A method and system for optimizing the capacity of distribution network equipment and the selection and configuration of line types

Abstract

The present invention relates to the technical field of power system optimization, and proposes an optimization method and system for the capacity of distribution network equipment and the selection and configuration of lines, including the following steps: collecting distribution network grid data, historical operation data, and equipment information available for planning and selection; establishing a life cycle cost calculation model; determining the planning scope for the selection of distribution network equipment and lines; based on the collected distribution network grid data, historical operation data, and equipment information available for planning and selection, performing scheme traversal and matching within the said planning scope to generate a number of configuration schemes; inputting all the configuration schemes into the life cycle cost calculation model, calculating the life cycle costs of each configuration scheme, and selecting the configuration scheme with the minimum life cycle cost as the optimal configuration scheme for output. The present invention realizes the purpose of taking into account the long-term economy and safety of distribution network planning through the life cycle cost model and considering the safety of load growth.

Description

Technical Field

[0001] The present invention relates to the technical field of power system optimization, and more specifically, to an optimization method and system for the capacity of distribution network equipment and the selection and configuration of line types. Background Art

[0002] With the continuous development of various industries at present, the expansion of industrial scale has brought greater electricity demand. There are certain power supply and demand imbalance problems in some original distribution networks. Therefore, the demand for distribution network expansion and capacity increase is also increasing. How to coordinate and balance the economy and security on the grid side during the distribution network planning process is an important research direction.

[0003] Currently, the existing intelligent distribution network planning methods input the underlying data and planning parameters, and after operations such as load forecasting, substation planning, grid framework planning, and reactive power planning, summarize the optimization results to obtain multiple feasible planning schemes, and then evaluate from the aspects of economy and reliability from the list of feasible planning schemes, and output the best distribution network planning scheme. It can be seen that the traditional distribution network planning methods generally adopt rough planning means, make plans based on the minimum equipment investment cost, lack the consideration of various costs in the long-term operation of the distribution network, and at the same time lack the consideration of the impact of future load growth on the security of the distribution network. Summary of the Invention

[0004] The present invention aims to overcome the defect of lacking the consideration of various costs in the long-term operation of the distribution network during the distribution network planning process, and provides an optimization method and system for the capacity of distribution network equipment and the selection and configuration of line types.

[0005] To solve the above technical problems, the technical solution of the present invention is as follows:

[0006] An optimization method for the capacity of distribution network equipment and the selection and configuration of line types, comprising the following steps:

[0007] Collect the distribution network grid data, historical operation data, and equipment information available for planning selection;

[0008] Establish a life cycle cost calculation model;

[0009] Determine the planning scope for the selection of distribution network equipment and line types;

[0010] Based on the collected distribution network grid data, historical operation data, and equipment information available for planning selection, perform scheme traversal and matching within the planning scope to generate a number of configuration schemes;

[0011] Input all the configuration schemes into the life cycle cost calculation model, calculate the life cycle costs of each configuration scheme, and select the configuration scheme with the minimum life cycle cost as the optimal configuration scheme for output.

[0012] In this technical solution, the life cycle cost calculation model fully considers the cost expenditures in all aspects of the distribution network operation, and the obtained configuration plan can achieve the optimal comprehensive economy.

[0013] As an optimal solution, the distribution network grid data includes the grid topology result, the length of each section of the grid line, and the impedance value of each section of the grid line; the historical operation data includes the load data of each node of the grid on the day of the highest historical load day of the distribution network; the equipment information available for planning selection includes the type of distribution transformer, the capacity of the distribution transformer, the construction cost of the distribution transformer, the line model, the unit impedance of the line, and the construction cost of the line.

[0014] As an optimal solution, the life cycle cost calculation model includes a distribution transformer life cycle cost model and a line life cycle cost model.

[0015] As an optimal solution, the distribution transformer life cycle cost model C T consists of the initial investment cost C I , the operation loss cost C W , the overhaul and maintenance cost C O , the fault cost C F , and the retirement and disposal cost C D , and its expression formula is as follows:

[0016] C T =C I +C W +C O +C F +C D

[0017] Among them, the initial investment cost C I includes the construction cost of the distribution transformer in the distribution network grid data;

[0018] The calculation formula of the operation loss cost C W is as follows:

[0019]

[0020] In the formula, r0 is the discount rate, c r is the comprehensive electricity price; is the average load loss of the distribution transformer in the i-th year, T is the operation life of the distribution transformer, and T t is the annual operation hours of the distribution transformer;

[0021] The calculation formula of the overhaul and maintenance cost C O is as follows:

[0022]

[0023] In the formula, c dx is the cost of a single major overhaul, cxx is the cost of single minor repair; H is the number of major repairs, and floor(·) represents the floor function; L T is the planning period;

[0024] The failure cost C F is calculated as follows:

[0025]

[0026] In the formula, c jx is the failure repair cost;

[0027] The decommissioning and disposal cost C D is calculated as follows:

[0028]

[0029] In the formula, c bf is the equipment scrapping cost, and c cz is the equipment residual value.

[0030] As an optimal solution, the whole life cycle cost model C of the line L consists of the initial investment cost C INV , the operation and maintenance cost C OM , the operation loss cost C LOSS , the power outage loss cost C P and the decommissioning and recycling cost C R , and its expression formula is as follows:

[0031] C L = C INV + C OM + C LOSS + C P + C R

[0032] Among them, the initial investment cost C INV is calculated as follows:

[0033] C INV = c L L

[0034] In the formula, L is the line length, and c L is the line cost per unit length;

[0035] The operation and maintenance cost C OM is calculated as follows:

[0036] C OM = λ om C INV

[0037] In the formula, λom is the operation and maintenance cost coefficient of the line;

[0038] The operating loss cost C LOSS has the following calculation formula:

[0039]

[0040] In the formula, r0 is the discount rate, and c r is the comprehensive electricity price; is the average load loss of the line in the i-th year, T is the operation life of the line, and T t is the annual operating hours of the line;

[0041] The power outage loss cost C P has the following calculation formula:

[0042]

[0043] In the formula, is the average value of the system power outage compliance in the y-th year, and t f is the average annual power outage time of the system, and p g is the power purchase price of the upper-level power grid; n L is the service life of the line;

[0044] The retirement and recovery cost C R consists of the line scrapping cost and the residual value of the line equipment.

[0045] As an optimal solution, the planning scope includes the distribution network node number, the line number, and the planning period T L .

[0046] As an optimal solution, the steps for selecting the optimal configuration solution include:

[0047] Traverse all configuration solutions, and calculate the life cycle cost of each configuration solution through the life cycle cost calculation model;

[0048] According to the planning period T L perform load growth prediction, and its calculation formula is as follows:

[0049]

[0050] In the formula, P1(t) represents the predicted operating load at the t-th moment on the highest load day in the T L -th year; P0(t) represents the operating load at the t-th moment on the historical highest load day, and η is the annual load growth rate;

[0051] Predict the load of each node at each moment and perform power flow calculation. Based on the power flow calculation results at each moment, perform safety judgment. If the current configuration plan meets the preset safety constraints, it is included in the list of optional plans; if it does not meet the preset safety constraints, the current configuration plan is eliminated;

[0052] Take the configuration plan with the minimum life cycle cost from the list of optional plans as the optimal configuration plan for output.

[0053] As an optimal plan, the safety constraints include node voltage constraints and line current constraints, and their expression formulas are as follows:

[0054] U min ≤U i (t)≤U max

[0055] I(t)≤I max

[0056] In the formula, U max and U min are the upper and lower limits of the safety voltage respectively; I max is the line carrying capacity; U i (t) represents the voltage of the i-th node at time t; I(t) represents the line current at time t.

[0057] As an optimal plan, during the load growth prediction calculation process, the following steps are also included: perform optimization and solution with the goal of minimizing the daily load variance after regulation using the current configuration plan, and use the fmincon optimization solver to optimize the load curve to obtain the optimized load curve; perform load growth prediction based on the planning period T L and the optimized load curve.

[0058] Furthermore, the present invention also proposes a distribution network equipment capacity and line selection configuration optimization system, which applies the distribution network equipment capacity and line selection configuration optimization method proposed in any of the above technical solutions, and includes a data acquisition module, a plan configuration module, a life cycle cost calculation module, and an optimization module.

[0059] Among them, the data acquisition module is used to collect distribution network grid data, historical operation data, and equipment information available for planning selection; the plan configuration module is used to perform plan traversal and matching based on the collected distribution network grid data, historical operation data, and equipment information available for planning selection within a preset planning scope, and output several configuration plans; the life cycle cost calculation module is used to calculate the life cycle cost of the configuration plan; the optimization module is used to optimize the input configuration plan and take the configuration plan with the minimum life cycle cost as the optimal configuration plan for output.

[0060] Compared with the prior art, the beneficial effect of the technical solution of the present invention is that the present invention achieves the purpose of balancing long-term economy and safety in distribution network planning by comprehensively outputting the optimal planning solution of distribution network equipment capacity and line selection through a full life cycle cost model and taking into account the safety of load growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a flow chart of the method for optimizing the capacity and line selection configuration of distribution network equipment in Example 1.

[0062] Figure 2 Flow chart of the configuration scheme optimization steps of Example 2.

[0063] Figure 3 This is the simulation distribution network topology diagram of Example 3.

[0064] Figure 4 This is a load curve diagram of each planning node on the highest load day of Example 3.

[0065] Figure 5 This is a flow chart for optimizing the load growth prediction calculation of Example 4.

[0066] Figure 6 This is an architecture diagram of the distribution network equipment capacity and line selection configuration optimization system of Example 5. DETAILED DESCRIPTION

[0067] The drawings are for illustrative purposes only and should not be construed as limiting the present patent;

[0068] It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0069] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0070] Example 1

[0071] This embodiment proposes a method for optimizing the capacity and line selection configuration of distribution network equipment, such as Figure 1 , which is a flow chart of the method for optimizing the capacity and line selection configuration of distribution network equipment in this embodiment.

[0072] The method for optimizing the capacity and line selection configuration of distribution network equipment proposed in this embodiment includes the following steps:

[0073] S1. Collect distribution network data, historical operation data and equipment information available for planning and selection.

[0074] S2. Establish a full life cycle cost calculation model.

[0075] S3. Determine the planning scope of distribution network equipment and line selection;

[0076] S4. Based on the collected distribution network data, historical operation data and equipment information available for planning and selection, a plan traversal and matching is performed based on the planning scope to generate several configuration plans;

[0077] S5. Input all configuration schemes into the life cycle cost calculation model, calculate the life cycle cost of each configuration scheme, and select the configuration scheme with the smallest life cycle cost as the optimal configuration scheme for output.

[0078] In the specific implementation process, the collected distribution network grid data includes grid topology results, the length of each section of the grid line and the impedance value of each section of the grid line. The collected historical operation data includes the load data of each node of the grid on the day of the highest load in the history of the distribution network. The collected equipment information available for planning selection includes distribution transformer type, distribution transformer capacity, distribution transformer construction cost, line model, line unit impedance and line construction cost.

[0079] According to the above data collected and the planning scope of distribution network equipment and line selection, determine which nodes and lines of the distribution network have distribution transformer planning requirements, traverse and match the solutions for the planning scope, and obtain a configuration solution including the target distribution transformer type, capacity and target line model. Then input all configuration solutions into the life cycle cost calculation model, calculate the life cycle cost of each configuration solution, and select the configuration solution with the smallest life cycle cost as the optimal configuration solution output.

[0080] This embodiment uses a full life cycle cost model and considers the safety of load growth to comprehensively output the optimal planning scheme for distribution network equipment capacity and line selection, thereby achieving the goal of balancing long-term economy and safety in distribution network planning.

[0081] Example 2

[0082] This embodiment provides a method for optimizing the capacity and line selection configuration of distribution network equipment, which includes the following steps:

[0083] S1. Collect distribution network data, historical operation data and equipment information available for planning and selection.

[0084] In this embodiment, the collected distribution network grid data includes grid topology results, the length of each grid line section and the impedance value of each grid line section. The collected historical operation data includes the load data of each node of the grid on the day of the highest load in the history of the distribution network. The collected equipment information available for planning selection includes distribution transformer type, distribution transformer capacity, distribution transformer construction cost, line model, line unit impedance and line construction cost.

[0085] S2. Establish a full life cycle cost calculation model.

[0086] The life - cycle cost calculation model in this embodiment includes a distribution transformer life - cycle cost model and a line life - cycle cost model. Among them, the distribution transformer life - cycle cost model C T consists of the initial investment cost C I , the operation loss cost C W , the overhaul and maintenance cost C O , the fault cost C F and the retirement and disposal cost C D .

[0087] The expression formula of the distribution transformer life - cycle cost model C T in this embodiment is as follows:

[0088] C T = C I + C W + C O + C F + C D .

[0089] Among them, the initial investment cost C I is the distribution transformer construction cost in the distribution network grid data.

[0090] The calculation formula of the operation loss cost C W is as follows:

[0091]

[0092] In the formula, r0 is the discount rate, c r is the comprehensive electricity price; is the average load loss of the distribution transformer in the i - th year, T is the operation life of the distribution transformer, T t is the annual operation hours of the distribution transformer.

[0093] Considering that generally, after a distribution transformer is put into operation, a minor overhaul is carried out once a year, a major overhaul is carried out in the 5th year, and then a major overhaul is carried out every 10 years. The calculation formula of the overhaul and maintenance cost C O in this embodiment is as follows:

[0094]

[0095] In the formula, c dx is the cost of a single major overhaul, which accounts for about 0.06 of the initial investment cost C I ; c xx is the cost of a single minor overhaul, which accounts for about 0.015 of the initial investment cost C I ; H is the number of major overhauls, floor(·) represents the floor function; L T is the planning period.

[0096] The fault cost CF The calculation formula is as follows:

[0097]

[0098] In the formula, c jx is the cost of fault repair, accounting for about 0.03 of the initial investment cost C I of 0.03.

[0099] The decommissioning disposal cost C D The calculation formula is as follows:

[0100]

[0101] In the formula, c bf is the equipment scrapping cost, the initial investment cost C I of 0.32; c cz is the equipment salvage value, accounting for about 0.05 of the initial investment cost C I of 0.05.

[0102] And the life cycle cost model C of the line in this embodiment L consists of the initial investment cost C INV , the operation and maintenance cost C OM , the operation loss cost C LOSS , the power outage loss cost C P and the decommissioning recovery cost C R . The life cycle cost model C of the line L The expression formula is as follows:

[0103] C L = C INV + C OM + C LOSS + C P + C R .

[0104] Among them, the calculation formula of the initial investment cost C INV is as follows:

[0105] C INV = c L L

[0106] In the formula, L is the line length, c L is the line cost per unit length.

[0107] The calculation formula of the operation and maintenance cost C OM is as follows:

[0108] C OM = λ om C INV

[0109] In the formula, λom It is the operation and maintenance cost coefficient of the line, which is set to 0.03 in this embodiment.

[0110] The operating loss cost C LOSS is calculated as follows:

[0111]

[0112] In the formula, r0 is the discount rate, and c r is the comprehensive electricity price; is the average load loss of the line in the i-th year, T is the operating life of the line, and T t is the annual operating hours of the line.

[0113] The power outage loss cost C P is calculated as follows:

[0114]

[0115] In the formula, is the average system power outage compliance in the y-th year, and t f is the average annual power outage time of the system, and p g is the power purchase price of the upper-level power grid; n L is the service life of the line.

[0116] The decommissioning and recycling cost C R consists of the line scrapping cost and the residual value of the line equipment. In this embodiment, the line scrapping cost is taken as 0.1 of the initial investment cost C INV of.

[0117] S3. Determine the planning scope of the distribution network equipment and line selection.

[0118] The planning scope determined in this embodiment includes the distribution network node numbers, line numbers, and planning period T L . That is, determine which nodes and which lines in the distribution network have the distribution transformer planning requirements.

[0119] S4. Based on the collected distribution network grid data, historical operation data, and equipment information available for planning, perform scheme traversal and matching based on the planning scope to generate several configuration schemes.

[0120] S5. Input all the configuration schemes into the full life cycle cost calculation model, calculate the full life cycle costs of each configuration scheme, and select the configuration scheme with the minimum full life cycle cost as the optimal configuration scheme for output.

[0121] The specific steps are as follows:

[0122] S5.1. Traverse all configuration schemes and calculate their life cycle costs for each configuration scheme through the life cycle cost calculation model.

[0123] S5.2. According to the planned time limit T L Conduct load growth prediction, and its calculation formula is as follows:

[0124]

[0125] In the formula, P1(t) represents the predicted operating load at the t-th moment on the highest load day in the T-th L year; P0(t) represents the operating load at the t-th moment on the historical highest load day, and η is the annual load growth rate.

[0126] S5.3. Predict the load at each moment for each node and conduct power flow calculation. According to the power flow calculation results at each moment, conduct safety judgment. If the current configuration scheme meets the preset safety constraints, list it in the optional scheme list; if it does not meet the preset safety constraints, eliminate the current configuration scheme.

[0127] Among them, the safety constraints include node voltage constraints and line current constraints, and their expression formulas are as follows:

[0128] U min ≤U i (t)≤U max

[0129] I(t)≤I max

[0130] In the formula, U max and U min are the upper and lower limits of the safety voltage respectively; I max is the line carrying capacity; U i (t) represents the voltage of the i-th node at the t-th moment; I(t) represents the line current at the t-th moment.

[0131] S5.4. Take the configuration scheme with the minimum life cycle cost from the optional scheme list as the optimal configuration scheme for output.

[0132] As Figure 2 shown, it is the flowchart of the configuration scheme optimization steps in this embodiment. In this step, the load at each moment for each node is predicted, and the predicted load is substituted into the power flow calculation. The safety of the power flow calculation results at each moment is judged to ensure that the voltages of each node and the line currents do not exceed the limits, so as to obtain the optional schemes, and then the configuration scheme with the minimum life cycle cost is selected as the optimal scheme for output. While ensuring the optimal comprehensive economy of the configuration scheme, it fully considers the impact of future load growth on the operation safety of the distribution network, so that the safety of the configuration scheme in long-term application is better guaranteed.

[0133] Example 3

[0134] This example applies the optimization method for the capacity of distribution network equipment and the selection and configuration of line types proposed in Example 2, and uses the general model of a 10 kV radial distribution network as a simulation example. As Figure 3 shown, it is the simulation distribution network topology diagram of this example.

[0135] Among them, the planning scope of this example is: the types and capacities of the distribution transformer equipment at nodes 4, 7, 10, 14, and 21, and the selection of the three lines of 1-10, 3-14, and 9-21. The planning years are taken as four gradients of 3, 5, 8, and 10 years. The data information of the distribution transformer equipment and lines is shown in Table 1 below.

[0136] Table 1 Data Information of Distribution Transformer Equipment and Lines

[0137]

[0138] In this example, the line length between two adjacent nodes is 0.5 km, the annual load growth rate is 5%, the discount rate is 10%, the comprehensive electricity price is 0.2 yuan / kWh, the line model of non-planned lines is LGJ-240, and the upper and lower limits of the safe operating voltage are 406 V and 342 V respectively. And the load curves of each planned node on the highest load day of this example are as Figure 4 shown.

[0139] According to the optimization method for the capacity of distribution network equipment and the selection and configuration of line types proposed in Example 2, the optimal planning schemes for this simulation scenario under different planning years can be obtained as shown in Table 2 below.

[0140] Table 2 Optimal Planning Schemes for the Simulation Scenario

[0141]

[0142] When the economic consideration period is relatively short, such as the planning economy in the range of 3 and 5 years, at this time, the construction cost of the distribution transformer is the main economic consideration factor. On the premise of ensuring normal power supply for regional electric vehicle charging and other loads, a distribution transformer with a relatively small capacity should be selected as much as possible, that is, the recommended capacity value is relatively small, and an oil-type transformer with a relatively low construction cost should be selected for assembly as much as possible. When the economic consideration period is relatively long, such as the planning economy in the range of 8 and 10 years, at this time, the equipment maintenance cost is the main economic consideration factor. Dry-type transformers with higher safety performance should be used as much as possible in the region. Although their initial construction cost is generally higher than that of oil-type transformers, from the perspective of long-term development, their economy is better than that of oil-type transformers. The overall planning scheme given takes into account the long-term economy and safety of the power grid, thus verifying the feasibility of the method proposed in the present invention.

[0143] Example 4

[0144] Based on the optimization method for the capacity of distribution network equipment and line selection configuration proposed in Embodiment 2, this embodiment further optimizes the load growth prediction calculation process. As Figure 5 shown, it is the flowchart of the optimization of the load growth prediction calculation in this embodiment.

[0145] During the load growth prediction calculation process of this embodiment, the following steps are further included:

[0146] First, input relevant parameters, including the data of the integrated distribution network grid, historical operation data, and equipment information available for planning selection, etc.

[0147] Taking the minimum daily load variance after regulation using the current configuration plan as the objective for optimization solution, and using the fmincon optimization solver to optimize the load curve to obtain the optimized load curve.

[0148] According to the planning period T L and the optimized load curve, conduct load growth prediction.

[0149] Specifically, according to the planning period T L conduct load growth prediction, and its calculation formula is as follows:

[0150]

[0151] In the formula, P1(t) represents the predicted operating load at the t-th moment on the highest load day in the T-th L year; P0(t) represents the operating load at the t-th moment on the historical highest load day, and η is the annual load growth rate.

[0152] Predict the load at each moment for each node and conduct power flow calculation. According to the power flow calculation results at each moment, conduct safety judgment. If the current configuration plan meets the preset safety constraints, it is included in the list of optional plans; if it does not meet the preset safety constraints, the current configuration plan is eliminated. Finally, select the configuration plan with the minimum life cycle cost from the list of optional plans as the optimal configuration plan for output.

[0153] This embodiment fully considers the impact of future load growth on the operation safety of the distribution network, and the planning plan has better guarantee in terms of long-term application safety.

[0154] Embodiment 5

[0155] This embodiment proposes an optimization system for the capacity of distribution network equipment and line selection configuration, which applies the optimization method for the capacity of distribution network equipment and line selection configuration described in Embodiment 1, 2 or 4. As Figure 6 shown, it is the architecture diagram of the optimization system for the capacity of distribution network equipment and line selection configuration in this embodiment.

[0156] In the optimized system for the capacity of distribution network equipment and line selection and configuration proposed in this embodiment, it includes:

[0157] A data acquisition module 1, which is used to acquire the distribution network grid data, historical operation data, and equipment information available for planning selection;

[0158] A scheme configuration module 2, which is used to perform scheme traversal and matching based on the acquired distribution network grid data, historical operation data, and equipment information available for planning selection within a preset planning scope, and output several configuration schemes;

[0159] A life cycle cost calculation module 3, which is used to calculate the life cycle cost of the configuration scheme;

[0160] An optimization module 4, which is used to optimize the input configuration scheme and output the configuration scheme with the minimum life cycle cost as the optimal configuration scheme.

[0161] In the specific implementation process, the data acquisition module 1 acquires the distribution network grid data, historical operation data, and equipment information available for planning selection. Specifically, the acquired distribution network grid data includes the grid topology result, the length of each section of the grid line, and the impedance value of each section of the grid line. The acquired historical operation data includes the load data of each node of the grid on the day of the highest historical load day of the distribution network. The acquired equipment information available for planning selection includes the distribution transformer type, distribution transformer capacity, distribution transformer construction cost, line model, unit impedance of the line, and line construction cost.

[0162] The data acquisition module 1 transmits the acquired data to the scheme configuration module 2. The scheme configuration module 2 performs scheme traversal and matching based on the received acquired data within a preset planning scope, and outputs several configuration schemes.

[0163] The configuration schemes output by the scheme configuration module 2 are used by the life cycle cost calculation module 3 to calculate the life cycle cost of each configuration scheme.

[0164] The optimization module 4 optimizes the configuration schemes output by the scheme configuration module 2.

[0165] During the optimization process, optionally, by traversing all configuration schemes, load growth prediction is performed according to the planning period T L Load prediction is performed for each node at each moment and power flow calculation is carried out. Safety judgment is performed according to the power flow calculation results at each moment, and the configuration schemes that meet the preset safety constraints are retained. Finally, the configuration scheme with the minimum life cycle cost is selected as the optimal configuration scheme for output.

[0166] The same or similar reference numerals correspond to the same or similar components;

[0167] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or alterations can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. An optimization method for the capacity of distribution network equipment and the selection and configuration of line types, characterized in that It includes the following steps: Collect the distribution network grid data, historical operation data, and equipment information available for planning selection; Establish a life cycle cost calculation model; the life cycle cost calculation model includes a distribution transformer life cycle cost model and a line life cycle cost model; the distribution transformer life cycle cost model C T consists of the initial investment cost C I , the operation loss cost C W , the overhaul and maintenance cost C O , the fault cost C F and the retirement and disposal cost C D ; the line life cycle cost model C L consists of the initial investment cost C INV , the operation and maintenance cost C OM , the operation loss cost C LOSS , the power outage loss cost C P and the retirement and recovery cost C R ; Determine the planning scope for the selection of distribution network equipment and lines; Based on the collected distribution network grid data, historical operation data, and equipment information available for planning selection, perform scheme traversal and matching within the said planning scope to generate several configuration schemes; Input all the configuration schemes into the full life cycle cost calculation model, calculate the full life cycle costs of each configuration scheme, and select the configuration scheme with the minimum full life cycle cost as the optimal configuration scheme for output; which includes the following steps: Traverse all the configuration schemes, and calculate the full life cycle cost of each configuration scheme through the full life cycle cost calculation model; Take the minimum daily load variance after regulation using the current configuration scheme as the objective for optimization and solution, and use the fmincon optimization solver to optimize the load curve to obtain the optimized load curve; perform load growth prediction based on the planning period TL and the optimized load curve; Predict the load at each moment of each node and perform power flow calculation, and conduct safety judgment based on the power flow calculation results at each moment. If the current configuration scheme meets the preset safety constraints, include it in the optional scheme list; if it does not meet the preset safety constraints, eliminate the current configuration scheme; Select the configuration scheme with the minimum full life cycle cost from the optional scheme list as the optimal configuration scheme for output.

2. The optimization method for the capacity of distribution network equipment and line selection and configuration according to claim 1, wherein The said distribution network grid data includes the grid topology results, the lengths of each section of the grid lines, and the impedance values of each section of the grid lines; the historical operation data includes the load data of each node of the grid on the day of the highest historical load day of the distribution network; the equipment information available for planning selection includes the distribution transformer type, distribution transformer capacity, distribution transformer construction cost, line model, line unit impedance, and line construction cost.

3. The optimization method for the capacity of distribution network equipment and line selection and configuration according to claim 1, characterized in that, The distribution transformer life cycle cost model C T consists of the initial investment cost C I , the operation loss cost C W , the overhaul and maintenance cost C O , the fault cost C F and the retirement and disposal cost C D and its expression formula is as follows: C T = C I + C W + C O + C F + C D Among them, the initial investment cost C I includes the construction cost of distribution transformers in the distribution network grid data; The operating loss cost C W has the following calculation formula: where \(r_0\) is the discount rate and \(c\) r is the comprehensive electricity price; is the average load loss of the distribution transformer in the \(i\)-th year, \(T\) is the operating life of the distribution transformer, and \(T\) t is the annual operating hours of the distribution transformer; The overhaul and maintenance cost C O has the following calculation formula: where c dx is the cost of a single major overhaul, and c xx is the cost of a single minor repair; H is the number of major overhauls, and floor(·) represents the floor function; L T is the planning period; The failure cost C F has the following calculation formula: where c jx is the troubleshooting cost; The decommissioning disposal cost C D has the following calculation formula: where c bf is the equipment scrapping cost, and c cz is the equipment residual value.

4. The optimization method for the capacity of distribution network equipment and line selection and configuration according to claim 1, characterized in that The full life cycle cost model C of the line L consists of the initial investment cost C INV , the operation and maintenance cost C OM , the operation loss cost C LOSS , the power outage loss cost C P and the decommissioning and recycling cost C R and its expression formula is as follows: C L = C INV + C OM + C LOSS + C P + C R Among them, the initial investment cost C INV has the following calculation formula: C INV = c L L where L is the line length, and c L is the line cost per unit length; The operating and maintenance cost C OM has the following calculation formula: C OM = λ om C INV where λ om is the operation and maintenance cost coefficient of the line; The operating loss cost C LOSS has the following calculation formula: where \(r_0\) is the discount rate and \(c\) r is the comprehensive electricity price; is the average load loss of the line in the \(i\)-th year, \(T\) is the operation life of the line, and \(T\) t is the annual operating hours of the line; The power outage loss cost C P has the following calculation formula: In the formula, is the average value of the system power outage compliance in the y-th year, and t f is the average annual power outage time of the system, and p g is the electricity purchase price of the upper-level power grid; n L is the service life of the line; The decommissioning and recycling cost C R consists of the line scrapping cost and the residual value of line equipment.

5. The optimized method for the capacity of distribution network equipment and line selection and configuration according to claim 1, characterized in that The planning scope includes the distribution network node numbers, line numbers, and the planning period T L .

6. The method for optimizing the capacity of distribution network equipment and the configuration of line selection according to claim 5, wherein, According to the planning period T L Carry out load growth prediction, and its calculation formula is as follows: Wherein, P1(t) represents the predicted operating load at the t-th moment on the day with the highest load in the T-th year; P0(t) represents the operating load at the t-th moment on the historical highest load day, and η is the annual load growth rate. L ​ 7. The optimization method for the capacity of distribution network equipment and line selection and configuration according to claim 1, wherein The said safety constraints include node voltage constraints and line current constraints, and their expression formulas are as follows: U min ≤U i (t)≤U max I(t) ≤ I max Where, U max and U min are respectively the upper limit and the lower limit of the safety voltage; I max is the line current-carrying capacity; U i (t) represents the voltage of the i-th node at time t; I(t) represents the line current at time t.

8. A distribution network equipment capacity and line selection configuration optimization system, which is applied to the distribution network equipment capacity and line selection configuration optimization method according to any one of claims 1 to 7, and is characterized in that, It includes: A data collection module for collecting the distribution network grid data, historical operation data, and equipment information available for planning selection; A scheme configuration module for performing scheme traversal and matching based on the collected distribution network grid data, historical operation data, and equipment information available for planning selection within the preset planning scope and outputting several configuration schemes; A full life cycle cost calculation module for calculating the full life cycle cost of the configuration scheme; An optimization module for optimizing the input configuration scheme and selecting the configuration scheme with the minimum full life cycle cost as the optimal configuration scheme for output.

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