CN112541618B - Grid-based active distribution network planning method and storage medium - Google Patents

Abstract

The invention discloses a grid-based active distribution network planning method and a storage medium. The method includes: dividing a preset planning area from small to large into unit plots, power supply units and power supply grids; Perform load forecasting in the area to obtain load forecasting results; perform capacity adjustment and site selection for substations according to the load forecasting results; perform grid analysis and grid evaluation for the planned area. The invention can provide data support and scientific basis for grid planning decision-making, realize precise planning, assist relevant technical personnel to make decisions, and achieve the purpose of improving work efficiency.

Description

Grid-based active distribution network planning method and storage medium

technical field

The invention relates to the technical field of active distribution networks, in particular to a grid-based active distribution network planning method and a storage medium.

Background technique

At present, the power grid development major has not applied geographic information technology to design the relevant power grid structure model, and the power grid models designed by other business departments are not completely suitable for the development major. In order to break through barriers such as different data standards and insufficient sharing of various business departments, how to design relevant power grid models to meet the needs of distribution network planning for hierarchical display of grid structures and display and analysis of related indicators is one of the key points and difficulties.

Power grid geographic information resources often only serve as a background kanban, without any association with power grid resources. In the power grid analysis, how to integrate the relevant information of the two sources according to the characteristics of the geographical resources and the power grid resources, and realize the new mode of integrated analysis and display of the two sources of the map and the network is one of the key points and difficulties.

In addition, traditional electrical calculation models and methods generally do not take into account the impact of more and more distributed power sources such as wind power and solar photovoltaic power generation in regional power grids. Taking the above factors into consideration, ensuring the scientificity and rationality of electrical calculations is one of the key points and difficulties.

The development level of the built distribution network, such as whether key indicators such as power supply reliability, voltage quality, frequency quality, and fault recovery time can support economic and social development, whether it can match the requirements of the new urbanization process, and whether it can meet the needs of the energy consumption revolution. The requirements of the power grid are an important criterion for judging whether the planning scheme is effective and reasonable. At the same time, the degree of matching between the target setting of the planning plan and the investment plan is also an important aspect to measure whether the planning plan is accurate and cost-effective. Therefore, how to select key indicators and evaluation models to evaluate whether the urban distribution network adopting new technology standards and new technologies can adapt to the needs of different urban industries and social development, and whether it is economical and efficient, is one of the key points and difficulties.

Contents of the invention

The technical problem to be solved by the present invention is to provide a grid-based active distribution network planning method and storage medium, which can realize precise planning and improve work efficiency.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a grid-based active distribution network planning method, including:

Divide the preset planning area into unit plots, power supply units and power supply grids in order from small to large;

performing load forecasting on the planning area to obtain a load forecasting result;

According to the load forecasting results, the constant capacity and site selection of substations are carried out;

Perform grid analysis and grid assessment for the planned area.

The present invention also proposes a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are realized.

The beneficial effect of the present invention is that it can realize active distribution network space load prediction, realize the determination of the location and capacity of the substation to be built in the target year and the middle year according to the space load prediction result, and realize multi-dimensional statistical analysis and topology analysis of the distribution network And wiring analysis, and complete further electrical calculation analysis. Based on the comprehensive analysis of the above data, it provides a scientific basis and effective support for the precise planning and efficient investment of the distribution network. The invention can provide data support and scientific basis for grid planning decision-making, realize accurate planning, assist relevant technical personnel to make decisions, and achieve the purpose of improving work efficiency.

Description of drawings

1 is a flowchart of a grid-based active distribution network planning method according to Embodiment 1 of the present invention;

2 is a schematic diagram of substation site selection in the planning area of an existing substation according to Embodiment 2 of the present invention;

Fig. 3 is a schematic diagram of substation site selection in a planned area without a substation in Embodiment 2 of the present invention.

detailed description

In order to describe the technical content, achieved goals and effects of the present invention in detail, the following will be described in detail in conjunction with the implementation and accompanying drawings.

Embodiment one

Please refer to Fig. 1, Embodiment 1 of the present invention is: a grid-based active distribution network planning method, which can be applied to active distribution network planning, including the following steps:

S1: Divide the preset planning area into unit plots, power supply units and power supply grids in order from small to large;

Specifically, according to the area corresponding to the county-level administrative region, the planning area is determined, that is, the jurisdiction area is divided into the county (district) unit to obtain the planning area; the planning area is divided into grids to obtain more than one power supply grid; respectively divide each power supply grid to obtain more than one power supply unit; divide each power supply unit respectively to obtain more than one unit plot.

S2: Perform load forecasting on the planning area to obtain a load forecasting result. The load forecasting includes long-term load forecasting and short-term load forecasting.

Among them, the perspective load forecasting is specifically:

S211: Collect functional land use index information in each unit plot respectively, where the functional land use index information includes large user information, distributed power source information, and multiple load information.

Among them, large user information includes: large user name, voltage level, installed capacity, commissioning time and historical maximum load; distributed power supply information includes: power supply name, voltage level, power supply category, capacity and commissioning time; multiple load information : Multi-load type, name, voltage level, storage capacity, peak power (capacity = peak power * time) and operation time.

S212: Calculate the saturated annual load of each unit plot respectively according to the functional land use index information.

Specifically, if there is a corresponding land planning map for a unit plot, the saturated annual load of the unit plot is calculated through the spatial load prediction method; if there is no corresponding land planning map for a unit plot, and the If the category of a unit plot is special land or water area or other land use, the saturation of the unit plot is calculated based on the number of users in the unit plot and the preset average maximum load typical value of the number of individual households. Annual load; if there is no corresponding land planning map for a unit plot and it belongs to a mature development area, the saturated annual load of the unit plot is calculated by the average growth rate method.

S213: Determine the saturated load value of the one-unit lot according to the maximum value of the historical annual maximum load and the saturated annual load in the large user information of the one-unit lot.

S214: According to the saturated load value of each unit plot in the power supply grid and the preset simultaneous rate, calculate the forecasted value of the long-term load of the power supply grid. Preferably, the default value of the simultaneous rate is 0.8, which can be modified according to the category of the unit plot.

Further, the long-range load prediction value of a power supply unit can also be calculated according to the saturated load value of each unit plot in a power supply unit and the preset simultaneous rate.

S215: Calculate and obtain the future annual load of the planning area according to the forecast value of the future load of each power supply grid.

The short and mid-term load forecasting is specifically:

S221: Collect the current year of the power supply grid and the basic data of the power grid in multiple historical years. The basic data of the power grid includes the distribution transformer of each unit plot, the maximum load information of the line and its corresponding time, and the load data of 8760 points of the line outlet switch ; Further, it also includes population, GDP, industry electricity consumption (including: agriculture, forestry, animal husbandry and fishery, industry, transportation, warehousing and postal industry, information transmission, software and information technology service industry, wholesale and retail industry, accommodation and catering industry , financial industry, real estate industry, leasing and business service industry, public service and management organization, others), industrial electricity consumption (including: primary industry, secondary industry, tertiary industry, electricity consumption for urban residents, electricity consumption for rural residents) Wait.

S222: Calculate the total social load of the region in the current year according to the basic data of the power grid in the current year.

S223: According to the total regional social load in the current year, and the ratio of the total load of a power supply grid in the saturated year to the total regional social load in the current year or the distribution transformer capacity of a power supply grid in the current year Calculate the current annual load of the power supply grid according to the ratio of the total distribution capacity of the power supply area in the current year.

In this step, two algorithms are proposed, which are the "top-down" proportional allocation algorithm based on the saturation year and the "top-down" proportional allocation method based on the distribution transformer capacity.

The calculation formula of the "top-down" proportional apportionment algorithm based on the saturation year is: the existing load of the grid = the total load of the whole society in the region × the proportion of the total load of the region that the grid accounts for in the saturation year.

The calculation formula based on the "top-down" proportional distribution method of distribution transformer capacity is: the existing load of the grid = the total load of the whole society in the region × the ratio of the current distribution transformer capacity of the grid to the total distribution transformer capacity of the region.

S224: Calculate the current annual load of the power supply area according to the current annual load of each power supply grid. That is, the current annual load of each power supply grid is accumulated to obtain the current annual load of the power supply area.

S225: According to the basic data of the power grid in each historical year, calculate the total load of the whole society in each historical year;

S226: Calculate the planning target annual load of the planning area through the short-to-medium-term load forecasting method according to the total load of the whole society in the current year and each historical year. The short-to-medium-term load forecasting method includes the average annual growth rate method, binary Regression method, ternary regression method, exponential growth method, S-curve model and large user method, also including unit consumption of output value, elastic coefficient, industrial power consumption method, industry power consumption method, maximum load utilization hours method, etc.

Wherein, the methods for calculating the total load of the whole society in the area in steps S222 and S225 include the "bottom-up" accumulation method based on the line load and the "bottom-up" accumulation method based on the distribution transformer.

Based on the line load "bottom-up" accumulation method, the specific value is that the data of all 10 kV lines belonging to the power supply grid are superimposed to take the maximum value after the data of 8,760 points are superimposed, and the data of 35 kV and above direct supply loads and distributed power sources need to be superimposed. The calculation formula It is: regional whole society load = regional 10kV network power supply line load + 10kV dedicated line load + 35kV and above direct supply load + 10kV grid-connected power output + low-voltage grid-connected power output + self-generated factory power. (equipment, line, power supply unit, grid) network power supply is directly accumulated, and the download power and upload power are calculated and stored separately.

Further, if a line crosses a power supply grid, the line belongs to which power supply grid the proportion of which is larger.

The "bottom-up" accumulation method based on the distribution transformer is specifically: the 8760 point data of the distribution transformer belonging to the power grid is superimposed and the maximum value is taken, and the 8760 point data is stored; it is necessary to superimpose the data of large power users and distributed power sources of 35kV and above. (equipment, line, power supply unit, grid) network power supply is directly accumulated, and the download power and upload power are calculated and stored separately.

S3: According to the load prediction result, the capacity and site selection of the substation are performed.

Firstly, the constant capacity of the substation is carried out, which specifically includes the following steps:

S311: Set the value range of the capacity-to-load ratio according to the preset planning area load growth rate. For example, if the load growth rate Kp≤7%, the capacity-to-load ratio ranges from 1.8-2.0; if 7%<Kp≤12%, the capacity-to-load ratio ranges from 1.9-2.1; if Kp>12%, Then the capacity-to-load ratio ranges from 2.0 to 2.2.

S312: Calculate the new capacity range according to the planning target annual load of the planning area, the value range of the capacity-to-load ratio and the existing capacity data.

Specifically, newly added capacity = planning target annual load * capacity-to-load ratio - existing capacity.

S313: Set a capacity-constant strategy, where the capacity-constant strategy is to deploy first or expand first. For fast-growing areas and mature and saturated areas, newly added points are the main points (difficult to set up points or quick returns); for areas with slow load growth and long-term investment returns that are difficult to recover, under the condition that the demand can be met, the expansion of the main transformer should be the main method .

S314: Determine the number and capacity of substations according to the capacity constant strategy, voltage level, and power supply area type.

Then select the location of the substation, specifically, for the planning area of the existing substation, determine the maximum power supply range of the existing substation in the planning area, and then eliminate the area of the maximum power supply range and the preset non-construction area in the planning area The area of the substation determines the site selection range of the substation; the geometric center point of the site selection range is used as a feasible distribution area.

For the planning area where the substation has not been built, the current load density of each power grid is calculated according to the current annual load and area of each power grid in the planning area; the current load density of the power grid is higher than the preset value. Topology identification to obtain the first center point; perform topology identification on all power supply grids in the planning area to obtain the second center point; use the midpoint of the connection line between the first center point and the second center point as a feasible distribution area ;

Finally, the address of the new substation is determined according to the feasible distribution area and the prospective annual load of the planning area.

S4: Perform grid analysis and grid evaluation on the planned area.

Specifically, grid statistics, grid topology analysis, wiring mode analysis, and auxiliary electrical calculations are performed on grids with a voltage level of 35kV and above in the planning area.

Among them, power grid statistics is to make statistics on the type, year, planning nature, etc. of power grid equipment, and view relevant information according to the statistical results. For example: for lines, statistical information includes line name, commissioning time, type (overhead, cable), starting power station, terminating power station, etc.

Power grid topology analysis is to analyze the grid structure of 35kV and above, find out the grid topology connection relationship and live range, prepare data for the identification of typical wiring methods, and give detailed analysis results.

Wiring mode analysis is to identify the wiring mode of 35kV and above grids, find out typical wiring modes such as radiation, chain, ring, T connection, π connection, etc., and give detailed analysis results.

Auxiliary electrical calculations include but are not limited to the following electrical calculations: (1) Power flow calculation; (2) Short circuit calculation; (3) N-1 pass rate calculation.

Further, grid statistics, grid topology analysis, wiring mode analysis, auxiliary electrical calculation and grid evaluation are also performed on grids with a voltage level of 10kV and below in the planning area.

Among them, the grid statistics are the same as above.

Grid topology analysis is to analyze the 10kV grid grid, find out the topological connection relationship and live range of the grid, and prepare data for typical wiring mode identification, backbone analysis, longest path analysis, topology island analysis, and segmental connection analysis. And give detailed analysis results.

Wiring mode analysis is to identify the wiring mode of the 10kV grid, find out the typical wiring mode of the overhead grid, cable network, and hybrid grid, and give detailed analysis results.

Auxiliary electrical calculations include but are not limited to the following electrical calculations: (1) Short circuit calculation; (2) N-1 pass rate calculation.

The indicators for power grid evaluation include comprehensive indicators, grid structure indicators, equipment level indicators, power supply capacity indicators, intelligent and green development indicators, and grid efficiency indicators.

Among them, the comprehensive indicators include the average power outage time per household, the comprehensive voltage qualification rate and the comprehensive line loss rate of 10kV and below. Grid structure indicators include the average power supply radius of 10kV lines, the average number of segments of 10kV overhead lines, the connection rate of 10kV lines, the connection rate between stations of 10kV lines, the N-1 pass rate of 10kV lines and the proportion of standardized wiring of 10kV lines. The equipment level indicators include the average service life of 10kV equipment in operation, the cable conversion rate of 10kV lines, the insulation rate of 10kV overhead lines, and the proportion of 10kV high-loss distribution transformers. Power supply capacity indicators include the average maximum load rate of 10kV lines, the proportion of 10kV heavy-duty lines, the average maximum load rate of 10kV distribution transformers, the proportion of 10kV heavy-duty distribution transformers, the installation capacity of 10kV lines and the unsafe load of 10kV lines. Intelligent and green development indicators include the coverage rate of distribution automation, the proportion of "three remote" terminals, the information collection rate of distribution transformers, the penetration rate of distributed power and the consumption rate of distributed power. Power grid efficiency indicators include unit investment to increase supply load and unit investment to increase sales of electricity.

This embodiment can realize active distribution network space load prediction, realize the location and capacity of substations to be built in the target year and intermediate years according to the space load prediction results, and realize multi-dimensional statistical analysis, topology analysis and wiring analysis of the distribution network. And complete further electrical calculation analysis. Based on the comprehensive analysis of the above data, it provides a scientific basis and effective support for the precise planning and efficient investment of the distribution network.

Embodiment two

This embodiment is a specific implementation scenario of the foregoing embodiments.

1. Grid planning business process

According to the characteristics of the online operation mode, follow the effective combination of problem-oriented and goal-oriented, establish a mode of hierarchical collaborative planning operations on the GIS map, and set up a three-layer management of "planning version-planning scheme-planning project" to realize regional The merging of planning versions, comparison and selection of different planning schemes, and unified management of planning projects can effectively strengthen the connection of planning at all levels and improve the integrity, coherence, and economy of grid planning. The preliminary business process is as follows:

1. Benchmark setting

Define the benchmark time of planning, generally take December 31st of each year as the time section, or take the power grid section at the end of the month before the start of the planning task as the benchmark map (the closer the time is to the current situation, the closer the grid topology relationship is to reality), and determine The authority of the authority can be clarified by the superior unit (State Grid, provincial and municipal companies).

2. Planning regional version management

The planning area version is created with the county (district) as the unit, and the division and drawing of the power supply area, power supply grid, power supply unit, and rural-urban network are carried out by the unit under the jurisdiction on the reference map. After the drawing is completed, it will be published. The version of the planning area can be modified according to the actual situation, and the new version can be modified on the basis of the released version.

3. Planning version creation

After completing the setting of the benchmark map and the release of the planning area version, for the normal planning work, the county (district) company will independently create the planning version of the next stage, and can create sub-versions according to actual needs, and each sub-version can be superimposed on each other, and the final Confirmed sub-versions are released, and the released sub-versions should have the merge function. For the unified release of planning tasks by higher-level units, the regulations of the higher-level units shall prevail.

4. Grid diagnosis

With the help of the diagnostic model, based on the typical daily data such as the maximum load day of the year where the planning reference time is located, combined with the list of problem databases collected during this time period, the diagnostic analysis of the power grid is carried out, and the list of problems such as dispatching and operation inspection is comprehensively considered. After the first review and confirmation, the confluence of the list of questions will be transferred to the question bank.

5. Load forecasting

Using the method of spatial load forecasting as the main method, the saturated load of the power supply grid and the annual load of each planning level are calculated step by step from bottom to top, and the division of the power supply grid is checked according to the predicted results of the saturated load. ) to be adjusted, the planning area version shall be revised.

6. Planning objectives

Import or manually draw the target network structure, set the planning target index value, and provide comparison standards for subsequent network structure planning and effectiveness analysis.

7. Create a plan

Take a single or multiple grids as a unit, screen out the list of problems existing in the grid area, combine the load forecasting requirements, associate the list of problems, consider a planning scheme that can solve multiple problems at the same time, and pay attention to the connection with the target grid , to create planning schemes for different solutions, and the same planning scheme can consist of one or several projects.

8. Comparison of economic and technical solutions

The different solutions to the problem are compared and selected by means of economic and technical methods, power flow calculations, and manual intervention.

9. Solidification of planning scheme

According to the comparison and selection results, a better planning scheme is determined, and the planning scheme is solidified. The projects in the planning scheme are automatically confirmed and transferred to the planning project library for management.

10. Planning version release

After completing the solidification of all the planning schemes of this version, merge the solidified planning schemes to form the stage planning version results, and release the version with the county (district) company as a unit, and each sub-version can be merged.

11. Planning results

Form a geographical wiring diagram of grid planning detailed to the grid in the first 3 years of planning with the county (district) as the unit, and make statistics on the scale of grid equipment and investment in the planning period, and the construction time sequence refined year by year in the first 3 years of the planning period.

2. Grid division

(1) Planning regional version management

The planning area version is created with the county (district) as the unit, and the division and drawing of the power supply area, power supply grid, and rural-urban network are carried out by the units under the jurisdiction on the reference map. After the drawing is completed, it will be published. The version of the planning area can be modified according to the actual situation, and the new version can be modified on the basis of the released version.

1. Planning regional version creation

The creation of the planning area version for the jurisdiction area in the unit of county (district) should include the name of the planning version, the area where the version is located, the time of creation, the creator and other information.

2. Planning area version drawing

The content of the planning area version should include the drawing of power supply area, power supply grid, power supply unit and urban-rural grid area, and set up three drawing modules of urban-rural grid, power supply area, and power supply grid.

3. Planning regional version release

After the drawing of the planning area version is completed, it will be confirmed and released after the review is completed.

4. Planning regional version update

According to actual needs, the published planning area version can be inherited, and modified, saved, and released on this basis.

(2) Planning version management

1. Planning version creation

According to the planning task, select the reference map and the planning area version of a certain time section, and on this basis, create the planning version for the jurisdiction area in units of counties (districts), which should include the name of the planning version, the area where the version is located, and the creation time , Creator and other information. After the planning version is created, a planning scheme can be created under this version.

2. Planning version release

A planning version consists of one or several planning schemes. After completing the preparation of all planning schemes in the planning area, check the confirmed planning schemes and release the planning version.

3. Planning version modification

According to actual needs, it can be modified and updated on the basis of the published planning version, and all planning schemes and the following planning items in any planning version can be viewed, and released after the modification is completed.

4. Plan version storage

All planning schemes in any planning version are stored, and new planning versions and planning schemes must not overwrite the original planning version and the planning schemes under it.

5. View the planning version

Permissions are set according to the jurisdictional area, and you can view the development of the grid planning version of the unit and its subordinate units.

3. Load Forecasting

Load forecasting is a task of estimating its future value based on the past and present of electric load. It is an important process link of grid planning and an important operation means to connect municipal control regulations and power demand balance. To carry out load forecasting in grid planning, it is first necessary to investigate and collect various data, including internal and external data of power companies, and data from relevant departments of the national economy, such as load, electricity, charging piles, distribution in the grid, etc. Type power supply data, historical annual data such as population, GDP, industrial electricity, and industrial electricity in the planning area, sorted out and screened for data analysis, combined with a variety of power demand forecast models, according to short-, medium-, and long-term planning goals, Carry out near-medium-term and long-term load forecasting work, and the forecast results can guide the development of related work such as site selection and capacity determination of substations.

(1) Long-term load forecasting

The functions of long-term load forecasting are mainly divided into: collection of functional land use indicators, load calculation per unit plot, parameter setting, and forecasting results and display; details are as follows.

1. Collection of functional land use indicators.

According to the government's land planning map, it is divided into unit plots, and the large user information, charging pile information, distributed power supply information and multi-load information in the unit plots are collected.

According to the scope of the planning area, the units are divided into: unit plots, power supply units, and power supply grids. The power supply grid is further upwards into county-level power supply areas, city-level power supply areas, and provincial-level power supply areas.

The collection content includes: land control planning information, large user information of the land, and distributed power supply information. Large user information includes: large user name, voltage level, installed capacity, commissioning time, and historical maximum load; distributed power supply information includes: power supply name, voltage level, power supply category, capacity, and commissioning time; multi-load information includes: Multiple load types, names, voltage levels, storage capacity, peak power (capacity = peak power * time), and commissioning time.

The display content of the unit plot includes: plot name, land type, power supply unit, power supply area type, land area, effective power supply area (default equal to land area, can be modified artificially), floor area ratio, building area, remarks (remarks It needs to be maintained when the land is controlled and used, and the remark information is mainly for the industry characteristics of large users and the description of annual power consumption).

The display content of the power supply unit includes: the name of the power supply unit, the power supply grid to which it belongs, the type of power supply area, the floor area, the effective power supply area, the building area, the floor area ratio, and the proportion of the main land types in the power supply unit (the first two with the larger ratio are displayed by default. ),Remark.

The display content of the power supply grid includes: the name of the power supply grid, the area it belongs to, the type of power supply area, the floor area, the effective power supply area, the building area, the floor area ratio, and the remarks.

Among them, floor area ratio = construction area / floor area. For areas with only general rules and no control rules, it is artificially determined according to the specific actual situation. If the value of the plot ratio given by the unit plot is within an interval range, the highest value is taken. The reference table of typical plot volume ratio is shown in Table 3.1.

Table 3.1: Reference table of plot ratio of typical plots

land use code Land use nature Volume rate G1 public lawn 0 M1 Industrial land 1.2 U21 public transport land 0.2 U12 Power supply land 0.5

2. Unit plot load calculation.

Integrate large users, charging piles, distributed power sources, and multiple load data in the unit plot, use the spatial load forecasting method to calculate the saturated annual load, provide basic data entry and maintenance functions, and support large users and charging piles in the unit plot , The modification of distributed power source data facilitates the modification of target annual load data.

The calculation method of the unit plot load is selected in three ways according to the type of the unit plot:

(1) Use the space load forecasting method to calculate the area of the existing land planning map; the calculation formula method is:

When the plot has only occupied area and no plot ratio, use the construction land density index to calculate the saturated load of the plot; when there is a simultaneous rate index, use the building density index to calculate the saturated load of the plot; the calculation formula is: : X ₁ = area * index;

Obtain the existing large user load of the plot, and calculate the reported large user load; the calculation formula is: X ₂ = reported installed capacity * load rate;

Calculate the maximum load of charging piles in the plot; the calculation formula is: X ₃ = number of slow-charging parking spaces * unit load + number of fast-charging parking spaces * unit load.

By superimposing the above three parts, the target value of the future load can be obtained, that is, y=X ₁ +X ₂ +k ₁ *X ₃ , where y is the target value of the future load, and k ₁ is the load of the charging pile and the saturated load of the plot The simultaneous rate coefficient of .

(2) For areas without a land planning map and belonging to categories D and E (category D is land for special use, such as military land, foreign affairs land, and security land; land for category E is water area and other land), the calculation shall be carried out according to the household average method; The calculation formula is: y=k ₂ *N, N is the number of users in the unit plot, k ₂ is the average maximum load of the unit number of households (given a typical value according to the local actual situation);

(3) For areas without land planning maps and mature development areas, the average growth rate method is used for calculation; the calculation formula is y=a*(1+k ₃ ) ⁿ , where a is the maximum area load in the planning base year, and n is the area The time required to reach saturation, k ₃ is the average value of recent load growth in mature areas.

3. Parameter setting.

(1) The load index of the unit plot of the long-term load forecasting index system is based on the standard document "Urban Power Planning GB/T 59023-2014" issued by the government, in the chapters of urban electricity load/load density index/planning unit construction land load index For the content of the load index range of various land uses, 5 initial values are given in order from small to large.

When using the construction land load density method for load forecasting, the construction land load indicators are shown in Table 3.2.

Table 3.2: Load indicators of construction land in planning units

Urban construction land category Unit construction land load index (kW/hm2) Residential land (R) 100～400 Land for commercial service facilities (B) 400～1200 Land for public management and public service facilities (A) 300～800 Industrial land (M) 200～800 Land for logistics and storage (W) 20～10 Land for roads and traffic facilities (S) 15～30 Land for public facilities (U) 150～250 Green space and square land (G) 10～30

The selection of construction land load indicators for other types of construction land other than the construction land in the table can be determined according to the specific conditions of the city where it is located.

When the unit building area load density index method is adopted, the building area load index is shown in Table 3.3.

Table 3.3: Planning Unit Floor Area Load Indicators

The selection of load density indicators for special land use and planned development reserve land can be determined in combination with local actual conditions and planned energy supply requirements, and determined according to local conditions.

When it comes to coal-to-electricity areas, it is recommended to appropriately increase the index value standard according to the actual local conditions.

(2) Calculation method of saturated load per unit plot: the saturated load per unit plot is taken as the larger value of the large user prediction value and the space load prediction value of the plot.

(3) Calculation method of long-term load forecasting: accumulation of saturated load value of power supply unit/unit plot of power supply grid*simultaneity rate. The simultaneity rate of the new area is given according to the typical value of the local industry; the simultaneity rate of the old urban area is the simultaneity rate of the existing industries. (At the same time, the default value is 0.8, which allows users to modify the plots individually or in batches. Except for mature areas, the rest are new types of areas. The current method is applicable to areas with land planning maps).

4. Prediction results and display.

The prediction result curve display interface can be divided according to the user's authority, and two display types are provided: table and curve. Refer to Table 3.4 for range size.

Table 3.4: Display scope corresponding to user permissions

The map interface is displayed in 2D in a style similar to a heat map.

Support a single power supply grid or power supply unit to display the forecast results in two ways: table and curve, and display the forecast result value of a single grid or unit on the GIS map, and you can circle the area to display the load forecast value of the area.

(2) Near and mid-term load forecasting

The functions of near and mid-term load forecasting are mainly divided into: grid basic data collection, historical data calculation, load forecasting method selection, forecasting results and display. The details are as follows.

1. Grid basic data collection.

It mainly includes: the distribution transformer in the unit plot (the distribution transformer in the power supply unit/power supply grid and the maximum load information of the line need to be obtained at the same time as its corresponding time), and the load data of 8760 points of the line outlet switch. Regional population, GDP, electricity consumption by industry (including: agriculture, forestry, animal husbandry and fishery, industry, transportation, warehousing and postal industry, information transmission, software and information technology service industry, wholesale and retail industry, accommodation and catering industry, financial industry industry, real estate industry, leasing and business service industry, public service and management organization, others), industrial electricity consumption (including: primary industry, secondary industry, tertiary industry, electricity consumption for urban residents, electricity consumption for rural residents), etc. The attribution of power grid equipment can be classified, filtered and aggregated according to the attributes of the unit plot/power supply unit/power supply grid.

2. Historical data calculation.

Relevant calculation methods include: "top-down" proportional apportionment method based on saturated years, "top-down" proportional apportionment method based on distribution transformer capacity, "bottom-up" accumulation method based on line load, and "automatic distribution method" based on distribution transformer load. Bottom-up” cumulative approach. The details are as follows.

(1) Based on the "top-down" proportional allocation algorithm in the saturation year: the existing load of the grid = the total load of the whole society in the region × the ratio of the grid's total regional load in the saturation year. The disadvantage of this algorithm is that for a mature saturated grid, the actual load ratio in the current year is relatively high, but the proportion of the grid load in the area may be low in the saturated year, resulting in a low proportion of the calculated current load value; For slow-growing regions, the proportion of actual load in the current year is relatively low, but the proportion of load in the saturated year may be relatively high, resulting in a relatively high proportion of the calculated current load value.

(2) Based on the "top-down" proportional allocation method of distribution transformer capacity: the existing load of the grid = the total load of the whole society in the region × the ratio of the current distribution transformer capacity of the grid to the total distribution transformer capacity of the region. The disadvantage of this algorithm is that due to the different load rates of distribution transformers, this method may have some errors.

(3) "Bottom-up" accumulation method based on line load: the maximum value is obtained after superimposition of 8,760 data points of all 10 kV lines belonging to the power supply unit or power grid; it is necessary to superimpose 35kV and above direct-supply loads and distributed power sources Data; calculation formula: Regional social load = regional 10kV network power supply line load + 10kV dedicated line load + 35kV and above direct supply load + 10kV grid-connected power supply output + low-voltage grid-connected power supply output + self-generated and self-consumed factory power. (equipment, line, power supply unit, grid) network power supply is directly accumulated, and the download power and upload power are calculated and stored separately.

Among them, each 10 kV line needs to add an attribute label to confirm the power supply grid or power supply unit to which it belongs. Through the distribution of line distribution transformer capacity, determine its ownership relationship (if the line crosses power supply units or power supply grids, whichever side has the largest proportion belongs to which side).

(4) Based on the “bottom-up” accumulative method of the distribution transformer: the distribution transformer belonging to the power supply unit or power supply grid has 8,760 points of data superimposed to take the maximum value, and the 8,760 points of data are stored; it is necessary to superimpose 35kV and above power supply large users, distribution format power data. (equipment, line, power supply unit, grid) network power supply is directly accumulated, and the download power and upload power are calculated and stored separately.

3. Selection of load forecasting method.

(1) Choose one or more of the mainstream calculation methods for averaging, including trend extrapolation (S-curve, average growth rate, binary regression, ternary regression, exponential growth), unit consumption of output value, elastic coefficient, industry Electricity consumption method, industrial electricity consumption method, maximum load utilization hours method, etc.

When a method is invalid for a certain prediction or the data is reliable, this method can not be selected. Different load forecasting methods are applicable to different scenarios, as shown in Table 3.5.

Table 3.5: Correspondence between load forecasting algorithm models and scenarios

2) Mixed load forecasting method: Since the mainstream algorithms have their own advantages and disadvantages, it is suggested that the load forecasting results of equipment or areas can be obtained by accumulating according to various forecasting results and given weights, and displayed graphically. The sum of the weights of multi-curve methods is 100%, and the weight ratio of each method is set by the planner.

4. Prediction results and display.

You can refer to the forecast results and display part in the above-mentioned long-term load forecast.

4. Site selection for fixed capacity of substation

(1) Constant capacity of substation

1. Collect the current year, planning target year, and future year load of the planning area, and the data comes from the load forecast results.

2. Refer to the "Technical Guidelines for Distribution Network Planning and Design" to plan the regional load growth rate, and set the value range of the capacity-load ratio, as shown in Table 4.1.

Table 4.1: 110kV～35kV grid capacity-load ratio selection range

Load growth slower growth medium growth Faster growth Average annual load growth rate Kp Kp≤7% 7%＜Kp≤12% Kp>12% 110kV～35kV grid capacity-load ratio (recommended value) 1.8～2.0 1.9～2.1 2.0～2.2

3. Obtain existing capacity data and calculate the upper and lower limits of new capacity

Newly added capacity = grid supply load in the planning year * capacity-to-load ratio - existing capacity.

4. Set optional options, choose to deploy first or expand first (for fast-growing areas and mature saturated areas, new deployment is the main method (difficult to deploy or quick returns); for areas with slow-growing loads in the early stages and long-term investment returns that are difficult to recover, in the Under the condition that the demand can be met, the expansion of the main transformer should be the main focus).

5. Determine the number and capacity of substations, and refer to Table 4.2 for details on setting options.

Table 4.2: Recommendation table for final capacity configuration of substations in different power supply areas

In Table 4.2, the low voltage side of the main transformer is 10kV. For the power supply area with a certain load, a small-capacity transformer can be used appropriately. 31.5MVA transformers (35kV) in Class A and B areas are suitable for the situation where the power source comes from a 220kV substation.

(2) Substation site selection

1. The selection method of the optimal station site (there are dotted areas), as shown in Figure 2.

1) Calculate the maximum 10 kV power supply radius of the substation in the planning area through the "load moment", and determine the maximum power supply range of the existing substation. The layout of the new substation should be outside this range. As the load increases, the range will gradually shrink.

2) Exclude types of land that cannot be used for construction of substations, including: lakes, roads, basic farmland, ecological protection areas, etc.

3) After eliminating the areas where substations cannot be built, the optimal location range of substations is narrowed down, and the geometric center point of the location range is selected in combination with boundary identification. Feasible layout areas or optimal layout suggestions are automatically given, and finally manual intervention determines the site selection.

2. The selection method of the optimal station site (starting area of development without distribution), as shown in Figure 3.

The above methods are not applicable to the initial development areas without substations. The area where the current load density is higher than a certain value can be used for topology identification to take the center point a, and the area for all unit plots can be used for topological identification to take the center point b, and the center of the line connecting a and b can be taken as the optimal point layout suggestion (taking into account Short-term and long-term load development), and finally manual intervention to determine the site selection.

Five, 35kV and above power grid analysis

(1) Grid statistics

Make statistics on the type, year, planning nature, etc. of power grid equipment, and view relevant information according to the statistical results. For example: for a line, the statistical information includes line name, commissioning time, starting power station, ending power station, etc.

(2) Grid topology analysis

Analyze the 35kV and above grids to find out the topological connection relationship and live range of the grids, prepare data for the identification of typical wiring methods, and give detailed analysis results.

(3) Analysis of wiring mode

Identify the wiring modes of 35kV and above grids, find out typical wiring modes such as radiation, chain, ring, T-connection, and π-connection, and give detailed analysis results.

(4) Auxiliary electrical calculation

Auxiliary electrical calculations include but are not limited to the following electrical calculations: (1) Power flow calculation; (2) Short circuit calculation; (3) N-1 pass rate calculation.

Six, 10kV and above power grid analysis

(1) Grid statistics

Make statistics on the type, year, planning nature, etc. of power grid equipment, and view relevant information according to the statistical results. For example: for lines, statistical information includes line name, commissioning time, type (overhead, cable), starting power station, terminating power station, etc.

(2) Grid topology analysis

Perform topology analysis on 10 (20, 6) kV grids, find out the topological connection relationship and live range of grids, and prepare data for typical wiring mode identification, backbone analysis, longest path analysis, topological island analysis, and segmental contact analysis , and give detailed analysis results.

(3) Analysis of wiring mode

Conduct wiring mode recognition on 10 (20, 6) kV grids, find out the typical wiring modes of overhead grids, cable networks, and hybrid grids, and give detailed analysis results.

(4) Auxiliary electrical calculation

Auxiliary electrical calculations include but are not limited to the following electrical calculations: (1) Short circuit calculation; (2) N-1 pass rate calculation.

(5) Grid assessment

(1) City, county (district) evaluation index system

It includes six aspects, including comprehensive indicators, grid structure indicators, equipment level indicators, power supply capacity indicators, intelligent and green development indicators, and grid efficiency indicators.

Among them, the comprehensive indicators include the average power outage time per household, the comprehensive voltage qualification rate and the comprehensive line loss rate of 10kV and below. Grid structure indicators include the average power supply radius of 10kV lines, the average number of segments of 10kV overhead lines, the connection rate of 10kV lines, the connection rate between stations of 10kV lines, the N-1 pass rate of 10kV lines and the proportion of standardized wiring of 10kV lines. The equipment level indicators include the average service life of 10kV equipment in operation, the cable conversion rate of 10kV lines, the insulation rate of 10kV overhead lines, and the proportion of 10kV high-loss distribution transformers. Power supply capacity indicators include the average maximum load rate of 10kV lines, the proportion of 10kV heavy-duty lines, the average maximum load rate of 10kV distribution transformers, the proportion of 10kV heavy-duty distribution transformers, the installation capacity of 10kV lines and the unsafe load of 10kV lines. Intelligent and green development indicators include the coverage rate of distribution automation, the proportion of "three remote" terminals, the information collection rate of distribution transformers, the penetration rate of distributed power and the consumption rate of distributed power. Power grid efficiency indicators include unit investment to increase supply load and unit investment to increase sales of electricity.

(2) Evaluation index system of distribution network power supply grid

It also includes six aspects, including comprehensive indicators, grid structure indicators, equipment level indicators, power supply capacity indicators, intelligent and green development indicators, and grid efficiency indicators.

Among them, the comprehensive index includes the average power outage time per household. Grid structure indicators include the average power supply radius of 10kV lines and the N-1 pass rate of 10kV lines. Equipment level indicators include 10kV line cable rate and 10kV overhead line insulation rate. Power supply capacity indicators include the proportion of 10kV heavy-duty lines, the proportion of 10kV heavy-duty distribution transformers, the installation capacity of 10kV lines and the unsafe load of 10kV lines. Intelligent and green development indicators include distribution automation coverage and distribution transformer information collection rate. Power grid efficiency indicators include unit investment to increase supply load.

This embodiment integrates power-related information system data to form a set of advanced, comprehensive and practical auxiliary tools for grid-based active distribution network planning auxiliary calculations, which can not only meet the needs of distribution network planning at all levels, but also It can also be extended to Class A and B areas such as the urban areas of six cities, providing data support and scientific basis for grid planning decisions, achieving precise planning, assisting relevant technical personnel in decision-making, and achieving the goal of improving work efficiency.

Embodiment Three

This embodiment is a computer-readable storage medium corresponding to the above-mentioned embodiments, on which a computer program is stored, and when the program is executed by a processor, the following steps are implemented:

Divide the preset planning area into unit plots, power supply units and power supply grids in order from small to large;

performing load forecasting on the planning area to obtain a load forecasting result;

According to the load forecasting results, the constant capacity and site selection of substations are carried out;

Perform grid analysis and grid assessment for the planned area.

Further, the preset planning area is divided into unit plots, power supply units and power supply grids in order from small to large; specifically:

Determine the planning area according to the area corresponding to the county-level administrative region;

performing grid division on the planning area to obtain more than one power supply grid;

Separately divide each power supply grid to obtain more than one power supply unit;

Each power supply unit is divided separately to obtain more than one unit plot.

Further, the load forecasting of the planning area is carried out, and the load forecasting result obtained is specifically:

Forecasting the future load of the planning area to obtain the future annual load of the planning area;

The near-medium-term load forecast is performed on the planning area to obtain the planning target annual load of the planning area and the current annual load of each power supply grid.

Further, the foresight load forecast of the planning area is carried out, and the foresight annual load of the planning area is specifically:

Separately collect the functional land use index information in each unit plot, the functional land use index information includes large user information, distributed power supply information and multiple load information;

Calculate the saturated annual load of each unit plot respectively according to the functional land use index information;

Determine the saturated load value of the unit plot according to the maximum historical annual load and the maximum value of the saturated annual load in the large user information of the unit plot;

According to the saturated load value of each unit plot in the power supply grid and the preset simultaneous rate, calculate the long-term load prediction value of the power supply grid;

The future annual load of the planning area is calculated according to the forecasted value of the future load of each power supply grid.

Further, according to the functional land use index information, the calculation of the saturated annual load of each unit plot is specifically:

If there is a corresponding land planning map for a unit plot, then calculate the saturated annual load of the unit plot through the spatial load prediction method;

If there is no corresponding land planning map for a unit plot, and the category of the unit plot is special land or water area and other land, then according to the number of users in the unit plot and the preset number of individual households The typical value of the highest average load in the future, calculate the saturated annual load of the one-unit plot;

If there is no corresponding land planning map for a unit plot and it belongs to a mature development area, the saturated annual load of the unit plot is calculated by the average growth rate method.

Further, the near-medium-term load forecast is performed on the planning area to obtain the planning target annual load of the planning area and the current annual load of each power supply grid.

Collect the current year of the power supply grid and the basic data of the power grid in multiple historical years. The basic data of the power grid includes the distribution transformer of each unit plot, the maximum load information of the line and its corresponding time, and the load data of 8760 points of the line outlet switch;

According to the basic data of the power grid in the current year, calculate the total load of the whole society in the current year;

According to the total load of the whole society in the current year, and the ratio of the total load of a power supply grid in the saturated year to the total load of the whole society in the current year or the distribution transformer capacity of a power grid in the current year accounts for the power supply in the current year The ratio of the total distribution capacity of the region in the present year, calculates the present annual load of the power supply grid;

Calculate the current annual load of the power supply area according to the current annual load of each power supply grid;

According to the basic data of the power grid in each historical year, calculate the total load of the whole society in each historical year;

According to the total load of the whole society in the current year and each historical year, the planned target annual load of the planning area is calculated through the near-medium-term load forecasting method, and the near-medium-term load forecasting method includes the average annual growth rate method and the binary regression method , ternary regression method, exponential growth method, S-curve model and large user method.

Further, the constant capacity of the substation is specifically

According to the preset planning area load growth rate, set the value range of capacity-load ratio;

Calculate the new capacity range according to the planning target annual load, capacity-load ratio value range and existing capacity data of the planning area;

Set the strategy of constant capacity, the strategy of constant capacity is to deploy first or expand first;

Determine the number and capacity of substations according to the capacity constant strategy, voltage level and power supply area type.

Further, the site selection of the substation is specifically as follows:

Determine whether there is a substation in the planning area;

If it already exists, determine the maximum power supply range of existing substations in the planning area;

Eliminate the areas with the largest power supply range and the preset areas where substations cannot be built in the planning area, and determine the site selection range of substations;

Taking the geometric center point of the site selection range as a feasible distribution area;

If it does not exist, then calculate the current load density of each power supply grid according to the current annual load and area of each power supply grid in the planning area;

Perform topology identification on the power supply grid whose current load density is higher than the preset value, and obtain the first central point;

Perform topology identification on all power supply grids in the planning area to obtain the second central point;

Taking the midpoint of the connection line between the first center point and the second center point as a feasible distribution area;

According to the feasible distribution area and the prospective annual load of the planning area, the address of the new substation is determined.

Further, the performing grid analysis and grid evaluation on the planning area is specifically:

Conduct grid statistics, grid topology analysis, wiring mode analysis, and auxiliary electrical calculations for grids with a voltage level of 35kV and above in the planning area;

Conduct grid statistics, grid topology analysis, wiring mode analysis, auxiliary electrical calculation and grid evaluation for grids with a voltage level of 10kV and below in the planning area.

In summary, the grid-based active distribution network planning method and storage medium provided by the present invention can realize the spatial load prediction of the active distribution network, and realize the determination of the target year and the intermediate year to be built according to the spatial load prediction results. The location and capacity of the substation realize the multi-dimensional statistical analysis, topology analysis and wiring analysis of the distribution network, and complete further electrical calculation and analysis. Based on the comprehensive analysis of the above data, it provides a scientific basis and effective support for the precise planning and efficient investment of the distribution network. The invention can provide data support and scientific basis for grid planning decision-making, realize accurate planning, assist relevant technical personnel to make decisions, and achieve the purpose of improving work efficiency.

The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent transformations made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in related technical fields, are all included in the same principle. Within the scope of patent protection of the present invention.

Claims (8)

1. An active power distribution network planning method based on gridding is characterized by comprising the following steps:

sequentially dividing a preset planning area into a unit plot, a power supply unit and a power supply grid from small to large;

carrying out load prediction on the planning area to obtain a load prediction result;

according to the load prediction result, carrying out constant volume and site selection on the transformer substation;

carrying out power grid analysis and power grid evaluation on the planning area;

the load prediction of the planned area is specifically as follows:

performing long-term load prediction on the planning area to obtain long-term load of the planning area;

performing near-medium term load prediction on the planning area to obtain a planning target annual load of the planning area and the current annual load of each power supply grid;

the site selection of the transformer substation is specifically as follows:

judging whether a transformer substation exists in the planned area or not;

if the maximum power supply range exists, determining the maximum power supply range of the existing transformer substation in the planning area;

removing the area of the maximum power supply range and a preset area where a transformer substation cannot be built in the planned area, and determining the site selection range of the transformer substation;

taking the geometric central point of the addressing range as a feasible point distribution area;

if the current year load and the current year load do not exist, calculating the current load density of each power supply grid according to the current year load and the current year area of each power supply grid in the planning area;

carrying out topology identification on the power supply grid with the current load density higher than a preset value to obtain a first central point;

carrying out topology identification on all power supply grids in the planned area to obtain a second central point;

taking the midpoint of the connecting line of the first central point and the second central point as a feasible point distribution area;

and determining the address of the newly-built substation according to the feasible stationing area and the perspective annual load of the planning area.

2. The active power distribution network planning method based on meshing of claim 1, wherein the preset planning area is divided into a unit plot, a power supply unit and a power supply grid from small to large; the method specifically comprises the following steps:

determining a planning area according to an area corresponding to a county-level administrative district;

gridding and dividing the planning area to obtain more than one power supply grid;

dividing each power supply grid respectively to obtain more than one power supply unit;

and dividing each power supply unit to obtain more than one unit block.

3. The active power distribution network planning method based on meshing of claim 1, wherein the perspective load prediction is performed on the planning region, and the perspective annual load of the planning region is obtained by:

respectively collecting functional land index information in each unit block, wherein the functional land index information comprises large user information, distributed power supply information and multi-element load information;

respectively calculating the saturation annual load of each unit plot according to the functional land index information;

determining a saturated load value of a unit plot according to the maximum value of historical annual maximum load and saturated annual load in the large user information of the unit plot;

calculating a distant view load predicted value of the power supply grid according to the saturated load value and a preset coincidence rate of each unit block in the power supply grid;

and calculating the long-term annual load of the planning area according to the long-term load predicted value of each power supply grid.

4. The active power distribution network planning method based on meshing of claim 3, wherein the calculating the saturation annual load of each unit plot according to the functional land use index information specifically comprises:

if a corresponding land planning map exists in a unit plot, calculating the saturation annual load of the unit plot by a space load prediction method;

if a unit plot does not have a corresponding land planning map and the category of the unit plot is a special land or a water area or other lands, calculating the saturation annual load of the unit plot according to the number of users in the unit plot and a preset single-user-number perspective average highest load typical value;

and if the unit plot does not have the corresponding land planning map and belongs to a mature development area, calculating the saturation annual load of the unit plot by using an average growth rate method.

5. The active power distribution network planning method based on meshing of claim 3, wherein the load prediction in the planning area in the near-middle period is performed to obtain a planning target annual load of the planning area and the current annual loads of the power supply grids specifically as follows:

collecting power grid basic data of a current year and a plurality of historical years of a power grid, wherein the power grid basic data comprise distribution transformer of each unit plot, maximum load information of a circuit and corresponding time of the maximum load information, and load data of a circuit outlet switch 8760 point;

calculating the total regional social load of the current year according to the power grid basic data of the current year;

calculating the current year load of a power supply grid according to the total regional social load of the current year, the proportion of the total load of the power supply grid in a saturated year to the total regional social load of the current year or the proportion of the distribution and transformation capacity of the power supply grid in the current year to the total distribution and transformation capacity of the power supply grid in the current year;

calculating the current annual load of the power supply area according to the current annual load of each power supply grid;

calculating the total regional social load of each historical year according to the basic data of the power grid of each historical year;

calculating the planned target annual load of the planned area through a near-middle period load forecasting method according to the total regional social load of the current year and each historical year, wherein the near-middle period load forecasting method comprises an annual average growth rate method, a binary regression method, a ternary regression method, an exponential growth method, an S curve model and a large user method.

6. The active power distribution network planning method based on meshing according to claim 5, wherein the volume determination of the transformer substation is specifically:

setting a value range of a capacity-to-load ratio according to a preset load acceleration rate of a planning area;

calculating a newly increased capacity range according to the planned target annual load, the capacity-to-load ratio value range and the existing capacity data of the planned area;

setting a constant volume strategy, wherein the constant volume strategy is point arrangement or expansion firstly;

and determining the number and the capacity of the transformer substations according to the constant volume strategy, the voltage grade and the type of the power supply area.

7. The active power distribution network planning method based on meshing of claim 1, wherein the grid analysis and grid evaluation of the planning area specifically comprises:

performing power grid statistics, power grid topology analysis, wiring mode analysis and auxiliary electrical calculation on the power grid with the voltage class of 35kV or more in the planned area;

and carrying out power grid statistics, power grid topology analysis, wiring mode analysis, auxiliary electrical calculation and power grid evaluation on the power grid with the voltage grade of 10kV or below in the planning area.

8. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 7.

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