate a resilience enhancement strategy based on the impact model of new energy power grid under sandstorm weather described in step S2. The objective function of the resilience enhancement strategy is to build a model with the maximum load increase and total photovoltaic power generation output as the goal. The constraints are: energy storage equipment constraints, unit output constraints, node power balance constraints, branch flow constraints, maintenance constraints and cleaning constraints.

2. The method for improving the resilience of a new energy power grid in sandstorm weather according to claim 1 is characterized in that: The solar thermal power station described in step S1 includes a heat collection system, a heat storage system and a power generation system, wherein: The collector system expression is as follows: (1)； (2)； In the formula, The effective light energy captured by the mirror field of the CSP power station; Direct solar radiation; The heat energy ultimately provided to the mirror field; is the energy loss of the collector system; The heat storage system expression is as follows: (3)； (4)； In the formula, is the heat stored in the thermal storage system; The heat energy provided to the generator through the heat transfer medium; is the heat energy loss of the heat storage system; is the energy storage loss coefficient; The power generation system expression is as follows: (5)； In the formula, for The power output of the solar thermal power station at all times; is the thermoelectric conversion efficiency; express The working status of the steam turbine unit of the CSP power station at all times; The energy consumed in starting the steam turbine unit.

3. The method for improving the resilience of a new energy power grid in sandstorm weather according to claim 2 is characterized in that: The wind-storage combined system expression described in step S1 is as follows: (6)； (7)； (8)； (9)； (10)； (11)； (12)； In the formula, for Total output power of wind turbines in the wind-storage combined system at any given moment; is the rated power of the wind turbine; for The actual wind speed in the area where the wind turbine is located at the moment; is the cut-in wind speed; To cut out the wind speed; To start the wind speed; The maximum wind speed that the wind turbine can withstand; The power provided by the wind turbine to the transmission grid model; The electric energy provided by the wind turbine to the energy storage device; Energy storage equipment connected to wind turbines The amount of power stored at any time; Energy storage equipment connected to wind turbines The amount of power stored at any time; and They represent charging efficiency and discharging efficiency respectively; The electrical energy released for the energy storage device; is the time step; for The electric energy provided by the wind-storage combined system to the transmission grid model at each moment; Indicates the energy storage device connected to the wind turbine The maximum storage capacity at the moment.

4. The method for improving the resilience of a new energy power grid in sandstorm weather according to claim 3 is characterized in that: The expression of the photovoltaic energy storage combined system described in step S1 is as follows: (13)； (14)； (15)； (16)； (17)； (18)； (19)； In the formula, The actual output power of the photovoltaic unit in the photovoltaic and energy storage combined system; is the rated output power of the photovoltaic unit under standard conditions; is the solar radiation received by the photovoltaic unit; is the light intensity under standard conditions; is the power temperature coefficient; is the surface temperature of the photovoltaic panel under working conditions; is the surface temperature of the photovoltaic panel under standard conditions; The electricity provided by the photovoltaic unit to the energy storage device; Release electrical energy to energy storage devices; Energy storage device connected to photovoltaic units The amount of power stored at any time; Energy storage device connected to photovoltaic units The amount of power stored at any time; The electricity provided by the photovoltaic unit directly to the transmission grid model; for The electricity provided by the photovoltaic and energy storage system to the transmission grid at all times; Energy storage equipment connected to photovoltaic units Maximum power storage at all times.

5. The method for improving the resilience of a new energy power grid in sandstorm weather according to claim 4 is characterized in that: The transmission line failure rate model expression described in step S2 is as follows: (20)； In the formula, For transmission lines Failure rate at any time; for The instantaneous wind speed on the transmission line at the moment; V l is the design wind speed of the transmission line; The maximum wind speed that the transmission line can withstand.

6. The method for improving the resilience of a new energy power grid in sandstorm weather according to claim 5 is characterized in that: The objective function of the toughness improvement strategy described in step S3 is as follows: (27)； In the formula, for Complete the maintenance of the selected transmission line nodes at any time The load lifting amount; for Total output of photovoltaic power generation at all times; is the total number of load nodes; The end time of the operation; And the energy storage device constraint expression is as follows: (28)； (29)； (30)； (31)； (32)； In the formula, and are the lower and upper limits of the charging power of the energy storage device connected to the wind-storage combined system, respectively; and are the lower and upper limits of the discharge power of the energy storage equipment connected to the wind-storage combined system, respectively; and The lower and upper limits of the charging power of the energy storage devices respectively connected to the photovoltaic and energy storage combined system; and The lower and upper limits of the discharge power of the energy storage devices respectively connected to the photovoltaic and energy storage combined system; The unit output constraint expression is as follows: (33)； (34)； (35)； (36)； (37)； (38)； (39)； In the formula, and They are the maximum and minimum output of thermal power units respectively; and They are Moment and The output of thermal power units at the moment; and are the maximum and minimum output of the CSP plant respectively; and They are Moment and The output of the CSP plant at the moment; It is the maximum output of the wind-storage combined system; The maximum output of the photovoltaic and energy storage combined system; It is the climbing ability of thermal power unit; The climbing ability of the CSP station; Node power balance constraints (40)； In the formula, , , , and They represent the total number of thermal power units, wind-storage combined systems, solar-thermal power stations, solar-storage combined systems and transmission lines respectively; is the element of the node-generator association matrix; is the element of the association matrix between the node and the wind-storage combined system; is the element of the association matrix between the node and the photovoltaic and energy storage combined system; is the element of the association matrix between the node and the CSP plant; is the element of the association matrix between the node and the branch of the transmission model; for time The load of the node; express Timeline The trend of represents the set of all transmission lines, and , For normal transmission line collection; A collection of faulty transmission lines; express time The load increase of the node; The branch power flow constraint expression is as follows: (41)； (42)； (43)； (44)； (45)； In the formula, and They are Timeline and lines The trend; and Line and lines Reactance; To express Timeline A binary variable for the state in which the line is selected When repairing, is 1, otherwise it is 0; is the maximum capacity of the transmission line; for Time Node The phase angle of and Node Maximum and minimum values ​​of the phase angle; and They are Time Node and nodes The voltage phase angle; The maintenance constraint expression is as follows: (46)； In the formula, Under normal circumstances Time Node The load capacity; The clean constraint expression is as follows: (47)； (48)； (49)； In the formula, It indicates the output of CSP power station in the post-disaster recovery phase; It represents the output of the photovoltaic and storage combined system during the post-disaster recovery phase; Indicates the cleaning work stage The CSP power station outputs power at all times; Indicates the cleaning work stage The output of the solar-storage combined system at all times; Binary variable representing cleaning work, when cleaning work is performed is 1 if the value is true, otherwise it is 0.

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