Power grid and energy storage coordinated power distribution network planning method

Abstract

The invention relates to the technical field of power grid planning, in particular to a power grid and energy storage coordinated power distribution network planning method, and provides a power grid and energy storage coordinated power distribution network planning method on the basis of meeting a load power supply capability principle and a new energy bearing capability principle. Comprising the following steps: carrying out source load prediction, determining a power supply capacity and a maximum load, analyzing a historical annual source load curve, forming a source load curve based on source load numerical prediction, coupling the source load curve to form a net load curve and net load characteristic parameters, determining a time section at a moment when bearing capacity is insufficient, and calculating power capacity vacancy. Calculating power grid construction and transformation cost under the condition that energy storage does not participate in peak regulation, gradually increasing the capacity of energy storage participating in peak regulation, calculating rental energy storage cost, response energy storage cost and new energy storage cost, comparing the total energy storage cost with the power grid construction cost, and selecting a planning scheme with the minimum total cost under network storage collaborative planning by combining the two.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid planning, and in particular to a distribution network planning method for coordinated power grid and energy storage. Background Art

[0002] Under the guidance of the "dual carbon" goals, a large number of new energy power generation, energy storage, microgrids, new loads, etc. are connected to the distribution network. The power load has evolved from a single user entity to multiple entities of source, grid, load and storage, bringing new challenges to the power balance of the distribution system.

[0003] The existing energy storage configuration planning methods all focus on the impact of energy storage itself on the planning and operation of the power grid, and use energy storage as an independent solution to the problems of insufficient power supply capacity of the power grid or insufficient new energy carrying capacity.

[0004] A Chinese patent discloses a distribution network planning method and system (publication number CN 117010619 A). This patented technology can integrate distributed photovoltaic and energy storage systems into active distribution network planning, and closely associate the planning of active distribution networks with flexible operation control characteristics, jointly optimize models, and comprehensively analyze line construction. It can dispatch the site selection and capacity planning schemes of distributed photovoltaic and energy storage systems and the corresponding coordinated operation strategies. However, the existing schemes rarely consider the overall planning strategy of the coordinated transformation of power grids and energy storage; at the same time, most of the existing energy storage configuration planning methods consider the cost of energy storage construction, do not clarify its investment subject, and do not consider the dispatching cost of power grid companies. Therefore, the present invention provides a distribution network planning method for the coordination of power grids and energy storage to solve the problems raised in the above background technology. Summary of the invention

[0005] The present invention provides a distribution network planning method for the coordination of power grid and energy storage on the basis of meeting the load power supply capacity principle and the new energy carrying capacity principle. It includes the following steps:

[0006] The first step is to conduct source load forecasting to determine power supply capacity and maximum load;

[0007] The second step is to analyze the historical source-load curves and form a source-load curve based on the source-load numerical prediction;

[0008] The third step is to couple the source-load curve to form the net load curve and net load characteristic parameters, and determine the time section when the carrying capacity is insufficient;

[0009] The fourth step is to calculate the power capacity shortfall and the cost of grid construction and transformation without the participation of energy storage.

[0010] Step 5: Gradually increase the capacity of energy storage for peak load regulation and calculate the cost of leasing energy storage, response energy storage and new energy storage.

[0011] The sixth step is to compare the total energy storage cost and the grid construction cost, and combine the two to select the planning scheme with the lowest total cost under the grid-storage collaborative planning.

[0012] According to the power supply planning or the forecast of the exploitable amount of new energy, the capacity of various power sources in the target year is clarified, and the capacity of thermal power units is recorded as S1, the capacity of wind turbines is S2, and the capacity of photovoltaic power generation is S3; according to the existing power grid planning or load forecasting, the maximum values ​​of various loads in the target year are clarified, the maximum load and power factor of residential electricity consumption are P1 and φ1, the maximum load and power factor of industrial and commercial electricity consumption are P2 and φ2, and the maximum load and power factor of charging piles are P3 and φ3.

[0013] According to the power supply capacity, maximum load and the standardized typical daily curve of source and load, the source and load curve of typical days in each season is calculated.

[0014] The photovoltaic standardized typical daily curve is recorded in column vector form as G0. The standardized typical daily curve has n recording points, and the interval between adjacent recording points is T, where:

[0015] G0=[g1,g2,...,g n ] T

[0016] g i It is the standardized output value of photovoltaic power generation at the i-th recording point in a day, which is determined by the characteristics of photovoltaic power generation. The maximum output coefficients of photovoltaic power generation on sunny days in spring, summer, autumn and winter are a1, a2, a3 and a4, and the maximum output coefficients on rainy days are b1, b2, b3 and b4. Then the output curve of photovoltaic power generation on a typical sunny day in the jth season is G aj And the output curve G on rainy days bj The calculation method is as follows:

[0017] G aj =a j S3G0

[0018] G bj =b j S3G0

[0019] The unit column vector is represented by E. The maximum output coefficient of wind power in spring, summer, autumn and winter is c1, c2, c3, c4, the minimum output coefficient is d1, d2, d3, d4, and the maximum peak-shaving depth of thermal power is e. The maximum total output curve of the regional power supply on a typical day in the jth season is G′ aj and the minimum total output curve G′ bj The calculation method is as follows:

[0020] G′ aj =G aj +(c j S2+S1)E

[0021] G′ bj =G bj +(d j S2+eS1)E

[0022] The standardized typical daily curve of residential electricity, industrial and commercial electricity, and charging pile load in the jth season is recorded in the form of column vector as F 1j 、F 2j 、F 3j The standardized typical daily curve has n recording points in total, and the interval between adjacent recording points is T. The standardized typical daily curve of the k-th load is expressed as follows:

[0023] F kj =[f kj-1 , f kj-2 , ..., f kj-n ] T

[0024] f kj-i That is, the standardized load value of the k-th load at the i-th recording point on the typical day of the j-th season. This value is determined by the load characteristics. The total load curve F′ of the j-th season region is j The calculation method is as follows:

[0025]

[0026] The third step is to form a net load curve by coupling the photovoltaic and total load curves; obtain the actual maximum power supply load, minimum power supply load, maximum external power and other parameters based on the net load curve, and perform power and electricity balance based on these key parameters; compare the power and electricity balance results with the safe operation requirements of the power grid to calculate the power capacity shortage; and finally calculate the energy storage capacity.

[0027] The third step is to calculate the net load curve:

[0028] The maximum net load curve of the jth season is recorded as M in column vector form aj , the minimum net load curve is M bj , the calculation method of the net load curve is as follows:

[0029] M aj =F′ j -G′ bj

[0030] M bj =F′ j -G′ aj

[0031] Calculate the net load characteristic parameters:

[0032] The annual maximum net load is Pmax , the minimum net load throughout the year is P min (The minimum net load may be less than 0, indicating power delivery), then the net load characteristic parameter calculation method is as follows.

[0033] P max =max(m)|m∈M aj

[0034] P min =min(m)|m∈M bj

[0035] Calculate the power capacity shortfall:

[0036] Let the power supply capacity of the power grid under the condition of N-1 be A, and the transmission capacity of the power grid equipment under the condition of no overload be B, then the power supply capacity shortage of the power grid is Q A and the power grid transmission capacity shortfall Q B The calculation method is as follows:

[0037] Q A =P max -A

[0038] Q B =-P min -B

[0039] If Q A ≤0 and Q B ≤0, the power supply capacity and transmission capacity of the power grid are sufficient, and no energy storage is required; if Q A > 0, the power supply capacity of the power grid is insufficient, and priority should be given to increasing the power grid transformation capacity and adding transmission and distribution lines. Under emergency needs, energy storage can be configured to discharge during peak load periods to reduce the maximum load; if Q B >0, the power grid’s transmission capacity is insufficient, and energy storage needs to be configured to charge during the peak period of power transmission to reduce the maximum transmission power.

[0040] Calculate energy storage capacity:

[0041] The goal of calculating the energy storage capacity is to determine the energy storage discharge power P E1 、Charging power P E2 and storage capacity W E Before determining the above parameters, it is necessary to clarify the energy conversion efficiency η and discharge depth D of the energy storage. This project mainly considers the energy storage configuration under the condition of insufficient new energy transmission capacity:

[0042] For Q B >0, the energy storage charging power P E2 and storage capacity W E The calculation method is as follows:

[0043] P E2 ≥QB

[0044]

[0045] In addition, if energy storage is required due to excessive voltage deviation, the energy storage capacity needs to be debugged in combination with power flow calculation.

[0046] The fifth step, for grid-rented energy storage, is calculated based on the rental cost, which also includes the rental power cost and the rental electricity cost; for pure demand response energy storage, it is calculated based on the response power cost and the response electricity cost.

[0047] In the sixth step, the total cost objective function is as follows:

[0048] minC=min[(a ess +b ess T)P ess +(a grid / ρ)P grid ]

[0049] Among them, P ess is the energy storage charging and discharging power, P grid To expand the power demand of the power grid; ess is the energy storage power cost, b ess is the energy storage electricity cost, a grid is the cost of grid expansion; T is the continuous charging and discharging time of energy storage, ρ is the power factor;

[0050] The initial value of the energy storage configuration duration can be predicted by the source-load curve (to determine the time of exceeding the limit). grid As the load increases, the overload line gradually increases, and the energy storage configuration time gradually shortens. Therefore, there are three solutions to this function:

[0051] ① a ess +b ess T>a grid / ρ: full construction power grid;

[0052] ② a ess +b ess T<a grid / ρ: full construction energy storage;

[0053] ③ a ess +b ess T=a grid / ρ: There is an optimal solution for network-storage collaboration. Find the T value that satisfies this condition and analyze the corresponding P in this case. grid and P ess , we can get the optimal solution for network-storage collaboration.

[0054] The sixth step is that the planning scheme includes the construction and transformation scale of the power grid itself, as well as the leasing scale, response reserve scale, and construction scale of the energy storage equipment. The energy storage operation mode is output as an additional result, and the energy storage charging and discharging time and the charging and discharging power at different times are clarified for reference by the power supply grid enterprise control center.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] The present invention takes into account both the planning and construction and transformation costs of the power grid and the energy storage configuration costs, and takes the minimization of the total investment cost of the two as the planning goal; at the same time, the costs of leasing energy storage, response energy storage and new energy storage are innovatively calculated separately in the energy storage configuration costs, and the source and response form of energy storage are clarified in the final network-storage collaborative planning scheme, which fully mobilizes the power supply side energy storage and user side energy storage to participate in the peak-shaving response of the power grid, reduces the investment pressure of power grid companies on energy storage construction, and improves the economic efficiency of energy storage applied to peak-shaving of power grid companies. The planning scheme conclusion has guiding significance for power grid companies to propose energy storage construction needs, activate shared energy storage potential, and improve power grid flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The present invention is a flow chart of a grid-storage collaborative planning method for a distribution network planning method that coordinates power grid and energy storage.

[0058] Figure 2 A flow chart of an energy storage sizing method for a distribution network planning method in which power grid and energy storage are coordinated. DETAILED DESCRIPTION

[0059] 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.

[0060] See also Figures 1-2 In an embodiment of the present invention, a distribution network planning method for coordinated power grid and energy storage includes the following steps:

[0061] 1. Determine the energy storage access mode based on the capacity of the energy storage power station.

[0062] In order to give full play to the role of energy storage power stations and expand the scope of energy storage applications, for 220kV substations, when the capacity of the energy storage power station does not exceed 100MW, it is recommended to connect the energy storage power station to the low-voltage side busbar, while serving the substation main transformer and high-voltage transmission lines; when the energy storage capacity exceeds 100MW, it is recommended to connect the energy storage power station to the high-voltage side busbar to alleviate the pressure on energy delivery of the transmission line.

[0063] 2. Determine power capacity and load forecast:

[0064] According to the power supply planning or the forecast of the exploitable amount of new energy, the capacity of various power sources in the target year is clarified, and the capacity of thermal power units is recorded as S1, the capacity of wind power units is recorded as S2, and the capacity of photovoltaic power generation is recorded as S3. According to the existing power grid planning or load forecasting, the maximum values ​​of various loads in the target year are clarified, and the maximum load and power factor of residential electricity consumption are recorded as P1, The maximum load and power factor for industry and commerce is P2. The maximum load and power factor of the charging pile is P3.

[0065] Forming source-load curve: Calculate the source-load curve of a typical day in each season based on power capacity, maximum load value and standardized typical day curve of source-load.

[0066] 1) Power output curve

[0067] The photovoltaic standardized typical daily curve is recorded in column vector form as G0. The standardized typical daily curve has n recording points, and the interval between adjacent recording points is T, where

[0068] G0=[g1,g2,…,gn] T

[0069] g i It is the standardized output value of photovoltaic power generation at the tth recording point in a day, which is determined by the characteristics of photovoltaic power generation. The maximum output coefficients of photovoltaic power generation on sunny days in spring, summer, autumn and winter are a1, a2, a3 and a4, and the maximum output coefficients on rainy days are b1, b2, b3 and b4. Then the output curve of photovoltaic power generation on a typical sunny day in the jth season is G aj And the output curve G on rainy days bj The calculation method is as follows.

[0070] G aj =a j S3G0

[0071] G bj =b j S3G0

[0072] The unit column vector is represented by E. The maximum output coefficient of wind power in spring, summer, autumn and winter is c1, c2, c3, c4, the minimum output coefficient is d1, d2, d3, d4, and the maximum peak-shaving depth of thermal power is e. The maximum total output curve of the regional power supply on a typical day in the jth season is G′ aj and the minimum total output curve G′ bj The calculation method of is as follows.

[0073] G′ aj =G aj +(c j S2+S1)E

[0074] G′ bj =G bj +(d j S2+eS1)E

[0075] 2) Load curve

[0076] The standardized typical daily curve of residential electricity, industrial and commercial electricity, and charging pile load in the jth season is recorded in the form of column vector as F 1j 、F 2j 、F 3j The standardized typical daily curve has a total of n recording points, and the interval time between adjacent recording points is T. The standardized typical daily curve of the kth type of load is expressed as follows.

[0077] F kj =[f kj-1 , f kj-2 , ..., f kj-n ] T

[0078] f kj-i That is, the standardized load value of the k-th load at the t-th recording point on a typical day in the j-th season, which is determined by the load characteristics. Then the total load curve F′ of the region in the j-th season j (Apparent Power) is calculated as follows.

[0079]

[0080] The net load curve is formed by coupling the photovoltaic and total load curves; the actual maximum power supply load, minimum power supply load, maximum external power transmission and other parameters are obtained based on the net load curve, and the power balance is performed based on these key parameters; the power balance results are compared with the safe operation requirements of the power grid to calculate the power capacity shortage; finally, the energy storage capacity is calculated.

[0081] Calculate the net load curve

[0082] The maximum net load curve of the jth season is recorded as M in column vector form aj , the minimum net load curve is Mbj , the calculation method of the net load curve is as follows.

[0083] M aj =F′ j -G′ bj

[0084] M bj =F′ j -G′ aj

[0085] (4) Calculation of net load characteristic parameters

[0086] The annual maximum net load is P max , the minimum net load throughout the year is P min (The minimum net load may be less than 0, indicating power delivery), then the net load characteristic parameter calculation method is as follows.

[0087] P max =max(m)|m∈M aj

[0088] P min =min(m)|m∈M bj

[0089] (5) Calculation of power capacity shortfall

[0090] Let the power supply capacity of the power grid under the condition of N-1 be A, and the transmission capacity of the power grid equipment under the condition of no overload be B, then the power supply capacity shortage of the power grid is Q A and the power grid transmission capacity shortfall Q B The calculation method is as follows.

[0091] Q A =P max -A

[0092] Q B =-P min -B

[0093] If Q A ≤0 and Q B ≤0, the power supply capacity and transmission capacity of the power grid are sufficient, and no energy storage is required; if Q A > 0, the power supply capacity of the power grid is insufficient, and priority should be given to increasing the power grid transformation capacity and adding transmission and distribution lines. Under emergency needs, energy storage can be configured to discharge during peak load periods to reduce the maximum load; if Q B >0, the power grid’s transmission capacity is insufficient, and energy storage needs to be configured to charge during the peak period of power transmission to reduce the maximum transmission power.

[0094] (6) Calculate energy storage capacity

[0095] The goal of calculating the energy storage capacity is to determine the energy storage discharge power P E1 、Charging power P E2 and storage capacity W E Before determining the above parameters, it is necessary to clarify the energy conversion efficiency η and discharge depth D of the energy storage. This project mainly considers the energy storage configuration when the new energy transmission capacity is insufficient.

[0096] For Q B >0, the energy storage charging power P E2 and storage capacity W E The calculation method of is as follows.

[0097] P E2 ≥Q B

[0098]

[0099] In addition, if energy storage is required due to excessive voltage deviation, the energy storage capacity needs to be debugged in combination with power flow calculation.

[0100] 3. Based on the network storage system planning model, the optimal solution for network storage collaboration is analyzed.

[0101] (1) Objective function and constraints

[0102] Objective function: Minimize the overall cost of the power grid

[0103] minC=min(C ess +C grid )

[0104] C ess =a ess P ess +b ess P ess T

[0105] C grid =a grid P grid / ρ

[0106] C ess is the energy storage construction cost, C grid is the grid construction cost; P ess is the energy storage charging and discharging power, P grid To expand the power demand of the power grid; ess is the energy storage power cost, b ess is the energy storage electricity cost, a grid is the cost of grid expansion; T is the continuous charging and discharging time of energy storage, and ρ is the power factor.

[0107] For grid-rented energy storage, the leasing cost is used for calculation, which also includes the leasing power cost and the leasing electricity cost. For pure demand response energy storage, the response power cost and the response electricity cost are used for calculation.

[0108] Constraints: Sufficient carrying capacity

[0109] 1. The load does not exceed the limit (not overloaded)

[0110] P max <P grid +P ess +V0ρ

[0111] V0 is the original capacity of the power grid.

[0112] 2. New energy can be absorbed (reverse transmission without overloading)

[0113] |P min |<P grid +P ess +V0ρ

[0114] (2) Solution method and solution process

[0115] minC=min[(a ess +b ess T)P ess +(a grid / ρ)P grid ]

[0116] a ess 、b ess 、a grid All are unit price constants. ρ is the power factor, which is 0.95 by default. ess and P grid It mainly changes according to T, that is, the energy storage configuration duration is the key factor affecting the power solution.

[0117] The initial value of the energy storage configuration duration can be predicted by the source-load curve (to determine the time of exceeding the limit). grid As the load increases, the overload line gradually increases, and the energy storage configuration time gradually shortens. Therefore, there are three solutions to this function:

[0118] ① a ess +b ess T>a grid / ρ: full construction power grid;

[0119] ② a ess +b ess T<a grid / ρ: full construction energy storage;

[0120] ③ a ess +b ess T=a grid / ρ: There is an optimal solution for network and storage collaboration.

[0121] According to the survey, the cost of energy storage power is relatively low, usually 100,000-200,000 yuan / MW; the capacity cost of lithium iron phosphate energy storage batteries is usually 1.3-1.7 million yuan / MWh; the cost of grid expansion can be 800,000-1.2 million yuan / MVA (main transformer and supporting facilities), then:

[0122] a ess <a grid <b ess

[0123] Right now a ess +b ess T=a grid / ρ. Find the T value that satisfies this condition and analyze the corresponding P in this case. grid and P ess , we can get the optimal solution for network-storage collaboration.

[0124] (3) Output of conclusions of network storage collaborative planning scheme

[0125] The grid-storage collaborative planning scheme includes the construction and transformation scale of the power grid itself, as well as the leasing scale, response reserve scale, and construction scale of energy storage equipment. It is used to guide power grid companies to flexibly dispatch resources from all parties to improve the flexibility of the power grid.

[0126] While outputting the conclusions of the grid-storage collaborative planning scheme, the energy storage operation mode can also be output as an additional result, that is, clarifying the energy storage charging and discharging time and the charging and discharging power at different times, which can be used as a reference for the power grid enterprise control center.

[0127] The working principle of the present invention is:

[0128] 1. Carry out source load forecasting to determine power supply capacity and maximum load.

[0129] 2. Analyze the source-load curves of historical years and form a source-load curve based on source-load numerical prediction.

[0130] 3. The source-load curve is coupled to form the net load curve and net load characteristic parameters to determine the time section when the carrying capacity is insufficient.

[0131] 4. Calculate the power capacity shortfall and the cost of grid construction and transformation without the participation of energy storage.

[0132] 5. Gradually increase the capacity of energy storage to participate in peak regulation, and calculate the costs of leasing energy storage, response energy storage and new energy storage.

[0133] 6. Compare the total energy storage cost and grid construction cost, and combine the two to select the planning scheme with the lowest total cost under the grid-storage collaborative planning.

[0134] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A distribution network planning method for coordinated power grid and energy storage, characterized in that: The steps include: The first step is to conduct source load forecasting to determine power supply capacity and maximum load; The second step is to analyze the historical source-load curves and form a source-load curve based on the source-load numerical prediction; The third step is to couple the source-load curve to form the net load curve and net load characteristic parameters, and determine the time section when the carrying capacity is insufficient; The fourth step is to calculate the power capacity shortfall and the cost of grid construction and transformation without the participation of energy storage. Step 5: Gradually increase the capacity of energy storage for peak load regulation and calculate the cost of leasing energy storage, response energy storage and new energy storage. The sixth step is to compare the total energy storage cost and the grid construction cost, and combine the two to select the planning scheme with the lowest total cost under the grid-storage collaborative planning.

2. A distribution network planning method for coordinated power grid and energy storage according to claim 1, characterized in that: According to the power supply planning or the forecast of the exploitable amount of new energy, the capacity of various power sources in the target year is clarified, and the capacity of thermal power units is recorded as S1, the capacity of wind turbines is S2, and the capacity of photovoltaic power generation is S3; according to the existing power grid planning or load forecasting, the maximum values ​​of various loads in the target year are clarified, the maximum load and power factor of residential electricity consumption are P1 and φ1, the maximum load and power factor of industrial and commercial electricity consumption are P2 and φ2, and the maximum load and power factor of charging piles are P3 and φ3.

3. A distribution network planning method for coordinated power grid and energy storage according to claim 2, characterized in that: According to the power supply capacity, maximum load and the standardized typical daily curve of source and load, the source and load curve of typical days in each season is calculated.

4. A distribution network planning method for coordinated power grid and energy storage according to claim 3, characterized in that: The photovoltaic standardized typical daily curve is recorded in column vector form as G0. The standardized typical daily curve has n recording points, and the interval between adjacent recording points is T, where: G0=[g1,g2,…,g n ] T g i It is the standardized output value of photovoltaic power generation at the i-th recording point in a day, which is determined by the characteristics of photovoltaic power generation. The maximum output coefficients of photovoltaic power generation on sunny days in spring, summer, autumn and winter are a1, a2, a3 and a4, and the maximum output coefficients on rainy days are b1, b2, b3 and b4. The typical output curve of photovoltaic power generation on sunny days in the jth season is G aj And the output curve G on rainy days aj The calculation method is as follows: G aj =a j S3G0 G bj =b j S3G0 The unit column vector is represented by E. The maximum output coefficient of wind power in spring, summer, autumn and winter is c1, c2, c3, c4, the minimum output coefficient is d1, d2, d3, d4, and the maximum peak-shaving depth of thermal power is e. The maximum total output curve of the regional power supply on a typical day in the jth season is G′ aj and the minimum total output curve G′ bj The calculation method is as follows: G′ aj =G aj +(c j S2+S1)E G′ bj =G bj +(d j S2+eS1)E The standardized typical daily curve of residential electricity, industrial and commercial electricity, and charging pile load in the jth season is recorded in the form of column vector as F 1j 、F 2j 、F 3j The standardized typical daily curve has n recording points in total, and the interval between adjacent recording points is T. The standardized typical daily curve of the k-th load is expressed as follows: F kj =[f kj-1 ,f kj-2 ,…,f kj-n ] T f kj-i That is, the standardized load value of the k-th load at the i-th recording point on the typical day of the j-th season. This value is determined by the load characteristics. The total load curve F′ of the j-th season region is j The calculation method is as follows:

5. A distribution network planning method for coordinated power grid and energy storage as claimed in claim 1, characterized in that: The third step is to form a net load curve by coupling the photovoltaic power generation with the total load curve; obtain the actual maximum power supply load, minimum power supply load, maximum external power and other parameters according to the net load curve, and balance the power and electricity based on these key parameters; Compare the power balance results with the grid's safe operation requirements to calculate the power capacity shortfall; finally, calculate the energy storage capacity.

6. A distribution network planning method for coordinated power grid and energy storage as claimed in claim 1, characterized in that: The third step is to calculate the net load curve: The maximum net load curve of the jth season is recorded as M in column vector form aj , the minimum net load curve is M bj , the net load curve is calculated as follows: M bj =F′ j -G′ bj M bj =F′ j -G′ aj Calculate the net load characteristic parameters: The annual maximum net load is P max , the minimum net load throughout the year is P min (The minimum net load may be less than 0, indicating power delivery), then the net load characteristic parameter calculation method is as follows. P max =max(m)|m∈M aj P min =min(m)|m∈M bj Calculate the power capacity shortfall: Let the power supply capacity of the power grid under the condition of N-1 be A, and the transmission capacity of the power grid equipment under the condition of no overload be B, then the power supply capacity shortage of the power grid is Q A and the power grid transmission capacity shortfall Q B The calculation method is as follows: Q A =P max -A Q B =-P min -B If Q A ≤0 and Q B ≤0, the power supply capacity and transmission capacity of the power grid are sufficient, and no energy storage is required; if Q A >0, the power supply capacity of the power grid is insufficient, and priority should be given to increasing the power transformation capacity of the power grid and adding transmission and distribution lines. Under emergency needs, energy storage can be configured to discharge during peak load periods to reduce the maximum load; if Q B >0, the power grid’s transmission capacity is insufficient, and energy storage must be configured to charge during the peak period of power transmission to reduce the maximum transmission power.

7. A distribution network planning method for coordinated power grid and energy storage as claimed in claim 1, characterized in that: Calculate energy storage capacity: The goal of calculating the energy storage capacity is to determine the energy storage discharge power P E1 、Charging power P E2 and storage capacity W E Before determining the above parameters, it is necessary to clarify the energy conversion efficiency η and discharge depth D of the energy storage. This project mainly considers the energy storage configuration under the condition of insufficient new energy transmission capacity: For Q B >0, the energy storage charging power P E2 and storage capacity W E The calculation method is as follows: P E2 ≥Q B In addition, if energy storage is required due to excessive voltage deviation, the energy storage capacity needs to be debugged in combination with power flow calculation.

8. A distribution network planning method for coordinated power grid and energy storage as claimed in claim 1, characterized in that: The fifth step, for grid-rented energy storage, is calculated based on the rental cost, which also includes the rental power cost and the rental electricity cost; for pure demand response energy storage, it is calculated based on the response power cost and the response electricity cost.

9. A distribution network planning method for coordinated power grid and energy storage as claimed in claim 1, characterized in that: In the sixth step, the total cost objective function is as follows: minC=min[(a ess +b ess T)P ess +(a grid / ρ)P grid ] Among them, P ess is the energy storage charging and discharging power, P grid To expand the power demand of the power grid; ess is the energy storage power cost, b ess is the energy storage electricity cost, a grid is the cost of grid expansion; T is the continuous charging and discharging time of energy storage, ρ is the power factor; The initial value of the energy storage configuration duration can be predicted by the source-load curve (to determine the time of exceeding the limit). grid As the load increases, the overload line gradually increases, and the energy storage configuration time gradually shortens. Therefore, there are three solutions to this function: ① Fully build power grid; ② Full construction energy storage; ③ There is an optimal solution for network-storage collaboration. Find the T value that satisfies this condition and analyze the corresponding P in this case. grid and P ess , we can get the optimal solution for network-storage collaboration.

10. A distribution network planning method for coordinated power grid and energy storage as claimed in claim 1, characterized in that: The sixth step is that the planning scheme includes the construction and transformation scale of the power grid itself, as well as the leasing scale, response reserve scale, and construction scale of the energy storage equipment. The energy storage operation mode is output as an additional result, and the energy storage charging and discharging time and the charging and discharging power at different times are clarified for reference by the power supply grid enterprise control center.

Images