Optical storage direct-flexible full-direct-current energy network system and energy optimization scheduling method thereof

Abstract

The invention provides an optical storage direct-flexible full direct-current energy network and an energy optimization scheduling method thereof, the optical storage direct-flexible full direct-current energy network comprises a full direct-current energy network main power distribution cabinet, and a water electrolysis hydrogen production system and a hydrogen fuel cell power generation system are connected to the full direct-current energy network main power distribution cabinet through circuit breakers; the plurality of light storage direct-current flexible energy quantum stations are sequentially interconnected through the energy network contact cabinet, and the energy subsystem is connected with the full-direct-current energy network main power distribution cabinet through contact cables of the light storage direct-current flexible energy quantum stations; the full-direct-current energy network management system sends a corresponding control instruction to a full-direct-current energy network main power distribution cabinet or each lower-layer energy subsystem according to an operation strategy, and when the load distribution of the light-storage direct-current flexible energy quantum stations is not uniform, deploying the deployable electric quantity to turn the surplus electric energy of the light-storage direct-current flexible energy quantum stations into the light-storage direct-current flexible energy quantum stations with insufficient electric energy; according to the invention, the optical storage direct-current flexible system is separated from the alternating-current power grid, and the renewable energy utilization efficiency and the flexible adjustment capability of the optical storage direct-current flexible system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network optimization control, and in particular to a photovoltaic storage direct-flexible full-DC energy network system and an energy optimization scheduling method thereof. Background Art

[0002] Most of the existing conventional PV-storage DC-flexible systems are independent and unrelated to each other, which means that the surplus DC power in adjacent PV-storage DC-flexible systems cannot be directly delivered to the PV-storage DC-flexible system with insufficient power, and can only be sent to the AC grid through inverter first. Similarly, the PV-storage DC-flexible system with insufficient power cannot directly obtain the surplus DC power of other PV-storage DC-flexible systems, and can only obtain electricity from the grid through another AC-DC inverter. The setting of a large number of bidirectional inverters and repeated AC-DC conversion greatly reduces the utilization efficiency of renewable energy and causes a certain amount of energy waste.

[0003] In addition, although the photovoltaic storage direct-flexible system has a flexible adjustment function, due to the randomness, volatility and intermittency of photovoltaic power generation, the access of a large number of photovoltaic storage direct-flexible systems during peak and valley periods of energy consumption will inevitably have a certain impact on the power grid.

[0004] In view of this, there is an urgent need to provide a photovoltaic storage direct-flexible system that is independent of the AC power grid, as well as an operation control strategy for the system. Summary of the invention

[0005] In order to overcome the problems existing in the related art, the present disclosure provides a photovoltaic energy storage direct-flexible full DC energy network system and its operation control method to solve the technical problems in the related art.

[0006] One or more embodiments of this specification provide a photovoltaic-storage-direct-flexible full-DC energy grid system, including:

[0007] The main power distribution cabinet of the full DC energy network, the water electrolysis hydrogen production system, and the hydrogen fuel cell power generation system are connected to the main power distribution cabinet of the full DC energy network through circuit breakers respectively;

[0008] An energy subsystem consisting of a photovoltaic storage direct-flexible energy substation group, wherein multiple photovoltaic storage direct-flexible energy substations are interconnected in sequence through circuit breakers, and the energy subsystem is connected to the main distribution cabinet of the full DC energy network through the interconnection cable of the photovoltaic storage direct-flexible energy substation; wherein each photovoltaic storage direct-flexible energy substation includes a photovoltaic power generation unit, an electrochemical energy storage device and a DC power-consuming device; and

[0009] It also includes a full DC energy network management system for formulating the operation strategy of the photovoltaic storage direct and flexible full DC energy network system. The full DC energy network management system sends corresponding control instructions to the full DC energy network main distribution cabinet or each lower-level energy subsystem according to the operation strategy it generates. When the load distribution of each photovoltaic storage direct and flexible energy substation is uneven, the deployable electricity is used to transfer the surplus electricity of the photovoltaic storage direct and flexible energy substation to the photovoltaic storage direct and flexible energy substation that is short of electricity, so as to realize the electricity allocation between the photovoltaic storage direct and flexible energy substations, and realize the electricity exchange between the photovoltaic storage direct and flexible energy substation and the full DC energy network main distribution cabinet during various periods of photovoltaic power generation and periods when photovoltaic power generation is not in progress.

[0010] One or more embodiments of this specification provide an energy optimization scheduling method for a photovoltaic-storage-direct-flexible all-DC energy grid system, including the following steps:

[0011] Establish mathematical models of photovoltaic modules, electrochemical energy storage devices, water electrolysis hydrogen production systems, hydrogen storage models, and hydrogen fuel cell power generation systems;

[0012] Taking the highest comprehensive energy utilization efficiency of the network and the minimum line loss as the objective function, a scheduling optimization model for the photovoltaic, storage, direct and flexible full DC energy network is constructed; and

[0013] By using a multi-objective genetic algorithm, the optimization model is solved according to the constraints, and the optimal scheduling strategy for the participation of hydrogen energy storage and photovoltaic storage, direct and flexible energy substations in the photovoltaic storage, direct and flexible DC energy network is obtained. The constraints include the electric power balance constraints of each photovoltaic storage, direct and flexible energy substation, the overall electric power balance constraints of the entire DC energy network, the DC bus voltage constraints and the constraints on equipment operating performance.

[0014] One or more embodiments of the present specification provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the energy optimization scheduling method for the photovoltaic-storage-direct-flexible all-DC energy grid system as described above when executing the computer program.

[0015] The present invention provides a photovoltaic, direct-current, flexible full-DC energy grid system and its energy optimization scheduling method, which have the advantages of interconnecting multiple photovoltaic, direct-current, flexible energy substations in sequence through circuit breakers and interconnecting with the full-DC energy grid main distribution cabinet. The optimization control strategy formulated by the full-DC energy grid management system can realize direct energy interaction between the photovoltaic, direct-current, flexible energy substations, and also can realize energy interaction between the photovoltaic, direct-current, flexible energy substations and the full-DC energy grid main distribution cabinet, thereby realizing energy interconnection between adjacent photovoltaic, direct-current, flexible energy systems and improving the utilization efficiency and flexible regulation capability of renewable energy in the photovoltaic, direct-current, flexible energy systems. In addition, the water electrolysis hydrogen production system and the hydrogen fuel cell power generation system regulate the full-DC energy grid during peak and valley periods, so that the photovoltaic, direct-current, flexible energy system is separated from the AC power grid to avoid its impact on the power grid during peak and valley periods. In the whole process of converting green hydrogen into electrical energy by the hydrogen fuel cell power generation system, no carbon monoxide and carbon dioxide are generated, which also makes the photovoltaic, direct-current, flexible energy system achieve zero carbon emissions in the true sense. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the structure of a photovoltaic-storage-direct-flexible all-DC energy network system provided for one or more embodiments of this specification;

[0018] Figure 2 A topological diagram of a total power distribution cabinet for a full DC energy network provided in one or more embodiments of this specification;

[0019] Figure 3 A topology diagram of a direct-flexible energy substation for solar energy storage provided in one or more embodiments of this specification;

[0020] Figure 4 A schematic diagram of another structure of a photovoltaic-storage-direct-flexible all-DC energy network system provided for one or more embodiments of this specification;

[0021] Figure 5 A flow chart of an energy optimization scheduling method for a photovoltaic-storage-direct-flexible all-DC energy grid system provided in one or more embodiments of this specification;

[0022] Figure 6 A control relationship diagram of a full DC energy network management system provided for one or more embodiments of this specification;

[0023] as well as

[0024] Figure 7 A schematic diagram of the structure of a computer device provided for one or more embodiments of this specification. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] The present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings.

[0027] System Example

[0028] According to an embodiment of the present invention, a photovoltaic energy storage direct-flexible full DC energy network system is provided, such as Figure 1 As shown, it is a schematic diagram of the architecture of the photovoltaic storage direct-flexible full DC energy network system provided in this embodiment. The photovoltaic storage direct-flexible full DC energy network system according to an embodiment of the present invention includes:

[0029] The main power distribution cabinet of the full DC energy network, the water electrolysis hydrogen production system, and the hydrogen fuel cell power generation system are connected to the main power distribution cabinet of the full DC energy network through circuit breakers respectively;

[0030] The energy subsystem consists of a group of photovoltaic storage direct-flexible energy substations, where multiple photovoltaic storage direct-flexible energy substations are interconnected in sequence through circuit breakers, and the energy subsystem is connected to the main distribution cabinet of the full DC energy network through the interconnection cable of the photovoltaic storage direct-flexible energy substation; wherein each photovoltaic storage direct-flexible energy substation includes a photovoltaic power generation unit, an electrochemical energy storage device and DC power equipment;

[0031] A full DC energy network management system used to formulate the operation strategy of the photovoltaic storage direct and flexible full DC energy network system. The full DC energy network management system sends corresponding control instructions to the full DC energy network main distribution cabinet or each lower-level energy subsystem according to the operation strategy it generates. When the load distribution of each photovoltaic storage direct and flexible energy substation is uneven, the deployable electricity is used to transfer the surplus electricity of the photovoltaic storage direct and flexible energy substation to the photovoltaic storage direct and flexible energy substation that is short of electricity, so as to realize the electricity allocation between the photovoltaic storage direct and flexible energy substations, and realize the electricity exchange between the photovoltaic storage direct and flexible energy substations and the full DC energy network main distribution cabinet during various periods of photovoltaic power generation and periods when photovoltaic power generation is not in progress.

[0032] The photovoltaic, direct and flexible energy grid system provided in this embodiment interconnects multiple photovoltaic, direct and flexible energy substations in sequence through circuit breakers, and interconnects them with the main distribution cabinet of the full DC energy grid. The optimization control strategy formulated by the full DC energy grid management system can realize direct energy interaction between each photovoltaic, direct and flexible energy substation, and also can realize energy interaction between each photovoltaic, direct and flexible energy substation and the main distribution cabinet of the full DC energy grid, thereby realizing energy interconnection between adjacent photovoltaic, direct and flexible energy systems, improving the utilization efficiency and flexible regulation capability of renewable energy in the photovoltaic, direct and flexible energy grid system, and the water electrolysis hydrogen production system and the hydrogen fuel cell power generation system regulate the full DC energy grid during peak and valley periods, so that the photovoltaic, direct and flexible energy system is separated from the AC power grid to avoid its impact on the power grid during peak and valley periods. The hydrogen fuel cell power generation system converts green hydrogen into electricity in the whole process without producing carbon monoxide and carbon dioxide, which also makes the photovoltaic, direct and flexible energy grid system truly zero-carbon emission.

[0033] In this embodiment, references 2 and 3 are respectively a topological diagram of a total distribution cabinet of a full DC energy network and a topological diagram of a photovoltaic storage direct flexible energy substation provided in this embodiment.

[0034] refer to Figure 2 The water electrolysis hydrogen production system and the hydrogen fuel cell power generation system are respectively connected to the centralized DC bus of the full DC energy network main distribution cabinet through the DC / DC converter and the first circuit breaker. The full DC energy network main distribution cabinet can provide 750V DC power;

[0035] refer to Figure 3 The photovoltaic power generation unit and load (DC power equipment) in the photovoltaic direct-flexible energy substation are connected to the DC bus through the DC / DC converter and the second circuit breaker, and the electrochemical energy storage device is connected to the DC bus through the third circuit breaker. The DC buses of each photovoltaic direct-flexible energy substation are connected in sequence through the fourth circuit breaker to realize the interconnection of the photovoltaic direct-flexible energy substations in sequence, and the DC bus of any photovoltaic direct-flexible energy substation is connected to the centralized DC bus through the fifth circuit breaker.

[0036] In this embodiment, reference Figure 4 As shown, multiple energy network interconnection cabinets are set between the photovoltaic storage direct-flexible energy substations for connecting them in series, and the fourth circuit breaker is set in the energy network interconnection cabinet, so that the energy network interconnection cabinet can receive commands from the full DC energy network management system to control the opening and closing of the fourth circuit breaker. In this embodiment, the energy network interconnection cabinet is a combination device consisting of a fourth circuit breaker, a bidirectional metering electric energy meter and a cabinet.

[0037] This embodiment is based on the above-mentioned full DC energy network management system and sets the following scheduling strategy for optimizing the photovoltaic, storage, direct and flexible full DC energy network according to different power consumption periods. The scheduling strategy specifically includes the following situations.

[0038] (1) Period when photovoltaic power generation is not in progress

[0039] During the period when photovoltaic power generation is not in progress, the electricity for the entire photovoltaic-storage-direct-flexible full-DC energy network is supplied by the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each photovoltaic-storage-direct-flexible energy substation. At this time, the water electrolysis hydrogen production system is not put into operation.

[0040] In this mode, the output of each device in each time period is calculated and generated by the photovoltaic storage direct and flexible full DC energy network management system through the NSGA-II algorithm, and then converted into a control signal, which is sent to the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each substation through the control cable / wireless communication / optical cable. At the same time, the photovoltaic storage direct and flexible full DC energy network management system will also send control instructions to the main distribution cabinet of the full DC energy network and the interconnection cabinets of each lower-level energy network to close the incoming circuit breaker and interconnection circuit breaker in the main distribution cabinet and the fourth circuit breaker in the energy network interconnection cabinet to which each photovoltaic storage direct and flexible energy substation that the NSGA-II algorithm determines needs to be interconnected, so that the electric energy is transmitted to each photovoltaic storage direct and flexible energy substation through the interconnection cable and the interconnection cable of the corresponding photovoltaic storage direct and flexible energy substation at the lower level, so as to be used by the power load of each photovoltaic storage direct and flexible energy substation.

[0041] (2) Photovoltaic power generation period, which can be divided into the following operating modes:

[0042] 1) The electric energy required by the photovoltaic, storage, direct and flexible full DC energy grid is provided by photovoltaic power generation units, electrochemical energy storage devices and hydrogen fuel cell power generation systems at the same time, and the water electrolysis hydrogen production system is not put into use.

[0043] In this mode, the output of each device in each time period is calculated and generated by the full DC energy network management system through the NSGA-II algorithm, and then converted into a control signal, which is sent to the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each substation through the control cable / wireless communication / optical cable. At the same time, the full DC energy network management system will also send control instructions to the full DC energy network main distribution cabinet and the lower-level energy network interconnection cabinets to close the incoming circuit breaker and interconnection circuit breaker in the full DC energy network main distribution cabinet and the fourth circuit breaker in the energy network interconnection cabinet to which each photovoltaic storage direct and flexible energy substation that the NSGA-II algorithm determines needs to be interconnected, so that the electric energy is transmitted to each photovoltaic storage direct and flexible energy substation through the interconnection cable and the interconnection cable of the corresponding photovoltaic storage direct and flexible energy substation in the lower layer, so as to be used by the power load of each photovoltaic storage direct and flexible energy substation.

[0044] 2) The electricity of the photovoltaic, storage and direct-flexible full-DC energy grid is provided by photovoltaic power generation units and electrochemical energy storage devices, and neither the hydrogen fuel cell power generation system nor the water electrolysis hydrogen production system is put into use.

[0045] In this mode, the output of each device in each time period is calculated and generated by the photovoltaic storage direct flexible full DC energy network management system through the NSGA-II algorithm, and then converted into a control signal, which is sent to the electrochemical energy storage device of each photovoltaic storage direct flexible energy substation through control cables / wireless communications / optical cables, etc. At the same time, the photovoltaic storage direct flexible full DC energy network management system will also send control instructions to the full DC energy network main distribution cabinet and each lower-level energy network interconnection cabinet to open the incoming circuit breaker and interconnection circuit breaker in the full DC energy network main distribution cabinet, close the fourth circuit breaker in the energy network interconnection cabinet to which each photovoltaic storage direct flexible energy substation that the NSGA-II algorithm determines needs to be interconnected, and open the circuit breaker in the energy network interconnection cabinet of the substation that does not need to be interconnected during this period, so that the electric energy of each substation can be reasonably distributed.

[0046] 3) The electricity of the photovoltaic, storage and direct-flexible full-DC energy grid is provided by photovoltaic power generation. The electrochemical energy storage device serves as the power load and enters the charging state. Neither the hydrogen fuel cell power generation system nor the water electrolysis hydrogen production system is put into operation.

[0047] In this mode, after the charging power of the electrochemical energy storage device of each photovoltaic direct-flexible energy substation is generated by the full DC energy grid management system, the control signal is sent to the corresponding electrochemical energy storage device through wireless communication / optical cable. At the same time, the fourth circuit breaker in the energy grid interconnection cabinet corresponding to the photovoltaic direct-flexible energy substation that the NSGA-II algorithm determines needs to be interconnected is closed, and the circuit breaker in the energy grid interconnection cabinet of the photovoltaic direct-flexible energy substation that does not need to be interconnected during this period is opened, so that the electric energy of each photovoltaic direct-flexible energy substation can be reasonably distributed.

[0048] The electricity in the above 2) and 3) time periods can be balanced inside the photovoltaic, direct-current and flexible energy substation group, and neither the DC hydrogen electrolysis nor the hydrogen fuel cell power generation systems will be started. This solves the problem that the surplus DC electricity in adjacent photovoltaic, direct-current and flexible systems in the photovoltaic, direct-current and flexible full DC energy grid system cannot be directly allocated and utilized under unstable photovoltaic power generation, solves the system's AC / DC conversion losses, improves the robustness of the configuration scheme, reduces the AC / DC conversion losses of photovoltaic power generation and energy storage, and improves energy utilization.

[0049] 4) The electricity of the photovoltaic storage direct flexible full DC energy grid is only provided by photovoltaic power generation, and the water electrolysis hydrogen production system is put into use.

[0050] In this mode, the photovoltaic storage direct flexible full DC energy network management system sends the control signal to each photovoltaic storage direct flexible energy substation through wireless communication / optical cable according to the calculation results of the NSGA-II algorithm, closes the fourth circuit breaker in the energy network contact cabinet corresponding to the substation that needs to be interconnected, and transmits the electric energy to each photovoltaic storage direct flexible energy substation through the contact cable corresponding to each energy network contact cabinet, so as to be used by the load of each photovoltaic storage direct flexible energy substation. At the same time, the contact circuit breaker in the total distribution cabinet of the full DC energy network and the distribution circuit breaker corresponding to the water electrolysis hydrogen production system are closed, and the water electrolysis hydrogen production system is started, and the photovoltaic power generation energy that cannot be consumed during this period is converted into hydrogen energy and stored in the hydrogen storage tank.

[0051] The photovoltaic-storage-direct-flexible full DC energy network system provided in this embodiment connects multiple photovoltaic-storage-direct-flexible energy substations in series to form a photovoltaic-storage-direct-flexible energy substation group, and manages the power allocation between the full DC energy network and each photovoltaic-storage-direct-flexible energy substation through the full DC energy network management system, thereby realizing a full DC power supply and consumption mode, and no inverter loss is generated in the whole process due to AC-DC conversion. This solves the problem of high AC-DC conversion loss in the photovoltaic-storage-direct-flexible system under unstable photovoltaic power generation, improves the robustness of the configuration scheme, reduces the AC-DC conversion loss of photovoltaic power generation and energy storage, and improves energy utilization.

[0052] Method Embodiment

[0053] According to an embodiment of the present invention, a method for optimizing energy scheduling of a photovoltaic-storage-direct-flexible all-DC energy grid system is provided, such as Figure 5 As shown, it is a flow chart of the energy optimization scheduling method of the photovoltaic storage direct flexible full DC energy network system provided in this embodiment. The energy optimization scheduling method of the photovoltaic storage direct flexible full DC energy network system according to the embodiment of the present invention includes the steps of:

[0054] Step S1, establishing mathematical models of photovoltaic components, electrochemical energy storage devices, water electrolysis hydrogen production systems, hydrogen storage models and hydrogen fuel cell power generation systems.

[0055] Step S2: Taking the highest comprehensive energy utilization efficiency of the network and the minimum line loss as the objective function, a scheduling optimization model of the photovoltaic, storage, direct and flexible full DC energy network is constructed.

[0056] Step S3, using the NSGA-II algorithm, solve the optimization model according to the constraints, and obtain the optimal scheduling strategy for the participation of hydrogen energy storage and photovoltaic storage, direct and flexible energy substations in the photovoltaic storage, direct and flexible full DC energy network, where the constraints include the power balance constraints of each photovoltaic storage, direct and flexible energy substation, the overall power balance constraints of the full DC energy network, the DC bus voltage constraints and the constraints on equipment operating performance.

[0057] The energy optimization scheduling method of the photovoltaic, storage, direct and flexible full DC energy network system provided in this embodiment fully considers the impact of hydrogen energy storage and flexible interconnection technology on the safe and stable operation of the distribution network, constructs the objective function of maximizing the comprehensive energy utilization efficiency of the network and minimizing the line loss, and realizes the full DC energy network involving multiple energy forms such as solar energy, electric energy, and hydrogen energy. The optimization scheduling strategy of the photovoltaic, storage, direct and flexible energy substations participating in the photovoltaic, storage, direct and flexible full DC energy network is obtained, which solves the problem that the large-scale coupling between power generation and storage equipment and the uncertainty of energy supply lead to the inability of simple time-sharing operation mode to meet the requirements of system variability. To solve this problem, both rationality and efficiency are taken into account at the same time, and the NSGA-II non-dominated sorting genetic algorithm is used to generate the equipment operation strategy within the preset time period of the full DC energy network, thereby improving the flexible operation capability of the system.

[0058] In this embodiment, the mathematical models of the photovoltaic module, the electrochemical energy storage device, the water electrolysis hydrogen production system, the hydrogen storage model, and the hydrogen fuel cell power generation system are specifically as follows.

[0059] 1) The mathematical model of photovoltaic modules is as follows:

[0060]

[0061] Where P g Indicates the actual photovoltaic power generation; P ge It represents the maximum photovoltaic power generation under standard test conditions, G represents the actual light intensity, and G r represents the light intensity under the standard test environment, α represents the temperature coefficient, T represents the actual temperature of the unit, and T r Indicates the unit reference temperature.

[0062] 2) The mathematical model of the electrochemical energy storage device is as follows:

[0063] The relationship between the state of charge and the charge and discharge power of an electrochemical energy storage device is:

[0064]

[0065] In the formula, S t+1 represents the storage capacity of the electrochemical energy storage device at time t+1, S t represents the storage capacity of the electrochemical energy storage device at time t, P cd , P fd Respectively represent the charge and discharge capacity of the electrochemical energy storage device, η cd , η fd They represent the charging and discharging efficiency of the electrochemical energy storage device respectively, and μ represents the self-loss rate of energy storage.

[0066] 3) Mathematical model of water electrolysis hydrogen production system;

[0067] The electrolyzer can decompose water into hydrogen and oxygen. The hydrogen production model is:

[0068] q dj =η dj ×P dj ;

[0069] In the formula, q dj Indicates the amount of hydrogen produced by the electrolyzer, η dj Indicates the electrolytic efficiency of the electrolytic cell, P dj Indicates power consumption.

[0070] 4) Mathematical model of hydrogen storage;

[0071] The hydrogen storage tank is used to store green hydrogen electrolyzed by the full DC energy grid and purchased green hydrogen (when the full DC energy grid is insufficient for electrolyzed hydrogen). Its mathematical model is as follows:

[0072]

[0073] In the formula, represents the storage capacity of the hydrogen storage tank at time t, represents the storage capacity of the hydrogen storage tank at time t-1, H ch , H fh Respectively represent the current moment of charging and discharging hydrogen, η ch , η fh Represent the efficiency of hydrogen charging and discharging respectively.

[0074] 5) The mathematical model of the hydrogen fuel cell power generation system is as follows:

[0075] P h =η h V h ;

[0076] Where P h represents the power generated by hydrogen fuel cells, η h Indicates the power released per unit volume of hydrogen, V h Indicates the volume of hydrogen consumed by the fuel cell.

[0077] In this embodiment, the objective function is to maximize the network comprehensive energy utilization efficiency and minimize the line loss as follows.

[0078] 1) The main goal is to maximize the comprehensive energy utilization efficiency of the network, and its objective function is:

[0079]

[0080] Where η IE is the comprehensive energy efficiency of the entire DC energy network, W D is the total energy demand of users; W T It is the total energy input of the whole DC energy grid.

[0081] Total energy demand of users W D The expression is:

[0082]

[0083] Where P t gi is the photovoltaic power generation power of the i-th photovoltaic storage direct flexible energy substation, P t si is the charge and discharge power of the electrochemical energy storage device of the i-th solar-storage direct flexible energy substation, which is “+” during discharge and “-” during charge; P t i+1 , P t i-1 are the electric power received by the ith PV-storage direct flexible energy substation and sent to the adjacent substation, the received power is “+” and the sent power is “-”; P t hi The power generated by the hydrogen fuel cell connected to the photovoltaic storage direct flexible energy substation; P t ni is the self-consumption power of the i-th solar-storage direct flexible energy substation.

[0084] W T is the total energy input of the entire DC energy network, and its expression is:

[0085]

[0086] Where P t gi is the photovoltaic power generation power of the i-th photovoltaic storage direct flexible energy substation; P t si is the discharge power of the electrochemical energy storage device of the i-th solar direct flexible energy storage substation; η fd Represents the discharge efficiency of electrochemical energy storage device; P t h is the power generated by the hydrogen fuel cell, η he Indicates the power generation efficiency of hydrogen fuel cells.

[0087] 2) Taking the minimum line loss as the secondary goal, the objective function is:

[0088]

[0089] Where P xs represents the line loss on the kth branch; represents the current value on the kth branch; R k represents the resistance of the kth branch; Δt represents the connection time of the solar-storage direct-flexible energy substation.

[0090] In this embodiment, the constraints are as follows:

[0091] 1) The power balance of each solar-storage direct-flexible energy substation is as follows:

[0092]

[0093] Where P t gi represents the photovoltaic power generation of the i-th photovoltaic storage direct flexible energy substation; P t si represents the charging and discharging power of the electrochemical energy storage device of the i-th photovoltaic direct flexible energy substation, which represents “+” when discharging and “-” when charging; P t i+1 , P t i-1 represents the electric power received by the ith PV-storage direct flexible energy substation and sent to the adjacent PV-storage direct flexible energy substation, with the received power represented by “+” and the sent power represented by “-”; P t hi P represents the power generation of the hydrogen fuel cell power generation system connected to the photovoltaic storage direct flexible energy substation; t ni represents the self-consumption power of the ith solar-storage direct-flexible energy substation; P ei Represents the power consumption of the user of the i-th solar-storage direct flexible energy substation.

[0094] 2) The overall power balance condition of the full DC energy grid is as follows:

[0095]

[0096] Where P t gi represents the photovoltaic power generation of the i-th photovoltaic storage direct flexible energy substation; P t si represents the charging and discharging power of the electrochemical energy storage device of the ith photovoltaic direct flexible energy substation, which indicates “+” when discharging and “-” when charging; P t h Indicates the power generated by hydrogen fuel cells; P t ei represents the power consumption of the user of the i-th PV-storage direct flexible energy substation; Indicates the power consumption of the electrolytic cell, P t n Indicates other self-consumption power of the full DC energy network.

[0097] 3) The DC bus voltage constraint condition is as follows:

[0098] U H ≤U t i ≤U L ;

[0099] Where U H Indicates the maximum voltage allowed to fluctuate on the DC bus; U t i Indicates the DC bus voltage value at time t; U L Indicates the lowest voltage allowed to fluctuate on the DC bus.

[0100] 4) Constraints on equipment performance

[0101] ① The equipment is not running or the equipment is running between the minimum output and the maximum output. The specific constraints are as follows:

[0102] P xmin ≤P t x ≤P xmax or P x =0;

[0103] Where P x represents the output of device x at time t, P xmin Indicates the minimum output of device x, P xmax Indicates the maximum output of device x.

[0104] ② The specific conditions for equipment climbing are as follows:

[0105] P xu ≤P t x -P (t-1) x ≤P xd ;

[0106] Where P t x , P (t-1) x They represent the output of device x at time t and time t-1, respectively, xu , P xd They represent the maximum output of device x that is allowed to increase or decrease per unit time.

[0107] Finally, the mathematical model of the above equipment, objective function, constraints, electrochemical energy storage device, hydrogen storage tank capacity, as well as the predicted photovoltaic power generation power of each substation, the predicted power of power load (as well as photovoltaic power generation period) and other data are input into the NSGA-II algorithm program, and the basic parameters such as the number of individuals, number of iterations, and mutation probability are set. After population initialization, objective function calculation, non-dominated sorting and congestion calculation, selection, crossover, mutation, population merging and other operations, the optimal operation strategy for each device in the future period (such as 24h) is finally output to complete the solution of the problem.

[0108] In a specific embodiment, the following operation strategies can be obtained by solving the model according to the NSGA-II algorithm, such as Figure 6 As shown, it is a control relationship diagram of the full DC energy network management system provided in this embodiment. The full DC energy network management system sends corresponding control commands to the full DC energy network main distribution cabinet, the water electrolysis hydrogen production system, the hydrogen fuel cell power generation system, the photovoltaic power generation unit and / or the electrochemical energy storage device, and the correspondingly set circuit breakers through the operation strategy, which are as follows:

[0109] (1) Period when photovoltaic power generation is not in progress

[0110] During the period when photovoltaic power generation is not in progress, the electricity for the entire photovoltaic-storage-direct-flexible full-DC energy network is supplied by the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each photovoltaic-storage-direct-flexible energy substation. At this time, the water electrolysis hydrogen production system is not put into operation.

[0111] In this mode, the output of each device in each time period is calculated and generated by the photovoltaic storage direct and flexible full DC energy network management system through the NSGA-II algorithm, and then converted into a control signal, which is sent to the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each substation through the control cable / wireless communication / optical cable. At the same time, the photovoltaic storage direct and flexible full DC energy network management system will also send control instructions to the main distribution cabinet of the full DC energy network and the interconnection cabinets of each lower-level energy network to close the incoming circuit breaker and interconnection circuit breaker in the main distribution cabinet and the fourth circuit breaker in the energy network interconnection cabinet to which each photovoltaic storage direct and flexible energy substation that the NSGA-II algorithm determines needs to be interconnected, so that the electric energy is transmitted to each photovoltaic storage direct and flexible energy substation through the interconnection cable and the interconnection cable of the corresponding photovoltaic storage direct and flexible energy substation at the lower level, so as to be used by the power load of each photovoltaic storage direct and flexible energy substation.

[0112] (2) Photovoltaic power generation period, which can be divided into the following operating modes:

[0113] 1) The electric energy required by the photovoltaic, storage, direct and flexible full DC energy grid is provided by photovoltaic power generation units, electrochemical energy storage devices and hydrogen fuel cell power generation systems at the same time, and the water electrolysis hydrogen production system is not put into use.

[0114] In this mode, the output of each device in each time period is calculated and generated by the full DC energy network management system through the NSGA-II algorithm, and then converted into a control signal, which is sent to the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each substation through the control cable / wireless communication / optical cable. At the same time, the full DC energy network management system will also send control instructions to the full DC energy network main distribution cabinet and the lower-level energy network interconnection cabinets to close the incoming circuit breaker and interconnection circuit breaker in the full DC energy network main distribution cabinet and the fourth circuit breaker in the energy network interconnection cabinet to which each photovoltaic storage direct and flexible energy substation that the NSGA-II algorithm determines needs to be interconnected, so that the electric energy is transmitted to each photovoltaic storage direct and flexible energy substation through the interconnection cable and the interconnection cable of the corresponding photovoltaic storage direct and flexible energy substation in the lower layer, so as to be used by the power load of each photovoltaic storage direct and flexible energy substation.

[0115] 2) The electricity of the photovoltaic, storage and direct-flexible full-DC energy grid is provided by photovoltaic power generation units and electrochemical energy storage devices, and neither the hydrogen fuel cell power generation system nor the water electrolysis hydrogen production system is put into use.

[0116] In this mode, the output of each device in each time period is calculated and generated by the photovoltaic storage direct flexible full DC energy network management system through the NSGA-II algorithm, and then converted into a control signal, which is sent to the electrochemical energy storage device of each photovoltaic storage direct flexible energy substation through control cables / wireless communications / optical cables, etc. At the same time, the photovoltaic storage direct flexible full DC energy network management system will also send control instructions to the full DC energy network main distribution cabinet and each lower-level energy network interconnection cabinet to open the incoming circuit breaker and interconnection circuit breaker in the full DC energy network main distribution cabinet, close the fourth circuit breaker in the energy network interconnection cabinet to which each photovoltaic storage direct flexible energy substation that the NSGA-II algorithm determines needs to be interconnected, and open the circuit breaker in the energy network interconnection cabinet of the substation that does not need to be interconnected during this period, so that the electric energy of each substation can be reasonably distributed.

[0117] 3) The electricity of the photovoltaic, storage and direct-flexible full-DC energy grid is provided by photovoltaic power generation. The electrochemical energy storage device serves as the power load and enters the charging state. Neither the hydrogen fuel cell power generation system nor the water electrolysis hydrogen production system is put into operation.

[0118] In this mode, after the charging power of the electrochemical energy storage device of each photovoltaic direct-flexible energy substation is generated by the full DC energy grid management system, the control signal is sent to the corresponding electrochemical energy storage device through wireless communication / optical cable. At the same time, the fourth circuit breaker in the energy grid interconnection cabinet corresponding to the photovoltaic direct-flexible energy substation that the NSGA-II algorithm determines needs to be interconnected is closed, and the circuit breaker in the energy grid interconnection cabinet of the photovoltaic direct-flexible energy substation that does not need to be interconnected during this period is opened, so that the electric energy of each photovoltaic direct-flexible energy substation can be reasonably distributed.

[0119] The electricity in the above 2) and 3) time periods can be balanced inside the photovoltaic, direct-current and flexible energy substation group, and neither the DC hydrogen electrolysis nor the hydrogen fuel cell power generation systems will be started. This solves the problem that the surplus DC electricity in adjacent photovoltaic, direct-current and flexible systems in the photovoltaic, direct-current and flexible full DC energy grid system cannot be directly allocated and utilized under unstable photovoltaic power generation, solves the system's AC / DC conversion losses, improves the robustness of the configuration scheme, reduces the AC / DC conversion losses of photovoltaic power generation and energy storage, and improves energy utilization.

[0120] 4) The electricity of the photovoltaic storage direct flexible full DC energy grid is only provided by photovoltaic power generation, and the water electrolysis hydrogen production system is put into use.

[0121] In this mode, the photovoltaic storage direct flexible full DC energy network management system sends the control signal to each photovoltaic storage direct flexible energy substation through wireless communication / optical cable according to the calculation results of the NSGA-II algorithm, closes the fourth circuit breaker in the energy network contact cabinet corresponding to the substation that needs to be interconnected, and transmits the electric energy to each photovoltaic storage direct flexible energy substation through the contact cable corresponding to each energy network contact cabinet, so as to be used by the load of each photovoltaic storage direct flexible energy substation. At the same time, the contact circuit breaker in the total distribution cabinet of the full DC energy network and the distribution circuit breaker corresponding to the water electrolysis hydrogen production system are closed, and the water electrolysis hydrogen production system is started, and the photovoltaic power generation energy that cannot be consumed during this period is converted into hydrogen energy and stored in the hydrogen storage tank.

[0122] like Figure 7 As shown, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the energy optimization scheduling method of the photovoltaic-storage-direct-flexible all-DC energy grid system in the above-mentioned embodiment is implemented.

[0123] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the energy optimization scheduling method of the photovoltaic, storage, direct and flexible all-DC energy grid system in the above-mentioned embodiment is implemented; or when the computer program is executed by a processor, the energy optimization scheduling method of the photovoltaic, storage, direct and flexible all-DC energy grid system in the above-mentioned embodiment is implemented.

[0124] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0125] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and the contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A solar-storage direct-flexible full-DC energy network system, characterized in that include: The main power distribution cabinet of the full DC energy network, the water electrolysis hydrogen production system, and the hydrogen fuel cell power generation system are connected to the main power distribution cabinet of the full DC energy network through circuit breakers respectively; An energy subsystem consisting of a photovoltaic storage direct-flexible energy substation group, wherein multiple photovoltaic storage direct-flexible energy substations are interconnected in sequence through circuit breakers, and the energy subsystem is connected to the main distribution cabinet of the full DC energy network through the interconnection cable of the photovoltaic storage direct-flexible energy substation; wherein each photovoltaic storage direct-flexible energy substation includes a photovoltaic power generation unit, an electrochemical energy storage device and a DC power-consuming device; and It also includes a full DC energy network management system for formulating the operation strategy of the photovoltaic storage direct and flexible full DC energy network system. The full DC energy network management system sends corresponding control instructions to the full DC energy network main distribution cabinet or each lower-level energy subsystem according to the operation strategy it generates. When the load distribution of each photovoltaic storage direct and flexible energy substation is uneven, the deployable electricity is used to transfer the surplus electricity of the photovoltaic storage direct and flexible energy substation to the photovoltaic storage direct and flexible energy substation that is short of electricity, so as to realize the electricity allocation between the photovoltaic storage direct and flexible energy substations, and realize the electricity exchange between the photovoltaic storage direct and flexible energy substation and the full DC energy network main distribution cabinet during various periods of photovoltaic power generation and periods when photovoltaic power generation is not in progress.

2. The photovoltaic energy storage and direct-flexible full DC energy network system according to claim 1, characterized in that: The water electrolysis hydrogen production system and the hydrogen fuel cell power generation system are respectively connected to the centralized DC bus of the total power distribution cabinet of the full DC energy network through a DC / DC converter and a first circuit breaker; The photovoltaic power generation unit and load of the photovoltaic direct and flexible energy substation are connected to the DC bus through the DC / DC converter and the second circuit breaker, the electrochemical energy storage device is connected to the DC bus through the third circuit breaker, and the DC buses of each photovoltaic direct and flexible energy substation are connected in sequence through the fourth circuit breaker, so that the photovoltaic direct and flexible energy substations are interconnected in sequence, and the DC bus of any photovoltaic direct and flexible energy substation is connected to the centralized DC bus through the fifth circuit breaker.

3. The photovoltaic energy storage and direct-flexible full DC energy network system as claimed in claim 2, characterized in that: The full DC energy network management system sets the following scheduling strategy for optimizing the photovoltaic, storage, direct and flexible full DC energy network according to different power consumption periods. The specific scheduling strategy is as follows: (1) Period when photovoltaic power generation is not in progress During the period when photovoltaic power generation is not in progress, the electricity of the entire photovoltaic storage direct and flexible full DC energy network is supplied by the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each photovoltaic storage direct and flexible energy substation. At this time, the water electrolysis hydrogen production system is not put into use; (2) Photovoltaic power generation period, which can be divided into the following operating modes: 1) The electric energy required by the photovoltaic storage direct flexible full DC energy grid is provided by the photovoltaic power generation unit, electrochemical energy storage device and hydrogen fuel cell power generation system at the same time, and the water electrolysis hydrogen production system is not put into use; In this mode, the output of each device in each time period is calculated and generated by the photovoltaic storage direct and flexible full DC energy network management system through a multi-objective genetic algorithm, and the corresponding control signal is generated and sent to the hydrogen fuel cell power generation system and the electrochemical energy storage device of each substation, and the incoming circuit breaker, the connecting circuit breaker and the fourth circuit breaker connected to each photovoltaic storage direct and flexible energy substation that needs to be interconnected in the total distribution cabinet of the full DC energy network are controlled to close, so that the electric energy is transmitted to each photovoltaic storage direct and flexible energy substation through the connecting cable and the corresponding photovoltaic storage direct and flexible energy substation connecting cable at the lower layer; 2) The power of the photovoltaic storage direct flexible full DC energy grid is provided by photovoltaic power generation units and electrochemical energy storage devices, and the hydrogen fuel cell power generation system and water electrolysis hydrogen production system are not put into use; In this mode, the output of each device in each time period is calculated and generated by the full DC energy network management system through a multi-objective genetic algorithm, and a corresponding control signal is generated and sent to the electrochemical energy storage device of each photovoltaic storage direct flexible energy substation, and the incoming circuit breaker and the connecting circuit breaker in the total distribution cabinet of the full DC energy network are controlled to open, and the fourth circuit breaker connected to each photovoltaic storage direct flexible energy substation that needs to be interconnected is controlled to close; 3) The power of the photovoltaic storage direct flexible full DC energy grid is provided by photovoltaic power generation. The electrochemical energy storage device is used as the power load and enters the charging state. The hydrogen fuel cell power generation system and the water electrolysis hydrogen production system are not put into use; In this mode, after the charging power of the electrochemical energy storage device of each photovoltaic direct-flexible energy substation is determined by the photovoltaic direct-flexible full DC energy network management system through a multi-objective genetic algorithm, the fourth circuit breaker corresponding to the photovoltaic direct-flexible energy substation that needs to be interconnected is closed, and the circuit breaker corresponding to the photovoltaic direct-flexible energy substation that does not need to be interconnected is opened, so that the electric energy of each photovoltaic direct-flexible energy substation can be reasonably distributed; 4) The power of the photovoltaic storage direct-flexible full-DC energy grid is only provided by photovoltaic power generation, and the water electrolysis hydrogen production system is put into use; In this mode, the photovoltaic storage direct-flexible full-DC energy network management system controls the closing of the fourth circuit breaker corresponding to the substation that needs to be interconnected based on the calculation results of the multi-objective genetic algorithm, transmits electric energy to each photovoltaic storage direct-flexible energy substation through the interconnection cable corresponding to each energy network interconnection cabinet, and controls the closing of the interconnection circuit breaker in the main distribution cabinet of the full-DC energy network and the distribution circuit breaker corresponding to the water electrolysis hydrogen production system, and starts the water electrolysis hydrogen production system to convert the unabsorbed electric energy into hydrogen energy and store it in the hydrogen storage tank.

4. The photovoltaic energy storage and direct-flexible full DC energy network system as claimed in claim 2, characterized in that: Said Energy grid connection cabinets are respectively provided between the photovoltaic storage direct-flexible energy substations, and the fourth circuit breaker is arranged in the energy grid connection cabinet. The energy grid connection cabinet receives commands from the full direct-current energy grid management system to control the opening and closing of the fourth circuit breaker.

5. An energy optimization scheduling method for a photovoltaic energy storage direct-flexible full-DC energy grid system, characterized in that Includes steps: Establish mathematical models of photovoltaic modules, electrochemical energy storage devices, water electrolysis hydrogen production systems, hydrogen storage models, and hydrogen fuel cell power generation systems; Taking the highest comprehensive energy utilization efficiency of the network and the minimum line loss as the objective function, a scheduling optimization model for the photovoltaic, storage, direct and flexible full DC energy network is constructed; and By using a multi-objective genetic algorithm, the optimization model is solved according to the constraints, and the optimal scheduling strategy for the participation of hydrogen energy storage and photovoltaic storage, direct and flexible energy substations in the photovoltaic storage, direct and flexible DC energy network is obtained. The constraints include the electric power balance constraints of each photovoltaic storage, direct and flexible energy substation, the overall electric power balance constraints of the entire DC energy network, the DC bus voltage constraints and the constraints on equipment operating performance.

6. The energy optimization scheduling method of the photovoltaic energy storage direct-flexible full DC energy grid system according to claim 5 is characterized in that: The mathematical models of the photovoltaic module, electrochemical energy storage device, water electrolysis hydrogen production system, hydrogen storage model, and hydrogen fuel cell power generation system are as follows: The mathematical model of photovoltaic modules is as follows: Where P g Indicates the actual photovoltaic power generation; P ge It represents the maximum photovoltaic power generation under standard test conditions, G represents the actual light intensity, and G r represents the light intensity under the standard test environment, α represents the temperature coefficient, T represents the actual temperature of the unit, and T r Indicates the unit reference temperature; 2) The mathematical model of the electrochemical energy storage device is as follows: The relationship between the state of charge and the charge and discharge power of an electrochemical energy storage device is: In the formula, S t+1 represents the storage capacity of the electrochemical energy storage device at time t+1, S t represents the storage capacity of the electrochemical energy storage device at time t, P cd , P fd Respectively represent the charge and discharge capacity of the electrochemical energy storage device, η cd , η fd They represent the charging and discharging efficiency of the electrochemical energy storage device, and μ represents the self-loss rate of the storage energy; 3) Mathematical model of water electrolysis hydrogen production system; The electrolyzer can decompose water into hydrogen and oxygen. The hydrogen production model is: q dj =the dj ×P dj ; In the formula, q dj Indicates the amount of hydrogen produced by the electrolyzer, η dj Indicates the electrolytic efficiency of the electrolytic cell, P dj Indicates power consumption; 4) Mathematical model of hydrogen storage; The hydrogen storage tank is used to store green hydrogen electrolyzed by the full DC energy grid and purchased green hydrogen. Its mathematical model is as follows: In the formula, represents the storage capacity of the hydrogen storage tank at time t, represents the storage capacity of the hydrogen storage tank at time t-1, H ch , H fh Respectively represent the current moment of charging and discharging hydrogen, η ch , η fh Respectively represent the efficiency of hydrogen charging and discharging; 5) The mathematical model of the hydrogen fuel cell power generation system is as follows: P h =the h V h ; Where P h represents the power generated by hydrogen fuel cells, η h Indicates the power released per unit volume of hydrogen, V h Indicates the volume of hydrogen consumed by the fuel cell.

7. The energy optimization scheduling method of the photovoltaic energy storage direct-flexible full DC energy grid system according to claim 5 is characterized in that: The objective function of maximizing the network comprehensive energy utilization efficiency and minimizing the line loss is as follows: 1) The main goal is to maximize the comprehensive energy utilization efficiency of the network, and its objective function is: Where η IE represents the comprehensive energy efficiency of the entire DC energy network, W D Represents the total energy demand of users; W T Represents the total energy input of the entire DC energy grid; Total energy demand of users W D The expression is: Where P t gi represents the photovoltaic power generation of the i-th photovoltaic storage direct flexible energy substation, P t si represents the charging and discharging power of the electrochemical energy storage device of the i-th photovoltaic direct flexible energy substation, which is represented by "+" when discharging and "-" when charging; P t i+1 , P t i-1 represents the electric power received by the ith PV-storage direct flexible energy substation and sent to the adjacent substation, with the received power represented by "+" and the sent power represented by "-"; P t hi P represents the power generated by the hydrogen fuel cell connected to the photovoltaic direct flexible energy substation; t ni represents the self-consumption power of the i-th PV-storage direct flexible energy substation; W T is the total energy input of the entire DC energy network, and its expression is: Where P t gi is the photovoltaic power generation power of the i-th photovoltaic storage direct flexible energy substation; P t si is the discharge power of the electrochemical energy storage device of the i-th solar direct flexible energy substation; η fd Represents the discharge efficiency of electrochemical energy storage device; P t h is the power generated by the hydrogen fuel cell, η he Indicates the power generation efficiency of hydrogen fuel cells; 2) Taking the minimum line loss as the secondary goal, the objective function is: Where P xs represents the line loss on the kth branch; represents the current value on the kth branch; R k represents the resistance of the kth branch; Δt represents the connection time of the solar-storage direct-flexible energy substation.

8. The energy optimization scheduling method of the photovoltaic energy storage direct-flexible full DC energy grid system according to claim 5 is characterized in that: The constraints are as follows: 1) The power balance of each solar-storage direct-flexible energy substation is as follows: Where P t gi represents the photovoltaic power generation of the i-th photovoltaic storage direct flexible energy substation; P t si represents the charging and discharging power of the electrochemical energy storage device of the i-th photovoltaic direct flexible energy substation, which is represented by "+" when discharging and "-" when charging; P t i+1 , P t i-1 represents the electric power received by the ith PV-storage direct flexible energy substation and sent to the adjacent PV-storage direct flexible energy substation, with the received power represented by "+" and the sent power represented by "-"; P t hi P represents the power generation of the hydrogen fuel cell power generation system connected to the photovoltaic storage direct flexible energy substation; t ni represents the self-consumption power of the ith solar-storage direct-flexible energy substation; P ei represents the power consumption of the user of the i-th PV-storage direct flexible energy substation; 2) The overall power balance condition of the full DC energy grid is as follows: Where P t gi represents the photovoltaic power generation of the i-th photovoltaic storage direct flexible energy substation; P t si represents the charging and discharging power of the electrochemical energy storage device of the ith photovoltaic direct flexible energy substation, which is represented by "+" when discharging and "-" when charging; P t h Indicates the power generated by hydrogen fuel cells; P t ei represents the power consumption of the user of the i-th PV-storage direct flexible energy substation; Indicates the power consumption of the electrolytic cell, P t n Indicates other self-consumption power of the full DC energy network; 3) The DC bus voltage constraint condition is as follows: IN H ≤U t i ≤U L ; Where U H Indicates the maximum voltage allowed to fluctuate on the DC bus, U t i Indicates the DC bus voltage value at time t; U L Indicates the lowest voltage allowed to fluctuate on the DC bus; 4) Constraints on equipment performance ① The equipment is not running or the equipment is running between the minimum output and the maximum output. The specific constraints are as follows: P xmin ≤P t x ≤P xmax or P x =0; Where P x represents the output of device x at time t, P xmin Indicates the minimum output of device x, P xmax Indicates the maximum output of device x; ② The specific conditions for equipment climbing are as follows: P xu ≤P t x -P (t-1) x ≤P xd ; Where P t x , P (t-1) x They represent the output of device x at time t and time t-1, respectively, xu , P xd They represent the maximum output of device x that is allowed to increase or decrease per unit time.

9. The energy optimization scheduling method of the photovoltaic energy storage direct-flexible full DC energy grid system according to claim 5 is characterized in that: The scheduling strategies include: (1) Period when photovoltaic power generation is not in progress During the period when photovoltaic power generation is not in progress, the electricity of the entire photovoltaic storage direct and flexible full DC energy network is supplied by the hydrogen fuel cell power generation system and the electrochemical energy storage devices of each photovoltaic storage direct and flexible energy substation. At this time, the water electrolysis hydrogen production system is not put into use; (2) Photovoltaic power generation period, which can be divided into the following operating modes: 1) The electric energy required by the photovoltaic storage direct flexible full DC energy grid is provided by the photovoltaic power generation unit, electrochemical energy storage device and hydrogen fuel cell power generation system at the same time, and the water electrolysis hydrogen production system is not put into use; In this mode, the output of each device in each time period is calculated and generated by the photovoltaic storage direct and flexible full DC energy network management system through a multi-objective genetic algorithm, and the corresponding control signal is generated and sent to the hydrogen fuel cell power generation system and the electrochemical energy storage device of each substation, and the incoming circuit breaker, the connecting circuit breaker and the fourth circuit breaker connected to each photovoltaic storage direct and flexible energy substation that needs to be interconnected in the total distribution cabinet of the full DC energy network are controlled to close, so that the electric energy is transmitted to each photovoltaic storage direct and flexible energy substation through the connecting cable and the corresponding photovoltaic storage direct and flexible energy substation connecting cable at the lower layer; 2) The power of the photovoltaic storage direct flexible full DC energy grid is provided by photovoltaic power generation units and electrochemical energy storage devices, and the hydrogen fuel cell power generation system and water electrolysis hydrogen production system are not put into use; In this mode, the output of each device in each time period is calculated and generated by the full DC energy network management system through a multi-objective genetic algorithm, and a corresponding control signal is generated and sent to the electrochemical energy storage device of each photovoltaic storage direct flexible energy substation, and the incoming circuit breaker and the connecting circuit breaker in the total distribution cabinet of the full DC energy network are controlled to open, and the fourth circuit breaker connected to each photovoltaic storage direct flexible energy substation that needs to be interconnected is controlled to close; 3) The power of the photovoltaic storage direct flexible full DC energy grid is provided by photovoltaic power generation. The electrochemical energy storage device is used as the power load and enters the charging state. The hydrogen fuel cell power generation system and the water electrolysis hydrogen production system are not put into use; In this mode, after the charging power of the electrochemical energy storage device of each photovoltaic direct-flexible energy substation is determined by the photovoltaic direct-flexible full DC energy network management system through a multi-objective genetic algorithm, the fourth circuit breaker corresponding to the photovoltaic direct-flexible energy substation that needs to be interconnected is closed, and the circuit breaker corresponding to the photovoltaic direct-flexible energy substation that does not need to be interconnected is opened, so that the electric energy of each photovoltaic direct-flexible energy substation can be reasonably distributed; 4) The power of the photovoltaic storage direct-flexible full-DC energy grid is only provided by photovoltaic power generation, and the water electrolysis hydrogen production system is put into use; In this mode, the photovoltaic storage direct-flexible full-DC energy network management system controls the closing of the fourth circuit breaker corresponding to the substation that needs to be interconnected based on the calculation results of the multi-objective genetic algorithm, transmits electric energy to each photovoltaic storage direct-flexible energy substation through the interconnection cable corresponding to each energy network interconnection cabinet, and controls the closing of the interconnection circuit breaker in the main distribution cabinet of the full-DC energy network and the distribution circuit breaker corresponding to the water electrolysis hydrogen production system, and starts the water electrolysis hydrogen production system to convert the unabsorbed electric energy into hydrogen energy and store it in the hydrogen storage tank.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the energy optimization scheduling method of the photovoltaic-storage-direct-flexible all-DC energy grid system as described in any one of claims 5 to 9.

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