A method for configuring distributed photovoltaic energy storage capacity in distribution networks considering voltage constraints

Abstract

The present invention discloses a method for configuring the capacity of distributed photovoltaic energy storage in a distribution network considering voltage constraints, comprising the following steps: calculating the ultimate transmission capacity of a line; dividing the power supply area; constraining the power supply radius of the power supply area; standardizing the quality of the power receiving voltage of various users; calculating the load moment; before the distributed photovoltaic is connected, verifying the current carrying capacity, transformer capacity, and load absorption level of the connected distribution line; analyzing the output of the distributed photovoltaic in the distribution network and calculating the distributed photovoltaic capacity that can be connected to the distribution network area; considering solving the photovoltaic absorption problem by configuring a certain capacity of energy storage; calculating the energy storage capacity of the distributed photovoltaic configuration in the distribution network, and solving the minimum energy storage capacity configuration under various constraint conditions. The present invention takes the minimum energy storage capacity configuration as the goal and establishes an objective function to solve the energy storage capacity of the distributed photovoltaic configuration in a 10kV distribution network.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage planning and distribution network optimization, and in particular relates to a method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints. Background Art

[0002] According to the design specifications for distributed generation (DG) access to distribution networks, power sources typically connected at voltage levels of 35kV or below, located near users, and primarily consumed locally are considered DGs. Because DGs are consumed locally, they avoid the construction costs and losses of transmission lines. DGs have two key characteristics: first, their output is highly volatile and intermittent, exhibiting anti-peaking characteristics; second, the integration of DGs introduces multiple power sources and multiple power flow directions into distribution networks, making them difficult to adapt to the existing radial distribution network model.

[0003] Distributed renewable energy offers advantages such as peak load regulation, reduced transmission and transformation investment, improved power supply reliability, and reduced network losses. Directly integrating distributed renewable energy into the distribution network to supply power to nearby loads reduces the busbar load at the terminal substation, alleviating power transmission requirements within the power system. The development of distributed renewable energy can easily lead to regional imbalances in power consumption and generation within the distribution network. The integration of distributed renewable energy into the distribution network will impact the network's voltage quality and power supply reliability, restricting its ability to accommodate distributed renewable energy. With the introduction of new market mechanisms, the uncertainty of distributed renewable energy output and market-based electricity trading will impact the distribution network's power supply capacity. New trading mechanisms will lead to increased development of distributed renewable energy, increasing the pressure of time uncertainty in spot trading for distributed renewable energy on the distribution network. Against the backdrop of the construction of new power systems, the distribution network is experiencing diversified and flexible development. Energy storage can address the randomness and volatility of the output of distributed renewable energy units in the distribution network while also improving the network's ability to accommodate new energy, as well as the flexibility and economic efficiency of system operation. Therefore, there is an urgent need to further enhance and optimize the control capabilities of the distribution network to improve its ability to accommodate new energy and enhance power quality. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints. Based on the maximum transmission capacity under the temperature correction coefficient of the 10kV line of the distribution network, the 10kV power supply radius of the distribution network and the allowable range of voltage offset, the method considers the constraints such as the 10kV bus voltage constraint, the 10kV line distributed photovoltaic transmission power, the 10kV line load moment constraint and the distributed photovoltaic absorption, and takes the minimum energy storage capacity configuration as the goal, an objective function is established to solve the energy storage capacity of the distributed photovoltaic configuration in the 10kV distribution network.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints includes the following steps:

[0007] S1: Calculate the line's maximum transmission capacity based on the continuous maximum transmission capacity under allowable heating conditions:

[0008]

[0009] Where: U e is the rated voltage of the distribution network, I max is the maximum current allowed by the conductor, and K is the temperature correction coefficient;

[0010] S2: Divide the power supply area according to the planned target annual load density of the planning area. The specific division is shown in the following table:

[0011]

[0012] Where σ is the planned target annual load density (MW / km 2 ), the power supply area should not be less than 5km 2 ;

[0013] S3: Constrain the power supply radius of the power supply area. The power supply radius of Class A+, A, and B power supply areas should not exceed 3km; the power supply radius of Class C should not exceed 5km; and the power supply radius of Class D should not exceed 15km.

[0014] S4: The quality of the power supply voltage for various types of users is regulated according to the provisions of GB / T 12325. The allowable deviation of the three-phase power supply voltage of 10kV and below is ±7% of the nominal voltage;

[0015] S5: Calculate load moment:

[0016] F=P×L

[0017] Where: F is the load moment (MW km); P is the port power (MW); L is the power supply radius (km);

[0018] S6: Before connecting distributed photovoltaic power plants, verify the current carrying capacity of the connected distribution lines, transformer capacity, and load absorption level;

[0019] S7: Analyze the output of distributed photovoltaic power generation in the distribution network and calculate the distributed photovoltaic capacity that can be connected to the distribution network under the conditions of photovoltaic transmission power constraints, main transformer capacity constraints during transmission, distributed photovoltaic power curtailment rate, and energy storage configuration constraints;

[0020] S8: Consider solving the photovoltaic absorption problem by configuring a certain capacity of energy storage; based on the distribution network load curve and the distributed photovoltaic output curve, considering the constraints such as the distributed photovoltaic transmission power, voltage, load moment, and distributed photovoltaic absorption of the line, calculate the distributed photovoltaic energy storage capacity of the distribution network, and solve the minimum energy storage capacity configuration while satisfying all the constraints.

[0021] Furthermore, in step S3, for some remote areas where the voltage quality of the distribution transformer outlet meets the requirements after verification, the power supply radius can be appropriately relaxed.

[0022] Furthermore, in step S6, after verifying the current carrying capacity, transformer capacity, and load absorption level of the connected distribution line, it is necessary to further consider the impact of the ambient temperature on the line's maximum transmission capacity.

[0023] Furthermore, in step S8, the minimum energy storage capacity configuration is solved under the conditions of satisfying various constraints.

[0024] The target function and constraints are shown in the following formula:

[0025] min C=S ESS

[0026] Where S ESS Configure the capacity (MW) for energy storage, satisfying the following constraints:

[0027] st

[0028] P PV,total =P load,A +P load,B +P load,ESS

[0029] F≤F max

[0030] 0.93U e ≤U≤1.07U e

[0031] W PV ≥W PV,constraint

[0032] Where, P PV,total is the total photovoltaic power; P load,B is the load at the distribution network busbar B (MW); P load,ESS is the energy storage power configured at distribution network busbar B (MW); P load,A is the power of distributed photovoltaic transmission headend (MW); F is the load moment (MW km); F max is the maximum load moment (MW km); U is the bus voltage in the distribution network; U e is the rated voltage of the distribution network; W PVis the proportion of distributed photovoltaic power consumption (%); W PV,constraint is the distributed photovoltaic power consumption ratio constraint (%); the nuclear power state constraint of the energy storage system is as follows:

[0033] SOC min ≤SOC(t)≤SOC max

[0034] Where, SOC min Indicates the lower limit of the state of charge (SOC) of the energy storage system; SOC max Indicates the upper limit of the energy storage system's state of charge (SOC); SOC represents the energy storage system's real-time state of charge, which is a function of time t.

[0035] Furthermore, it should be ensured that SOC(0)=SOC(24)=SOC in each cycle. min , and its calculation formula is:

[0036]

[0037] Where, E B is the capacity of the energy storage system.

[0038] Furthermore, when the excess power meets the 10kV line's maximum transmission capacity constraint, the energy storage system does not participate in power regulation; however, when the distributed photovoltaic excess power does not meet the 10kV line's maximum transmission capacity constraint, the energy storage system participates in power regulation.

[0039] Furthermore, during the afternoon load period, the energy storage can continue to be charged using the load-normal electricity price. The charging power is the sum of the distributed photovoltaic power and the system power, and the charged amount is used during the evening load peak period.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network that considers voltage constraints. In step S3, for some remote areas where the voltage quality of the distribution transformer outlet meets the requirements after verification, the power supply radius can be appropriately relaxed. This fully considers the problem of uneven distribution of users in remote areas and provides maximum convenience for users in the area.

[0042] 2. The present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network that considers voltage constraints. In step S6, after verifying the current carrying capacity, transformer capacity, and load absorption level of the connected distribution line, in order to improve the distributed photovoltaic transmission capacity, it is necessary to further consider the impact of ambient temperature on the line's maximum transmission capacity.

[0043] 3. The present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints. In step S8, with the development of distributed photovoltaics, the distribution network will face the problem of distributed photovoltaic absorption. By configuring a certain capacity of energy storage, the photovoltaic absorption problem can be solved; based on the distribution network load curve and the distributed photovoltaic output curve, considering the above-mentioned 10kV line distributed photovoltaic transmission power, 10kV voltage, load moment, distributed photovoltaic absorption and other constraints, the distributed photovoltaic configuration energy storage capacity of the distribution network can be calculated.

[0044] 4. The present invention provides a method for configuring the capacity of distributed photovoltaic energy storage in a distribution network considering voltage constraints. Since the energy storage system operates in a daily cycle, it should be ensured that SOC(0)=SOC(24)=SOC in each cycle. min .

[0045] 5. This invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network that considers voltage constraints. To ensure that the energy storage device can effectively absorb excess power during midday operation, the energy storage system does not participate in power regulation when the excess power meets the 10kV line's maximum transmission capacity constraint. However, when the distributed photovoltaic excess power does not meet the 10kV line's maximum transmission capacity constraint, the energy storage system participates in power regulation to avoid power curtailment.

[0046] 6. The present invention provides a method for configuring the capacity of distributed photovoltaic energy storage in a distribution network that considers voltage constraints. Taking into account the impact of the system's time-of-use electricity price, during the afternoon load flat period, the energy storage can continue to be charged using the load flat period electricity price. The charging power is the sum of the distributed photovoltaic power and the system power, and the charged amount is used during the evening load peak period. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram of a method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints provided by the present invention when distributed photovoltaics are centrally connected to the end of a 10kV line in the distribution network;

[0048] Figure 2 A distributed photovoltaic energy storage capacity configuration method for a distribution network considering voltage constraints provided by the present invention, and an analysis curve diagram of the renewable energy generation power and system load power on a typical day in an actual 10kV regional power grid;

[0049] Figure 3 The present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints, and an analysis curve diagram of the 10kV line power, renewable energy generation power, and system load power in a typical day in an actual 10kV regional power grid;

[0050] Figure 4The present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network that considers voltage constraints, and an analytical graph showing 10kV line power, renewable energy generation power, energy storage absorbed active power, and system load power in a typical day for an actual 10kV regional power grid. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following will be combined with the specific embodiments of the present application and refer to the attached Figure 1-4 , clearly and completely describe the technical solution of the present invention.

[0052] Example 1

[0053] Taking a real-world 10kV distribution network as an example, the 10kV distribution network has one 35kV substation with two 35kV main transformers. The capacity of each main transformer is typically 10MVA, and the total main transformer capacity of the 35kV substation is 20MVA. One 35kV main transformer has 4-6 10kV outgoing lines. The 35kV substation has 10 10kV outgoing lines, and the capacity of the 10kV distribution transformer is 0.4MVA. In actual operation, due to the low simultaneity rate of the 10kV distribution transformers in the distribution network, which can usually be around 0.3, a 35kV station supplies an average of approximately 100 10kV distribution transformers, meaning that a single 10kV line supplies an average of approximately 10 distribution transformers. The generally permissible long-term current carrying capacity and conductor cross-section of 10kV overhead conductors are shown in the following table:

[0054] Table 1 Long-term allowable current carrying capacity of 10kV overhead conductors

[0055] <![CDATA[Cross-sectional area of wire (mm 2 )]]> LGJ Model (A) JKLYJ Model (A) 16 105 95 52 135 122 35 170 153 50 220 198 70 275 249 95 335 302 120 380 352 150 445 403 185 515 465 240 610 553

[0056] Assuming that the distributed photovoltaic is centrally connected to the end of the 10kV line of the distribution network, the load of the 10kV distribution station in the middle area and the output of the distributed power supply basically achieve power self-balancing, and the cross-section of the 10kV line is selected as 120mm 2 , scenes such as Figure 1 shown.

[0057] The present invention provides a method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints, comprising the following steps:

[0058] S1: Calculate the maximum transmission capacity of the line according to the continuous maximum transmission capacity under the allowable heating conditions; for 10kV conductors, the cross-section is 120mm 2 For overhead lines, assuming an ambient temperature of 35°C, according to the Power System Design Manual, the temperature correction coefficient K of the conductor's maximum transmission capacity is 0.88. At this time, the maximum transmission capacity of the 10kV line is:

[0059]

[0060] Where: P line，N is the maximum transmission capacity of 10kV line; U e is the rated voltage of the distribution network; I max is the maximum continuous current allowed by the conductor (A); K is the temperature correction coefficient;

[0061] Therefore, for a 10kV conductor, the cross-section is 120mm 2 The overhead line has a maximum transmission capacity of 5.79MW at an ambient temperature of 35℃ (K=0.88).

[0062] S2: The power supply area is divided mainly based on the planned target annual load density of the planning area. The specific divisions are shown in the following table:

[0063] Table 2 Power supply area division table

[0064]

[0065] In Table 2, σ is the planned target annual load density (MW / km 2 ); the power supply area should not be less than 5km 2 .

[0066] S3: Constrain the power supply radius of the power supply area; the power supply radius of a 10kV line is defined as the line length from the outgoing line of the substation to the farthest distribution transformer it supplies power to. The power supply radius of a 10kV line should meet the voltage quality requirements of the power distribution transformer outlet. The power supply radius of A+, A, and B power supply areas should not exceed 3km; the power supply radius of Class C should not exceed 5km; and the radius of Class D power supply areas should not exceed 15km. For some remote areas where the voltage quality of the distribution transformer outlet meets the requirements after verification, the radius can be appropriately relaxed. Therefore, for county-level distribution networks, the power supply radius constraint of a 10kV line is:

[0067] L≤5km

[0068] Where, L is the power supply radius (km);

[0069] Therefore, the power supply radius of the 10kV line to the grid is 4km, that is, L = 4km;

[0070] S4: According to GB / T 12325, the quality of the power supply voltage for various types of users is regulated. The allowable deviation of the three-phase power supply voltage of 10kV and below is ±7% of the nominal voltage. Therefore, the voltage constraint conditions are:

[0071] 9.3kV≤U≤10.7kV

[0072] Where U is the 10kV bus voltage at the distributed photovoltaic transmission point (kV).

[0073] According to the data in Table 1, 120mm 2 The maximum line current is 380 A. When line AC on a 10kV bus is a pure load line, the voltage constraint at 10kV bus A can be calculated based on the load on 10kV bus C and the given line length. This voltage constraint allows for further analysis of the PV access capacity of distributed PV systems on the 10kV line when they are connected to the grid.

[0074] Therefore, the voltage at 10kV busbar B is based on the allowable deviation requirements for three-phase power supply voltages of 10kV and below:

[0075] U B，max =10.7kV

[0076] S5: Generally, the 10kV voltage constraint is mainly affected by the terminal voltage, line resistance, and line current. The 10kV line power supply radius and the terminal load size will also affect the terminal voltage. For uplink transmission, the power of distributed photovoltaics at the uplink point will also affect the voltage at the uplink point. Therefore, the concept of 10kV load moment is proposed. The calculation formula for the load moment is as follows:

[0077] F=P×L

[0078] Where: F is the load moment (MW km); P is the 10kV port power (MW); L is the power supply radius (km);

[0079] Considering the maximum integration of distributed photovoltaic power into the 10kV distribution network, the voltage at the head end of the 10kV line is 10.7kV. Due to the voltage constraint of the load line, the voltage at the end is 10.12kV. Based on the resistivity calculation, the line resistance is 3.16Ω. From this calculation, the line current is 105.97A, so the power at the head end of the line is 1.96MW.

[0080] According to the definition of load moment, the maximum load moment of distributed photovoltaic transmission lines is:

[0081]

[0082] Where: I max is the 10kV line current; U N is the bus voltage at the head end of the load line or the voltage at the head end of the distributed photovoltaic transmission line (kV), and L is the power supply radius (km).

[0083] S6: Distributed photovoltaic access should comply with the relevant provisions of the current industry standard "Technical Regulations for Distributed Power Generation Access to Distribution Networks" NB / T 32015. The total scale of all types of photovoltaic development within county-level administrative divisions should not feed back power to 110kV and above power grids, and the scale of distributed photovoltaic development should not exceed the available capacity of distribution networks at all levels and the region's absorption capacity. For distributed photovoltaics that exceed the available capacity of distribution networks but still require access, flexible adjustment capabilities must be implemented before they can be connected to the grid. Therefore, before distributed photovoltaic access is connected, the current carrying capacity, transformer capacity, and load absorption level of the connected distribution line should be verified. At the same time, to improve the transmission capacity of distributed photovoltaics, it is necessary to further consider the impact of ambient temperature on the line's maximum transmission capacity.

[0084] S7: Analyze the output of distributed photovoltaics in the distribution network and calculate the distributed photovoltaic capacity that can be connected to the distribution network under the conditions of photovoltaic transmission power constraints, main transformer capacity constraints during transmission, distributed photovoltaic power curtailment rate, and energy storage configuration constraints.

[0085] When the 10kV power supply radius changes and the voltage of 10kV busbar B is at the maximum allowable deviation, the 10kV port voltage will be greater than the rated value. Based on the long-term allowable current of the line and the port voltage, the port power value can be calculated as the power transmitted to the 35kV voltage level through 10kV. Therefore, the distributed photovoltaic power value PPV is equal to the transmitted head end power P load,A The load P of the terminal 10kV busbar B load,B The sum is as follows:

[0086] P PV =P load,B +P load,A

[0087] S8: Based on the above constraints, the installed capacity of photovoltaic power generation at the end of the 10kV distribution network in this area is 4.5MW, and there is no power abandonment in distributed photovoltaic power generation. The photovoltaic output curve and load curve of the regional power grid on a typical day are as follows: Figure 2 As shown;

[0088] Depend on Figure 2 As can be seen, during peak distributed photovoltaic power generation, the power output exceeds the regional load. The remaining distributed photovoltaic power is then transmitted to the upper grid via 10kV lines, subject to the voltage and current constraints of these lines. To ensure both renewable energy consumption and transmission needs, energy storage can be deployed.

[0089] Based on the distribution network load curve and distributed photovoltaic output curve, considering the above-mentioned 10kV line distributed photovoltaic transmission power, 10kV voltage, load moment, distributed photovoltaic absorption and other constraints, the distributed photovoltaic energy storage capacity of the distribution network is calculated. When all constraints are met, the minimum energy storage capacity configuration is solved. The objective function and constraints are shown in the following formula:

[0090] min C=S ESS

[0091] st

[0092] P PV,total =P load,A +P load,B +P load,ESS

[0093] F≤F max

[0094] 9.3kV≤U≤10.7kV

[0095] W PV ≥W PV,constraint

[0096] Where S ESS Configure the capacity of energy storage (MW); P PV,ESS is the distributed photovoltaic power (MW); P load,B is the load at 10kV busbar B (MW); P load,ESS is the energy storage power configured at 10kV busbar B (MW); P load,A is the power of distributed photovoltaic transmission headend (MW); F is the load moment (MW km); F max is the maximum load moment (MW km); U is the bus voltage in the 10kV distribution network, W PV is the proportion of distributed photovoltaic power consumption (%); W PV,constraint is the distributed photovoltaic power consumption ratio constraint (%).

[0097] The nuclear power state constraint of the energy storage system is as follows:

[0098] SOC min ≤SOC(t)≤SOC max

[0099] Where: SOC min The lower limit of the state of charge (SOC) of the energy storage system; SOC max is the upper limit of the state of charge (SOC) of the energy storage system; SOC is the real-time state of charge of the energy storage system, which is a function of time t.

[0100] Since the energy storage system operates in a daily cycle, it should be ensured that SOC(0)=SOC(24)=SOC min , and its calculation formula is:

[0101]

[0102] Where, E B Indicates the capacity of the energy storage system.

[0103] When energy storage is not considered, the system operation curve is as follows: Figure 3 As shown in Figure 2. Since the transmission of the surplus power of distributed photovoltaic to the upper grid is subject to the voltage at the end of the line, the line transmission power is 1.96MW. Figure 3 As shown in the curve, when the 10kV line power curve shows that the excess power of distributed photovoltaic power is transmitted to the upper grid, an over-limit situation will occur, so energy storage needs to be configured to participate in regulation.

[0104] Taking energy storage into account, to ensure charging capacity during the midday peak of distributed PV generation, energy storage is not involved in system power regulation when the 10kV line transmission power constraint is not met. When the power transmitted by distributed PV to the upper grid exceeds the 10kV line transmission power constraint, energy storage is absorbed to meet the 10kV line transmission power constraint.

[0105] Further considering the impact of time-of-use electricity prices after noon, energy storage is charged during the normal load period to support the power during the evening peak load period. The charging power is the distributed photovoltaic power and the system power. The system curve is as follows: Figure 4 shown.

[0106] Through simulation analysis, it is found that in order to ensure that distributed photovoltaic power does not abandon the phenomenon, the system is configured with a side energy storage capacity of 1.5MW. After the energy storage is configured, it can effectively constrain the 10kV line to send the excess power of distributed photovoltaic power to the upper power grid, and the system meets the voltage constraint and the line's maximum transmission capacity constraint.

[0107] This patent is based on the ultimate transmission capacity under the temperature correction coefficient of the 10kV line of the distribution network, the 10kV power supply radius of the distribution network and the allowable range of voltage offset. It considers the constraints of 10kV bus voltage, 10kV line distributed photovoltaic transmission power, 10kV line load moment constraint and distributed photovoltaic absorption, and takes the minimum energy storage capacity configuration as the goal. It establishes an objective function to solve the energy storage capacity of the distributed photovoltaic configuration of the 10kV distribution network. The proposed method has very important engineering practical significance for the development of distributed photovoltaic in the distribution network.

[0108] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the creative concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints, characterized in that: The following steps are involved: S1: Calculate the line's maximum transmission capacity based on the continuous maximum transmission capacity under allowable heating conditions: Where: U e is the rated voltage of the distribution network, I max is the maximum current allowed by the conductor, and K is the temperature correction coefficient; S2: Divide the power supply area according to the planned target annual load density of the planning area. The specific division is shown in the following table: Where σ is the planned target annual load density of the planning area, in MW / km 2 The power supply area should not be less than 5km 2 ; S3: Constrain the power supply radius of the power supply area. The power supply radius of Class A+, A, and B power supply areas should not exceed 3km; the power supply radius of Class C should not exceed 5km; and the power supply radius of Class D should not exceed 15km. S4: The quality of the power supply voltage for various types of users is regulated according to the provisions of GB / T 12325. The allowable deviation of the three-phase power supply voltage of 10kV and below is ±7% of the nominal voltage; S5: Calculate load moment: F=P×L Where: F is the load moment, in MW km; P is the port power, in MW; L is the power supply radius (km); S6: Before connecting distributed photovoltaic power plants, verify the current carrying capacity of the connected distribution lines, transformer capacity, and load absorption level; S7: Analyze the output of distributed photovoltaic power generation in the distribution network and calculate the distributed photovoltaic capacity that can be connected to the distribution network under the conditions of photovoltaic transmission power constraints, main transformer capacity constraints during transmission, distributed photovoltaic power curtailment rate, and energy storage configuration constraints; S8: Consider solving the photovoltaic absorption problem by configuring a certain capacity of energy storage. Based on the distribution network load curve and the distributed photovoltaic output curve, considering the distributed photovoltaic transmission power, voltage, load moment, and distributed photovoltaic absorption constraints of the line, calculate the energy storage capacity of the distributed photovoltaic configuration of the distribution network, and solve the minimum energy storage capacity configuration while satisfying all the constraints. The objective function and constraints are shown in the following formula: my C=S ESS Where S ESS Configure the capacity of the energy storage in MW, subject to the following constraints: st P PV,total =P load,A +P load,B +P load,ESS F≤F max 0.93U e ≤U≤1.07U e IN PV ≥In PV,consyraint Where, P PV,total is the total photovoltaic power; P load,B is the load at the distribution network busbar B, in MW; P load,ESS is the energy storage power configured at the distribution network busbar B, in MW; P load,A The power transmitted from distributed photovoltaic power generation to the headend, in MW; F is the load moment, in MW km; F max is the maximum load moment, in MW km; U is the bus voltage in the distribution network; U e is the rated voltage of the distribution network; W PV is the proportion of distributed photovoltaic power consumption, in %; W PV,constraint is the distributed photovoltaic power consumption ratio constraint, in %. The nuclear power state constraint of the energy storage system is as follows: SOC min ≤SOC(t)≤SOC max Where, SOC min Indicates the lower limit of SOC; SOC max Indicates the upper limit of SOC; SOC represents the real-time state of charge of the energy storage system, which is a function of time t.

2. A method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints according to claim 1, characterized in that: In step S3, for some remote areas where the voltage quality of the distribution transformer outlet meets the requirements after verification, the power supply radius can be appropriately relaxed.

3. The method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints according to claim 1, characterized in that: In step S6, after verifying the current carrying capacity, transformer capacity, and load absorption level of the connected distribution line, it is necessary to further consider the impact of the ambient temperature on the line's maximum transmission capacity.

4. The method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints according to claim 1, characterized in that: In each cycle, SOC(0)=SOC(24)=SOC min , and its calculation formula is: Where, E B is the capacity of the energy storage system.

5. A method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints according to claim 4, characterized in that: When the excess power meets the 10kV line's maximum transmission capacity constraint, the energy storage system does not participate in power regulation; however, when the distributed photovoltaic excess power does not meet the 10kV line's maximum transmission capacity constraint, the energy storage system participates in power regulation.

6. A method for configuring distributed photovoltaic energy storage capacity in a distribution network considering voltage constraints according to claim 5, characterized in that: During the afternoon load period, the energy storage can continue to be charged using the electricity price during the load period. The charging power is the sum of the distributed photovoltaic power and the system power, and the charged amount is used during the evening load peak period.

Images