An optimization method and terminal for new energy access to the distribution network

Abstract

The present invention discloses an optimization method and a terminal for new energy access to a distribution network, which determine the access position and the corresponding access capacity of the new energy to be accessed in the distribution network; determine the corresponding distribution network equipment in the distribution network according to the access position, and match the corresponding evaluation model based on the distribution network equipment; evaluate the new energy consumption level of the distribution network equipment according to the evaluation model, compare the new energy consumption level with the access capacity, and optimize the distribution network according to the comparison result; through the matching of the access position of the new energy, the distribution network equipment corresponding to the access position, and the evaluation model corresponding to the distribution network equipment, an accurate evaluation of the new energy consumption level of the distribution network equipment is realized, thereby ensuring the correctness of the determined distribution network equipment with potential problems, and further improving the optimization effect of the distribution network after the new energy is accessed to the distribution network.

Description

Technical Field

[0001] The present invention relates to the field of distribution network optimization, and particularly to an optimization method and terminal for new energy access to the distribution network. Background Art

[0002] New energy is an unconventional energy different from traditional energy, such as photovoltaic, wind power, biomass energy, etc., which has the characteristics of rich resources, renewability, environmental protection, etc. Therefore, in view of the shortage of existing energy, new energy is widely used in all walks of life. Among them, in the power industry, new energy will be accessed to the distribution network to supplement the electricity quantity and supply power to some remote areas.

[0003] In the current development and utilization of new energy in the power industry, the promotion speed of photovoltaic power generation is the fastest, and the most common one is the access of distributed photovoltaic to the distribution network. However, with the continuous increase in the access capacity of distributed photovoltaic to the distribution network, the distribution network equipment may have insufficient consumption capacity, resulting in problems such as voltage deviation exceeding the limit, reverse power flow overloading, and short-circuit current being too large.

[0004] To avoid the above problems, it is necessary to pre-optimize the distribution network equipment with potential problems to ensure the safe operation of the distribution network. Before the optimization process, it is necessary to first evaluate the distribution network equipment to find out the distribution network equipment with potential problems. However, the evaluation accuracy of the existing evaluation methods for distribution network equipment is not high, which affects the correctness of the determined distribution network equipment with potential problems, and further affects the optimization effect of the distribution network. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to provide an optimization method and terminal for new energy access to the distribution network, which can improve the optimization effect of the distribution network after new energy access.

[0006] To solve the above technical problem, a technical solution adopted by the present invention is:

[0007] An optimization method for new energy access to the distribution network includes the steps of:

[0008] S1. Determine the access position and corresponding access capacity of the new energy to be accessed in the distribution network;

[0009] S2. Determine the corresponding distribution network equipment in the distribution network according to the access position, and match the corresponding evaluation model based on the distribution network equipment;

[0010] S3. Evaluate the new energy consumption level of the distribution network equipment according to the evaluation model, compare the new energy consumption level with the access capacity, and optimize the distribution network according to the comparison result.

[0011] To solve the above technical problems, another technical solution adopted by the present invention is as follows:

[0012] An optimization terminal for new energy access to a distribution network includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, each step in the above optimization method for new energy access to a distribution network is implemented.

[0013] The beneficial effects of the present invention are as follows: After new energy is accessed to the distribution network, first determine its access position and corresponding access capacity in the distribution network, then determine the corresponding distribution network equipment in the distribution network according to the access position, match the corresponding evaluation model based on the distribution network equipment, evaluate the new energy consumption level of the distribution network equipment according to the evaluation model, and then optimize the distribution network by comparing the evaluated new energy consumption level with the new energy access capacity. Through the matching of the access position of new energy, the corresponding distribution network equipment at the access position, and the evaluation model corresponding to the distribution network equipment, an accurate evaluation of the new energy consumption level of the distribution network equipment is achieved, thereby ensuring the correctness of the determined distribution network equipment with potential problems, and further improving the optimization effect of the distribution network after new energy access. Description of the Drawings

[0014] Figure 1 It is a flowchart of the steps of an optimization method for new energy access to a distribution network according to an embodiment of the present invention;

[0015] Figure 2 It is a schematic structural diagram of an optimization terminal for new energy access to a distribution network according to an embodiment of the present invention;

[0016] Figure 3 It is a judgment flowchart for optimizing grid equipment when new energy is accessed to a distribution network according to an embodiment of the present invention;

[0017] Figure 4 It is a flowchart for evaluating the new energy consumption level when the distribution network equipment is a 10kV line according to an embodiment of the present invention;

[0018] Figure 5 It is a flowchart for evaluating the new energy consumption level when the distribution network equipment is a low-voltage feeder according to an embodiment of the present invention;

[0019] Figure 6 It is a flowchart of the steps for optimizing grid equipment according to an embodiment of the present invention. Detailed Embodiments

[0020] To describe the technical content, achieved objectives, and effects of the present invention in detail, the following is described in conjunction with the embodiments and with reference to the accompanying drawings.

[0021] The above optimization method and terminal for new energy access to the distribution network can be applied to various optimization scenarios of the distribution network after new energy access, such as photovoltaic, wind power, biomass energy, etc. The following is an illustration through specific implementation manners:

[0022] In an alternative implementation manner, as Figure 1 shown, an optimization method for new energy access to the distribution network includes the steps of:

[0023] S1. Determine the access position and corresponding access capacity of the new energy to be accessed in the distribution network;

[0024] S2. Determine the corresponding distribution network equipment in the distribution network according to the access position, and match the corresponding evaluation model based on the distribution network equipment;

[0025] S3. Evaluate the new energy consumption level of the distribution network equipment according to the evaluation model, compare the new energy consumption level with the access capacity, and optimize the distribution network according to the comparison result;

[0026] Among them, the optimization of the distribution network according to the comparison result includes:

[0027] If the access capacity is greater than the new energy consumption level, the distribution network needs to be optimized; otherwise, the distribution network does not need to be optimized;

[0028] Specifically, as Figure 3 shown, according to the declaration of the user, obtain the access capacity and access position of the new energy in the distribution network in the future, then evaluate the new energy consumption level (referred to as the equipment consumption level) of the grid equipment in the distribution network based on the access position, and then compare the equipment consumption level with the future new energy capacity. If the future new energy capacity is greater than the equipment consumption level, the equipment needs to be optimized and transformed; otherwise, the equipment does not need to be optimized and transformed.

[0029] Among them, the distribution network equipment may include various equipment in the distribution network:

[0030] In an alternative implementation manner, the distribution network equipment includes a 10kV line;

[0031] The matching of the corresponding evaluation model based on the distribution network equipment and the evaluation of the new energy consumption level of the distribution network equipment according to the evaluation model include:

[0032] Respectively determine the new energy access capacity evaluation model corresponding to the 10kV line based on thermal stability check, short-circuit current, voltage deviation, and line loss;

[0033] Receive the respective constraint conditions corresponding to the thermal stability check, short-circuit current, voltage deviation, and line loss;

[0034] Determine the maximum new energy access capacity of the 10kV line according to the new energy access capacity evaluation model corresponding to the thermal stability check, short-circuit current, voltage deviation and line loss and its corresponding constraint conditions, and determine the new energy consumption level of the 10kV line according to the maximum new energy access capacity.

[0035] Among them, the new energy access capacity evaluation model and constraint conditions corresponding to the thermal stability check are respectively:

[0036]

[0037]

[0038] λ max ≤80%

[0039] In the formula, λ represents the reverse load rate, P D represents the output of the distributed power source, P L represents the equivalent power consumption load at the same time, that is, the load minus the output of other power sources except the output of the distributed power source. represents the new energy access capacity of the 10kV line determined based on the thermal stability check, λ max represents the maximum value of the reverse load rate λ after excluding the reverse load rate λ in special periods during the evaluation period, S e represents the rated capacity of the 10kV line, K r represents the operation margin coefficient of the 10kV line. The operation margin coefficient can be set according to the actual application scenario. In this embodiment, it is taken as 0.8;

[0040] The new energy access capacity evaluation model and constraint conditions corresponding to the short-circuit current are respectively:

[0041] Increase the new energy access capacity of the distribution network with a preset step length. During the increase process, calculate the three-phase short-circuit current of the connection point of the distributed power source and the nodes related to the connection point in real time. When the short-circuit current of any node reaches the short-circuit current upper limit value, determine the new energy access capacity of the 10kV line determined based on the voltage deviation as the new energy access capacity at this time

[0042] Specifically, after the distributed new energy power source is connected to the distribution network, it will cause the short-circuit current to increase. Continuously increase the access capacity of the distributed new energy power source, and calculate the short-circuit current in the distribution network according to the following principle. When the short-circuit current of a certain node reaches the upper limit, obtain the new energy access capacity of this line

[0043] The short-circuit calculation of the distributed power access system shall follow the following principles:

[0044] a) Under the maximum operating mode of the distributed power source, calculate the three-phase short-circuit current at the connection point of the distributed power source and the nodes related to the connection point. When necessary, it is advisable to calculate the single-phase short-circuit current;

[0045] b) The short-circuit current provided by the distributed converter-type power generation system is calculated according to 1.5 times the rated current; the short-circuit current I provided by the distributed synchronous motor and induction motor-type power generation system G is calculated according to the following formula:

[0046]

[0047] In the formula, U n represents the reference voltage at the outlet of the synchronous motor or induction motor-type power generation system; X d ″ represents the direct-axis subtransient impedance of the synchronous motor or induction motor.

[0048] The new energy access capacity evaluation model and constraint conditions corresponding to the voltage deviation are respectively:

[0049] Increase the new energy access capacity connected to the distribution network in a preset step. During the increase process, calculate the voltage of each node of the 10kV line in real time. When the voltage of any node in the 10kV line reaches the voltage upper limit value, determine the new energy access capacity connected at this time as the new energy access capacity of the 10kV line determined based on the voltage deviation

[0050] Specifically, after the distributed new energy power source is connected to the distribution network, it will cause the voltage at the connection point to rise. Continuously increase the access capacity of the distributed new energy power source, and use the power flow calculation method to calculate the voltage of each connection point in the distribution network. When the voltage of a certain node reaches the voltage upper limit, obtain the new energy access capacity of this line

[0051]

[0052] Among them, represents the voltage of each node after connecting the new energy, V imax is the voltage upper limit value of each node;

[0053] The new energy access capacity evaluation model and constraint conditions corresponding to the line loss are respectively:

[0054]

[0055]

[0056] P l≤P e

[0057] In the above formula, after the distributed power source is connected to the distribution network, it will cause the line loss to increase. Continuously increase the installed capacity of the distributed power source, and use the power flow calculation method to calculate the line loss. When the overall line loss rate reaches the limit value, the new energy capacity Φ that can be added to this line is obtained l4 :

[0058] Among them, (ΔP loss %)Φ l4 represents the line loss rate when the distributed access capacity is Φ l4 , Φ l4 represents the new energy access capacity of the 10kV line determined based on the line loss, I i represents the current amplitude of the i-th branch, r i represents the resistance of the i-th branch, L represents the set of branches, P l represents the original supply power value of the 10kV line, P e represents the rated supply power value of the 10kV line, (ΔP loss %) max represents the maximum specified value of the line loss rate;

[0059] Among them, determining the maximum new energy access capacity of the 10kV line according to the new energy access capacity evaluation model corresponding to the thermal stability check, short-circuit current, voltage deviation and line loss and its corresponding constraint conditions includes:

[0060] Determine according to the constraint conditions corresponding to the thermal stability check, short-circuit current, voltage deviation and line loss and Φ l4 respective maximum values;

[0061] Determine and Φ l4 the minimum value among the respective maximum values, and determine the minimum value as the maximum new energy access capacity of the 10kV line;

[0062] In this embodiment, for the 10kV line, considering 4 constraint indicators including thermal stability check, short-circuit current, voltage deviation, and line loss, the peak value of the new energy access capacity is obtained, so as to evaluate the maximum new energy access capacity corresponding to the 10kV line. Considering multiple factors and constructing the corresponding evaluation model and constraint conditions ensure the accuracy of the evaluated new energy consumption level of the 10kV line;

[0063] As Figure 4 shown, the following is the specific process for evaluating the new energy consumption level of the distribution network equipment when the distribution network equipment is a 10kV line:

[0064] 1) The circuit is connected to a new energy power source, and the new energy access type at the input location is received, such as photovoltaic, wind power, and biomass energy;

[0065] 2) The new energy access method and access location at the setting location are received. The access methods include distributed or centralized access;

[0066] 3) The input line parameters are received to construct a grid model. Among them, the line parameters include: a, the rated current value of the distributed power source; b, the actual line parameters: line length l, wire diameter area S, bus voltage V0, line average load rate β, load power factor α, and distribution transformer connection capacity Sn;

[0067] 4) Select whether there is reverse power flow in the power grid. If there is reverse power flow, set λ max = 0.8; if there is no reverse power flow, set λ max = 0;

[0068] 5) Under the constraint conditions of thermal stability check, calculate the maximum new energy access capacity

[0069] 6) Under the constraint conditions of short-circuit current, calculate the maximum new energy access capacity

[0070] 7) Under the constraint conditions of voltage deviation, calculate the maximum new energy access capacity

[0071] 8) Set the system line loss rate index value and calculate the maximum new energy access capacity

[0072] 9) Take the minimum value of the calculated above as the maximum new energy access capacity F that meets the constraint conditions max .

[0073] In another alternative implementation, the distribution network equipment includes a low-voltage feeder;

[0074] Matching the corresponding evaluation model based on the distribution network equipment, and evaluating the new energy consumption level of the distribution network equipment according to the evaluation model includes:

[0075] Respectively determine the new energy access capacity evaluation model corresponding to the low-voltage feeder based on thermal stability check, three-phase unbalance degree, and voltage deviation;

[0076] Receive the constraint conditions corresponding to the thermal stability check, three-phase unbalance degree, and voltage deviation respectively;

[0077] Determine the maximum new - energy access capacity of the low - voltage feeder according to the new - energy access capacity evaluation model corresponding to the thermal stability check, three - phase unbalance degree, and voltage deviation, and its corresponding constraint conditions, and determine the new - energy consumption level of the low - voltage feeder according to the maximum new - energy access capacity;

[0078] Among them, the new - energy access capacity evaluation model and constraint conditions corresponding to the thermal stability check are respectively:

[0079]

[0080]

[0081] λ maX ≤80%

[0082] In the formula, λ represents the reverse load rate, P D represents the output of the distributed power source, P L represents the equivalent power consumption load at the same time, that is, the load minus the output of other power sources except the output of the distributed power source, represents the new - energy access capacity of the low - voltage feeder determined based on the thermal stability check, λmax represents the maximum value of the reverse load rate λ after excluding the reverse load rate λ in special periods during the evaluation period, S e represents the rated capacity of the 10kV line, K r represents the operation margin coefficient of the 10kV line. The operation margin coefficient can be set according to the actual application scenario. In this embodiment, it takes 0.8;

[0083] The new - energy access capacity evaluation model and constraint conditions corresponding to the three - phase unbalance degree are respectively:

[0084] Increase the new - energy access capacity connected to the distribution network with a preset step length. During the increase process, calculate the three - phase unbalance degree α in real - time:

[0085]

[0086]

[0087] 0≤α≤15%

[0088] In the formula, I 1 and I 2 respectively represent the root - mean - square values of the positive and negative sequence components of the three - phase current, norm() represents the 2 - norm function for parsing vectors, I a 、I b 、I c respectively represent the vector values of the three - phase current after new - energy access, a = e j120 ,P lmRepresents the original power of the corresponding phase of the three-phase line, P 0 Represents the new energy output power, V m Represents the voltage of the corresponding phase of the three-phase line. Each three-phase unbalance degree α corresponds to a new energy access capacity Φ l6 ;

[0089] Among them, single-phase access will reduce the current of a certain phase line. After three-phase access, the three-phase currents will all decrease, resulting in a change in the current unbalance degree. As the new energy access capacity increases, the line current value becomes smaller, thus exacerbating the three-phase current unbalance degree of the line. It can be seen that single-phase access has a greater impact on the three-phase unbalance degree than three-phase access. Therefore, by gradually increasing the new energy access capacity and observing the corresponding three-phase unbalance degree, the new energy access capacity corresponding to the three-phase unbalance degree constraint can be determined;

[0090] Increase the new energy access capacity of the distribution network with a preset step. During the increase process, calculate the voltage of each node of the low-voltage feeder in real time. When the voltage of any node in the low-voltage feeder reaches the voltage upper limit value, determine the new energy access capacity of the low-voltage feeder determined based on the voltage deviation as the new energy access capacity Φ of the low-voltage feeder at this time l7 ;

[0091] Among them, determining the maximum new energy access capacity of the low-voltage feeder according to the new energy access capacity evaluation model corresponding to the thermal stability check, three-phase unbalance degree and voltage deviation and its corresponding constraint conditions includes:

[0092] Determine according to the constraint conditions corresponding to the thermal stability check, three-phase unbalance degree and voltage deviation Φ l6 and Ф l7 Respective maximum values;

[0093] Determine Ф l6 and Ф l7 The minimum value among the respective maximum values, and determine the minimum value as the maximum new energy access capacity of the low-voltage feeder;

[0094] In this embodiment, for the low-voltage feeder, considering the three constraint indexes of thermal stability check, three-phase unbalance and voltage deviation, the peak value of the new energy access capacity is obtained, so as to evaluate the maximum new energy access capacity corresponding to the low-voltage feeder. Considering various factors and constructing the corresponding evaluation model and constraint conditions ensure the accuracy of the evaluated new energy consumption level of the low-voltage feeder.

[0095] As Figure 5 shown, the following is the specific process for evaluating the new energy consumption level of the distribution network equipment when the distribution network equipment is a low-voltage feeder:

[0096] 1) Connect new energy power sources to the low-voltage substation lines, and select the types of new energy access, such as photovoltaic, wind power, and biomass energy;

[0097] 2) Set the new energy access method and access location, and select distributed or centralized access;

[0098] 3) Receive the input relevant calculation parameters: the length l of the low-voltage line, the wire diameter area S, the low-voltage side bus voltage V0, the average load rate β of the low-voltage side, the load power factor α, the average access user capacity Sn, and the phase A, B, and C current values on the low-voltage side of the substation area;

[0099] 4) Calculate the maximum new energy access capacity under the constraint conditions of thermal stability check

[0100] 5) Select single-phase or three-phase access;

[0101] 6) Calculate the initial three-phase current unbalance degree;

[0102] 7) Calculate the maximum new energy access capacity under the constraint of single-phase / three-phase unbalance degree

[0103] 8) Calculate the maximum new energy access capacity under the constraint of voltage not exceeding the limit

[0104] 9) Take the minimum value of the and calculated previously, which is the maximum capacity F of the new energy power source access that meets the constraint conditions max .

[0105] In another alternative implementation, the distribution network equipment includes a distribution transformer, and the new energy consumption level of the distribution transformer is calculated according to the rated capacity of the distribution transformer.

[0106] For the case where the new energy consumption capacity of the distribution network equipment does not meet the requirements, it is necessary to optimize and transform the distribution network equipment. The specific optimization methods include building new distribution network equipment, transforming distribution network equipment, flexible interconnection of lines, flexible interconnection of distribution transformers, building energy storage facilities, etc.;

[0107] Among them, for the case where the new energy consumption capacity of the upper-level 35kV and 110kV voltage-level distribution networks is sufficient, the 10kV distribution network can improve its new energy consumption capacity by building or transforming existing lines and distribution transformers. When the conventional model equipment can meet the consumption demand, the consumption capacity of the equipment can be improved by transforming and upgrading the original equipment. When the conventional model equipment cannot meet the demand, a new step-up transformer or line can be built to improve the new energy consumption capacity;

[0108] For areas with sufficient new energy consumption capacity in adjacent substations or lines, flexible interconnections between substations and between lines can be built to balance the local new energy consumption capacity;

[0109] For scenarios with a small consumption gap and a low coupling degree between new energy output and load, grid-side energy storage facilities can be built to improve the new energy consumption capacity;

[0110] In an optional implementation, when optimizing the distribution network, factors such as the new energy consumption capacity of the superior grid, the new energy consumption capacity of adjacent substations, and the cost of building energy storage facilities can be comprehensively considered to carry out specific optimization measures. Specifically:

[0111] Such as Figure 6 shown, the optimization of the distribution network includes:

[0112] When the new energy consumption capacity of the 10kV distribution transformer / line is insufficient, a plan for configuring energy storage facilities in the distribution network is formulated and added to the alternative plan library. Specifically, energy storage facilities can be configured on the low-voltage side of the distribution transformer or in the 10kV line to assist in consumption;

[0113] Judge whether the new energy consumption capacity of the adjacent substations or lines of the distribution network is greater than a first preset value. This first preset value is used to determine whether the new energy consumption capacity of the adjacent substations or new lines of the distribution network is sufficient and can be set according to the actual application scenario. If it is greater than the first preset value, a plan for building a flexible interconnection device is formulated and added to the alternative plan library. By building a flexible interconnection device in the distribution network, consumption can be carried out in adjacent substations or lines;

[0114] If it is less than or equal to the first preset value, judge whether the new energy carrying capacity of the superior grid of the distribution network is greater than a second preset value. This second preset value is used to determine whether the new energy carrying capacity of the distribution network is sufficient and can be set according to the actual application scenario. If it is less than or equal to the second preset value, a plan for building a new outgoing line to connect to a higher-level grid for consumption is formulated and added to the alternative plan library;

[0115] If it is greater than the second preset value, judge whether the 10kV grid equipment is reversely overloaded. If not, a plan for the new energy to be fed back through the distribution transformer or line to connect to the superior grid for consumption is formulated and added to the alternative plan library. If so, a plan for transforming the distribution transformer or line to overcome the reverse overload is formulated and added to the alternative plan library, and a plan for building a new distribution transformer or line to overcome the reverse overload is formulated and added to the alternative plan library;

[0116] Calculate the economic benefits of each solution in the alternative solution library, and select the solution with the optimal economic benefits to optimize the distribution network;

[0117] In this embodiment, when the new energy consumption capacity of the distribution network equipment is insufficient, for the scenario where multiple measures can be applied to solve the new energy consumption problem, through economic analysis, select the solution with low cost and high income to upgrade and optimize the distribution network, ensuring cost reduction and income increase while optimizing.

[0118] In another alternative embodiment, as Figure 2 shown, an optimization terminal for new energy access to the distribution network includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements each step in the optimization method for new energy access to the distribution network in each of the above embodiments.

[0119] In summary, for an optimization method and terminal for new energy access to the distribution network provided by the present invention, after new energy is accessed to the distribution network, first determine its access position and corresponding access capacity in the distribution network, then determine the corresponding distribution network equipment in the distribution network according to the access position, match the corresponding evaluation model based on the distribution network equipment, evaluate the new energy consumption level of the distribution network equipment according to the evaluation model, and then optimize the distribution network by comparing the evaluated new energy consumption level with the new energy access capacity. Through the matching of the new energy access position, the distribution network equipment corresponding to the access position, and the evaluation model corresponding to the distribution network equipment, the accurate evaluation of the new energy consumption level of the distribution network equipment is realized, thus ensuring the correctness of the determined distribution network equipment with potential problems, and further improving the optimization effect of the distribution network after new energy access. The distribution network equipment includes 10kV lines, low-voltage feeders, distribution transformers, etc., and has good applicability. At the same time, when optimizing the distribution network, for the scenario where multiple measures can be applied to solve the new energy consumption problem, comprehensively consider the costs and benefits of various optimization transformation solutions, and select the solution with low cost and high income to upgrade and optimize the distribution network, further improving the optimization effect of the distribution network.

[0120] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent transformation made using the content of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An optimization method for new energy access to the distribution network, characterized in that, it includes the steps of: S1. Determine the access location and corresponding access capacity of the new energy to be accessed in the distribution network; S2. Determine the corresponding distribution network equipment in the distribution network according to the access location, and match the corresponding evaluation model based on the distribution network equipment; S3. Evaluate the new energy consumption level of the distribution network equipment according to the evaluation model, compare the new energy consumption level with the access capacity, and optimize the distribution network according to the comparison result; The distribution network equipment includes 10kV lines or low-voltage feeders; When the distribution network equipment includes 10kV lines, matching the corresponding evaluation model based on the distribution network equipment, and evaluating the new energy consumption level of the distribution network equipment according to the evaluation model includes: Respectively determine the new energy access capacity evaluation model corresponding to the 10kV line based on thermal stability check, short-circuit current, voltage deviation and line loss; Receive the constraint conditions corresponding to thermal stability check, short-circuit current, voltage deviation and line loss respectively; Determine the maximum new energy access capacity of the 10kV line according to the new energy access capacity evaluation model corresponding to thermal stability check, short-circuit current, voltage deviation and line loss and its corresponding constraint conditions, and determine the new energy consumption level of the 10kV line according to the maximum new energy access capacity; When the distribution network equipment includes low-voltage feeders, matching the corresponding evaluation model based on the distribution network equipment, and evaluating the new energy consumption level of the distribution network equipment according to the evaluation model includes: Respectively determine the new energy access capacity evaluation model corresponding to the low-voltage feeder based on thermal stability check, three-phase unbalance degree and voltage deviation; Receive the constraint conditions corresponding to thermal stability check, three-phase unbalance degree and voltage deviation respectively; Determine the maximum new energy access capacity of the low-voltage feeder according to the new energy access capacity evaluation model corresponding to thermal stability check, three-phase unbalance degree and voltage deviation and its corresponding constraint conditions, and determine the new energy consumption level of the low-voltage feeder according to the maximum new energy access capacity; Optimizing the distribution network according to the comparison result includes: If the access capacity is greater than the new energy consumption level, the distribution network needs to be optimized, otherwise, the distribution network does not need to be optimized; Optimizing the distribution network includes: Formulate a plan for configuring energy storage facilities in the distribution network, and add this plan to the alternative plan library; Judge whether the new energy consumption capacity of the adjacent substations or lines of the distribution network is greater than a first preset value. This first preset value is used to determine whether the new energy consumption capacity of the adjacent substations or new lines of the distribution network is sufficient, and is set according to the actual application scenario. If it is greater than the first preset value, formulate a plan for building a flexible interconnection device, and add this plan to the alternative plan library; If it is less than or equal to the first preset value, judge whether the new energy carrying capacity of the superior grid of the distribution network is greater than a second preset value. This second preset value is used to determine whether the new energy carrying capacity of the distribution network is sufficient, and is set according to the actual application scenario. If it is less than or equal to the second preset value, then formulate a plan for building a new outgoing line to access a higher-level grid for consumption, and add this plan to the alternative plan library; If it is greater than the second preset value, determine whether the 10 kV grid equipment is reversely overloaded. If not, formulate a plan for new energy to be fed back through a distribution transformer or line to be connected to the superior grid for consumption, and add this plan to the alternative plan library. If so, formulate a plan to transform the distribution transformer or line to overcome the reverse overload, and add this plan to the alternative plan library, and formulate a plan to build a new distribution transformer or line to overcome the reverse overload, and add this plan to the alternative plan library; Calculate the economic benefits of each plan in the alternative plan library, and select the plan with the best economic benefits to optimize the distribution network.

2. A method for optimizing the access of new energy to a distribution network according to claim 1, characterized in that, characterized in that, The new energy access capacity evaluation model and constraint conditions corresponding to the thermal stability check are respectively: λ max ≤80% Where λ represents the reverse load rate, P D represents the output of distributed power sources, P L represents the equivalent power consumption load at the same time, that is, the load minus the output of other power sources except the output of distributed power sources, represents the new energy access capacity of the 10kV line determined based on the thermal stability check, λ max represents the maximum value of the reverse load rate λ after excluding the reverse load rate λ in special periods during the evaluation period, S e represents the rated capacity of the 10kV line, K r represents the operating margin coefficient of the 10kV line; The new energy access capacity evaluation model and constraint conditions corresponding to the short-circuit current are respectively: Increase the new energy access capacity of the access distribution network with a preset step size. During the increase process, calculate the three-phase short-circuit current of the connection point of the distributed power source and the nodes related to the connection point in real time. When the short-circuit current of any node reaches the upper limit value of the short-circuit current, determine the new energy access capacity connected at this time as the new energy access capacity of the 10kV line determined based on the voltage deviation. The new energy access capacity evaluation model and constraint conditions corresponding to the voltage deviation are respectively: Increase the new energy access capacity of the access distribution network with a preset step. During the increase process, calculate the voltage of each node on the 10kV line in real time. When the voltage of any node on the 10kV line reaches the voltage upper limit value, determine the new energy access capacity connected at this time as the new energy access capacity of the 10kV line determined based on the voltage deviation The new energy access capacity evaluation model and constraint conditions corresponding to the line loss are respectively: P l ≤P e Wherein, represents the distributed access capacity as Φ l4 when the line loss rate of the line represents the line loss rate of the line, Φ l4 represents the new energy access capacity of the 10kV line determined based on the line damage, I i represents the current amplitude of the i-th branch, r i represents the resistance of the i-th branch, L represents the set of branches, P l represents the original supply power value of the 10kV line, P e represents the rated supply power value of the 10kV line, (ΔP loss %) max represents the maximum specified value of the line loss rate.

3. A method for optimizing the access of new energy to a distribution network according to claim 2, characterized in that, Determining the maximum new energy access capacity of the 10 kV line according to the new energy access capacity evaluation models corresponding to the thermal stability check, short-circuit current, voltage deviation and line loss and their corresponding constraint conditions includes: Determine according to the constraint conditions corresponding to the thermal stability check, short-circuit current, voltage deviation, and line loss and Φ l4 their respective maximum values; Determine and Φ l4 the minimum value among their respective maximum values, and determine the minimum value as the maximum new energy access capacity of the 10 kV line.

4. A method for optimizing the access of new energy to a distribution network according to claim 1, characterized in that, The new energy access capacity evaluation model and constraint conditions corresponding to the three-phase unbalance are respectively: Increase the new energy access capacity of the distribution network in a preset step. During the increase process, calculate the three-phase unbalance α in real time: 0≤α≤15％ Wherein, I 1 and I 2 respectively represent the root mean square values of the positive and negative sequence components of the three-phase current, norm() represents the 2-norm function for parsing vectors, Ia, Ib, and Ic respectively represent the vector values of the three-phase current after the new energy is connected, α = e j120 , P lm represents the original power of the corresponding phase of the three-phase line, P 0 represents the new energy output power, V m represents the voltage of the corresponding phase of the three-phase line, and each three-phase unbalance degree α corresponds to a new energy access capacity Φ l6 ; Increase the new energy access capacity of the access distribution network with a preset step. During the increase process, calculate the voltage of each node of the low-voltage feeder in real time. When the voltage of any node in the low-voltage feeder reaches the voltage upper limit value, determine the new energy access capacity connected at this time as the new energy access capacity Φ of the low-voltage feeder determined based on the voltage deviation l7 .

5. A method for optimizing the access of new energy to a distribution network according to claim 4, characterized in that, Determining the maximum new energy access capacity of the low-voltage feeder according to the new energy access capacity evaluation models corresponding to the thermal stability check, three-phase unbalance and voltage deviation and their corresponding constraint conditions includes: Determine according to the constraint conditions corresponding to the thermal stability check, three-phase unbalance degree, and voltage deviation and Φ l6 and Φ l7 their respective maximum values, indicating the new energy access capacity of the low-voltage feeder determined based on the thermal stability check; Determine Φ l6 and Φ l7 the minimum value among their respective maximum values, and determine the minimum value as the maximum new energy access capacity of the low-voltage feeder.

6. An optimization terminal for new energy access to a distribution network, including a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it realizes each step in the method for optimizing the access of new energy to a distribution network according to any one of claims 1 to 5.

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