Network construction and network following mode control method and system of new energy-energy storage system cluster

Abstract

The application discloses a new energy-energy storage system cluster network construction and network following mode control method and system, and relates to the new energy-energy storage system cluster control field. After the regional power system structure and the data information containing the new energy-energy storage system cluster are acquired, the data information is normalized to obtain normalized data. The network construction ability of each new energy-energy storage system is evaluated according to the normalized data, a new energy-energy storage system cluster network construction and network following mode combination optimization mathematical model for new energy-energy storage system cluster operation mode control is constructed, and a mixed integer programming algorithm is used to determine the decision instruction and the control instruction of each new energy-energy storage system cluster network construction operation mode, so as to plan and schedule each new energy and energy storage converter in the power grid, realize the dynamic adjustment of the network construction control and network following control proportion of the new energy and energy storage converter in the power grid, and further maximally improve the power quality and the power grid power supply stability.

Description

Technical Field

[0001] This invention relates to the field of new energy-storage system cluster control, and in particular to a method and system for controlling the network construction and following modes of a new energy-storage system cluster. Background Technology

[0002] Currently, most new energy and energy storage converters are grid-connected. However, with the high proportion of new energy sources integrated into new power systems, the proportion of new energy capacity in the grid is increasing while the proportion of thermal power unit capacity is decreasing. This leads to a decline in the overall inertia of the system, resulting in a weakening of local grids (i.e., a decrease in the equivalent short-circuit ratio). Consequently, traditional grid-connected converters experience a series of broadband oscillation problems, making grid voltage and frequency more susceptible to fluctuations from new energy sources and loads. To strengthen the support capabilities of wind and solar power generation systems and energy storage systems for weak grids, and to explore the role of converter power synchronization in improving grid stability, new energy and energy storage converters are now transitioning from grid-connected to grid-connected control. Unlike traditional grid-connected converters, grid-connected converters can be understood as power-oriented voltage sources. Their current-source-based operation leads to weak grid voltage control capabilities, as there are no generating units to establish and support voltage. This is unacceptable for current power systems operating primarily as voltage sources. To build a new power system based on renewable energy sources, these renewable energy sources also need to exhibit voltage source characteristics to the grid; this is the more fundamental requirement of grid-connected converters. However, if all renewable energy converters and energy storage system converters in a real power grid are converted to grid-connected control, the overall power system exhibits the characteristics of multiple voltage sources connected in parallel. When grid impedance is inappropriate, the system is prone to oscillations or even instability. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, this invention provides a method and system for controlling the network construction and grid connection modes of a new energy-storage system cluster.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A method for controlling the grid construction and grid connection modes of a new energy-storage system cluster, comprising:

[0006] Data information of the new energy-energy storage system cluster in the region is acquired, and the data information is processed into per-unit data. The data information includes: the number of power network nodes, the number of branches, the impedance and admittance values ​​of the branches, the rated capacity of the power network, the voltage level, the active power of the load users on each node of the power network, the reactive power of the load users on each node of the power network, the installed capacity of new energy on each node of the power network, and the rated power and rated capacity of the energy storage system.

[0007] Based on the per-unit data, the power supply and demand of the power grid in the region are assessed to obtain the power supply capacity of new energy and energy storage systems at each node and the power demand of the load at each node.

[0008] Multiple new energy-energy storage system cluster network operation modes are established based on the sum of the power supply capacity of new energy and energy storage systems at each node and the sum of the load power demand at each node.

[0009] Based on the aforementioned new energy-storage system cluster network operation mode, a combined optimization mathematical model for new energy-storage system cluster network construction and follow-up network mode is constructed;

[0010] Based on the mathematical model of the combined optimization of the network construction and following modes of new energy-storage system clusters, the decision and control commands of each new energy-storage system cluster network construction mode are obtained by using the mixed integer programming algorithm.

[0011] Based on the decision instructions and control instructions, the network construction and grid connection mode control of the new energy-storage system cluster is completed.

[0012] Optionally, based on the per-unit data, the power supply and demand of the power grid within the region are assessed to obtain the power supply capacity of new energy and energy storage systems at each node, as well as the load power demand at each node, specifically including:

[0013] The electricity demand of each node is determined based on the historical and current electricity load data of each node in the regional power grid. The electricity load data includes the active power and reactive power of the load users at each node of the power network.

[0014] The power supply capacity of new energy sources and energy storage systems at each node is determined based on the active power of load users at each node of the regional power grid, the reactive power of load users at each node of the power grid, the installed capacity of new energy sources at each node of the power grid, and the rated power and rated capacity of energy storage systems.

[0015] Optionally, the power supply capacity of the new energy and energy storage systems at each node includes: the power supply capacity of the new energy at each node of the regional power grid, the discharge capacity of the energy storage systems at each node of the regional power grid, and the charging capacity of the energy storage systems at each node of the regional power grid.

[0016] Optionally, multiple new energy-energy storage system cluster network operation modes can be established based on the sum of the power supply capacity of the new energy and energy storage systems at each node and the sum of the load power demand at each node, specifically including:

[0017] When the sum of the power supply capacity of new energy sources at each node of the regional power grid is greater than or equal to the sum of the load power demand of each node, a new energy-energy storage system cluster network operation mode I is formed.

[0018] When the sum of the power supply capacity of new energy sources at each node of the regional power grid is less than the sum of the power demand of the load at each node, and the discharge capacity of the energy storage system is greater than the set value, a new energy-energy storage system cluster network operation mode II is formed.

[0019] When the sum of the power supply capacity of new energy sources at each node of the regional power grid is less than the sum of the power demand of the load at each node, and the energy storage discharge capacity is less than or equal to the set value, a new energy-energy storage system cluster network operation mode III is formed.

[0020] Optionally, the new energy-storage system cluster network operation mode II includes: new energy-storage system cluster network operation mode II.1, new energy-storage system cluster network operation mode II.2 and new energy-storage system cluster network operation mode II.3;

[0021] Among them, the new energy-energy storage system cluster network operation mode II.1 is the grid-connected operation mode of the energy storage system, and some new energy systems in the power grid participate in the network operation mode; the new energy systems participating in the network operation mode are affected by their own power supply capacity.

[0022] Both the new energy-energy storage system cluster network construction operation mode II.2 and the new energy-energy storage system cluster network construction operation mode II.3 involve some new energy systems and some energy storage systems participating in the network construction operation mode, and some new energy systems and some energy storage systems participating in the grid-following operation mode. The new energy systems participating in the network construction operation mode are affected by their own power supply capacity, while the energy storage systems participating in the network construction operation mode are affected by their own discharge capacity.

[0023] Optionally, based on the aforementioned new energy-energy storage system cluster network operation mode, a combined optimization mathematical model for new energy-energy storage system cluster network construction and grid connection modes is constructed, specifically including:

[0024] Based on the aforementioned new energy-storage system cluster network operation mode I, a first new energy-storage system cluster network construction and follow-up network mode combination optimization mathematical model is constructed;

[0025] Based on the aforementioned new energy-storage system cluster network operation mode II, a second new energy-storage system cluster network construction and follow-up network mode combination optimization mathematical model is constructed;

[0026] Based on the aforementioned new energy-energy storage system cluster network operation mode III, a third new energy-energy storage system cluster network construction and follow-up network mode combination optimization mathematical model is constructed.

[0027] Optionally, the first new energy-energy storage system cluster network construction and grid-following mode combination optimization mathematical model, the second new energy-energy storage system cluster network construction and grid-following mode combination optimization mathematical model, and the third new energy-energy storage system cluster network construction and grid-following mode combination optimization mathematical model all include: optimization variables, objective function, and constraints.

[0028] Furthermore, the present invention also provides a grid-connection and grid-following mode control system for a new energy-storage system cluster. This system applies the aforementioned grid-connection and grid-following mode control method for the new energy-storage system cluster; the system includes:

[0029] The basic information module is used to acquire data information of the new energy-energy storage system cluster in the region and to perform per-unit processing on the data information to obtain per-unit data. The data information includes: the number of power network nodes, the number of branches, the branch impedance and admittance values, the rated capacity of the power network, the voltage level, the active power of the load users on each node of the power network, the reactive power of the load users on each node of the power network, the installed capacity of new energy on each node of the power network, and the rated power and rated capacity of the energy storage system.

[0030] The capacity assessment and analysis module is used to assess the power supply and demand of the power grid in the region based on the per-unit data, obtain the power supply capacity of new energy and energy storage systems at each node and the power demand of the load at each node, and to establish multiple new energy-energy storage system cluster network operation modes based on the sum of the power supply capacity of new energy and energy storage systems at each node and the sum of the power demand of the load at each node.

[0031] The control model module is used to construct a combined optimization mathematical model of the new energy-storage system cluster network construction and grid connection mode based on the new energy-storage system cluster network construction and operation mode.

[0032] The calculation module is used to optimize the mathematical model of the combination of network construction and following modes of the new energy-energy storage system cluster based on the new energy-energy storage system cluster. It uses a mixed integer programming algorithm to optimize and obtain the decision instructions and control instructions for the network construction and operation modes of each new energy-energy storage system cluster. It is also used to complete the network construction and following mode control of the new energy-energy storage system cluster based on the decision instructions and control instructions.

[0033] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] This invention requires acquiring basic information (i.e., data information) about the power system structure within a region and the distribution of new energy-storage system clusters within the power system. This data information is then processed to obtain per-unit data. Based on the per-unit data, the grid-building capability of each new energy-storage system is evaluated. A mathematical model for optimizing the combination of grid-building and grid-following modes of new energy-storage system clusters is constructed, oriented towards the control of their operation modes. Finally, a mixed-integer programming algorithm is used to determine the decision-making and control commands for the grid-building operation modes of each new energy-storage system cluster. This allows for the overall planning and scheduling of various new energy and energy storage converters in the power grid, enabling dynamic adjustment of the ratio of grid-building control to grid-following control for new energy and energy storage converters. Ultimately, this maximizes power quality and grid stability, reducing the potential for oscillations caused by large-scale grid-building of new energy-storage systems. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart of the grid construction and grid-following mode control method for a new energy-storage system cluster provided by the present invention;

[0037] Figure 2 A flowchart illustrating the implementation of the grid construction and grid-following mode control method for a new energy-storage system cluster provided in this embodiment of the invention;

[0038] Figure 3 A power network structure diagram provided for an embodiment of the present invention;

[0039] Figure 4 This is a flowchart illustrating the capability assessment and analysis of a new energy-energy storage system cluster network as described in an embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The purpose of this invention is to provide a method and system for controlling the grid construction and grid connection modes of a new energy-storage system cluster. This method can coordinate and schedule various new energy and energy storage converters in the power grid to dynamically adjust the ratio of grid construction control and grid connection control of new energy and energy storage converters in the power grid, thereby ensuring the stable operation of the system.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] like Figure 1 As shown, the present invention provides a method for controlling the grid construction and grid connection modes of a new energy-storage system cluster, comprising:

[0044] Step 100: Obtain data information of the new energy-energy storage system cluster within the region, and perform per-unit processing on the data information to obtain per-unit data. The data information includes the regional power network structure, new energy power plants, energy storage systems, and load user information.

[0045] In practical applications, this step is implemented as follows:

[0046] Step 1001: Obtain the power network structure information within the region and perform ideal equivalence and per-unit processing. Specific information in this step includes the number of power network nodes, the number of branches, branch impedance and admittance values, the rated capacity of the power network, and voltage levels.

[0047] Step 1002: Obtain information on power sources, energy storage, and load users within the region and perform per-unit processing. Specific information in this step includes the active power, reactive power, renewable energy installed capacity, rated power, and rated capacity of energy storage systems at each node of the power network.

[0048] Step 101: Based on per-unit data, assess the power supply and demand of the power grid in the region to obtain the power supply capacity of new energy and energy storage systems at each node and the power demand of the load at each node.

[0049] In practical applications, this step is implemented as follows:

[0050] Step 1011: Determine the power demand of each node based on the historical power load data and the current power load data of each node in the regional power grid. The power load data includes the active power and reactive power of the load users at each node of the power network. For example, assume that at time t, the active power and reactive power of the load at the i-th node are Pi and Pi, respectively. load,i (t) and Q load,i (t).

[0051] Step 1012: Determine the power supply capacity of new energy sources and energy storage systems at each node based on the active power of load users at each node of the power grid, the reactive power of load users at each node of the power grid, the installed capacity of new energy sources at each node of the power grid, and the rated power and rated capacity of energy storage systems.

[0052] In assessing the power supply capacity of new energy sources within the regional power grid, it is assumed that at time t, the active and reactive power provided by the new energy system at the i-th node is P. new,i (t) and Q new,i (t).

[0053] In evaluating the discharge and charging capabilities of energy storage systems within a regional power grid, it is assumed that the rated power and rated capacity of the energy storage system at the i-th node are P. E,i and C E,i The upper limit of charging capacity and the lower limit of discharging capacity are respectively and The charging and discharging efficiencies are respectively and At time t, the capacity state of the energy storage system at the i-th node is C. E,i (t), that is Then the discharge capacity and active power capacity of the energy storage system at the i-th node are: Reactive power capability is The charging capacity and active power capacity of the energy storage system at the i-th node are: Reactive power capability is

[0054] Step 102: Establish multiple new energy-energy storage system cluster network operation modes based on the sum of the power supply capacity of each node's new energy and energy storage systems and the sum of the load power demand of each node.

[0055] In practical applications, this step is implemented as follows:

[0056] Step 1021: When the sum of the power supply capacity of new energy sources at each node of the regional power grid is greater than or equal to the sum of the load power demand of each node, that is... and At this point, the energy storage system does not participate in the grid-connected operation mode, but instead operates in the grid-following operation mode. Some new energy systems participate in the grid-connected operation mode, and the participation of these new energy systems is influenced by their power supply capacity. New energy systems with strong power supply capacity, i.e., high active power capacity, are given priority in participating in the grid-connected operation mode. The specific number of new energy systems participating in the grid-connected operation mode is optimized and calculated in subsequent steps 103 and 104, forming the new energy-energy storage system cluster grid-connected operation mode I. Where P L,i (t) and Q L,i(t) represents the active and reactive power of the electrical load at the i-th node.

[0057] Step 1022: When the sum of the power supply capacity of new energy sources at each node of the regional power grid is less than the sum of the load demand of each node, and the discharge capacity of the energy storage system is greater than the set value (sufficient energy storage discharge capacity), i.e., when one of the following three conditions is met, some energy storage systems participate in the grid construction mode. The energy storage systems participating in the grid construction mode are affected by their discharge capacity. Energy storage systems with strong discharge capacity, i.e., large active power capacity, are given priority to participate in grid construction operation. The specific number of energy storage systems participating in grid construction operation will be optimized and calculated in subsequent steps to form the new energy-energy storage system cluster grid construction operation mode II.

[0058] Scenario 1: as well as The new energy system has sufficient active power supply but insufficient reactive power supply, while the energy storage system has sufficient discharge capacity, and the reactive power it can provide can compensate for the insufficient reactive power of the new energy system. In this case, the energy storage system does not participate in the grid construction mode, but operates in the grid-following mode. Some new energy systems participate in the grid construction mode, and the new energy systems participating in the grid construction mode are affected by their power supply capacity. The mode obtained under this case is the new energy-energy storage system cluster grid construction operation mode II.1.

[0059] Scenario 2: as well as When the active power supply of the new energy system is insufficient, the reactive power supply is sufficient, and the discharge capacity of the energy storage system is adequate, the active power provided can compensate for the insufficient active power of the new energy system. In this case, some new energy systems and energy storage systems participate in the grid-connected mode, and some new energy systems and energy storage systems participate in the grid-following mode. The new energy systems participating in the grid-connected mode are affected by their power supply capacity, and the energy storage systems participating in the grid-connected mode are affected by their discharge capacity. The resulting mode is the new energy-energy storage system cluster grid-connected operation mode II.2.

[0060] Scenario 3: as well as When both active and reactive power supply from the new energy system are insufficient, while the energy storage system has sufficient discharge capacity (meaning the available active and reactive power can compensate for the insufficient reactive power of the new energy system), some new energy systems and energy storage systems participate in the grid-connected mode, while others participate in the grid-following mode. The new energy systems participating in the grid-connected mode are affected by their power supply capacity, while the energy storage systems participating in the grid-connected mode are affected by their discharge capacity. The resulting mode is called New Energy-Energy Storage System Cluster Grid-Connected Operation Mode II.3.

[0061] Step 1023: When the sum of the power supply capacity of new energy sources at each node of the regional power grid is less than the sum of the power demand of the load at each node, and the energy storage discharge capacity is less than or equal to the set value (insufficient energy storage discharge capacity), i.e. or Based on the importance of the electricity load, some electricity load needs to be cut off. The specific amount of load to be cut off and the control quantities of the new energy and energy storage systems involved in the operation will be optimized and calculated in subsequent steps 103 and 104. The new energy-energy storage system cluster adopts a grid construction mode, forming the new energy-energy storage system cluster grid construction operation mode III.

[0062] Step 103: Construct a mathematical model for the combined optimization of network construction and grid connection modes for new energy-storage system clusters based on the cluster network operation mode. This step mainly involves constructing a mathematical model for the combined optimization of network construction and grid connection modes for new energy-storage system clusters based on the network construction and operation mode obtained in Step 102, forming a control model module for new energy-storage system clusters that considers the combination of network construction and grid connection modes. The constructed mathematical model for the combined optimization of network construction and grid connection modes for new energy-storage system clusters mainly includes the definition of model optimization variables, the design of the objective function, and the construction of constraints.

[0063] Corresponding to the three new energy-storage system cluster network operation modes listed above, the process of constructing different combined optimization mathematical models for new energy-storage system cluster network and grid connection modes is as follows:

[0064] Step 1031: Construct a mathematical model for the combined optimization of the first new energy-energy storage system cluster network construction and follow-up network mode based on the new energy-energy storage system cluster network construction and operation mode I.

[0065] Among them, the optimization variables of the mathematical model for the combined optimization of the first new energy-energy storage system cluster network construction and grid-following mode include: 1) the identifier variable I of the new energy system network construction or grid-following mode. new Its value is a 0-1 variable. At time t, when the new energy system identifier variable I at the i-th node... new,i When (t) = 1, it indicates a network configuration mode. When the new energy system identifier variable I on the i-th node... new,i When (t) = 0, it indicates that it is in grid-fed mode. 2) The output active power and reactive power variables of the new energy system are continuous variables. At time t, the output active power and reactive power of the new energy system at the i-th node are represented as X. new,i (t) and Y new,i (t). 3) The active and reactive power outputs of the energy storage system are continuous variables. At time t, the active and reactive power outputs of the energy storage system at the i-th node are represented as X. E,i (t) and Y E,i(t). 4) The voltage at each node on the power network and the current on each branch of the power network.

[0066] The objective function J of the mathematical model for the combined optimization of cluster construction and grid connection modes of the first new energy storage system is... * This includes: 1) To reduce the oscillations that may be generated by multi-system network construction, it is desirable to minimize the number of new energy systems operating in the network configuration mode, i.e. 2) To improve power grid stability, it is desirable to maximize the power supply capacity of new energy sources in the grid configuration mode, i.e. 3) To improve the utilization rate of new energy sources, it is desirable that the actual active power output of new energy sources is as close as possible to the maximum active power that they can output at the current moment, i.e.

[0067] The constraints of the mathematical model for the combined optimization of the first new energy-energy storage system cluster network and grid-connected mode include: active and reactive power balance constraints of the power system, node voltage and power constraints, active power output constraints of new energy sources, and energy balance of the energy storage system, etc. The specific formulas are shown below:

[0068]

[0069] Among them, X new,i (t), X E,i (t) and P load,i (t) represents the actual active power output of the new energy system, energy storage system, and load user at time t of the i-th power system node. new,i (t), Y E,i (t) and Q load,i (t) represents the actual reactive power output of the new energy system, energy storage system, and load user at time t of the i-th power system node. i (t) and U j (t) represents the square of the voltages at nodes i and j at time t, while R i,j and X i,j These represent the resistance and reactance between node j and node i, respectively. and I represents the squares of the upper and lower limits of the node voltage, respectively. max This indicates the maximum current that can pass through the branch. and C E,i (t) represents the upper and lower limits of the energy storage system capacity state at the i-th power system node, and the capacity state at time t, respectively. and Let P represent the charging and discharging efficiencies of the energy storage system at the i-th power system node, respectively. Δt represents the time interval. i,j (t), Q i,j (t) and Ii,j (t) represents the active power, reactive power, and squared current output from the i-th power system node to the j-th power system node, respectively. Node represents the number of nodes.

[0070] Step 1032: Construct a mathematical model for the combined optimization of the second new energy-storage system cluster network construction and follow-up network mode based on the second new energy-storage system cluster network construction and operation mode II.

[0071] Among them, (I) when the new energy-energy storage system cluster network operation mode is II.1, the optimization variables of the constructed second new energy-energy storage system cluster network and grid-following mode combination optimization mathematical model include: 1) New energy system network or grid-following mode identifier variable I new Its value is a 0-1 variable. At time t, when the new energy system identifier variable I at the i-th node... new,i When (t) = 1, it indicates a network configuration mode. When the new energy system identifier variable I on the i-th node... new,i When (t) = 0, it indicates that it is in grid-fed mode. 2) The output active power and reactive power variables of the new energy system are continuous variables. At time t, the output active power and reactive power of the new energy system at the i-th node are represented as X. new,i (t) and Y new,i (t). 3) The active and reactive power outputs of the energy storage system are continuous variables. At time t, the active and reactive power outputs of the energy storage system at the i-th node are represented as X. E,i (t) and Y E,i (t). 4) The voltage at each node on the power network and the current on each branch of the power network.

[0072] When the new energy-energy storage system cluster network operation mode is II.1, the objective function of the constructed second new energy-energy storage system cluster network and grid-following mode combined optimization mathematical model includes: 1) To reduce the oscillations that may be generated by multi-system network construction, the number of new energy systems operating in the network mode is expected to be as small as possible, i.e. 2) To improve power grid stability, it is desirable to maximize the power supply capacity of new energy sources in the grid configuration mode, i.e. 3) To improve the utilization rate of new energy sources, it is desirable that the actual active power output of new energy sources is as close as possible to the maximum active power that they can output at the current moment, i.e. 4) To improve the utilization rate of the energy storage system, it is desirable to minimize the actual reactive power output of the energy storage system, i.e.

[0073] When the new energy-energy storage system cluster network operation mode is II.1, the constraints of the constructed second new energy-energy storage system cluster network and grid-connected mode combined optimization mathematical model include: active and reactive power balance constraints of the power system, node voltage and power constraints, active power output constraints of new energy, energy balance of the energy storage system, etc., and the specific formulas are as follows:

[0074]

[0075] (II) When the new energy-energy storage system cluster network operation mode is II.2, the optimization variables of the constructed second new energy-energy storage system cluster network and grid-following mode combination optimization mathematical model include: 1) New energy system network or grid-following mode identifier variable I new Its value is a 0-1 variable. At time t, when the new energy system identifier variable I at the i-th node... new,i When (t) = 1, it indicates a network configuration mode. When the new energy system identifier variable I on the i-th node... new,i When (t) = 0, it indicates that it is in grid-fed mode. 2) The output active power and reactive power variables of the new energy system are continuous variables. At time t, the output active power and reactive power of the new energy system at the i-th node are represented as X. new,i (t) and Y new,i (t). 3) Identifier variable for energy storage system grid construction or grid connection mode E Its value is a 0-1 variable. At time t, when the energy storage system identification variable I on the i-th node... E,i When (t) = 1, it indicates a network configuration. When the energy storage system identifier I on the i-th node... E,i When (t) = 0, it indicates that it is in grid-connected mode. 4) The active and reactive power outputs of the energy storage system are continuous variables. At time t, the active and reactive power outputs of the energy storage system at the i-th node are represented as X. E,i (t) and Y E,i (t). 5) The voltage at each node on the power network and the current on each branch of the power network.

[0076] When the new energy-energy storage system cluster network operation mode is II.2, the objective function of the constructed second new energy-energy storage system cluster network and grid-following mode combined optimization mathematical model includes: 1) To reduce the oscillations that may be generated by multi-system network construction, the number of new energy systems and energy storage systems operating in the network mode is expected to be as small as possible, i.e. 2) To improve power grid stability, it is desirable for renewable energy and energy storage systems operating in grid configuration mode to have the largest possible power supply capacity, i.e. 3) To improve the utilization rate of new energy sources, it is desirable that the actual active power output of new energy sources is as close as possible to the maximum active power that they can output at the current moment, i.e.

[0077] When the new energy-energy storage system cluster network operation mode is II.2, the constraints of the constructed second new energy-energy storage system cluster network and grid-connected mode combined optimization mathematical model include: power system active and reactive power balance constraints, node voltage and power constraints, new energy active power output constraints, energy balance of the energy storage system, etc., and the specific formulas are as follows:

[0078]

[0079] In the formula, I E,i (t) represents the current value of the energy storage system at the i-th node at time t, P E,i (t) represents the active power of the energy storage system at the i-th node at time t.

[0080] (III) When the new energy-energy storage system cluster network operation mode is II.3, the optimization variables of the constructed second new energy-energy storage system cluster network and grid-following mode combination optimization mathematical model include: 1) New energy system network or grid-following mode identifier variable I new Its value is a 0-1 variable. At time t, when the new energy system identifier variable I at the i-th node... new,i When (t) = 1, it indicates a network configuration mode. When the new energy system identifier variable I on the i-th node... new,i When (t) = 0, it indicates that it is in grid-fed mode. 2) The output active power and reactive power variables of the new energy system are continuous variables. At time t, the output active power and reactive power of the new energy system at the i-th node are represented as X. new,i (t) and Y new,i (t). 3) Identifier variable for energy storage system grid construction or grid connection mode E Its value is a 0-1 variable. At time t, when the energy storage system identification variable I on the i-th node... E,i When (t) = 1, it indicates a network configuration. When the energy storage system identifier I on the i-th node... E,i When (t) = 0, it indicates that it is in grid-connected mode. 4) The active and reactive power outputs of the energy storage system are continuous variables. At time t, the active and reactive power outputs of the energy storage system at the i-th node are represented as X. E,i (t) and Y E,i (t). 5) The voltage at each node on the power network and the current on each branch of the power network.

[0081] The objective function of the model includes: 1) To reduce the oscillations that may be generated by multi-system grid construction, the number of new energy systems and energy storage systems operating in the grid construction mode should be minimized, i.e. 2) To improve power grid stability, it is desirable for renewable energy and energy storage systems operating in grid configuration mode to have the largest possible power supply capacity, i.e. 3) To improve the utilization rate of new energy sources, it is desirable that the actual active power output of new energy sources is as close as possible to the maximum active power that they can output at the current moment, i.e. 4) To improve the utilization rate of the energy storage system, it is desirable to minimize the actual reactive power output of the energy storage system, i.e.

[0082] The constraints of the model include: active and reactive power balance constraints of the power system, node voltage and power constraints, active power output constraints of new energy sources, energy balance of energy storage system, etc., and the specific formulas are shown below.

[0083]

[0084] Step 1033: Construct a mathematical model for the combined optimization of the third new energy-storage system cluster network construction and follow-up network mode based on the third new energy-storage system cluster network construction and operation mode III.

[0085] Among them, the optimization variables of the mathematical model for the combined optimization of the third new energy-energy storage system cluster network and grid-connected mode include: 1) the active power and reactive power output variables of the energy storage system, which are continuous variables. At time t, the active power and reactive power output of the energy storage system at the i-th node are respectively represented as X. E,i (t) and Y E,i (t). 2) Voltage at each node on the power network and current on each branch of the power network. 3) Actual active and reactive power variables of the electrical load, which are continuous variables. At time t, the actual active and reactive power of the electrical load at the i-th node are represented as X. load,i (t) and Y load,i (t).

[0086] The objective function of the mathematical model for the combined optimization of the third new energy-energy storage system cluster network and grid connection mode includes: 1) To ensure the power system load consumption as much as possible, it is desirable to reduce the load shedding amount, i.e.

[0087] The constraints of the mathematical model for the combined optimization of the third new energy-energy storage system cluster network and grid connection mode include: active and reactive power balance constraints of the power system, node voltage and power constraints, active power output constraints of new energy sources, and energy balance of the energy storage system, etc. The specific formulas are shown below.

[0088]

[0089] Step 104: Based on the mathematical model of the combined optimization of the network construction and following modes of the new energy-energy storage system cluster, the decision and control instructions of each new energy-energy storage system cluster network construction operation mode are optimized by using the mixed integer programming algorithm.

[0090] In practical applications, this step can be implemented as follows:

[0091] Step 1041: Based on the new energy system, energy storage system cluster and load electricity consumption in the regional power system, determine whether the new energy-energy storage system cluster is in Mode I, Mode II.1, Mode II.2, Mode II.1 or Mode III.

[0092] Step 1042: Select the mathematical model for the combination optimization of the network construction and following modes of the new energy-storage system cluster obtained in step 103 under the current mode of the new energy-storage system cluster.

[0093] Step 1043: Use a mixed integer programming algorithm to optimize and calculate the decision and control commands for the combination of the new energy-storage system cluster network construction and grid-connected operation modes, so as to obtain the operation mode and output power of the new energy-storage system at each node.

[0094] Step 105: Complete the network construction and grid connection mode control of the new energy-storage system cluster based on decision-making and control commands.

[0095] Based on the above description, this invention first obtains basic information on the power system structure and the distribution of new energy-storage system clusters within a certain region. Then, based on factors such as load demand within the regional power system and the installed capacity and current energy state of the new energy-storage systems, the grid-connection capability of each new energy-storage system is evaluated. Next, using the operating mode and output power of the new energy-storage systems at each power node as variables, a constrained mixed-integer programming model for controlling the operating mode of the new energy-storage system cluster is constructed. Finally, the mixed-integer programming algorithm is used to calculate the operating mode and output power of the new energy-storage systems at each node, maximizing power quality and grid stability, and reducing the potential for oscillations caused by large-scale grid-connection of new energy-storage systems.

[0096] Furthermore, this invention also provides a grid-connection and grid-following mode control system for a new energy-storage system cluster. This system applies the aforementioned grid-connection and grid-following mode control method for new energy-storage system clusters. The system includes:

[0097] The basic information module is used to acquire data information of the new energy-energy storage system cluster within the region and to standardize the data to obtain per-unit data. The data information includes: the number of power network nodes, the number of branches, branch impedance and admittance values, the rated capacity of the power network, voltage levels, and the active power and reactive power of load users at each node of the power network, the installed capacity of new energy sources at each node of the power network, and the rated power and rated capacity of the energy storage system.

[0098] The capacity assessment and analysis module is used to assess the power supply and demand of the power grid in the region based on per-unit data, obtain the power supply capacity of new energy and energy storage systems at each node and the power demand of the load at each node, and establish multiple new energy-energy storage system cluster network operation modes based on the sum of the power supply capacity of new energy and energy storage systems at each node and the sum of the power demand of the load at each node.

[0099] The control model module is used to construct a combined optimization mathematical model of the new energy-energy storage system cluster network construction and grid connection mode based on the new energy-energy storage system cluster network construction and operation mode.

[0100] The calculation module is used to optimize the mathematical model based on the combination of network construction and follow-up modes of new energy-energy storage system clusters. It uses a mixed integer programming algorithm to optimize and obtain the decision and control instructions for the network construction and operation modes of each new energy-energy storage system cluster. Based on the decision and control instructions, it completes the network construction and follow-up mode control of the new energy-energy storage system cluster.

[0101] The following provides a specific implementation method, which uses the control method and system provided by the present invention to control, as shown below. Figure 3 The control of the power network structure shown is explained. For example... Figure 2 As shown, in this embodiment, the grid construction and grid connection mode control process of the new energy-energy storage system cluster includes:

[0102] S1: Acquire information on the power network structure, new energy power plants, energy storage systems, and load users within the region to form the basic information module for the new energy-energy storage system cluster.

[0103] S2: Based on information such as the status of renewable energy generation, real-time energy status of energy storage, and user electricity consumption information within the power network, assess the regional power grid's supply and demand, and establish a capability assessment and analysis module for renewable energy-energy storage system cluster networking. The specific implementation process of the capability assessment and analysis module is as follows: Figure 4 As shown.

[0104] S3: Based on the new energy-storage system cluster network operation mode obtained in S2, construct a mathematical model for the combined optimization of the new energy-storage system cluster network construction and follow-up mode under different conditions, forming a new energy-storage system cluster control model module that takes into account the combination of network construction and follow-up mode. This mainly includes the definition of model optimization variables, the design of objective functions, and the construction of constraints.

[0105] S4: Based on the new energy-energy storage system cluster network construction and grid-following mode operation mode obtained in S2 and the corresponding new energy-energy storage system cluster network construction and grid-following mode combination optimization mathematical model obtained in S3, the decision command and control command of the new energy-energy storage system cluster network construction and grid-following mode combination are optimized and calculated using the mixed integer programming algorithm, forming the calculation module of new energy-energy storage system cluster network construction and grid-following mode.

[0106] For the specific implementation process of each step in S1-S4 above, please refer to the description above.

[0107] Compared to current research on power electronic control of grid-connected and grid-linked converters, this invention addresses the presence of multiple new energy and energy storage systems at the power system level. Assuming each system can operate in either grid-connected or grid-linked mode, this invention proposes a new energy-energy storage system cluster operation mode combination and control optimization process. The key feature of this invention is the real-time dynamic analysis and evaluation of the converter's grid-connection capability based on the energy state of the new energy and energy storage systems. Based on the power supply and demand of the new energy and energy storage systems, a multi-mode operation model and optimized control structure for the new energy and energy storage system cluster are formed. Using mixed-integer programming, the invention considers the new energy-energy storage system cluster operation mode combination and control optimization process from a global power system perspective, calculating the optimal collaborative control result and operation mode for the new energy-energy storage system cluster. This effectively forms a system-optimal controller that balances power supply and demand, which is of great significance for the new energy-energy storage system cluster to actively support grid operation.

[0108] Furthermore, when the aforementioned control method is implemented as a computer program through software functional units and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or a portion 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 this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0109] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0110] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for controlling the grid construction and grid connection modes of a new energy-energy storage system cluster, characterized in that, include: Acquire data information of new energy-energy storage system clusters within the region, and perform per-unit processing on the data information to obtain per-unit data; The data information includes: the number of power network nodes, the number of branches, the impedance and admittance values ​​of branches, the rated capacity of the power network, the voltage level, the active power of load users on each node of the power network, the reactive power of load users on each node of the power network, the installed capacity of new energy on each node of the power network, and the rated power and rated capacity of energy storage systems. Based on the per-unit data, the power supply and demand of the power grid in the region are assessed to obtain the power supply capacity of new energy and energy storage systems at each node and the power demand of the load at each node. Based on the sum of the power supply capacity of new energy and energy storage systems at each node and the sum of the load demand at each node, multiple new energy-energy storage system cluster network operation modes are established, including: when the sum of the power supply capacity of new energy at each node of the regional power grid is greater than or equal to the sum of the load demand at each node, a new energy-energy storage system cluster network operation mode I is formed; when the sum of the power supply capacity of new energy at each node of the regional power grid is less than the sum of the load demand at each node, and the discharge capacity of the energy storage system is greater than a set value, a new energy-energy storage system cluster network operation mode II is formed; when the sum of the power supply capacity of new energy at each node of the regional power grid is less than the sum of the load demand at each node, and the discharge capacity of the energy storage system is less than or equal to a set value, a new energy-energy storage system cluster network operation mode III is formed; New energy-energy storage system cluster network operation mode II includes: new energy... The system comprises three network operation modes: Energy Source-Energy Storage System Cluster Operation Mode II.1, New Energy-Energy Storage System Cluster Operation Mode II.2, and New Energy-Energy Storage System Cluster Operation Mode II.

3. In New Energy-Energy Storage System Cluster Operation Mode II.1, the energy storage system operates in a grid-connected mode, with some new energy systems participating in the network operation. The new energy systems participating in the network operation mode are affected by their own power supply capacity. In New Energy-Energy Storage System Cluster Operation Modes II.2 and II.3, some new energy systems and some energy storage systems participate in the network operation mode, while others operate in a grid-connected mode. The new energy systems participating in the network operation mode are affected by their own power supply capacity, and the energy storage systems participating in the network operation mode are affected by their own discharge capacity. Based on the aforementioned new energy-storage system cluster network operation mode, a combined optimization mathematical model for new energy-storage system cluster network construction and follow-up network mode is constructed; Based on the mathematical model of the combined optimization of the network construction and following modes of new energy-storage system clusters, the decision and control commands of each new energy-storage system cluster network construction operation mode are obtained by using the mixed integer programming algorithm. Based on the decision instructions and control instructions, the network construction and grid connection mode control of the new energy-storage system cluster is completed.

2. The method for controlling the grid construction and grid connection modes of a new energy-energy storage system cluster according to claim 1, characterized in that, Based on the per-unit data, the power supply and demand of the power grid within the region are assessed to obtain the power supply capacity of new energy and energy storage systems at each node, as well as the load power demand at each node, specifically including: The electricity demand of each node is determined based on the historical and current electricity load data of each node in the regional power grid. The electricity load data includes the active power and reactive power of the load users at each node of the power network. The power supply capacity of new energy sources and energy storage systems at each node is determined based on the active power of load users at each node of the power grid, the reactive power of load users at each node of the power grid, the installed capacity of new energy sources at each node of the power grid, and the rated power and rated capacity of energy storage systems.

3. The method for controlling the network construction and grid connection modes of a new energy-energy storage system cluster according to claim 2, characterized in that, The power supply capacity of new energy and energy storage systems at each node includes: the power supply capacity of new energy at each node of the regional power grid, the discharge capacity of energy storage systems at each node of the regional power grid, and the charging capacity of energy storage systems at each node of the regional power grid.

4. The method for controlling the grid construction and grid connection modes of a new energy-energy storage system cluster according to claim 1, characterized in that, Based on the aforementioned new energy-energy storage system cluster network operation mode, a combined optimization mathematical model for new energy-energy storage system cluster network construction and grid connection modes is constructed, specifically including: Based on the aforementioned new energy-storage system cluster network operation mode I, a first new energy-storage system cluster network construction and follow-up network mode combination optimization mathematical model is constructed; Based on the aforementioned new energy-storage system cluster network operation mode II, a second new energy-storage system cluster network construction and follow-up network mode combination optimization mathematical model is constructed; Based on the aforementioned new energy-energy storage system cluster network operation mode III, a third new energy-energy storage system cluster network construction and follow-up network mode combination optimization mathematical model is constructed.

5. The method for controlling the network construction and grid connection modes of a new energy-energy storage system cluster according to claim 4, characterized in that, The first, second, and third new energy-storage system cluster network construction and grid-following mode combination optimization mathematical models all include: optimization variables, objective function, and constraints.

6. A grid-connection and grid-following mode control system for a new energy-energy storage system cluster, characterized in that, The system employs the grid construction and grid connection mode control method for a new energy-storage system cluster as described in any one of claims 1-5; the system includes: The basic information module is used to acquire data information of the new energy-energy storage system cluster in the region and to perform per-unit processing on the data information to obtain per-unit data. The data information includes: the number of power network nodes, the number of branches, the branch impedance and admittance values, the rated capacity of the power network, the voltage level, the active power of the load users on each node of the power network, the reactive power of the load users on each node of the power network, the installed capacity of new energy on each node of the power network, and the rated power and rated capacity of the energy storage system. The capacity assessment and analysis module is used to assess the power supply and demand of the power grid in the region based on the per-unit data, obtain the power supply capacity of new energy and energy storage systems at each node and the power demand of the load at each node, and to establish multiple new energy-energy storage system cluster network operation modes based on the sum of the power supply capacity of new energy and energy storage systems at each node and the sum of the power demand of the load at each node. The control model module is used to construct a combined optimization mathematical model of the new energy-storage system cluster network construction and grid connection mode based on the new energy-storage system cluster network construction and operation mode. The calculation module is used to optimize the mathematical model of the combination of network construction and following modes of the new energy-energy storage system cluster based on the new energy-energy storage system cluster. It uses a mixed integer programming algorithm to optimize and obtain the decision instructions and control instructions for the network construction and operation modes of each new energy-energy storage system cluster. It is also used to complete the network construction and following mode control of the new energy-energy storage system cluster based on the decision instructions and control instructions.

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