A double-layer optimization method for operation of a fish-light storage complementary system

Abstract

The present application relates to a kind of fishlight storage complementary system operation double-layer optimization method, comprising: the parameter data of photovoltaic equipment and energy storage equipment are collected, and select feeding equipment, aerator and irrigation equipment as load, construct fishlight storage complementary system model;Net load upper objective function of fishlight storage complementary system considering light rejection rate is constructed, optimization is solved, and the system net load and energy storage charge-discharge power of each period are obtained;Photovoltaic system grid-connected risk safety judgment is carried out, if not satisfied, then increase light rejection rate and optimize again to solve;If satisfied, then construct the lower objective function of fishlight storage complementary system low-carbon economic operation considering carbon emissions and the lowest comprehensive operation cost, optimization is solved, and the output power of each photovoltaic equipment and energy storage equipment is obtained.Compared with prior art, the present application can effectively improve photovoltaic consumption rate, system operation economy and energy utilization efficiency under the premise of meeting system load demand and safe operation constraints, and reduce carbon emissions.

Description

Technical Field

[0001] This invention relates to the field of fishery-solar-storage complementary systems, and in particular to a two-layer optimization method for the operation of such systems. Background Technology

[0002] The "fishery-solar-storage" complementary integrated energy system is one of the typical representatives of new smart fisheries. However, there is currently little research and analysis on the optimized configuration and safe and coordinated operation of the "fishery-solar-storage" complementary system specifically for the photovoltaic, energy storage and typical aquaculture loads in fish farms.

[0003] Current research on integrated energy systems related to fisheries mostly focuses on the parameter optimization of individual typical equipment, and often only considers one aspect such as capacity configuration or optimized control. There is limited analysis of the typical load characteristics of aquaculture, and insufficient consideration is given to the safety risks of grid-connected photovoltaic systems in "fishery-solar-storage" systems. With the advancement of the construction of all-electric "fishery-solar-storage" fish farms, in order to balance the absorption of photovoltaic power, energy storage output, and load demand, it is necessary to conduct in-depth research on low-carbon operation optimization methods for complementary "fishery-solar-storage" systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a two-layer optimization method for the operation of a fishery-solar-storage complementary system, thereby improving the photovoltaic absorption rate, system operation economy and energy utilization efficiency, and reducing carbon emissions.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A two-level optimization method for operating a fishery-solar-storage complementary system includes the following steps:

[0007] Collect parameter data of photovoltaic equipment and energy storage equipment, and select feeding equipment, aerators and irrigation and drainage equipment as loads to construct a load power consumption model of aquaculture equipment, thereby constructing a fishery-solar-storage complementary system model;

[0008] An upper-level objective function for the net load of the fishery-solar-storage complementary system considering the curtailment rate is constructed, and corresponding constraints are set, including curtailment rate constraints, energy storage device charging and discharging and charge number constraints. The fishery-solar complementary system model is optimized and solved to obtain the system net load and energy storage charging and discharging power for each time period.

[0009] Considering the voltage deviation, voltage fluctuation, and harmonic levels at the photovoltaic grid connection point of the fishery-solar-storage complementary system, a safety assessment of the photovoltaic system's grid connection risk is conducted. If the assessment conditions are not met, the curtailment rate in the upper-level objective function calculation process is increased, and the optimization solution is sought again. If the assessment conditions are met, based on the obtained optimal curtailment rate, system net load, and energy storage charging and discharging power, a lower-level objective function for the low-carbon economic operation of the fishery-solar-storage complementary system, considering the lowest carbon emissions and overall operating costs, is constructed. Corresponding constraints are set, including system power balance constraints and transmission line capacity constraints. The fishery-solar-storage complementary system model is then optimized to obtain the output power of each photovoltaic device and energy storage device, which serves as the system's collaborative operation optimization scheme.

[0010] Furthermore, the expression for the upper-level objective function of the net load of the fishery-solar-storage complementary system considering the light curtailment rate is as follows:

[0011]

[0012] P D，1 =W D (1) / Δt

[0013] In the formula, F1 is the upper-level objective function of the net load of the fishery-solar-storage complementary system considering the curtailment rate, and P D,t The net load of the system during time period t. P represents the system's daily average load. D，1 W represents the initial load of the system during the day. D (1) represents the initial total daily electricity consumption of the system, Δt represents the time interval between each period, and ω pv,t Let ω be the light rejection rate of the system during time period t, 0≤ω pv,t ≤1, P pv,t Let P be the photovoltaic power generation of the system during time period t. d,t P represents the discharge power of the energy storage system during time period t. c,t The charging power of the energy storage system during period t, η d η represents the discharge efficiency of the system energy storage device. c The charging efficiency of the system's energy storage device is given by T, which represents the total daily cycle.

[0014] Furthermore, the expression for the light rejection rate constraint is:

[0015] 0≤ω pv,t ≤1

[0016] The expression for the charging and discharging of the energy storage device and the constraint on the number of charges is as follows:

[0017]

[0018] In the formula, P c,max P is the maximum charging power of the energy storage system. d,max u is the maximum discharge power of the energy storage system.c,t For the energy storage system, the charging state during time period t, u d,t Q represents the discharge state of the energy storage system during time period t. soc,t Let Q be the charge of the energy storage device during time period t. soc,min Q is the minimum allowable charge number of the energy storage device. soc,max This represents the maximum allowable charge of the energy storage device.

[0019] Furthermore, the grid connection risk assessment of the photovoltaic system includes: risk assessment of voltage deviation caused by distributed photovoltaic grid connection, risk assessment of voltage fluctuation at the common coupling point of distributed photovoltaic grid connection, and risk assessment of harmonics in distributed photovoltaic grid connection;

[0020] The expression for judging the voltage deviation risk caused by distributed photovoltaic grid connection is:

[0021] U PV,t ≤U PVref,max

[0022]

[0023] In the formula, U PV,t U is the photovoltaic voltage at the grid connection point during time period t. PVref,max U0 is the upper limit of the allowable reference voltage at the grid connection point, R is the line resistance from the grid connection point to the bus, X is the line reactance from the grid connection point to the bus, and P is the upper limit of the allowable reference voltage at the grid connection point. t Q represents the active power of the load at the grid connection point during time period t. t Q represents the reactive power of the load at the grid connection point during time period t. PV,t The reactive power of the photovoltaic grid connection during time period t;

[0024] The expression for judging the voltage fluctuation risk at the common coupling point of distributed photovoltaic grid connection is as follows:

[0025] ΔU PCC,t ≤U PVref,PCC

[0026]

[0027] ΔS=P PV +jQ PV

[0028] In the formula, ΔU PCC,t For the voltage fluctuation at the photovoltaic grid-connected common coupling point during time period t, U PVref,PCC S is the allowable reference voltage value for the grid connection point. N U is the line's rated apparent power. N The voltage is the line rated voltage, and ΔS is the apparent power change after photovoltaic installation. The impedance angle is the equivalent impedance of the system, θ is the power factor angle of the photovoltaic power source, and j is the imaginary unit;

[0029] The expression for determining the harmonic risk of distributed photovoltaic grid connection is as follows:

[0030]

[0031] In the formula, Let t be the harmonic current generated by the photovoltaic system at the grid connection point. This is a reference value for harmonic current. Z is the photovoltaic current at the grid connection point. eq,load Z is the equivalent surge impedance of the load at the grid connection point. eq,grid The equivalent surge impedance on the grid side, The harmonic voltage generated by the photovoltaic system at the grid connection point during time period t. This is a reference value for harmonic voltage. Z represents the harmonic current generated by the photovoltaic system at the grid connection point during time period t. k To neglect the line impedance of adjacent load nodes when filtering components are not considered, Z L The impedance of adjacent loads is not considered when filtering components are neglected, and n is the total number of nodes in the distribution network.

[0032] Furthermore, if any one of the following conditions is not met: voltage deviation risk judgment caused by distributed photovoltaic grid connection, voltage fluctuation risk judgment at the common coupling point of distributed photovoltaic grid connection, or harmonic risk judgment of distributed photovoltaic grid connection, then the judgment condition is considered not met.

[0033] Furthermore, the expression for increasing the light rejection rate in the calculation process of the upper-level objective function is as follows:

[0034] ω pv,t =ω pv,t +Δω pv

[0035] In the formula, Δω pv The increment is the unit of light waste rate.

[0036] Furthermore, in the aforementioned fishery-solar-storage complementary system model, the expression for calculating the total power consumption of the system is as follows:

[0037] W D (t)=W fee (t)+W oxy (t)+W pum (t)+W other (t)

[0038] In the formula, W D (t) represents the total electricity consumption of the fishery-solar-storage complementary system, W. fee (t) represents the electricity consumption of the feeding equipment, W. oxy (t) represents the electricity consumption of the oxygenation equipment, W pum (t) represents the electricity consumption of irrigation and drainage equipment, W other(t) represents the electricity consumption excluding aquaculture equipment;

[0039]

[0040] In the formula, P fee For the power of the feeding equipment, k f S represents the number of times bait is applied. f V is the distance for bait placement. f P is the speed at which bait is released. oxy For the power of the oxygenation equipment, t o For the working time of the oxygenation equipment, P pum For the power of irrigation and drainage equipment, k p To determine the frequency of water changes in the fish farm, n ac For the scale of fish farming, h p For water exchange volume height, y p This refers to the flow rate of the aerator's water pump.

[0041] Furthermore, the expression for the lower-level objective function of the fishery-solar-storage complementary system, which considers the lowest carbon emissions and overall operating costs, is as follows:

[0042] minF2=C1+C2+C3+C4-C5

[0043] In the formula, F2 is the lower-level objective function for the low-carbon economic operation of the fishery-solar-storage complementary system, which takes into account the lowest carbon emissions and overall operating costs; C1 is the operating cost of the photovoltaic system; C2 is the operating and maintenance cost of the energy storage device; C3 is the carbon trading cost of the system; C4 is the grid purchase cost of the system; and C5 is the grid-connected revenue of the photovoltaic system.

[0044] Furthermore, the formula for calculating the operating cost of the photovoltaic system is as follows:

[0045]

[0046] In the formula, ρ pv P represents the operation and maintenance cost coefficient of the photovoltaic system. pv,t Let T be the photovoltaic power generation of the system during time period t, and T be the total daily period.

[0047] The formula for calculating the operation and maintenance cost of the system's energy storage device is as follows:

[0048]

[0049] In the formula, ρ soc P represents the operation and maintenance cost coefficient for energy storage devices. soc,t Let P be the power of the energy storage system during time period t. d,t P represents the discharge power of the energy storage system during time period t. c,t The charging power of the energy storage system during time period t;

[0050] The formula for calculating the carbon trading cost of the system is as follows:

[0051]

[0052] In the formula, d is the carbon capture cost coefficient, and P buy,t Let C be the amount of electricity the system purchases from the grid during time period t, where Δt is the time interval between each period. i Coal consumption coefficient per unit of electricity;

[0053] The formula for calculating the power purchase cost of the system grid is as follows:

[0054]

[0055] In the formula, p grid,t The electricity price sold on the distribution network during time period t;

[0056] The formula for calculating the grid-connected photovoltaic revenue is as follows:

[0057]

[0058] In the formula, p pvout,t P is the grid-connected purchase price of photovoltaic power during period t. pvout,t The photovoltaic grid-connected power generation during system period t is the amount of electricity generated.

[0059] Furthermore, the expression for the system power balance constraint is:

[0060] P buy,t +P pv,t +P d,t =P D,t +P c,t +P pvout,t

[0061] In the formula, P buy,t P represents the amount of electricity the system purchases from the grid during time period t. pvout,t P represents the grid-connected photovoltaic power generation during time period t of the system. d,t P represents the discharge power of the energy storage system during time period t. c,t The charging power of the energy storage system during time period t, P D,t P represents the net load of the system during time period t. pv,t The photovoltaic power of the system during time period t;

[0062] The expression for the transmission line capacity constraint is:

[0063] 0 < P buy,t <P Lmax

[0064] In the formula, P Lmax This represents the maximum transmission power of the power transmission line.

[0065] Compared with the prior art, the present invention has the following advantages:

[0066] The proposed dual-layer optimization method for the operation of the fishery-solar-storage complementary system first solves the objective function of the system net load considering the optimal absorption rate based on the system net load and the system's daily average load. Then, it introduces a discriminant formula that considers the grid connection safety risk of the photovoltaic system to adjust the curtailment rate and achieve the optimal photovoltaic absorption of the "fishery-solar-storage" system on the basis of ensuring the safe and stable operation of the system.

[0067] Then, based on the optimal curtailment rate and the net load and energy storage charging and discharging power obtained from the solution, the lower objective function of the low-carbon economic operation of the fishery-solar-storage complementary system is solved according to the minimum carbon emissions and comprehensive operating costs. The output power of each photovoltaic device and energy storage device is obtained, which improves the economic operation of the entire system and reduces the carbon emission level.

[0068] Overall, this invention can effectively coordinate the fluctuations in photovoltaic output of the "fishery-solar-storage" system with the charging and discharging power of the energy storage device. Under the premise of meeting system load requirements and safe operation constraints, it can effectively improve the photovoltaic absorption rate, system operation economy and energy utilization efficiency, and reduce carbon emissions. Attached Figure Description

[0069] Figure 1 This is a flowchart illustrating a two-layer optimization method for the operation of a fishery-solar-storage complementary system provided in an embodiment of the present invention;

[0070] Figure 2 This is a schematic diagram of a typical distributed photovoltaic grid-connected structure provided in an embodiment of the present invention;

[0071] Figure 3 This is a schematic diagram of an equivalent circuit for analyzing grid-connected photovoltaic voltage fluctuations provided in an embodiment of the present invention;

[0072] Figure 4 This is a schematic diagram of an equivalent circuit of a photovoltaic grid-connected harmonic source provided in an embodiment of the present invention. Detailed Implementation

[0073] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0074] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0075] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0076] Example 1

[0077] like Figure 1 As shown, this embodiment provides a two-layer optimization method for the operation of a fishery-solar-storage complementary system, including the following steps:

[0078] S1: Collect parameter data of energy equipment and energy-consuming equipment such as photovoltaic equipment and energy storage equipment in the fishery-solar-storage complementary system, data such as grid connection line parameters of the photovoltaic system, and basic data of fishery load during typical periods. Consider the typical aquaculture operation mode of fishery, and select three important typical loads as loads: feeding equipment, aerators and drainage and irrigation (filtration and replacement) equipment. Construct a load power consumption model of typical aquaculture equipment in the "fishery-solar-storage" system, thereby constructing a fishery-solar-storage complementary system model.

[0079] The typical power consumption model for aquaculture equipment in the "aquaculture-solar-storage" system is as follows:

[0080]

[0081] In the formula: W fee W oxy W pum Electricity consumption for feeding, aeration, and irrigation / drainage equipment, in kW·h; P fee P oxy P pum Power of feeding, aeration, and irrigation / drainage equipment, in kW; S f V represents the distance from which bait is placed, in meters (m). f The speed at which bait is released is expressed in m / s; k f t represents the number of times bait is placed; o The operating time of the aeration equipment is in hours (h); yp is the flow rate of the aerator's water pump (m³). 3 / h;n ac For the scale of fish farming, m 2 ;k p Frequency of water change in the fish farm; h p The height for water exchange is in meters (m).

[0082] The comprehensive load of the "fishery-solar-storage" system is defined as:

[0083] W D (t)=W fee (t)+W oxy (t)+W pum (t)+W other (t)

[0084] In the formula, W D The total electricity consumption of the "fishery-solar-storage" system is W. other This includes electricity consumption other than that for aquaculture equipment, including but not limited to system lighting, domestic electricity, central air conditioning, and factory electricity.

[0085] S2: Considering the photovoltaic output characteristics of the "fishery-solar-storage" system, curtailment constraints, and energy storage device charge / discharge and capacity constraints, construct the relevant constraints of the upper-level objective function:

[0086] 1) Waste light rate constraint

[0087] 0≤ω pv,t ≤1

[0088] In the formula, ω pv,t This represents the system's light rejection rate.

[0089] 2) Energy storage device charging and discharging and charge number constraints

[0090]

[0091] In the formula, P c,max P is the maximum charging power of the energy storage system. d,max is the maximum discharge power of the energy storage system; d and tu represent the energy storage charging and discharging states, respectively. Both are variables of 0 and 1, indicating that the energy storage device can only operate in one of the three states: charging, discharging, and standby.

[0092]

[0093] In the formula, Q soc,min Q is the minimum allowable charge number of the energy storage device. soc,min This represents the maximum allowable charge number of the energy storage device; simultaneously, the energy storage device operates continuously, ensuring that the initial and final values ​​of the energy storage charge number are equal throughout the cycle.

[0094] S3: Based on the proposed constraints, construct the upper objective function of the net load of the fishery-solar-storage complementary system considering the curtailment rate, and perform optimization to obtain the system net load and energy storage charging and discharging power for each time period;

[0095] The upper-level objective function is as follows:

[0096]

[0097] P D，1=W D (1) / Δt

[0098] In the formula, P D,t P represents the net load of the system during time period t. D,t When P > 0, it indicates that the system's internal energy equipment cannot meet the demand, and electricity needs to be purchased from the grid. D,t When P = 0, it indicates that the supply and demand within the system are in balance. D,t When P < 0, it indicates that the output of the internal energy equipment exceeds the load demand, the energy storage device cannot absorb the excess photovoltaic power generation, and the excess photovoltaic output participates in grid connection; av D P represents the system's daily average load. D,1 This represents the initial load of the system during the day; ω pv,t The system's light rejection rate, 0≤ω pv,t ≤1, for the first calculation, take ω pv,t =0, meaning that all excess photovoltaic power generation participates in grid connection at this time; η c η d These represent the charging and discharging efficiencies of the system's energy storage device, where 0 < η. c <1,0<η d <1; T is the total daily period, and T is 24.

[0099] S4: Considering the voltage deviation, voltage fluctuation, and harmonic levels at the photovoltaic grid connection point of the fishery-solar-storage complementary system, conduct a safety assessment of the grid connection risk of the photovoltaic system; specifically:

[0100] 1) Risk assessment of voltage deviation caused by distributed photovoltaic grid connection

[0101] U PV,t ≤U PVref,max

[0102]

[0103] In the formula, U PV,t U is the photovoltaic voltage at the grid connection point during time period t; PVref,max The upper limit of the allowable reference voltage at the grid connection point; R and X are the resistance and reactance of the line from the grid connection point to the bus, respectively; P t Q t U0 represents the load at the grid connection point; U0 represents the bus voltage. Distributed photovoltaic (PV) grid connection alters the power flow distribution of the distribution network, causing voltage fluctuations at various load nodes within the system, potentially leading to voltage exceedances at nodes. A typical distributed PV grid connection structure is shown below. Figure 2 As shown;

[0104] 2) Risk assessment of voltage fluctuations at the common coupling point of distributed photovoltaic grid connection

[0105] ΔU PCC,t ≤U PVref,PCC

[0106]

[0107] ΔS=P PV +jQ PV

[0108] In the formula, ΔU PCC For the voltage fluctuation at the point of common coupling (PCC) of photovoltaic grid connection, U PVref,PCC This is the allowable reference voltage value for the grid connection point; S N The line's rated apparent power is ΔS; ΔS represents the change in apparent power after photovoltaic (PV) grid connection. The equivalent circuit for PV grid-connected voltage fluctuation analysis is as follows: Figure 3 As shown;

[0109] 3) Distributed photovoltaic grid-connected harmonic risk assessment

[0110]

[0111] In the formula, For the harmonic current generated by the photovoltaic system at the grid connection point, This is a reference value for harmonic current; The harmonic voltage generated by the photovoltaic system at the grid connection point. This is the reference value for harmonic voltage; Z eq,load Z is the equivalent surge impedance of the load at the grid connection point. eq,grid Z is the equivalent surge impedance on the grid side; k To neglect the line impedance of adjacent load nodes when filtering components are not considered, Z L Neglecting the impedance of adjacent loads, the equivalent circuit of a photovoltaic grid-connected harmonic source is as follows: Figure 4 As shown.

[0112] S5: If the judgment condition of step S4 is not met, increase the light curtailment rate in the calculation process of the upper objective function in step S3, and solve the net load of the system and the energy storage charging and discharging power again; if the judgment condition is met, construct the power balance constraints and safe operation constraints of the lower model based on the total power supply and load power balance of the "fishery-solar-storage" system and the upper and lower limits of the output of each power supply device and energy storage device.

[0113] Specifically, the expression for increasing the light rejection rate in step S3 is:

[0114] ω pv,t =ω pv,t +Δω pv

[0115] In the formula, Δω pv The increment is the unit of light waste rate.

[0116] The specific power balance constraints and safe operation constraints of the lower-level model are as follows:

[0117] 1) System power balance constraints

[0118] P buy,t +P pv,t +P d,t =P D,t +P c,t +P pvout,t

[0119] In the formula, P buy,t P represents the electricity purchased from the grid during time period t, used to compensate for power shortages when the output of energy equipment within the system is insufficient; pvout,t The total electricity generated by the photovoltaic system connected to the grid is equal to the electricity purchased from the grid by the "fishery-photovoltaic-storage" system and the discharge of the grid-connected photovoltaic and energy storage devices.

[0120] 2) Transmission line capacity constraints

[0121] 0 < P buy,t <P Lmax

[0122] In the formula, P Lmax This represents the maximum transmission power of the power transmission line.

[0123] S6: Based on the desired optimal curtailment rate, system net load, and energy storage charging and discharging power, construct the lower-level objective function for the low-carbon economic operation of the "fishery-solar-storage" system that minimizes carbon emissions and overall operating costs, and perform optimization to obtain the specific output power of each energy supply device in the system that meets the optimization objective, thus forming a system collaborative operation optimization scheme.

[0124] The lower-level objective function is as follows:

[0125] minF2=C1+C2+C3+C4-C5

[0126] In the formula, C1 is the operating cost of the photovoltaic system; C2 is the operating and maintenance cost of the energy storage device; C3 is the carbon trading cost of the system; C4 is the electricity purchase cost of the grid; and C5 is the photovoltaic grid connection revenue.

[0127] 1) Operating cost of the photovoltaic system

[0128]

[0129] In the formula, ρ pv This represents the cost coefficient for the operation and maintenance of the photovoltaic system.

[0130] 2) Operating costs of the system's energy storage device

[0131]

[0132] In the formula, ρ soc This represents the cost coefficient for the operation and maintenance of energy storage devices.

[0133] 3) System carbon trading costs

[0134]

[0135] In the formula, d is the carbon capture cost coefficient (yuan / kg), and C i The unit electricity coal consumption coefficient (kg / kWh) is taken as the standard coal conversion factor of 0.1229 kg / kWh.

[0136] 4) Electricity purchase cost from the power grid

[0137]

[0138] In the formula, p grid,t The electricity price sold on the distribution network during time period t is (yuan / kWh).

[0139] 5) Revenue from grid-connected photovoltaic power

[0140]

[0141] In the formula, p pvout,t The grid-connected purchase price for photovoltaic power during period t is (RMB / kWh).

[0142] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A two-layer optimization method for the operation of a fishery-solar-storage complementary system, characterized in that, Includes the following steps: Collect parameter data of photovoltaic equipment and energy storage equipment, and select feeding equipment, aerators and irrigation and drainage equipment as loads to construct a load power consumption model of aquaculture equipment, thereby constructing a fishery-solar-storage complementary system model; An upper-level objective function for the net load of the fishery-solar-storage complementary system considering the curtailment rate is constructed, and corresponding constraints are set, including curtailment rate constraints, energy storage device charging and discharging and charge number constraints. The fishery-solar complementary system model is optimized and solved to obtain the system net load and energy storage charging and discharging power for each time period. Considering the voltage deviation, voltage fluctuation, and harmonic levels at the photovoltaic grid connection point of the fishery-solar-storage complementary system, a safety assessment of the grid connection risk of the photovoltaic system is conducted. If the assessment conditions are not met, the curtailment rate in the calculation process of the upper objective function is increased, and the optimization solution is performed again. If the assessment conditions are met, based on the obtained optimal curtailment rate, system net load, and energy storage charging and discharging power, a lower objective function for the low-carbon economic operation of the fishery-solar-storage complementary system that minimizes carbon emissions and overall operating costs is constructed. Corresponding constraints are set, including system power balance constraints and transmission line capacity constraints. The fishery-solar-storage complementary system model is optimized and solved to obtain the output power of each photovoltaic device and energy storage device, which serves as the system collaborative operation optimization scheme. The expression for the upper-level objective function of the net load of the fishery-solar-storage complementary system, considering the light curtailment rate, is as follows: In the formula, To consider the upper-level objective function of the net load of the fishery-solar-storage complementary system taking into account the curtailment rate, For the system t Net load during the period This represents the system's daily average load. This represents the initial load of the system during the day. This represents the system's initial total daily electricity consumption. The time interval between each period. For the system t Time-limited light rejection rate, 0≤ ω pv,t ≤1, For the system t Photovoltaic power generation during the period For energy storage systems t Discharge power over time period For energy storage systems t Charging power during different time periods The discharge efficiency of the system's energy storage device. To improve the charging efficiency of the system's energy storage device. T The total daily cycle; The expression for the lower-level objective function of the fishery-solar-storage complementary system, which considers the lowest carbon emissions and overall operating costs, is as follows: In the formula, To achieve the lowest possible carbon emissions and overall operating costs for a fishery-solar-storage complementary system, the lower-level objective function is needed for low-carbon economic operation. C 1 represents the operating cost of the photovoltaic system; C 2 represents the operation and maintenance costs of the system's energy storage device; C 3 represents the system's carbon trading costs. C 4 represents the system's grid purchase cost. C 5 represents the revenue from grid-connected photovoltaic power.

2. The dual-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 1, characterized in that, The expression for the waste rate constraint is: The expression for the charging and discharging of the energy storage device and the constraint on the number of charges is as follows: In the formula, This represents the maximum charging power of the energy storage system. This represents the maximum discharge power of the energy storage system. For energy storage systems t Charging status during the period, For energy storage systems t Discharge state during a certain period of time For energy storage devices t Charge count during the time period The minimum charge number allowed for the energy storage device. This represents the maximum allowable charge of the energy storage device.

3. The dual-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 1, characterized in that, The grid connection risk assessment of the photovoltaic system includes: risk assessment of voltage deviation caused by distributed photovoltaic grid connection, risk assessment of voltage fluctuation at the common coupling point of distributed photovoltaic grid connection, and risk assessment of harmonics caused by distributed photovoltaic grid connection; The expression for judging the voltage deviation risk caused by distributed photovoltaic grid connection is: In the formula, for t Photovoltaic voltage at grid connection point during the time period, This is the upper limit of the allowable reference voltage at the grid connection point. Bus voltage The resistance of the line from the grid connection point to the busbar. For the line reactance from the grid connection point to the busbar, for t Active power of load at grid connection point during time period for t Reactive power of load at grid connection point during time period for t Reactive power of grid-connected photovoltaic systems during specific time periods; The expression for judging the voltage fluctuation risk at the common coupling point of distributed photovoltaic grid connection is as follows: In the formula, for t Voltage fluctuations at the photovoltaic grid-connected common coupling point during the period This is the allowable reference voltage value for the grid connection point. The line's rated apparent power. This is the line's rated voltage. This refers to the change in apparent power after photovoltaic (PV) grid connection. The impedance angle is the equivalent impedance of the system. The power factor angle of the photovoltaic power source. The imaginary unit; The expression for determining the harmonic risk of distributed photovoltaic grid connection is as follows: In the formula, for t Harmonic currents generated by the photovoltaic system at the grid connection point during certain periods. This is a reference value for harmonic current. For the photovoltaic current at the grid connection point, The equivalent surge impedance of the load at the grid connection point, The equivalent surge impedance on the grid side, for t Harmonic voltage generated by the photovoltaic system at the grid connection point during the specified time period. This is a reference value for harmonic voltage. For t Harmonic currents generated by the photovoltaic system at the grid connection point during certain periods. Neglecting the line impedance of adjacent load nodes, Neglecting the impedance of adjacent loads, This represents the total number of nodes in the distribution network.

4. The dual-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 3, characterized in that, If any one of the following conditions is not met: voltage deviation risk judgment caused by distributed photovoltaic grid connection, voltage fluctuation risk judgment at the common coupling point of distributed photovoltaic grid connection, or harmonic risk judgment of distributed photovoltaic grid connection, then the judgment condition is considered not met.

5. The two-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 1, characterized in that, The expression for the light rejection rate in the process of increasing the upper-level objective function is as follows: In the formula, The increment is the unit of light waste rate.

6. The two-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 1, characterized in that, In the aforementioned fishery-solar-storage complementary system model, the formula for calculating the total power consumption of the system is as follows: In the formula, This represents the total electricity consumption of the fishery-solar-storage complementary system. Electricity consumption for the feeding equipment Electricity consumption for oxygenation equipment, Electricity consumption for irrigation and drainage equipment This refers to electricity consumption excluding that used for aquaculture equipment. In the formula, For the power of the feeding equipment, The number of times to feed, Distance for bait placement To increase the speed of bait distribution, For the power of the oxygenation equipment, Operating time of the oxygenation equipment. For the power of irrigation and drainage equipment, The frequency of water changes in the fish farm. For the scale of fish farming, For water exchange volume height, This refers to the flow rate of the aerator's water pump.

7. The two-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 1, characterized in that, The formula for calculating the operating cost of the photovoltaic system is as follows: In the formula, ρ pv This is the coefficient for the operation and maintenance costs of the photovoltaic system. For the system t Photovoltaic power generation during the period T The total daily cycle; The formula for calculating the operation and maintenance cost of the system's energy storage device is as follows: In the formula, This is the coefficient for the operation and maintenance costs of energy storage devices. For energy storage systems t Power of charge during time period For energy storage systems t Discharge power over time period For energy storage systems t Charging power during a specific time period; The formula for calculating the carbon trading cost of the system is as follows: In the formula, d The carbon capture cost coefficient. For the system's electricity purchase from the grid during time period t, The time interval between each period. C i Coal consumption coefficient per unit of electricity; The formula for calculating the power purchase cost of the system grid is as follows: In the formula, p grid,t The electricity price sold on the distribution network during time period t; The formula for calculating the grid-connected photovoltaic revenue is as follows: In the formula, The grid-connected purchase price for photovoltaic power generation during period t. The photovoltaic grid-connected power generation during system period t is the amount of electricity generated.

8. The two-layer optimization method for the operation of a fishery-solar-storage complementary system according to claim 1, characterized in that, The expression for the system power balance constraint is: In the formula, P buy,t For the system's electricity purchase from the grid during time period t, P pvout,t For the system's photovoltaic grid-connected power generation during time period t, For energy storage systems t Discharge power over time period For energy storage systems t Charging power during different time periods For the system t Net load during the period For the system t Photovoltaic power during a given time period; The expression for the transmission line capacity constraint is: In the formula, This represents the maximum transmission power of the power transmission line.

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