Offshore island micro-grid energy storage configuration method and device considering steady-state and transient multi-time scale demand

Abstract

The application provides an offshore island micro-grid energy storage configuration method and device considering steady-state and transient multi-time scale demand, and the method comprises the following steps: constructing a first operation model and a second operation model of the island micro-grid, the first operation model and the second operation model respectively reflect the relationship between the physical parameters of non-energy storage equipment and energy storage equipment in the micro-grid, and the energy storage equipment comprises energy-type energy storage equipment and power-type energy storage equipment; constructing a frequency response model of the micro-grid; constructing a constraint condition based on the physical parameters of the equipment in the micro-grid and the frequency response model; solving a target optimization function based on the first operation model, the second operation model, the frequency response model and the constraint condition to obtain an energy storage configuration scheme in the micro-grid, and the optimization target of the target optimization function is the maximum cost difference before and after the energy storage equipment is configured in the micro-grid. The application can reduce the offshore island micro-grid energy storage configuration cost.

Description

Technical Field

[0001] This invention relates to the field of microgrids, and more particularly to a method and apparatus for configuring energy storage in an isolated offshore microgrid that takes into account both steady-state and transient multi-timescale requirements. Background Technology

[0002] Offshore microgrids have diverse application scenarios, typically including artificial energy islands, natural islands, large ships, offshore ranches, and various offshore work platform clusters. Most offshore microgrids are located far from land, and connecting them to the onshore power grid via submarine cables is not economically feasible. Therefore, operating as isolated microgrids requires ensuring their power supply self-sufficiency. Traditional turbine generators suffer from high power supply costs and large carbon emissions, making the introduction of new energy sources such as wind power an important means to address the energy needs of offshore isolated microgrids. However, the intermittency and volatility of wind power affect the hourly operation and scheduling of offshore isolated microgrids. Furthermore, due to the limited internal space of offshore isolated microgrids, wind turbines are usually installed at a certain distance from the grid via submarine cables. Harsh offshore operating conditions increase the probability of submarine cable and wind turbine failures, and such failures are difficult to eliminate and repair in a short time, placing higher demands on the transient frequency response of offshore isolated microgrids at the second to minute level.

[0003] Energy storage offers high operational flexibility and can serve as a key technology for addressing the aforementioned steady-state and transient multi-timescale demands. However, the current investment cost of energy storage is high, resulting in high energy storage configuration costs for offshore microgrids. Summary of the Invention

[0004] This invention provides a method and apparatus for configuring energy storage in offshore island microgrids that takes into account the needs of steady-state and transient multi-timescale applications, in order to solve the problem of high configuration cost of energy storage in offshore island microgrids in the prior art and reduce the configuration cost of energy storage in offshore island microgrids.

[0005] This invention provides a method for configuring energy storage in offshore island microgrids that considers both steady-state and transient multi-timescale requirements. The method includes:

[0006] A first operating model and a second operating model are constructed for an islanded microgrid. The first operating model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operating model reflects the relationship between the physical parameters of energy storage devices. The energy storage devices include energy-type energy storage devices and power-type energy storage devices.

[0007] A frequency response model of the microgrid is constructed, which reflects the frequency response of each device in the microgrid after a transient fault event occurs.

[0008] Constraints are constructed based on the physical parameters of the devices in the microgrid and the frequency response model.

[0009] Based on the first operating model, the second operating model, the frequency response model, and the constraints, the objective optimization function is solved to obtain the energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of energy-type energy storage devices and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0010] According to the present invention, a method for configuring energy storage in an isolated offshore microgrid that considers steady-state and transient multi-timescale demands is provided. The frequency response model includes the spinning standby gas turbine generator, power-type energy storage device, energy-type energy storage device, and load in the microgrid. τ The frequency response power at time t, where, , τ = 0 indicates the start time of the transient fault event. The time required for a static standby turbine generator to reach its target power from the onset of a transient fault event;

[0011] The frequency response model is as follows:

[0012] ;

[0013] ;

[0014] ;

[0015] ;

[0016] in, , , and These include a rotating standby gas turbine generator, a power-type energy storage device, an energy-type energy storage device, and a frequency response reserve for the load. , and These are the frequency response delay times for energy storage devices, loads, and spinning standby turbine generators, respectively. , and These are the complete frequency response times for power-type energy storage devices, energy-type energy storage devices, and spinning standby turbine generators, respectively. This refers to the time it takes for a power-type energy storage device to exit the frequency response.

[0017] According to the present invention, a method for configuring energy storage in an isolated offshore microgrid that considers steady-state and transient multi-timescale demands is provided, wherein the objective optimization function is:

[0018] ;

[0019] in, The equivalent annual cost of an isolated offshore microgrid without energy storage; The equivalent annual cost of configuring energy storage for microgrids on offshore islands This is the annual value coefficient;

[0020] ;

[0021] in, and These are the discounted investment cost and residual value recovery benefits of energy storage equipment, respectively. and These are annual gas costs and carbon tax costs, respectively. and These are the annual operating and maintenance costs for energy storage and turbine generators, respectively.

[0022] According to the present invention, a method for configuring energy storage in an offshore island microgrid that considers steady-state and transient multi-timescale demands is provided. The formula for calculating the discounted investment cost of the energy storage device in the objective optimization function is as follows:

[0023] ;

[0024] The formula for calculating the output value recovery benefit of energy storage equipment in the objective optimization function is as follows:

[0025] ;

[0026] in, A collection of energy storage systems. and Energy storage devices e Rated energy and rated power; and Energy storage devices e The investment cost per unit rated energy and per unit rated power; For energy storage devices e Life expectancy Indicates energy storage devices e The number of investments, among which Indicates not less than x The smallest integer, For the expected lifespan of microgrids on offshore islands; All energy storage systems invested in this time will be replaced at the end of their expected lifespan. For energy storage devices e The residual value rate; the recovery rate of the last invested energy storage equipment when it is decommissioned in an offshore microgrid is denoted as... ; To optimize the number of runtime scheduling periods selected in the model; The number of annual operation and scheduling periods; I g ( t ) is a turbine generator g During the period t Gas consumption rate within the unit; For energy storage devices e The ratio of annual maintenance costs to initial investment costs; is the discount rate.

[0027] According to the present invention, a method for configuring energy storage in an isolated offshore microgrid that considers steady-state and transient multi-timescale demands is provided. The first operating model includes a network power flow model, wherein the network power flow model is as follows:

[0028] ;

[0029] t Indicates the optimized scheduling period; , where Ω N Represents the set of nodes in a network; Represents nodes in the network i The set of connected nodes; Ω gt Ω wt Ω ess and Ω load These respectively represent a collection of gas turbine generators, wind turbine generators, energy storage, and load devices. g , w , e and l They represent sets Ω respectively. gt Ω wt Ω ess and Ω load Elements in; P g,i ( t ), P w,i ( t ), P e,i ( t )and P l,i ( t ) represent nodes respectively i Turbine generator g Wind turbine w Energy storage e and loadl During the period t The active operating power, of which the operating power during energy storage discharge is positive and the operating power during charging is negative; U i ( t ) represents a node i During the period t The voltage amplitude; G ij and B ij Representing branches ij The electrical conductance and susceptance between them; δ ij ( t ) represents a node i and nodes j During the period t The phase angle difference.

[0030] According to the present invention, a method for configuring energy storage in an offshore island microgrid that considers steady-state and transient multi-timescale demands is provided. The second operating model includes a charging and discharging process model of the energy storage device, wherein the charging and discharging process model is as follows:

[0031] ;

[0032] in, , A collection of energy storage devices; Energy storage devices eE During the period t Stored energy; and These are energy storage devices. eE During the period t Internal charging and discharging power; To optimize the duration of scheduling periods for the system; , and These are energy storage devices. eE Its self-consumption rate, charging efficiency, and discharging efficiency.

[0033] The present invention also provides an energy storage configuration device for an offshore island microgrid that considers steady-state and transient multi-timescale requirements, the device comprising:

[0034] The operation model construction module is used to construct a first operation model and a second operation model of the islanded microgrid. The first operation model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operation model reflects the relationship between the physical parameters of energy storage devices. The energy storage devices include energy-type energy storage devices and power-type energy storage devices.

[0035] The response model construction module is used to construct the frequency response model of the microgrid, which reflects the frequency response of each device in the microgrid after a transient fault event occurs.

[0036] A constraint construction module is used to construct constraints based on the physical parameters of the devices in the microgrid and the frequency response model.

[0037] An optimization module is used to solve the objective optimization function based on the first operating model, the second operating model, the frequency response model, and the constraints to obtain an energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of energy-type energy storage devices and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0038] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the energy storage configuration method for offshore island microgrids that takes into account steady-state and transient multi-timescale requirements as described above.

[0039] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the energy storage configuration method for offshore island microgrids that takes into account both steady-state and transient multi-timescale requirements as described above.

[0040] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the energy storage configuration method for offshore island microgrids that takes into account steady-state and transient multi-timescale requirements as described above.

[0041] This invention provides a method and apparatus for configuring energy storage in an isolated offshore microgrid, considering both steady-state and transient multi-timescale requirements. It constructs a first and a second operating model for non-energy storage devices and energy storage devices within the isolated microgrid, and establishes a frequency response model reflecting the frequency response of each device in the microgrid after a transient fault event. Constraints are constructed based on the physical parameters of the devices and the frequency response model. The objective optimization function is solved using the first and second operating models, the frequency response model, and the constraints to obtain an energy storage configuration scheme for the microgrid. This scheme includes the rated power and rated energy capacity of both energy-type and power-type energy storage devices in the microgrid. The objective of the optimization function is the cost difference before and after configuring energy storage devices in the microgrid. Thus, by considering not only the optimized scheduling during steady-state operation of the microgrid but also the frequency response after a transient fault event, and aiming to minimize costs, this method configures different types of energy storage devices in the isolated microgrid, achieving the effect of reducing the energy storage configuration cost of the offshore isolated microgrid. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating the energy storage configuration method for offshore island microgrids that takes into account steady-state and transient multi-timescale requirements provided by the present invention.

[0044] Figure 2 This is a schematic diagram of the frequency response strategy and frequency fluctuation after transient faults in the energy storage configuration method for offshore island microgrids that takes into account the steady-state and transient multi-timescale requirements provided by the present invention.

[0045] Figure 3 This is an experimental example of a microgrid system structure diagram for an offshore island microgrid energy storage configuration method that takes into account steady-state and transient multi-timescale requirements provided by the present invention.

[0046] Figure 4 This is a schematic diagram of the experimental results of the offshore island microgrid energy storage configuration method that takes into account steady-state and transient multi-timescale requirements provided by the present invention. Figure 1 .

[0047] Figure 5 This is a schematic diagram of the experimental results of the offshore island microgrid energy storage configuration method that takes into account steady-state and transient multi-timescale requirements provided by the present invention. Figure 2 .

[0048] Figure 6 This is a schematic diagram of the energy storage configuration device for an isolated offshore microgrid that takes into account the needs of steady-state and transient multi-timescale applications provided by the present invention.

[0049] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0051] The following is combined Figure 1-5 This invention describes a method for configuring energy storage in offshore island microgrids that considers both steady-state and transient multi-timescale requirements. For example... Figure 1 As shown, the energy storage configuration method for offshore island microgrids that considers steady-state and transient multi-timescale requirements provided by the present invention includes the following steps:

[0052] S110. Construct the first and second operating models of the islanded microgrid. The first operating model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operating model reflects the relationship between the physical parameters of energy storage devices. Energy storage devices include energy-type energy storage devices and power-type energy storage devices.

[0053] S120. Construct a frequency response model, which reflects the frequency response of each device in the microgrid after a transient fault event.

[0054] S130. Constructing constraints based on the physical parameters and frequency response model of devices in the microgrid;

[0055] S140. Based on the first operating model, the second operating model, the frequency response model, and the constraints, the objective optimization function is solved to obtain the energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of energy-type energy storage devices and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0056] In the method provided by this invention, when constructing the first operating model and the second operating model, the operating parameters of the offshore island microgrid are collected. These parameters include the topology of the offshore island microgrid, the physical parameters of each device and the system structural parameters, environmental parameters such as sea wind speed, etc. When constructing the objective optimization function, cost parameters such as energy storage, gas, carbon, equipment operation and maintenance prices, discount rate, etc. are also collected.

[0057] In the method provided by this invention, the first operating model includes a network power flow model, a wind turbine generator model, and a gas turbine generator model. The microgrid is dominated by gas turbine generators, and the network power flow model is shown below:

[0058] (1)

[0059] In the formula: t Indicates the optimized scheduling period; , where Ω N Represents the set of nodes in a network; Represents nodes in the network i The set of connected nodes; Ω gt Ω wt Ω ess and Ω load These respectively represent a collection of gas turbine generators, wind turbine generators, energy storage, and load devices. g , w , e and l They represent sets Ω respectively. gt Ω wt Ω ess and Ω load Elements in; P g,i ( t ), P w,i ( t ), P e,i ( t )and P l,i ( t ) represent nodes respectively i Turbine generator g Wind turbine w Energy storage e and load l During the period t The active operating power, of which the operating power during energy storage discharge is positive and the operating power during charging is negative; U i ( t ) represents a node i During the period t The voltage amplitude;G ij and B ij Representing branches ij The electrical conductance and susceptance between them; δ ij ( t ) represents a node i and nodes j During the period t The phase angle difference.

[0060] The wind turbine model reflects the output power of the wind turbine in maximum power point tracking mode. Wind speed at the current time v t The relationship between them is as follows:

[0061] (2)

[0062] In the formula: v in , v r and v out These are the cut-in wind speed, rated wind speed, and cut-out wind speed of the wind turbine, respectively. Indicates wind turbine w Rated power.

[0063] The gas turbine generator model reflects the fuel consumption characteristics of the gas turbine generator, as shown in the following formula:

[0064] (3)

[0065] In the formula: Indicates the time period of the gas turbine generator t fuel consumption, and It is based on turbine generator g The power-fuel consumption constant obtained by fitting experimental data; For turbine generator g Rated power; Indicates turbine generator g During the period t power, To characterize the turbine generator g The 0 / 1 variable represents the start / stop status; a value of 1 indicates the turbine generator. g When in startup mode, a value of 0 indicates that the turbine generator is in operation. g It is currently closed.

[0066] The gas turbine generator model also includes the relationship between the generator's inertia and rotor kinetic energy, expressed as follows:

[0067] (4)

[0068] (5)

[0069] In the formula: and Turbine generator g The inertia and inertial time constant; For turbine generator g The moment of inertia of the rotor; For turbine generator g Rated apparent power; This refers to the system's synchronous angular velocity.

[0070] The method provided by this invention classifies energy storage devices into two types: power-type energy storage devices (e.g., supercapacitors) and energy-type energy storage devices (e.g., lithium-ion batteries). Power-type energy storage devices do not participate in system optimization scheduling, but only in system inertia support and frequency response reserves. Energy-type energy storage devices participate in both optimization scheduling and, when there are margins in energy and operating power, in system inertia support and frequency response reserves. The second operating model includes modeling the charging and discharging process of energy-type energy storage devices when participating in optimization scheduling, as shown in the following equation:

[0071] (6)

[0072] In the formula: ,in A collection of energy storage devices; Energy storage devices eE During the period t Stored energy; and These are energy storage devices. eE During the period t Internal charging and discharging power; To optimize the duration of scheduling periods for the system; , and These are energy storage devices. eE Its self-consumption rate, charging efficiency, and discharging efficiency.

[0073] In the second operating model, the equivalent virtual inertia of the energy storage system is an adjustable quantity, as shown below:

[0074] (7)

[0075] In the formula: For energy storage e The equivalent virtual inertia; For energy storage e The equivalent virtual inertial time constant; For energy storage e Rated power; for The upper limit of the possible values.

[0076] In the method provided by this invention, a frequency response model is also constructed. This model reflects the frequency response of the microgrid after a transient fault event. The frequency response model includes a spinning standby gas turbine generator, a power-type energy storage device, an energy-type energy storage device, and loads within the microgrid. τ The frequency response power at time t, where, , τ = 0 indicates the start time of the transient fault event. The time required for a static standby turbine generator to reach its target power from the onset of a transient fault event.

[0077] Specifically, in the method provided by this invention, the multi-device collaborative frequency response strategy and frequency fluctuation diagram are as follows: Figure 2 As shown, to avoid conflict with the optimized scheduling period t Confusion, using symbols τ This is used to represent the time during the frequency response process.

[0078] In the picture, τ = 0 indicates the start time of the transient fault event. , , and These are respectively a rotating standby gas turbine generator, power-type energy storage, energy-type energy storage, and load frequency response reserve. , and These are the frequency response delay times for energy storage, load, and spinning standby turbine generators, respectively. They represent the time required for each device to begin power regulation from the occurrence of a transient fault event. , and These refer to the complete frequency response time of power-type energy storage, energy-type energy storage, and spinning standby turbine generator, respectively. The meaning is the time required for each device to start power regulation and reach the target power of frequency response. This refers to the time required for power-type energy storage to exit the frequency response phase. In offshore island microgrids, the capacity of static standby turbine generators is generally ample. The time required for a static standby turbine generator to reach its target power from the onset of a transient fault event.

[0079] Microgrids on offshore islands Total frequency response power over the time period It can be represented as:

[0080] (8)

[0081] In the formula: , , and These respectively represent the rotating standby gas turbine generator, power-type energy storage, energy-type energy storage, and load within the system. τ The frequency response power at any given time. Figure 2 The frequency response strategy shown can be used to obtain the expressions for the power of each frequency response term, as follows:

[0082] (9)

[0083] (10)

[0084] (11)

[0085] (12)

[0086] Target power of frequency response in offshore island microgrid systems , , and Since it is obtained by aggregating individual devices, the expressions for the target power of the frequency response of the above items are as follows:

[0087] (13)

[0088] In the formula: , , and These respectively represent the collection of gas turbine generators, power-type energy storage, energy-type energy storage, and loads; g , eP , eE and l Each device in the corresponding set; , , and Representing the equipment g , eP , eE and l The frequency response target power.

[0089] In the method provided by this invention, to intuitively characterize the economic differences before and after energy storage configuration in offshore island microgrids, the net present value index of energy storage investment is defined according to formula (14). And the net present value is maximized as the objective optimization function.

[0090] (14)

[0091] In the formula: The equivalent annual cost of an isolated offshore microgrid without energy storage; The equivalent annual cost of configuring energy storage for a microgrid on an isolated offshore island is expressed as formula (15); This is the annual value coefficient.

[0092] (15)

[0093] In the formula: and These are the discounted investment cost and residual value recovery benefits of energy storage, respectively. and These are annual gas costs and carbon tax costs, respectively. and These are the annual operating and maintenance costs for energy storage and turbine generators, respectively.

[0094] The expressions for each cost item in formula (15) are shown in formulas (16) to (21), and the expression for the annual value coefficient is shown in formula (22).

[0095] (16)

[0096] (17)

[0097] (18)

[0098] (19)

[0099] (20)

[0100] (twenty one)

[0101] (twenty two)

[0102] In the formula: It is a collection of energy storage, and ; and Energy storage e Rated energy and rated power; and Energy storagee The investment cost per unit rated energy and per unit rated power; For energy storage e Life expectancy; Indicates energy storage e The number of investments, among which Indicates not less than x The smallest integer, For the expected lifespan of microgrids on offshore islands; All energy storage systems invested in this time will be replaced at the end of their expected lifespan. For energy storage e The residual value rate; the recovery rate of the last investment in energy storage on an offshore microgrid may still have a remaining lifespan when it is decommissioned. It can be estimated from the remaining lifespan of the energy storage and the corresponding health status; To optimize the number of runtime scheduling periods selected in the model; The number of annual operation and scheduling periods; Cost per unit of gas consumption; I g ( t ) is a turbine generator g During the period t Gas consumption rate within the unit; To optimize the duration of scheduling periods for the system; Cost per unit of carbon emissions; The conversion rate of carbon emissions from fuel gas; The maintenance cost of a turbine generator per unit output power; For energy storage e The ratio of annual maintenance costs to initial investment costs; is the discount rate.

[0103] To ensure the feasibility of the energy storage configuration scheme obtained by solving the objective optimization function, the method provided in this invention constructs constraints based on a first operating model, a second operating model, and a frequency response model. These constraints limit the practical feasibility of the solutions obtained during the objective optimization function solution process. The constraints in the method provided in this invention include system network power flow constraints, energy storage constraints, wind turbine generator constraints, gas turbine generator constraints, load constraints, and frequency constraints, which are described below.

[0104] 1) System network power flow

[0105] Microgrids on offshore islands need to monitor node voltage. Apply constraints as follows:

[0106] (twenty three)

[0107] In the formula: and They represent The upper and lower limits.

[0108] 2) Energy storage

[0109] The upper and lower limits of energy storage configuration capacity constraints are as follows:

[0110] (twenty four)

[0111] (25)

[0112] In the formula, and These represent energy storage devices. e The upper limit of rated energy and rated power.

[0113] The energy-to-power ratio of energy storage products is also subject to certain limitations, as shown below:

[0114] (26)

[0115] In the formula: and Energy storage e The upper and lower limits of the energy-to-power ratio are related to the type of energy storage.

[0116] Energy storage during the period t charging power and discharge power The following constraints need to be met:

[0117] (27)

[0118] (28)

[0119] (29)

[0120] In the formula: For energy storage eE Rated power; and These are characterizing energy storage. eE During the period t 0 / 1 variables for internal charging and discharging states.

[0121] Energy storage is subject to energy boundary constraints (30), as shown below:

[0122] (30)

[0123] In the formula: and Energy storage eE The maximum and minimum state of charge limits.

[0124] Energy storage requires one charge-discharge cycle in each scheduling period to ensure the energy at the beginning and end states is equal. and To achieve equilibrium, the constraints are as follows:

[0125] (31)

[0126] Energy-type energy storage transient frequency response reserve The following constraints need to be met:

[0127] (32)

[0128] (33)

[0129] (34)

[0130] In the formula: For energy storage eE Frequency response limiting factor, Indicates energy storage eE During the scheduling period t The power within.

[0131] Power-type energy storage during dispatch periods t Internal frequency response reserve The following constraints must be met:

[0132] (35)

[0133] (36)

[0134] In the formula: and Power-type energy storage eP Rated power and rated energy; Power-type energy storage eP Frequency response limiting factor; Power-type energy storage eP The maintained state of charge.

[0135] 3) Wind turbine

[0136] Active power output of wind turbine The following constraints must be met:

[0137] (37)

[0138] 4) Gas turbine generator

[0139] The operating power of a gas turbine generator should meet the following constraints:

[0140] (38)

[0141] (39)

[0142] In the formula: and Turbine generator g Rate limits for climbing uphill and downhill.

[0143] Turbine generator during time period t transient frequency response reserve It is also limited by steady-state operating power and frequency response limits, as shown below:

[0144] (40)

[0145] (41)

[0146] In the formula: For turbine generator g Rated power; For turbine generator g Speed ​​controller frequency response limiting factor.

[0147] 5) Load

[0148] Load during time period t Frequency response reserve The following constraints must be met:

[0149] (42)

[0150] In the formula: for The upper limit of this value is set as the maximum load shedding of the system.

[0151] 6) Frequency constraints under transient faults of wind turbine disconnection

[0152] Based on the proposed multi-device collaborative frequency response strategy for offshore island microgrids, the system frequency constraints under wind turbine disconnection faults are derived. The frequency change rate should satisfy the following constraints:

[0153] (43)

[0154] In the formula: The initial frequency change rate under transient fault events; for Maximum allowed value, This represents the total inertia of the system. This is the system's nominal frequency.

[0155] The frequency quasi-steady-state deviation constraint for a microgrid on an isolated offshore island is shown below:

[0156] (44)

[0157] Based on the proposed multi-device cooperative frequency response strategy, the maximum frequency deviation constraint for the offshore island microgrid is as follows:

[0158] (45)

[0160] (46)

[0161] In the formula: || x ||2 indicates x The second norm; H gt , H Eess , H Pess These are the inertia of gas turbine generators, energy storage, and power storage, respectively. This is the maximum tolerance for system frequency deviation. , , , , and To simplify the coefficients, the values ​​for each coefficient are as follows: , , , , , .

[0162] Based on the above model and constraints, the model for energy storage optimization configuration in the method provided by this invention can be expressed as:

[0163] (47)

[0164] It can be seen that the optimization model shown in formula (47) is a mixed integer quadratic convex programming problem. It can be solved by precise methods such as branch and bound method and cutting plane method, or heuristic algorithms such as genetic algorithm, particle swarm algorithm, simulated annealing algorithm, hybrid improved algorithm based on the above algorithms, and by calling external mature commercial solvers.

[0165] To verify the effectiveness of the method provided by this invention, a microgrid on an isolated offshore island was used as the research object. The system structure and equipment parameters of this research object are as follows: Figure 3 As shown, the microgrid on this offshore island has a lifespan of 30 years. The system is equipped with four gas turbine generators (GTG1~GTG4) for spinning reserve, and also has sufficient static reserve gas turbine generators. The microgrid on this offshore island plans to invest in supercapacitors and lithium-ion batteries. To verify the superiority of the method provided by this invention, six energy storage configuration strategies were compared and set up as shown in Table 1.

[0166] Table 1

[0167]

[0168] Energy storage configuration results under different strategies are as follows Figure 4 As shown, the net present value and wind curtailment rate are as follows: Figure 5 As shown in the figure, the net present value of the proposed strategies 3-6 is improved by 4.9%, 10.5%, 3.2%, and 3.1% respectively compared to strategy 2 in the existing literature, while the wind curtailment rate is reduced by 4.9%, 5.7%, 3.6%, and 2.2% respectively, thus verifying the superiority of the energy storage configuration method proposed in this invention. Among them, the proposed strategy 4 achieves the highest net present value and the lowest wind curtailment rate, therefore, the energy storage configuration scheme corresponding to strategy 4 is recommended in this example.

[0169] The following describes the energy storage configuration device for an isolated offshore microgrid that considers both steady-state and transient multi-timescale requirements, provided by this invention. The energy storage configuration device for an isolated offshore microgrid that considers both steady-state and transient multi-timescale requirements described below can be referred to in correspondence with the energy storage configuration method for an isolated offshore microgrid that considers both steady-state and transient multi-timescale requirements described above. Figure 6 As shown, the offshore island microgrid energy storage configuration device that considers steady-state and transient multi-timescale requirements provided by the present invention includes the following modules:

[0170] The operation model construction module 610 is used to construct the first operation model and the second operation model of the islanded microgrid. The first operation model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operation model reflects the relationship between the physical parameters of energy storage devices. The energy storage devices include energy-type energy storage devices and power-type energy storage devices.

[0171] The response model construction module 620 is used to construct the frequency response model of the microgrid, which reflects the frequency response of each device in the microgrid after a transient fault event occurs.

[0172] Constraint construction module 630 is used to construct constraints based on the physical parameters and frequency response models of devices in the microgrid.

[0173] The optimization module 640 is used to solve the objective optimization function based on the first operating model, the second operating model, the frequency response model, and the constraints to obtain the energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of energy-type energy storage devices and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0174] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7 As shown, the electronic device may include: a processor 710, a communications interface 720, a memory 730, and a communications bus 740, wherein the processor 710, the communications interface 720, and the memory 730 communicate with each other through the communications bus 740. The processor 710 can call logic instructions in the memory 730 to execute a method for configuring energy storage in an isolated offshore microgrid that considers steady-state and transient multi-timescale requirements. This method includes: constructing a first operating model and a second operating model for the isolated microgrid. The first operating model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operating model reflects the relationship between the physical parameters of energy storage devices, including energy-type and power-type energy storage devices; constructing a frequency response model for the microgrid, reflecting the frequency response of each device in the microgrid after a transient fault event; constructing constraints based on the physical parameters of the devices in the microgrid and the frequency response model; and solving the objective optimization function based on the first operating model, the second operating model, the frequency response model, and the constraints to obtain an energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of the energy-type and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0175] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0176] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the energy storage configuration method for an isolated island microgrid in the above-mentioned methods, which takes into account steady-state and transient multi-timescale requirements. The method includes: constructing a first operating model and a second operating model of the isolated island microgrid. The first operating model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operating model reflects the relationship between the physical parameters of energy storage devices. The energy storage devices include energy-type energy storage devices and power-type energy storage devices. Constructing a frequency response model of the microgrid, which reflects the frequency response of each device in the microgrid after a transient fault event. Constructing constraints based on the physical parameters of the devices in the microgrid and the frequency response model. Solving the objective optimization function based on the first operating model, the second operating model, the frequency response model, and the constraints to obtain an energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of the energy-type energy storage devices and the power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0177] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the above-described method for configuring energy storage in an isolated offshore microgrid, taking into account steady-state and transient multi-timescale requirements. This method includes: constructing a first operating model and a second operating model of the isolated microgrid. The first operating model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operating model reflects the relationship between the physical parameters of energy storage devices, including energy-type energy storage devices and power-type energy storage devices; constructing a frequency response model of the microgrid, reflecting the frequency response of each device in the microgrid after a transient fault event; constructing constraints based on the physical parameters of the devices in the microgrid and the frequency response model; and solving an objective optimization function based on the first operating model, the second operating model, the frequency response model, and the constraints to obtain an energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of the energy-type and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid.

[0178] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0179] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for configuring energy storage in an isolated offshore microgrid that considers both steady-state and transient multi-timescale demands, characterized in that, The method includes: A first operating model and a second operating model are constructed for an islanded microgrid. The first operating model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operating model reflects the relationship between the physical parameters of energy storage devices. The energy storage devices include energy-type energy storage devices and power-type energy storage devices. Power-type energy storage devices do not participate in optimized scheduling, but only participate in system inertia support and frequency response reserve. Energy-type energy storage devices participate in optimized scheduling and also participate in system inertia support and frequency response reserve when there are margins in energy and operating power. A frequency response model of the microgrid is constructed, which reflects the frequency response of each device in the microgrid after a transient fault event occurs. Constraints are constructed based on the physical parameters of the devices in the microgrid and the frequency response model. Based on the first operating model, the second operating model, the frequency response model, and the constraints, the objective optimization function is solved to obtain the energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of energy-type energy storage devices and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid. The frequency response model includes the spinning standby gas turbine generator, power-type energy storage device, energy-type energy storage device, and load in the microgrid. τ The frequency response power at time t, where, , τ = 0 indicates the start time of the transient fault event. The time required for a static standby turbine generator to reach its target power from the onset of a transient fault event; The constraints include the maximum frequency deviation constraint under wind turbine disconnection faults in the microgrid, which is: ； Among them, || x ||2 indicates x The second norm; , , and These include a rotating standby gas turbine generator, a power-type energy storage device, an energy-type energy storage device, and a frequency response reserve for the load. The total inertia of the system. This refers to the active power output of the wind turbine. , , , , and To simplify the coefficients, the values ​​for each coefficient are as follows: , , , , , , , and These are the frequency response delay times for energy storage devices, loads, and spinning standby turbine generators, respectively. , and These are the complete frequency response times for power-type energy storage devices, energy-type energy storage devices, and spinning standby turbine generators, respectively. This is the maximum tolerance for system frequency deviation. This is the system's nominal frequency.

2. The method for configuring energy storage in an isolated offshore microgrid considering steady-state and transient multi-timescale requirements as described in claim 1, characterized in that, The frequency response model is as follows: ； ； ； ； in, , , and These respectively represent the rotating standby gas turbine generator, power-type energy storage, energy-type energy storage, and load within the system. τ Frequency response power at time t, This refers to the time it takes for a power-type energy storage device to exit the frequency response.

3. The method for configuring energy storage in an isolated offshore microgrid considering steady-state and transient multi-timescale requirements as described in claim 1, characterized in that, The objective optimization function is: ； in, The equivalent annual cost of an isolated offshore microgrid without energy storage; The equivalent annual cost of configuring energy storage for microgrids on offshore islands This is the annual value coefficient; ； in, and These are the discounted investment cost and residual value recovery benefits of energy storage equipment, respectively. and These are annual gas costs and carbon tax costs, respectively. and These are the annual operating and maintenance costs for energy storage and turbine generators, respectively.

4. The method for configuring energy storage in an isolated offshore microgrid considering steady-state and transient multi-timescale requirements as described in claim 3, characterized in that, The formula for calculating the discounted investment cost of energy storage equipment in the objective optimization function is as follows: ； The formula for calculating the output value recovery benefit of energy storage equipment in the objective optimization function is as follows: ； in, A collection of energy storage systems. and Energy storage devices e Rated energy and rated power; and Energy storage devices e The investment cost per unit rated energy and per unit rated power; For energy storage devices e Life expectancy Indicates energy storage devices e The number of investments, among which Indicates not less than x The smallest integer, For the expected lifespan of microgrids on offshore islands; All energy storage systems invested in this time will be replaced at the end of their expected lifespan. For energy storage devices e The residual value rate; the recovery rate of the last invested energy storage equipment when decommissioned in an offshore microgrid is denoted as... ; is the discount rate.

5. The method for configuring energy storage in an isolated offshore microgrid considering steady-state and transient multi-timescale requirements as described in claim 1, characterized in that, The first operating model includes a network power flow model, which is as follows: ； t Indicates the optimized scheduling period; , where Ω N Represents the set of nodes in a network; Represents nodes in the network i The set of connected nodes; Ω gt Ω wt Ω ess and Ω load These respectively represent a collection of gas turbine generators, wind turbine generators, energy storage, and load devices. g , w , e and l They represent sets Ω respectively. gt Ω wt Ω ess and Ω load Elements in; P g,i ( t ), P w,i ( t ), P e,i ( t )and P l,i ( t ) represent nodes respectively i Turbine generator g Wind turbine w Energy storage e and load l During the period t The active operating power, of which the operating power during energy storage discharge is positive and the operating power during charging is negative; U i ( t ) represents a node i During the period t The voltage amplitude; G ij and B ij Representing branch roads ij The electrical conductance and susceptance between them; δ ij ( t ) represents a node i and nodes j During the period t The phase angle difference.

6. The method for configuring energy storage in an isolated offshore microgrid considering steady-state and transient multi-timescale requirements as described in claim 1, characterized in that, The second operating model includes a charging and discharging process model for energy storage devices, wherein the charging and discharging process model is as follows: ； in, , A collection of energy storage devices; Energy storage devices eE During the period t Stored energy; and For energy storage devices eE, the time period is as follows: t Internal charging and discharging power; To optimize the duration of scheduling periods for the system; , and These are energy storage devices. eE Its self-consumption rate, charging efficiency, and discharging efficiency.

7. A marine island microgrid energy storage configuration device considering steady-state and transient multi-timescale requirements, characterized in that, The device includes: The operation model construction module is used to construct a first operation model and a second operation model for the islanded microgrid. The first operation model reflects the relationship between the physical parameters of non-energy storage devices in the microgrid, and the second operation model reflects the relationship between the physical parameters of energy storage devices. The energy storage devices include energy-type energy storage devices and power-type energy storage devices. Power-type energy storage devices do not participate in optimized scheduling, but only participate in system inertia support and frequency response reserve. Energy-type energy storage devices participate in optimized scheduling and also participate in system inertia support and frequency response reserve when there are margins in energy and operating power. The response model construction module is used to construct the frequency response model of the microgrid, which reflects the frequency response of each device in the microgrid after a transient fault event occurs. A constraint construction module is used to construct constraints based on the physical parameters of the devices in the microgrid and the frequency response model. An optimization module is used to solve the objective optimization function based on the first operating model, the second operating model, the frequency response model, and the constraints to obtain an energy storage configuration scheme in the microgrid. The energy storage configuration scheme includes the rated power and rated energy of energy-type energy storage devices and power-type energy storage devices in the microgrid. The optimization objective of the objective optimization function is to maximize the cost difference before and after configuring energy storage devices in the microgrid. The frequency response model includes the spinning standby gas turbine generator, power-type energy storage device, energy-type energy storage device, and load in the microgrid. τ The frequency response power at time t, where, , τ = 0 indicates the start time of the transient fault event. The time required for a static standby turbine generator to reach its target power from the onset of a transient fault event; The constraints include the maximum frequency deviation constraint under wind turbine disconnection faults in the microgrid, which is: ； Among them, || x ||2 indicates x The second norm; , , and These include a rotating standby gas turbine generator, a power-type energy storage device, an energy-type energy storage device, and a frequency response reserve for the load. The total inertia of the system. This refers to the active power output of the wind turbine. , , , , and To simplify the coefficients, the values ​​for each coefficient are as follows: , , , , , , , and These are the frequency response delay times for energy storage devices, loads, and spinning standby turbine generators, respectively. , and These are the complete frequency response times for power-type energy storage devices, energy-type energy storage devices, and spinning standby turbine generators, respectively. This is the maximum tolerance for system frequency deviation. This is the system's nominal frequency.

8. An electronic 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 storage configuration method for offshore island microgrids that takes into account steady-state and transient multi-timescale requirements as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the energy storage configuration method for offshore island microgrids that takes into account steady-state and transient multi-timescale requirements as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the energy storage configuration method for offshore island microgrids that takes into account steady-state and transient multi-timescale requirements as described in any one of claims 1 to 6.

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