Method for Configuring Accessible Capacity of Distributed Photovoltaics in Distribution Network Based on Capacity Ratio

Abstract

The present invention discloses a method for configuring the accessible capacity of distributed photovoltaic in a distribution network based on the capacity ratio, which includes the following steps: determining the capacity ratio of the photovoltaic power station, determining the actual power on the AC side of the distributed photovoltaic inverter in the distribution network according to the simultaneous output rate among multiple distributed photovoltaic power stations to be built, determining the energy storage capacity required to be configured for the distributed photovoltaic in the distribution network, considering the parameters of possible power abandonment of the photovoltaic power station during the peak power generation period, determining the maximum allowable power abandonment amount of the distributed photovoltaic power station, determining the limit transmission capacity of the distribution network accessed by the distributed photovoltaic power station, and finally determining the maximum capacity on the DC side of the configurable distributed photovoltaic according to the capacity ratio, actual power, energy storage capacity, maximum allowable power abandonment amount, and maximum allowable calorific value. The configuration method proposed by the present invention provides an efficient configuration method for the distribution network planning and the distributed photovoltaic power station planning, and reduces the waste of solar energy resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution network construction, and in particular relates to a method for configuring the accessible capacity of distributed photovoltaic power generation in a distribution network based on a capacity-matching ratio. Background Art

[0002] In recent years, with the expansion of newly installed photovoltaic capacity in my country, the average number of hours of photovoltaic utilization has increased nationwide, and the amount of distributed photovoltaic power connected to the grid has also increased. However, the energy obtained from photovoltaic power generation depends on meteorological conditions such as the seasons, day and night, and whether it is cloudy or sunny. This leads to a lack of controllability and unstable power supply, which in turn brings volatility to the power grid. As a result, the losses caused by photovoltaic power generation to the distribution network and the deterioration of voltage quality are becoming increasingly prominent.

[0003] Reasonable planning of the location and capacity of distributed photovoltaic systems within distribution networks can reduce losses associated with long-distance power transmission and leverage their positive role in supporting distribution network voltage. Compared to traditional long-distance transmission methods, distributed photovoltaic systems integrated into distribution networks reduce costs and power consumption, allowing for local energy consumption. However, unconstrained integration or widespread grid-connected use of distributed photovoltaic systems can transform the entire distribution system into a multi-source system, leading to changes in system power flows and voltage distribution, and resulting in voltage overshoots, voltage fluctuations, and harmonic pollution. Typical residential loads may not match photovoltaic generation during peak hours, causing voltage overshoots, increasing line losses and impacting system operation, as well as the safety, economy, and reliability of the distribution network. Therefore, research on the capacity of distributed photovoltaic systems integrated into distribution networks is essential, and determining this capacity remains a pressing issue. Furthermore, the capacity-to-grid ratio of distributed photovoltaic systems significantly impacts photovoltaic output, power balance, and grid operation. Therefore, this capacity-to-grid ratio should be further considered when analyzing the available capacity of distributed photovoltaic systems. If the capacity ratio of distributed photovoltaics is not taken into consideration, it is easy for the access capacity of distributed photovoltaics on the DC side of the distribution network system to fail to reach the maximum value, resulting in an unreasonable configuration. Summary of the Invention

[0004] The present invention provides a method for configuring the accessible capacity of distributed photovoltaic power generation in a distribution network based on a capacity matching ratio, aiming to solve the problem of unreasonable configuration when configuring the accessible capacity of distributed photovoltaic power generation in the prior art.

[0005] To solve the above technical problems, the present invention proposes a method for configuring the accessible capacity of distributed photovoltaic power generation in a distribution network based on a capacity matching ratio, comprising the following steps:

[0006] S1: Determine the capacity ratio of the photovoltaic power station, where the capacity ratio is the ratio of the installed capacity of the photovoltaic power generation system components to the rated capacity of the photovoltaic power generation system;

[0007] S2: Determine the actual power on the AC side of the distributed PV inverters in the distribution network according to the simultaneous output rate among multiple distributed PV power stations to be built.

[0008] S3: Determine the energy storage capacity to be configured for the distributed PV in the distribution network, where the energy storage capacity is used to absorb the electricity of the distributed PV power stations.

[0009] S4: Consider the parameters of possible power curtailment of the PV power stations during the peak power generation period, and determine the maximum allowable power curtailment of the distributed PV power stations according to the power curtailment rate requirement of the distribution network for the distributed PV.

[0010] S5: Determine the limit transmission capacity of the distribution network accessed by the distributed PV power stations, where the limit transmission capacity depends on the maximum allowable heat generation of the transmission lines in the distribution network.

[0011] S6: According to the capacity ratio, actual power, energy storage capacity, maximum allowable power curtailment, and maximum allowable heat generation, and based on the constraints of the distribution network technical parameters by the PV power station construction specifications, determine the maximum capacity on the DC side of the configurable distributed PV through iterative loop solving.

[0012] Preferably, the calculation formula for the capacity ratio is as follows:

[0013]

[0014] In the formula, R is the capacity ratio of the PV power station, P DC is the installed capacity of the components of the distributed PV power generation system, and P AC is the rated capacity on the AC side of the inverter of the distributed PV power generation system.

[0015] Preferably, the calculation formula for the actual power is as follows:

[0016] P AC，PV = P DC ·α·β·λ

[0017] In the formula, P AC，PV is the actual power on the AC side of the distributed PV inverters in the distribution network, α is the output coefficient of each PV module in the distributed PV power station, β is the conversion efficiency of the distributed PV inverters in the distribution network, and λ is the simultaneous output rate of different distributed PV power stations.

[0018] Preferably, the energy storage capacity needs to satisfy the following constraints:

[0019]

[0020] In the formula, S ESS is the energy storage capacity to be configured for the distributed PV in the distribution network, is the coefficient of the energy storage configuration ratio of the distributed PV, and PAC is the rated capacity of the AC side of the inverter in the distributed photovoltaic power generation system.

[0021] Preferably, the maximum allowable power curtailment should satisfy the following constraints:

[0022] W PV，ab ≤ηW PV

[0023] In the formula, W PV，ab is the maximum allowable power curtailment of the distributed photovoltaic power station, η is the power curtailment rate requirement of the distribution network for distributed photovoltaics, and W PV is the total power generation of the distributed photovoltaic power station.

[0024] Preferably, the calculation formula for the maximum allowable power curtailment W PV，ab is as follows:

[0025]

[0026] In the formula, W PV，ab is the maximum allowable power curtailment of the distributed photovoltaic power station, P i，PV is the output power of the AC side of the distributed photovoltaic inverter at the i-th hour of the whole day, P i，load is the load of the distribution network system at the i-th hour of the whole day, P i，ESS is the absorption power of the distributed photovoltaic energy storage at the i-th hour of the whole day, P i，line is the power sent by the photovoltaic power station through the distribution line at the i-th hour of the whole day, Δt is the time interval, and the value is 1h; among them, P i，PV -P i，load -P i，ESS -P i，line >0.

[0027] Preferably, the calculation formula for the total power generation W PV is as follows:

[0028]

[0029] In the formula, W PV is the total power generation of the distributed photovoltaic power station, P i，PV is the output power of the AC side of the distributed photovoltaic inverter at the i-th hour of the whole day, and Δt is the time interval, and the value is 1h.

[0030] Preferably, the maximum allowable heat generation depends on the maximum allowable current of the line, and the calculation formula for the limit transmission capacity is as follows:

[0031]

[0032] In the formula, P line，N is the limit transmission capacity of the distribution network accessed by the distributed photovoltaic power station, Ue is the rated voltage of the distribution network, I max is the continuous maximum allowable current of the transmission line in the distribution network, is the power factor of the transmission line in the distribution network, and K is the environmental temperature correction coefficient.

[0033] Preferably, the construction specifications for the distribution network technical parameters specifically include the following constraints:

[0034] P AC，PV = P DC ·α·β·λ

[0035] P i，ESS ≤0.5S ESS

[0036]

[0037] W PV，ab ≤ηW PV

[0038] P i，line ≤P line，N

[0039] 0.93U e ≤U≤1.07U e

[0040] In the formula, P AC，PV is the actual power on the AC side of the distributed PV inverter in the distribution network, P DC is the installed capacity of the distributed PV power generation system components, α is the output coefficient of each PV module in the distributed PV power station, β is the conversion efficiency of the distributed PV inverter in the distribution network, λ is the simultaneity rate of the outputs of different distributed PV power stations, P i，ESS is the absorption power of the distributed PV energy storage at the i-th hour of the whole day, S ESS is the absorption capacity of the distributed PV energy storage for the whole day, is the coefficient of the distributed PV configured energy storage ratio, P AC is the rated capacity on the AC side of the inverter of the distributed PV power generation system, W PV，ab is the maximum allowable power curtailment of the distributed PV power station, η is the power curtailment rate requirement of the distribution network for the distributed PV, W PV is the total power generation of the distributed PV power station, P i，line is the power sent by the PV power station through the distribution line at the i-th hour of the whole day, P line，N is the limit transmission capacity of the distribution network accessed by the distributed PV power station, U eis the rated voltage of the distribution network, and U is the real-time voltage at the connection point of the distributed photovoltaic (PV) system to the grid. According to the specifications, the allowable deviation of the supply voltage is ±7% of the nominal voltage. Therefore, the value range of the real-time voltage U at the connection point of the distributed PV system to the grid should be between 0.93U e and 1.07U e in between.

[0041] Compared with the prior art, the present invention has the following technical effects:

[0042] The method for configuring the accessible capacity of distributed PV in the distribution network based on the capacity ratio proposed by the present invention fully considers the constraints such as the capacity ratio of distributed PV, the configuration and operation control strategy of distributed PV energy storage, the accommodation of distributed PV, the line limit transmission capacity, and voltage during the construction process of connecting distributed PV to the distribution network. A target function with the maximum DC-side capacity of configurable distributed PV as the target is established. Through the target function, the capacity configuration of distributed PV connected to the distribution network is planned, providing an efficient configuration method for distribution network planning and distributed PV power station planning. Under the condition of meeting the various specification constraints of the distribution network, the maximum distributed PV capacity is configured to reduce the waste of solar energy resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a flowchart of the method for configuring the accessible capacity of distributed PV in the distribution network based on the capacity ratio according to the present invention;

[0044] Figure 2 is the output characteristic curve of the distributed PV under typical days in the method for configuring the accessible capacity of distributed PV in the distribution network based on the capacity ratio according to the present invention;

[0045] Figure 3 is the distribution network system curve without considering the capacity ratio in the method for configuring the accessible capacity of distributed PV in the distribution network based on the capacity ratio according to the present invention;

[0046] Figure 4 is the distribution network system curve considering the capacity ratio in the method for configuring the accessible capacity of distributed PV in the distribution network based on the capacity ratio according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present application and with reference to the accompanying drawings.

[0048] As Figure 1 shown, it is a flowchart of the method for configuring the accessible capacity of distributed PV in the distribution network based on the capacity ratio proposed by the present invention, including the following steps:

[0049] S1: Determine the capacity ratio of the photovoltaic power station. The capacity ratio is the ratio of the installed capacity of the photovoltaic power generation system components to the rated capacity of the photovoltaic power generation system. The calculation formula for the capacity ratio is as follows:

[0050]

[0051] In the formula, R is the capacity ratio of the photovoltaic power station, P DC is the installed capacity of the distributed photovoltaic power generation system components, and P AC is the rated capacity of the inverter AC side of the distributed photovoltaic power generation system.

[0052] S2: Determine the actual power of the distributed photovoltaic inverters on the AC side of the distribution network according to the simultaneous output rate among multiple distributed photovoltaic power stations to be built. The simultaneous output rate, also known as the cluster effect coefficient, is defined as the ratio of the maximum possible output of the photovoltaic cluster within the sampling time to the installed capacity of the photovoltaic cluster within the same sampling time. The simultaneous output rate characterizes the comprehensive capacity utilization rate of multiple photovoltaic power stations and reflects the maximum possible output of the photovoltaic cluster. The calculation formula for the actual power is as follows:

[0053] P AC,PV =P DC ·α·β·λ

[0054] In the formula, P AC,PV is the actual power of the distributed photovoltaic inverters on the AC side of the distribution network, α is the output coefficient of each photovoltaic component in the distributed photovoltaic power station, β is the conversion efficiency of the distributed photovoltaic inverters in the distribution network, and λ is the simultaneous output rate of different distributed photovoltaic power stations.

[0055] S3: Determine the energy storage capacity required to be configured for the distributed photovoltaic in the distribution network. The energy storage capacity is used to absorb the electricity of the distributed photovoltaic power station. Generally, it is considered that the distributed photovoltaic electricity is not sent to the 110 kV or 220 kV power grid for absorption. At the same time, due to the volatility, intermittency, and randomness of the distributed photovoltaic output, a certain amount of energy storage can be considered to be configured to meet the absorption of the distributed photovoltaic. The energy storage capacity needs to meet the following constraints:

[0056]

[0057] In the formula, S ESS is the energy storage capacity required to be configured for the distributed photovoltaic in the distribution network, is the coefficient of the energy storage ratio configured for the distributed photovoltaic, and generally can take values between 0.1 and 0.15. P AC is the rated capacity of the inverter AC side of the distributed photovoltaic power generation system.

[0058] S4: Consider the parameters of possible curtailment of electricity in the photovoltaic power station during the peak power generation period, and determine the maximum allowable curtailment of electricity of the distributed photovoltaic power station according to the curtailment rate requirement of the distribution network for distributed photovoltaics; the maximum allowable curtailment of electricity should satisfy the following constraints:

[0059] W PV，ab ≤ηW PV

[0060] In the formula, W PV，ab is the maximum allowable curtailment of electricity of the distributed photovoltaic power station, η is the curtailment rate requirement of the distribution network for distributed photovoltaics, and W PV is the total power generation of the distributed photovoltaic power station.

[0061] The calculation formula for the maximum allowable curtailment of electricity W PV，ab is as follows:

[0062]

[0063] In the formula, W PV，ab is the maximum allowable curtailment of electricity of the distributed photovoltaic power station, P i，PV is the output power of the AC side of the distributed photovoltaic inverter at the i-th hour of the whole day, P i，load is the load of the distribution network system at the i-th hour of the whole day, P i，ESS is the absorption power of the distributed photovoltaic energy storage at the i-th hour of the whole day. When this value is greater than 0, it indicates that it absorbs distributed photovoltaic power or absorbs power from the grid. When this value is less than 0, it means that the energy storage releases power to participate in system peak shaving. P i，line is the power sent by the photovoltaic power station through the distribution line at the i-th hour of the whole day, Δt is the time interval, and the value is 1h; among them, P i，PV -P i，load -P i，ESS -P i，line >0.

[0064] The calculation formula for the total power generation W PV is as follows:

[0065]

[0066] In the formula, W PV is the total power generation of the distributed photovoltaic power station, P i，PV is the output power of the AC side of the distributed photovoltaic inverter at the i-th hour of the whole day, and Δt is the time interval, and the value is 1h.

[0067] S5: Determine the limit transmission capacity of the distribution network to which the distributed photovoltaic power station is connected. The limit transmission capacity depends on the maximum allowable heat generation of the transmission line in the distribution network;

[0068] The maximum allowable calorific value depends on the maximum allowable current of the line. The calculation formula for the limit transmission capacity is as follows:

[0069]

[0070] In the formula, P line，N is the limit transmission capacity of the distribution network connected to the distributed photovoltaic power station, U e is the rated voltage of the distribution network, I max is the continuous allowable maximum current of the transmission line in the distribution network, is the power factor of the transmission line in the distribution network, and K is the environmental temperature correction coefficient.

[0071] Generally, the long-term allowable current-carrying capacity and wire cross-section of 10kV overhead conductors are shown in Table 1, and the cross-section sequence of 10kV overhead lines is 240, 120, 70mm 2 , and the environmental temperature correction coefficient is shown in Table 2.

[0072]

[0073]

[0074] Table 1 Long-term allowable current-carrying capacity of common 10kV overhead conductors

[0075]

[0076] Table 2 Temperature correction coefficient

[0077] The power supply voltage quality of various users shall comply with 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. Therefore, the voltage constraint condition is:

[0078] 0.93 e ≤U≤1.07 e

[0079] Due to the characteristics of photovoltaic output, the photovoltaic output is mainly concentrated from 7:00 am to 5:00 pm, and the large photovoltaic output is mainly concentrated in the period from 11:00 am to 3:00 pm. In some areas, considering the time-of-use electricity price at different times, the period from 3:00 pm to 6:00 pm usually belongs to a flat load stage. Therefore, for the operation control of distributed photovoltaic energy storage, two aspects mainly need to be considered: one is that during the period of large distributed photovoltaic output, it is necessary to ensure that the stored energy of the energy storage is 0, so as to ensure that as much energy as possible can be absorbed during the large distributed photovoltaic output at noon, and the absorbed energy is used for the peak of the evening peak load period. The other is that in the noon mode, if the energy storage is not fully charged by the excess distributed photovoltaic power, the energy storage can be further charged using the electricity price during the flat load period, thereby reducing the electricity cost during the evening load period.

[0080] The constraint conditions for time-of-use electricity prices are shown in the following formula.

[0081]

[0082] 1) When 0 < t ≤ t1, t1 < t ≤ t2 or t6 < t ≤ 24, P i,ESS = 0;

[0083] 2) When t2 < i ≤ t3 or t3 < t ≤ t4, P i，ESS > 0;

[0084] 3) When t4 < i ≤ t5, P i，ESS < 0.

[0085] S6: According to the content ratio, actual power, energy storage capacity, allowable maximum power curtailment, and maximum allowable calorific value, and based on the constraints of the technical parameters of the distribution network in accordance with the construction specifications of the photovoltaic power station, the maximum capacity of the DC side of the configurable distributed photovoltaic is determined through iterative loop solving.

[0086] The construction specifications for the technical parameters of the distribution network specifically include the following constraints:

[0087] P AC，PV = P DC ·α·β·λ

[0088] P i，ESS ≤ 0.5S ESS

[0089]

[0090] W PV，ab ≤ ηW PV

[0091] P i，line ≤ P line，N

[0092] 0.93U e ≤ U ≤ 1.07U e

[0093] In the formula, P AC，PV is the actual power on the AC side of the distributed photovoltaic inverter in the distribution network, P DC is the installed capacity of the components of the distributed photovoltaic power generation system, α is the output coefficient of each photovoltaic module in the distributed photovoltaic power station, β is the conversion efficiency of the distributed photovoltaic inverter in the distribution network, λ is the simultaneity rate of the output of different distributed photovoltaic power stations, P i，ESS is the absorption power of the distributed photovoltaic energy storage in the i-th hour of the whole day, S ESS is the absorption capacity of the distributed photovoltaic energy storage throughout the day, is the coefficient of the distributed photovoltaic configured energy storage ratio, PAC is the rated capacity on the AC side of the inverter of the distributed PV power generation system, in W PV，ab is the maximum allowable power curtailment of the distributed PV power station, η is the power curtailment rate requirement of the distribution network for distributed PV, in W PV is the total power generation of the distributed PV power station, P i，line is the power sent by the PV power station through the distribution line at the i-th hour of the whole day, P line，N is the limit transmission capacity of the distribution network accessed by the distributed PV power station, U e is the rated voltage of the distribution network, U is the real-time voltage at the distributed PV power feeding point; according to the specification, the allowable deviation of the supply voltage is ±7% of the nominal voltage. Therefore, the value range of the real-time voltage U at the distributed PV power feeding point should be between 0.93U e and 1.07U e in between.

[0094] In this embodiment, with reference to the actual operating conditions of a distribution network, if the distribution network uses a wire with a cross-sectional area of 120 mm 2 to transmit 10 kV voltage, the limit transmission capacity P of the distribution network accessed by the distributed PV power station can be calculated according to the above calculation line，N = 2.75 MW. The output coefficient α of the PV module takes a value of 0.92; the inverter conversion efficiency β takes a value of 0.82; the simultaneity factor λ of the output of different distributed PV power stations takes a value of 0.95. According to the construction specification, the energy storage configuration capacity takes a value of 15% of the distributed PV installed capacity, and the distributed PV power curtailment must be less than or equal to 5% of the distributed PV power generation.

[0095] Therefore, the actual power P on the AC side of the distributed PV inverter in the distribution network can be calculated AC，PV = P DC ·0.92·0.82·0.95 = 0.717P DC , in this distribution network system, with the development of distributed PV, the capacity ratio of the newly built distributed PV station takes 1.3. Therefore, the above formula can be changed to P AC，PV = 0.932P AC , which means that the distributed PV output power on the AC side of the inverter is 93.2% of the inverter AC side capacity.

[0096] As Figure 2 shown, it is the output characteristic curves of distributed PV considering the capacity ratio and not considering the capacity ratio in a typical day for this distribution network. Without considering the capacity ratio, the load curve, distributed PV output curve, energy storage power curve and 10 kV line power curve of this distribution network system are as Figure 3As shown in the figure, it can be seen that the power transmitted from the 10kV line to the 35kV grid at this time does not reach the line transmission power constraint. Therefore, the distribution network system still has the ability to absorb the distributed photovoltaic power generation during the corresponding period. At this time, the distributed photovoltaic capacity connected to the DC side is 5.2MW, and the distributed photovoltaic power is 35.81MWh. Under this condition and boundary conditions, although the distribution network system meets all the constraint conditions, the access capacity of the distributed photovoltaic on the DC side is not the maximum at this time.

[0097] As Figure 4 shown, for the distribution network considering the capacity ratio, the load curve, distributed photovoltaic output curve, energy storage power curve, and 10kV line power curve of the distribution network system are shown. It can be seen from the figure that the transmission power of the 10kV line is greater than its power constraint during some periods. Therefore, this part of the distributed photovoltaic power cannot be absorbed, and power curtailment will occur. Through simulation calculation and analysis, it can be obtained that in the typical mode of the distribution network system, the distributed photovoltaic capacity that can be connected to the DC side is 6.8MW. At this time, the energy storage configuration capacity of the system is 1.02MWh, and the energy storage capacity is 0.51MW. The total distributed photovoltaic power generation of the system at this time is 46.55MWh, the power curtailment due to the line power transmission constraint is 2.29MWh, and the distributed photovoltaic power curtailment rate is 4.92%, meeting the construction specification constraint conditions.

[0098] From the above examples, it can be seen that when analyzing the accessible capacity of distributed photovoltaic in the distribution network, considering constraints such as the distributed photovoltaic capacity ratio, distributed photovoltaic energy storage configuration and its operation control strategy, distributed photovoltaic absorption, line limit transmission capacity, and voltage can effectively improve the distributed photovoltaic capacity connected to the DC side of the distribution network system, increase the absorption of distributed photovoltaic power, and at the same time meet constraints such as distributed photovoltaic power curtailment. This method considers the actual operation constraints of the power grid and analyzes the distributed photovoltaic access capacity, providing an effective method and reference for distribution network planning, distributed photovoltaic access planning, and distribution network construction, and has very important engineering practical significance.

[0099] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for configuring the accessible capacity of distributed photovoltaic power in a distribution network based on the capacitance ratio, characterized in that Including the following steps: S1: Determine the capacity ratio of the photovoltaic power station, where the capacity ratio is the ratio of the installed capacity of the photovoltaic power generation system components to the rated capacity of the photovoltaic power generation system; the calculation formula for the capacity ratio is as follows: In the formula, is the capacity ratio of the photovoltaic power station, is the installed capacity of the components of the distributed photovoltaic power generation system, is the rated capacity on the AC side of the inverter of the distributed photovoltaic power generation system; S2: Determine the actual power on the AC side of the distributed photovoltaic inverter in the distribution network according to the simultaneous output rate among multiple distributed photovoltaic power stations to be built. S3: Determine the energy storage capacity required to be configured in the distribution network for the distributed photovoltaic, where the energy storage capacity is used to absorb the electricity of the distributed photovoltaic power station. S4: Consider the parameters of power curtailment that occur during the peak power generation period of the photovoltaic power station, and determine the maximum allowable power curtailment of the distributed photovoltaic power station according to the power curtailment rate requirement of the distribution network for distributed photovoltaics. S5: Determine the limit transmission capacity of the distribution network accessed by the distributed photovoltaic power station, where the limit transmission capacity depends on the maximum allowable heat generation of the transmission line in the distribution network. S6: Based on the capacity ratio, actual power, energy storage capacity, maximum allowable power curtailment, maximum allowable heat generation, and the constraints of the photovoltaic power station construction specifications on the distribution network technical parameters, determine the maximum capacity of the DC side of the configurable distributed photovoltaic through iterative loop solution; the construction specifications for the distribution network technical parameters specifically include the following constraints: Wherein, is the actual power on the AC side of the distributed PV inverter in the distribution network; is the installed capacity of the distributed PV power generation system components; is the output coefficient of each PV module in the distributed PV power station; is the conversion efficiency of the distributed PV inverter in the distribution network; is the simultaneous output rate of different distributed PV power stations; is the th-hour distributed PV energy storage absorption power throughout the day; is the distributed PV energy storage absorption capacity throughout the day; is the coefficient of the distributed PV configured energy storage ratio; is the rated capacity on the AC side of the inverter of the distributed PV power generation system; is the maximum allowable power curtailment of the distributed PV power station; is the power curtailment rate requirement of the distribution network for distributed PV; is the total power generation of the distributed PV power station; is the th-hour power sent by the PV power station through the distribution line throughout the day; is the limit transmission capacity of the distribution network accessed by the distributed PV power station; is the rated voltage of the distribution network; is the real-time voltage at the distributed PV power sending point; According to the specification, the allowable deviation of the supply voltage is of the nominal voltage. Therefore, the real-time voltage of the distributed PV power sending point should be in the range of between.

2. The method for configuring the accessible capacity of distributed photovoltaic power in a distribution network based on the capacity ratio according to claim 1, wherein, The allowable maximum discarded power The calculation formula is as follows: In the formula, is the maximum allowable curtailment of the distributed PV power station, is the output power of the AC side of the distributed PV inverter at the th hour of the whole day, is the load of the distribution network system at the th hour of the whole day, is the absorption power of the distributed PV energy storage at the th hour of the whole day, is the power sent by the PV power station through the distribution line at the th hour of the whole day, is the time interval, with a value of 1 h; among them, .

3. The method for configuring the accessible capacity of distributed photovoltaic power in a distribution network based on the capacitance ratio according to claim 1, wherein The total power generation is calculated as follows: Wherein, is the total power generation of the distributed photovoltaic power station, is the output power of the AC side of the distributed photovoltaic inverter at the th hour of the whole day, is the time interval, with a value of 1h.

4. The method for configuring the accessible capacity of distributed photovoltaic power in a distribution network based on the capacitance ratio according to claim 1, wherein The maximum allowable heat generation depends on the maximum allowable current of the line, and the calculation formula for the limit transmission capacity is as follows: In the formula, is the limit transmission capacity of the distribution network connected to the distributed photovoltaic power station, is the rated voltage of the distribution network, is the continuous allowable maximum current of the transmission line in the distribution network, is the power factor of the transmission line in the distribution network, is the environmental temperature correction factor.

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