Independent energy storage multi-stage planning method considering dynamic updating of power transmission key section

Abstract

The invention discloses an independent energy storage multi-stage planning method considering dynamic updating of a power transmission key section, which comprises the following steps of: determining the power transmission section of a power transmission network through a power transmission key section searching method, screening out a key section from the power transmission section, and setting a power transmission key section dynamic updating method; constructing a constraint according to the screened power transmission key section, and establishing an independent energy storage planning model considering the constraint of the key section; and according to the independent energy storage planning model, solving an nth year energy storage planning model, and outputting an energy storage planning result, an energy storage planning position, an energy storage planning capacity and planning power. According to the method, multi-stage rolling optimization configuration of independent energy storage is realized, the problems of dynamic updating and load increase of a power grid structure under a long time scale can be effectively solved, and the purposes of relieving power transmission congestion, delaying power grid extension and improving the safety and stability margin of the power grid can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage multi-stage planning, and more specifically, to an independent energy storage multi-stage planning method considering dynamic updating of key power transmission sections. Background Art

[0002] In recent years, with the widespread application of new energy and the continuous increase in load, its uncertainty has brought challenges to the security of the power grid. The structure and operation of the power grid have become more complex and dynamic, and the problem of imbalance between supply and demand has become prominent. Especially during high-load periods and when new energy fluctuates, the power grid often faces line flow blockage, affecting the stable operation of the system. The existing power system requires flexibility on a longer time scale to cope with the large-scale integration of these uncertain renewable energy sources and loads. The multi-stage planning of energy storage can effectively compensate for the uncertainty of the system and achieve real-time balance of energy supply. It is a key method to solve the problem of load and new energy fluctuations on a long time scale. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides an independent energy storage multi-stage planning method that takes into account the dynamic update of key transmission sections, so as to better adapt to the changes in power grid operation and long-term development trends, take into account the uncertainties of renewable energy and loads at multiple time scales in future power systems, and achieve the purpose of improving power flow distribution, alleviating transmission congestion, delaying large-scale upgrades of the power grid, and improving line power supply reliability, thereby providing a reference for power grid planners to optimize energy storage planning.

[0004] To achieve the above object, the present invention provides the following technical solutions: A multi-stage planning method for independent energy storage considering dynamic update of key transmission sections comprises the following steps: determining the transmission sections of a transmission network and screening out key sections therefrom through a transmission key section search method, and setting a dynamic update method for the transmission key sections; constructing constraints based on the screened transmission key sections, and establishing an independent energy storage planning model considering the constraints of the key sections; solving the energy storage planning model for the nth year based on the independent energy storage planning model, and outputting energy storage planning results, energy storage planning location, energy storage planning capacity and planned power.

[0005] The technical effects and advantages of the independent energy storage multi-stage planning method considering the dynamic update of key transmission sections of the present invention are as follows: 1. The method of the present invention determines the key transmission section by calculating the power flow and transmission capacity margin of the transmission section and comparing them; based on the key transmission section search method, the key section is dynamically updated and multi-stage energy storage planning is performed; and the key section of the transmission network is searched to construct its constraints, and an independent energy storage planning model considering the key section constraints is established. The model comprehensively considers the investment and operation and maintenance costs of independent energy storage, the spot price difference income and the system congestion penalty cost, and considers multiple planning objectives, so as to obtain more reasonable planning results.

[0006] 2. The method described in the present invention realizes multi-stage rolling optimization configuration of independent energy storage by updating the key sections of the transmission network, adopting multi-stage planning, and rationally configuring the energy storage equipment; at the same time, it takes into account the key transmission sections that have an important impact on the grid planning, and can effectively solve the dynamic update and load growth problems of the grid structure on a long time scale, and can achieve the purpose of alleviating transmission congestion, delaying grid expansion, and improving the safety and stability margin of the grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a flow chart of a multi-stage planning method for independent energy storage considering dynamic updating of key power transmission sections of the present invention; Figure 2 It is a topological diagram of the test system of the present invention; Figure 3 This is a topological diagram of the test system after partitioning according to the present invention. DETAILED DESCRIPTION

[0008] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0009] Embodiment 1, Figure 1 The present invention provides a multi-stage planning method for independent energy storage considering dynamic updating of key transmission sections, comprising the following steps: Step 1: Through the key transmission section search method, the transmission sections of the transmission network are determined and the key sections are screened out, and then a dynamic update method for the key transmission sections is proposed: Step 1.1, based on the given initial data of the power grid to be planned, calculate the power flow of each branch of the power grid, and perform initial partitioning of the power grid system according to whether the power flow directions of the lines are consistent; Step 1.2, find the connecting lines between the various zones and identify them as transmission sections; Step 1.3: Select a section with heavy section flow and small transmission capacity margin from the transmission sections as the key transmission section, and calculate the section transmission capacity margin using formula (1): (1) In formula (1), For cross section The transmission capacity margin; For cross section The power transmitted; For cross section Rated transmission power.

[0010] Step 1.4: Assume that the planning cycle is N years. After the key transmission sections of the first year are screened out through the above steps 1.1-1.3, the key transmission sections are dynamically updated after the annual energy storage planning. The specific method is to add the energy storage planning results and the grid update data to the original grid, and then perform steps 1.1-1.3 again to search for the key transmission sections, and then plan the energy storage for the next year until the end of the planning cycle of N years.

[0011] Step 2: Construct the constraints of the key transmission sections selected in step 1, and then establish and solve the independent energy storage planning model considering the key section constraints; Step 2.1: Based on the goal of improving the power flow congestion at key sections of the power grid, the objective function of the independent energy storage planning model for the power grid is established to minimize the investment cost and operation and maintenance cost of the planned energy storage. The objective function is expressed as: (2) In formula (2), Daily investment and operation and maintenance costs for energy storage; Penalty costs for system congestion; It is the profit from the spot price difference of energy storage.

[0012] Step 2.1.1, establish the energy storage equivalent daily investment and operation and maintenance cost model; (3) (4) (5) (6) In formulas (3)-(6), For energy storage investment costs; For energy storage Annual operation and maintenance costs; and Energy storage The planned capacity and planned power; and They are the unit capacity cost of energy storage and the unit power cost of energy storage respectively; and They are the annual operation and maintenance cost per unit capacity and per unit power of the energy storage system respectively; The economic service life of the energy storage system; is the discount rate; To consider the energy storage service life and discount rate to convert to annual investment cost coefficient; Plan quantities for energy storage.

[0013] Step 2.1.2, establish a system congestion penalty cost model; (7) (8) (9) In formulas (7)-(9), for The blocking power of the system section at the moment; is the blocking cost per unit power; for Time section trend; is the cross-section tidal flow limit; , , They are Load, power output and energy storage charging and discharging power within the section at any time; is the typical day length, .

[0014] Step 2.1.3: Establish a spot price difference profit model for energy storage; (10) In formula (10), , They are Energy storage at all times The charging and discharging power; , They are respectively the time-of-use electricity sales and purchase prices of the power grid.

[0015] Step 2.2: Establish the conventional constraints of the model. The constraints of the energy storage planning model include equality constraints and inequality constraints. The equality constraints mainly include energy storage power balance constraints and node power balance constraints; the inequality constraints mainly include the number of energy storages allowed to be installed, the rated power and capacity of energy storages allowed to be installed, the energy storage charging and discharging power constraints, the energy storage charge state constraints, the conventional unit output constraints, and the new energy station output constraints.

[0016] Step 2.2.1, establish energy storage power balance constraints; (11) In formula (11), and Energy storage exist , The capacity of the time slot; and Energy storage Charging and discharging efficiency.

[0017] Step 2.2.2, establish node power balance constraints; (12) In formula (12), , , , and Connected to the nodes The generator set, new energy station set, independent energy storage set, branch line set and load set; for Moment Generator Power; for New energy stations at all times Power; For line exist The trend of the moment; for Load at any time of power.

[0018] Step 2.2.3, establish the constraints on the amount of energy storage that can be installed; (13) In formula (13), Is a 0-1 variable, indicating whether The node is equipped with energy storage. If installed, the value is 1, otherwise the value is 0; A collection of nodes that can be installed with energy storage; The maximum number of independent energy storage installations.

[0019] Step 2.2.4: Establish the rated power and capacity constraints of energy storage that can be installed; (14) (15) In formula (14)-(15), and Allow independent energy storage The maximum power rating and capacity of the installation.

[0020] Step 2.2.5, establish energy storage charging and discharging power constraints; (16) (17) (18) In formulas (16)-(18), and Independent energy storage Maximum charging and discharging power; and They are the state variables of the energy storage system charging and discharging, both of which are 0-1 variables. The value is 1, when discharging The value is 1.

[0021] Step 2.2.6, establishing energy storage charge state constraints; (19) (20) (twenty one) In formulas (19) to (21), and Energy storage The state of charge at the beginning and end of the period; For independent energy storage In the period The state of charge; and are the maximum and minimum states of charge of the energy storage system, respectively.

[0022] Step 2.2.7, establish conventional unit constraints; (twenty two) (twenty three) (twenty four) In formulas (22)-(24), and For each unit Minimum and maximum active technical output; and They are and time crew contribution; and For each unit The maximum uphill speed and the maximum downhill speed.

[0023] Step 2.2.8: Establish the output constraint of the new energy power station; (25) In formula (25), is the real-time output of the new energy power station at time The maximum output of the new energy power station.

[0024] Step 2.3: To consider the impact of section congestion on the safe operation of the power system, establish the critical section power flow constraint according to the transmission critical section determined in Step 1. The transmission section is a set of a cluster of lines, and its power flow constraint is: (26) In formula (26), and are the lower limit and upper limit of the power flow of the critical section respectively; is the set of lines belonging to section .

[0025] Step 3: Based on the dynamic update of the critical section and the independent energy storage planning model considering the critical section constraint, propose a multi-stage planning method for independent energy storage. Search for the transmission critical section according to the method in Step 1, use the independent energy storage planning model considering the critical section constraint established in Step 2 to solve, obtain the energy storage planning result, and repeat Step 1 for the dynamic update of the critical section, and repeat Step 2 for model solution until the multi-stage planning period of N years ends; Step 3.1: Based on Steps 1 and 2, establish an independent energy storage planning model considering the critical section constraint, solve the energy storage planning model for the nth year, and output the energy storage planning result, the energy storage planning location, the energy storage planning capacity, and the planning power; Step 3.2: Judge whether the planned number of years n is less than the planned period of N years; Step 3.2.1: If n < N, then let n = n + 1, add the energy storage planning result of the nth year and the grid update data to the original grid, recalculate the section transmission capacity margin after the (n + 1)th year planning, then search for the critical section according to the method in Step 1, perform the dynamic update of the transmission critical section, update the transmission critical section constraint, and use the independent energy storage planning model considering the transmission critical section constraint established in Step 2 to calculate the next year's planning result; Step 3.2.2: If n = N, then end the energy storage planning process.

[0026] The experiments to verify the present invention "a multi-stage planning method for independent energy storage considering the dynamic update of transmission critical sections" mainly include the following steps: The test system is a 39-node system consisting of 10 thermal power units and 3 new energy units. The test system topology is shown in the figure below. Figure 2 shown.

[0027] Calculate the initial power flow of the test system line, partition the test system and screen out the key sections of power transmission. The topological structure of the test system after partitioning is shown in the figure below: Figure 3 The initial section division results are shown in Table 1.

[0028] Table 1 Section division results

[0029] Determine the energy storage planning scheme for the 1st to 5th year: This example considers a multi-stage planning period of 5 years, assuming that the node load increases by 3% each year. Figure 1 The independent energy storage multi-stage planning process diagram method is used for planning, and the annual energy storage planning results are obtained.

[0030] The program of this method is written in Python and solved by calling GUROBI solver on Intel Core i5-10400F platform. The effectiveness and applicability of this method are proved.

[0031] Comparison of section transmission capacity margin results before and after planning: After calculation and analysis, the line flow direction remains basically unchanged, and the key section division results are still as shown in Table 1. The section transmission capacity margins of the system before and after the 1st to 5th year planning are shown in Table 2-6. Comparing the section transmission capacity margins before and after the 1st to 5th year planning in Table 2-6, we can see the significant effect of energy storage configuration. The introduction of energy storage has greatly reduced the section flow, making the section transmission capacity margin significantly improved compared to before planning.

[0032] Table 2 Section transmission capacity margin before and after the first year of planning

[0033]

[0034] Table 3 Section transmission capacity margin before and after the second year of planning

[0035]

[0036] Table 4 Section transmission capacity margin before and after the third year of planning

[0037]

[0038]

[0039] Table 5 Section transmission capacity margin before and after the fourth year of planning

[0040]

[0041] Table 6 Section transmission capacity margin before and after the 5th year planning

[0042]

[0043] In summary, the present invention proposes a multi-stage planning method for independent energy storage that considers the dynamic update of key transmission sections. It comprehensively considers the cost, benefit and grid congestion cost of independent energy storage planning, and establishes an independent energy storage planning model that considers the flow constraints of key sections. It can effectively alleviate network congestion, improve the operating efficiency of the grid, and provide greater flexibility for the long-term planning and optimization of the grid.

[0044] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product.

[0045] Those of ordinary skill in the art will appreciate that the modules and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0046] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0047] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0048] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-stage planning method for independent energy storage considering dynamic update of key transmission sections, characterized in that: The steps include: Through the key transmission section search method, the transmission sections of the transmission network are determined and the key sections are screened out, and the dynamic update method of the key transmission sections is set; According to the selected key transmission sections, the constraints are constructed and an independent energy storage planning model considering the key section constraints is established; According to the independent energy storage planning model, the energy storage planning model for the nth year is solved, and the energy storage planning results, energy storage planning location, energy storage planning capacity and planned power are output.

2. The independent energy storage multi-stage planning method considering dynamic update of key transmission sections according to claim 1 is characterized in that: The method of searching for a key transmission section is used to determine the transmission section of the transmission network and select the key sections therefrom, and the method of dynamically updating the key transmission section is set, which specifically includes: Obtain the initial data of the power grid to be planned, calculate the power flow of each branch of the power grid, determine the power flow direction of the line, and perform initial partitioning of the power grid system; Find the connecting lines between each subarea and determine the transmission section; According to the transmission section, the section with heavy section flow and small transmission capacity margin is selected as the key transmission section, and the section transmission capacity margin is calculated: In the formula, For cross section The transmission capacity margin; For cross section The power transmitted; For cross section Rated transmission power.

3. The independent energy storage multi-stage planning method considering dynamic update of key transmission sections according to claim 2 is characterized in that: The method of constructing constraints on the selected key transmission sections and establishing an independent energy storage planning model that takes into account the constraints on the key sections specifically includes: Based on the goal of improving the power flow congestion in key sections of the power grid, the objective function of the independent energy storage planning model for the power grid is established to minimize the investment cost and operation and maintenance cost of the planned energy storage; Establish constraints for the energy storage planning model, wherein the constraints for the energy storage planning model include equality constraints and inequality constraints; the equality constraints include energy storage quantity balance constraints and node power balance constraints; the inequality constraints include constraints on the number of energy storage units allowed to be installed, constraints on the rated power and capacity of energy storage units allowed to be installed, constraints on energy storage charging and discharging power, constraints on energy storage charge state, constraints on conventional unit output, and constraints on new energy station output.

4. According to the independent energy storage multi-stage planning method considering dynamic update of key transmission sections according to claim 3, the objective function is expressed as: ； In the formula, Daily investment and operation and maintenance costs for energy storage; Penalty costs for system congestion; It is the profit from the spot price difference of energy storage.

5. The independent energy storage multi-stage planning method considering dynamic update of key transmission sections according to claim 4 is characterized in that: The constraints for establishing the energy storage planning model are as follows: Energy storage power balance constraints: In the formula, and Energy storage exist , The capacity of the time slot; and Energy storage Charging and discharging efficiency, , They are Energy storage at all times The charging and discharging power; Node power balance constraints: In the formula, , , , and Connected to the nodes The generator set, new energy station set, independent energy storage set, branch line set and load set; for The generator of time Power; for New energy stations at all times Power; For line exist The trend of the moment; for Load at any time Power; The number of energy storage installations allowed is: In the formula, Is a 0-1 variable, indicating whether The node is equipped with energy storage. If installed, the value is 1, otherwise the value is 0; A collection of nodes that can be installed with energy storage; The maximum amount of independent energy storage to be installed; Allowed installed energy storage rated power and capacity constraints: In the formula, and Allow independent energy storage The maximum power rating and capacity of the installation, and Energy storage The planned capacity and planned power; Energy storage charging and discharging power constraints: In the formula, and Independent energy storage Maximum charging and discharging power; and They are the state variables of the energy storage system charging and discharging, both of which are 0-1 variables. The value is 1, when discharging The value is 1; Energy storage state of charge constraints; In the formula, and Energy storage The state of charge at the beginning and end of the period; For independent energy storage In the period The state of charge; and are the maximum and minimum states of charge of the energy storage system, respectively; Conventional unit constraints; (24) In the formula, and For each unit Minimum and maximum active technical output; and They are and Time crew contribution; and For each unit Maximum uphill speed and maximum downhill speed; Output constraints of new energy stations; ； In the formula, For new energy stations Always make efforts in real time; The maximum output of new energy stations.

6. The independent energy storage multi-stage planning method considering dynamic update of key transmission sections according to claim 5 is characterized in that: The constraints for establishing the energy storage planning model also include power flow constraints, which are: ； In the formula, , Key sections Tidal lower and upper limits; For the cross section A collection of lines.

7. The independent energy storage multi-stage planning method considering dynamic update of key transmission sections according to claim 4 is characterized in that: The step of solving the energy storage planning model for the nth year according to the independent energy storage planning model and outputting the energy storage planning result, the energy storage planning location, the energy storage planning capacity and the planned power specifically includes: According to the independent energy storage planning model, solve the energy storage planning model for the nth year, and output the energy storage planning results, including the energy storage planning location, energy storage planning capacity and planned power; Determine whether the planning years n is less than the planning cycle N years; If \(n < N\), then let \(n=n + 1\), add the energy storage planning results and grid update data of the \(n\)th year to the original power grid, recalculate the section transmission capacity margin after the \(n + 1\)th year's planning, then search for the key sections according to the method in Step 1, perform dynamic update of the key transmission sections, update the constraints of the key transmission sections, and use the independent energy storage planning model considering the constraints of the key transmission sections established in Step 2 to calculate the planning results for the next year; If \(n = N\), then end the energy storage planning process.

Images