CN106487012B

CN106487012B - A kind of selection method and system of high voltage distribution network powering mode

Info

Publication number: CN106487012B
Application number: CN201611080427.2A
Authority: CN
Inventors: 刘民伟
Original assignee: Yunnan Power Grid Co Ltd
Current assignee: Yunnan Power Grid Co Ltd
Priority date: 2016-11-30
Filing date: 2016-11-30
Publication date: 2019-02-22
Anticipated expiration: 2036-11-30
Also published as: CN106487012A

Abstract

The present invention provides the selection methods and system of a kind of high voltage distribution network powering mode, wherein the selection method includes the relationship according to total load and main transformer capacity, or the relationship of radius of electricity supply and the power supply area gross area, determine the corresponding substation's scale of 110/10kV powering mode and corresponding line size；110/35/10kV substation scale is calculated according to total load and main transformer capacity, and according to 35/10kV substation scale is obtained, determines the corresponding substation's scale of 110/35/10kV powering mode and corresponding line size；The power distribution network cost of investment of different powering modes under same load density is calculated separately according to the relational model between substation's scale, line size and power distribution network cost of investment；Powering mode is selected according to power distribution network cost of investment.Technical solution of the present invention can be reduced the case where unreasonable voltage class and investment waste.

Description

Method and system for selecting power supply mode of high-voltage distribution network

Technical Field

The invention relates to the technical field of high-voltage power distribution, in particular to a method and a system for selecting a power supply mode of a high-voltage power distribution network.

Background

The high-voltage distribution transmits and configures electric energy for users in a mode of high transmission voltage and low transmission current, can reduce the heat loss and material cost of the current during power transmission, and is a long-distance and low-loss power distribution mode.

The high-voltage distribution network voltage sequence mainly comprises 110kV and 35kV, wherein the voltage of a low-voltage side corresponding to a 110kV transformer substation is 10kV, and the voltage of a medium-voltage side corresponding to the 110kV transformer substation is 35 kV. Corresponding to the voltage sequence of a high-voltage distribution network, the conventional high-voltage distribution network mainly has two power supply modes of 110/10kV one-stage voltage reduction and 110/35/10kV two-stage voltage reduction.

Under normal conditions, an urban network with higher load density usually adopts a 110kV transformer substation to directly output a 10kV line for power supply; rural power grids with lower load density usually adopt a medium-voltage side-out 35kV line of a 110kV transformer substation to supply power to the 35kV transformer substation, and a 35kV transformer substation is further provided with a 10kV line to perform two-stage voltage reduction power supply. However, in the prior art, a power supply mode of 110/10kV one-stage voltage reduction or 110/35/10kV two-stage voltage reduction is selected, and a mature selection strategy is not provided, so that the situations of unreasonable voltage level, repeated construction and investment waste exist in the actual power grid planning and construction process.

Disclosure of Invention

The invention aims to provide a technical scheme of a method and a system for selecting a power supply mode of a high-voltage distribution network, and aims to solve the problems of unreasonable voltage level, repeated construction and investment waste caused by the fact that a mature selection strategy is not available for two power supply modes of primary voltage reduction and secondary voltage reduction in the prior art introduced in the background art.

In order to solve the technical problems, the invention provides the following technical scheme:

according to a first aspect of the present invention, there is provided a method for selecting a power supply mode of a high voltage distribution network, including:

determining the scale of a transformer substation corresponding to the 110/10kV power supply mode according to the relation between the total load of a power supply area and the main transformer capacity of a 110kV transformer or the relation between the power supply radius of the 110kV transformer substation and the total area of the power supply area;

calculating the line scale corresponding to the 110/10kV power supply mode according to the scale of the substation corresponding to the 110/10kV power supply mode;

determining the substation scale corresponding to the 110/35/10kV power supply mode according to 110/35/10kV substation scale obtained by calculating the relation between the total load of the power supply area and the main transformer capacity of the 110kV transformer and 35/10kV substation scale, wherein the 35/10kV substation scale is obtained by calculating according to the relation between the load density of the power supply area and the main transformer capacity of the 35/10kV transformer or according to the power supply radius of the 35/10kV substation;

calculating the line scale corresponding to the 110/35/10kV power supply mode according to the scale of the substation corresponding to the 110/35/10kV power supply mode;

according to a relation model among the scale of the transformer substation, the scale of the line and the investment cost of the power distribution network, respectively calculating the investment cost of the power distribution network corresponding to the 110/10kV power supply mode and the investment cost of the power distribution network corresponding to the 110/35/10kV power supply mode under the same load density within a preset load density range;

and according to the investment cost of the power distribution network, selecting the 110/10kV power supply mode or the 110/35/10kV power supply mode as the power supply mode of the high-voltage power distribution network.

Preferably, the determining the scale of the substation corresponding to the 110/10kV power supply mode according to the relationship between the total load of the power supply area and the main transformer capacity of the 110kV transformer, or according to the relationship between the power supply radius of the 110kV substation and the total area of the power supply area, includes:

calculating the ratio of the total load of the power supply area to the main transformer capacity of the 110kV transformer, and calculating the number of the 110kV transformers corresponding to the power supply capacity according to the product of the ratio and the capacity-to-load ratio of the 110kV transformers;

according to the number of the 110kV transformers corresponding to the power supply capacity, the number of the 110kV transformer substation seats corresponding to the power supply capacity is obtained through calculation by combining the corresponding relation between the number of the transformers and the number of the transformer substation seats;

determining the number of 110kV transformers and the number of 110kV transformer substation bases corresponding to the power supply capacity as the 110/10kV transformer substation scale corresponding to the power supply capacity;

calculating the power supply area of a single 110kV transformer substation according to the power supply radius of the 110kV transformer substation, and calculating the number of 110kV transformer substation seats corresponding to the power supply radius according to the relation between the power supply area of the single 110kV transformer substation and the total area of the power supply area;

according to the number of the 110kV transformer substation seats corresponding to the power supply radius, calculating to obtain the number of the 110kV transformers corresponding to the power supply radius by combining the corresponding relation between the number of the transformers and the number of the transformer substation seats;

determining the number of 110kV transformers and the number of 110kV transformer substation seats corresponding to the power supply radius to be 110/10kV transformer substation scales corresponding to the power supply radius;

and selecting 110/10kV substation scale corresponding to the power supply capacity or 110/10kV substation scale corresponding to the power supply radius as the substation scale corresponding to the 110/10kV power supply mode according to the number of 110kV substation seats.

Preferably, the determining a substation scale corresponding to a 110/35/10kV power supply mode according to the 110/35/10kV substation scale calculated according to the relationship between the total load of the power supply region and the main transformer capacity of the 110kV transformer, and the 35/10kV substation scale calculated according to the relationship between the load density of the power supply region and the main transformer capacity of the 35/10kV transformer or according to the power supply radius of the 35/10kV substation includes:

calculating the ratio of the total load of the power supply area to the main transformer capacity of the 110kV transformer, and calculating the number of the 110kV transformers according to the product of the ratio and the capacity-load ratio of the 110kV transformer;

calculating the number of the 110kV transformer substation seats according to the number of the 110kV transformers and by combining the corresponding relation between the number of the transformers and the number of the transformer substation seats;

and determining the number of the 110kV transformers and the number of the 110kV transformer substation bases to be 110/35/10kV transformer substation scales.

Preferably, the determining a substation scale corresponding to a 110/35/10kV power supply mode according to the 110/35/10kV substation scale calculated according to the relationship between the total load of the power supply region and the main transformer capacity of the 110kV transformer, and the 35/10kV substation scale calculated according to the relationship between the load density of the power supply region and the main transformer capacity of the 35/10kV transformer or according to the power supply radius of the 35/10kV substation further includes:

calculating the number of 35/10kV transformers corresponding to power supply capacity in the power supply range of each 110kV transformer substation according to the power supply area and the load density corresponding to the power supply range of each 110kV transformer substation, and the capacity-to-load ratio and the main transformer capacity of the 35/10kV transformer;

according to the 35/10kV transformer number corresponding to the power supply capacity and the corresponding relation between the transformer number and the transformer substation number, calculating the 35/10kV transformer substation number corresponding to the power supply capacity in the power supply range of each 110kV transformer substation;

determining the number of 35/10kV transformers and the number of 35/10kV transformer substations corresponding to the power supply capacity in the power supply range of the 110kV transformer substation as the 35/10kV transformer substation scale corresponding to the power supply capacity in the power supply range of each 110kV transformer substation;

and the number of the first and second groups,

calculating the number of 35/10kV transformer substation seats corresponding to the power supply radius in the power supply range of each 110kV transformer substation according to the power supply area corresponding to the power supply range of each 110kV transformer substation and the power supply radius of each 35/10kV transformer substation;

according to the 35/10kV substation number corresponding to the power supply radius and the corresponding relation between the transformer number and the substation number, calculating the 35/10kV transformer number corresponding to the power supply radius in the power supply range of each 110kV substation;

determining the number of 35/10kV transformer substation seats and the number of 35/10kV transformers corresponding to the power supply radius as the 35/10kV transformer substation scale corresponding to the power supply radius in the power supply range of each 110kV transformer substation;

selecting the 35/10kV transformer substation scale corresponding to the power supply capacity or the 35/10kV transformer substation scale corresponding to the power supply radius as the 35/10kV transformer substation scale in the 110/35/10kV power supply mode according to the number of 35/10kV transformer substation seats;

and determining the substation scale corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale and the 35/10kV substation scale.

Preferably, the calculating, according to a relation model among the substation scale, the line scale and the distribution network investment cost, the distribution network investment cost corresponding to the 110/10kV power supply mode and the distribution network investment cost corresponding to the 110/35/10kV power supply mode under the same load density within the predetermined load density range includes:

according to the relationship model:respectively calculating the investment cost of a power distribution network corresponding to an 110/10kV power supply mode and the investment cost of the power distribution network corresponding to a 110/35/10kV power supply mode; wherein, C_munRepresents the investment cost of the distribution network, C_SUBRepresents the investment cost of the transformer substation scale, C_lenRepresents the investment cost of the line scale, C^kThe cost of each high-voltage substation is expressed, and k is expressed as a voltage grade; NS (server)^kExpressed as the number of seats of the substation corresponding to the voltage class, NT^kExpressed as the number of transformers corresponding to the voltage class,expressed as the maximum number of transformers corresponding to the voltage class, Mo represents the unit price of the line, Len^kIndicating voltage classAnd the corresponding total line length and lambda are the investment cost ratio corresponding to the number of the transformer substation seats.

Preferably, the calculating the line scale corresponding to the 110/10kV power supply mode according to the substation scale corresponding to the 110/10kV power supply mode includes:

determining a grid structure corresponding to the 110/10kV power supply mode according to the load density of a power supply area;

calculating the total length of the 110kV high-voltage distribution line according to the number of the 110kV transformer substation seats and the grid structure corresponding to the 110/10kV power supply mode;

determining the power supply radius of the 10kV medium-voltage distribution line according to the number of the 110kV transformer substation seats, and calculating the total length of the 10kV medium-voltage distribution line according to the power supply radius and the number of returns of the 10kV medium-voltage distribution line;

and calculating the sum of the total length of the 110kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line as the line scale corresponding to the 110/10kV power supply mode.

Preferably, the calculating the line scale corresponding to the 110/35/10kV power supply mode according to the substation scale corresponding to the 110/35/10kV power supply mode includes:

determining a grid structure corresponding to the 110/35/10kV power supply mode according to the load density of a power supply area;

calculating the total length of the 110kV high-voltage distribution line according to the number of the 110kV transformer substation seats and the grid structure corresponding to the 110/35/10kV power supply mode;

calculating the average distance and the circuit number of 35/10kV transformer substations in the power supply range of each 110kV transformer substation according to the number of 35/10kV transformer substation seats and the number of transformer substations in the power supply range of each 110kV transformer substation;

calculating the total length of the 35kV high-voltage distribution line according to the average distance and the circuit number of the 35/10kV transformer substation;

calculating the total length of the 10kV medium-voltage distribution line according to the main transformer capacity and the number of 35/10kV transformers;

and calculating the sum of the total length of the 110kV high-voltage distribution line, the total length of the 35kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line as the line scale corresponding to the 110/35/10kV power supply mode.

According to a second aspect of the present invention, there is also provided a system for selecting a power supply mode of a high voltage distribution network, comprising:

the first substation scale determining module is used for determining the substation scale corresponding to the 110/10kV power supply mode according to the relation between the total load of a power supply area and the main transformer capacity of the 110kV transformer or the relation between the power supply radius of the 110kV substation and the total area of the power supply area;

the first line scale calculation module is used for calculating the line scale corresponding to the 110/10kV power supply mode according to the substation scale corresponding to the 110/10kV power supply mode;

the second substation scale determining module is used for determining the substation scale corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale obtained by calculation according to the relation between the total load of the power supply area and the main transformer capacity of the 110kV transformer and the 35/10kV substation scale, wherein the 35/10kV substation scale is obtained by calculation according to the relation between the load density of the power supply area and the main transformer capacity of the 35/10kV transformer or according to the power supply radius of the 35/10kV substation;

the second line scale calculation module is used for calculating the line scale corresponding to the 110/35/10kV power supply mode according to the substation scale corresponding to the 110/35/10kV power supply mode;

the cost calculation module is used for respectively calculating the investment cost of the power distribution network corresponding to the 110/10kV power supply mode and the investment cost of the power distribution network corresponding to the 110/35/10kV power supply mode under the same load density according to the relationship among the scale of the transformer substation, the scale of the line and the investment cost of the power distribution network;

and the power supply mode selection module is used for selecting the 110/10kV power supply mode or the 110/35/10kV power supply mode as a power supply mode of a high-voltage distribution network according to the investment cost of the distribution network.

Preferably, the first substation size determination module includes:

the first transformer number calculation submodule is used for calculating the ratio of the total load of the power supply area to the main transformer capacity of the 110kV transformer, and calculating the number of the 110kV transformers corresponding to the power supply capacity according to the product of the ratio and the capacity-load ratio of the 110kV transformer;

the first substation seat number calculation submodule is used for calculating the 110kV substation seat number corresponding to the power supply capacity according to the 110kV transformer seat number corresponding to the power supply capacity and by combining the corresponding relation between the transformer seat number and the substation seat number;

the first substation scale determining submodule is used for determining the number of the 110kV transformers and the number of the 110kV substation seats corresponding to the power supply capacity as the 110/10kV substation scale corresponding to the power supply capacity;

the second substation seat number calculation submodule is used for calculating the power supply area of a single 110kV substation according to the power supply radius of the 110kV substation, and calculating the seat number of the 110kV substation corresponding to the power supply radius according to the relation between the power supply area of the single 110kV substation and the total area of the power supply area;

the second transformer number calculating submodule is used for calculating the number of 110kV transformers corresponding to the power supply radius according to the number of 110kV transformer substation seats corresponding to the power supply radius and by combining the corresponding relation between the number of transformers and the number of transformer substation seats;

the second substation scale determining submodule is used for determining the number of the 110kV transformers and the number of the 110kV substation seats corresponding to the power supply radius to be 110/35/10kV substation scale corresponding to the power supply radius;

and the first substation scale selection submodule is used for selecting 110/10kV substation scale corresponding to power supply capacity or selecting 110/10kV substation scale corresponding to power supply radius as the substation scale corresponding to the 110/10kV power supply mode according to the number of 110kV substation seats.

Preferably, the second substation size determination module includes:

the third transformer number calculation submodule is used for calculating the ratio of the total load of the power supply area to the main transformer capacity of the 110kV transformer, and calculating the number of the 110kV transformers according to the product of the ratio and the capacity-load ratio of the 110kV transformers;

the third substation seat number calculation submodule is used for calculating the seat number of the 110kV substation according to the number of the 110kV transformers and by combining the corresponding relation between the number of the transformers and the seat number of the substation;

and the third substation scale determining submodule is used for determining the scale of the substation with the number of the 110kV transformers and the number of the 110kV substations as 110/35/10 kV.

Preferably, the second substation size determining module further includes:

the fourth transformer number calculating submodule is used for calculating the number of 35/10kV transformers corresponding to power supply capacity in the power supply range of each 110kV transformer substation according to the power supply area and the load density corresponding to the power supply range of each 110kV transformer substation, and the capacity-to-load ratio and the main transformer capacity of the 35/10kV transformer;

the fourth substation seat number calculation submodule is used for calculating the seat number of the 35/10kV substation corresponding to the power supply capacity in the power supply range of each 110kV substation according to the 35/10kV transformer seat number corresponding to the power supply capacity and by combining the corresponding relation between the transformer seat number and the transformer seat number;

the fourth substation scale determining submodule is used for determining the 35/10kV transformer station number and the 35/10kV substation seat number corresponding to the power supply capacity in the power supply range of the 110kV substation as the 35/10kV substation scale corresponding to the power supply capacity in the power supply range of each 110kV substation;

and the number of the first and second groups,

the fifth substation seat number calculation submodule is used for calculating the seat number of the 35/10kV substation corresponding to the power supply radius in the power supply range of each 110kV substation according to the power supply area corresponding to the power supply range of each 110kV substation and the power supply radius of each 35/10kV substation;

the fifth transformer number calculating submodule is used for calculating the number of 35/10kV transformers corresponding to the power supply radius in the power supply range of each 110kV transformer substation according to the 35/10kV transformer substation number corresponding to the power supply radius and by combining the corresponding relation between the number of transformers and the number of transformer substation numbers;

the fifth substation scale determining submodule is used for determining the 35/10kV substation seat number and the 35/10kV transformer seat number corresponding to the power supply radius as the 35/10kV substation scale corresponding to the power supply radius in the power supply range of each 110kV substation;

the second substation scale selection submodule is used for selecting the 35/10kV substation scale corresponding to the power supply capacity or the 35/10kV substation scale corresponding to the power supply radius as the 35/10kV substation scale in the 110/35/10kV power supply mode according to the number of 35/10kV substation seats;

and the sixth substation scale determining submodule is used for determining the substation scale corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale and the 35/10kV substation scale.

Preferably, the cost calculation module is specifically configured to, according to the relationship model:respectively calculating the investment cost of a power distribution network corresponding to an 110/10kV power supply mode and the investment cost of the power distribution network corresponding to a 110/35/10kV power supply mode; wherein, C_munRepresents the investment cost of the distribution network, C_SUBRepresents the investment cost of the transformer substation scale, C_lenRepresents the investment cost of the line scale, C^kThe cost of each high-voltage substation is expressed, and k is expressed as a voltage grade; NS (server)^kExpressed as the number of seats of the substation corresponding to the voltage class, NT^kExpressed as the number of transformers corresponding to the voltage class,expressed as the maximum number of transformers corresponding to the voltage class, Mo represents the unit price of the line, Len^kAnd the total length of the line is shown, and lambda is the investment cost ratio corresponding to the number of the transformer substation seats.

Preferably, the first line scale calculation module includes:

the first grid structure determining submodule is used for determining the grid structure corresponding to the 110/10kV power supply mode according to the load density of a power supply area;

the first line length calculation submodule is used for calculating the total length of the 110kV high-voltage distribution line according to the number of the 110kV transformer substation seats and the grid structure corresponding to the 110/10kV power supply mode;

the second line length calculation submodule is used for determining the power supply radius of the 10kV medium-voltage distribution line according to the number of the 110kV transformer substation seats and calculating the total length of the 10kV medium-voltage distribution line according to the power supply radius and the number of returns of the 10kV medium-voltage distribution line;

and the first line scale determining submodule is used for calculating the sum of the total length of the 110kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line as the line scale corresponding to the 110/10kV power supply mode.

Preferably, the second line scale calculation module includes:

the second grid structure determining submodule is used for determining the grid structure corresponding to the 110/35/10kV power supply mode according to the load density of a power supply area;

the third line length calculating submodule is used for calculating the total length of the 110kV high-voltage distribution line according to the number of seats and the grid structure of the 110kV transformer substation corresponding to the 110/35/10kV power supply mode;

the distance and return number calculating submodule is used for calculating the average distance and the circuit return number of the 35/10kV transformer substation in the power supply range of each 110kV transformer substation according to the number of 35/10kV transformer substation seats and the number of transformer substations in the power supply range of each 110kV transformer substation;

the fourth line length calculating submodule is used for calculating the total length of the 35kV high-voltage distribution line according to the average distance and the line return number of the 35/10kV transformer substation;

the fifth line length calculation submodule is used for calculating the total length of the 10kV medium-voltage distribution line according to the main transformer capacity and the number of the 35/10kV transformers;

and the second line scale determining submodule is used for calculating the sum of the total length of the 110kV high-voltage distribution line, the total length of the 35kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line as the line scale corresponding to the 110/35/10kV power supply mode.

According to the selection scheme of the power supply mode of the high-voltage distribution network, the substation scale corresponding to the 110/10kV power supply mode and the substation scale corresponding to the 110/35/10kV power supply mode are respectively determined according to the relation among the total load and the load density of a power supply area and the main transformer capacity of a transformer, or the relation between the power supply radius of the substation and the total area of the power supply area, the line scale corresponding to the power supply mode is calculated according to the substation scale, and the substation scale with lower investment cost under the same load density is selected as the power supply mode of the distribution network according to the relation model among the substation scale related to the load density, the line scale and the investment cost of the distribution network. The scheme has a mature power supply mode selection strategy of the power distribution network, so that the situations of unreasonable voltage level setting, repeated construction and investment waste can be reduced in the actual power grid planning and construction process. Wherein the investment cost of the power distribution network comprises the investment cost of a transformer substation and the investment cost of a line scale.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic flow chart illustrating a method for selecting a power supply mode of a high-voltage distribution network according to an exemplary embodiment of the present invention;

fig. 2 is a schematic flow chart of a substation size determination method corresponding to the 110/10kV power supply size shown in the embodiment of fig. 1;

fig. 3 is a schematic flow chart of a line scale calculation method corresponding to the 110/10kV power supply mode shown in the embodiment of fig. 1;

fig. 4 is a schematic flow chart of a substation size determination method corresponding to the first 110/35/10kV power supply mode shown in the embodiment of fig. 1;

fig. 5 is a schematic flow chart of a substation size determination method corresponding to the second 110/35/10kV power supply mode shown in the embodiment of fig. 1;

fig. 6 is a schematic flow chart of a line size calculation method corresponding to the 110/35/10kV power supply mode shown in the embodiment of fig. 1;

fig. 7 is a schematic structural diagram illustrating a system for selecting a power supply mode of a high-voltage distribution network according to an exemplary embodiment of the present invention;

fig. 8 is a schematic structural diagram of a first substation scale determination module according to the embodiment shown in fig. 7;

FIG. 9 is a block diagram of a first line scale calculation module according to the embodiment shown in FIG. 7;

fig. 10 is a schematic structural diagram of a first and second substation scale determination module according to the embodiment shown in fig. 7;

fig. 11 is a schematic structural diagram of a second substation scale determination module according to the embodiment shown in fig. 7;

fig. 12 is a schematic structural diagram of a second line scale calculation module according to the embodiment shown in fig. 7.

Detailed Description

The selection scheme of the power supply mode of the high-power distribution network provided by the embodiment of the invention solves the problems of unreasonable voltage level, repeated construction and investment waste caused by the lack of mature selection measurement introduced in the background art.

In order to make the technical solutions in the embodiments of the present invention better understood and make the above objects, features and advantages of the embodiments of the present invention more comprehensible, the technical solutions in the embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

In the following embodiments of the present invention, the following requirements can be satisfied by the relevant technical principles and assumptions of the power supply region:

(1) the area is square; (2) the selection of a line corridor is restricted by the factors of no mountains and rivers in the area;

(3) the problem of transformation of an original power grid in the power supply area is not considered; (4) the load in the power supply area is uniformly distributed;

(5) the load is supplied with power by medium voltage class, such as 10kV, and the high-voltage direct supply load is not considered;

(6) the capacity-load ratio of the 110kV transformer is 1.8-2.1, and the capacity-load ratio of the 35kV transformer is 1.8-2.1.

(7) In the power supply mode of the invention, 110kV transformer substations comprise 110/10kV stations and 110/35/10kV stations, and the scale of each transformer substation is 2 transformersConfiguration considerations; the scale of the 35kV transformer substation is considered according to the configuration of 2 main transformers; the selection of the main transformer capacity of the transformer substation is determined according to the difference of load density as follows: for a 110kV transformer, the load density is 0.1MW/km²The following 20MVA was selected, and the loading density was 0.1MW/km²40MVA is selected; the main transformer capacity of 35/10kV transformers is 6.3 MVA.

(8) The power grid structure of the 35kV high-voltage power distribution network is considered according to the single-loop chain of the power supplies on the two sides; the 10kV grid is planned as single radiation.

Referring to fig. 1, fig. 1 is a schematic flow chart illustrating a method for selecting a power supply mode of a high voltage distribution network according to an exemplary embodiment of the present invention. The method for selecting the power supply mode of the high-voltage distribution network provided by the embodiment of the invention, as shown in fig. 1, comprises the following steps:

s110: and determining the scale of the substation corresponding to the 110/10kV power supply mode according to the relation between the total load of the power supply area and the main transformer capacity of the 110kV transformer or the relation between the power supply radius of the 110kV transformer substation and the total area of the power supply area.

As shown in fig. 2, step S110: according to the total load of a power supply area and the main transformer capacity of a 110kV transformer, or according to the power supply radius of the 110kV transformer and the total area of the power supply area, determining the scale of a transformer substation corresponding to the 110/10kV power supply mode, wherein the method comprises the following steps:

s111: calculating the ratio of the total load of a power supply area to the main transformer capacity of the 110kV transformer, and calculating the number of the 110kV transformers corresponding to the power supply capacity according to the product of the ratio and the capacity-load ratio of the 110kV transformers;

the main transformer capacity reflects the power supply capacity of the transformer, the capacity-to-load ratio of the 110kV transformer is known to be 1.8-2.1 from the above, after the main transformer capacity of the 110kV transformer is confirmed, the load which can be borne by each 110kV transformer can be determined according to the ratio of the main transformer capacity to the capacity-to-load ratio, and then the number of the 110kV transformers required by the power supply area calculated according to the power supply capacity can be confirmed according to the total load of the power supply area and the load of each 110kV transformer;

for example: assuming that the total number of transformers in the power supply area is NT, the total load in the power supply area is P, and the power supply capacity of a single main transformer is SMT, the total number of transformers in the power supply area can be represented as:

NT＝M×P/S_MTwherein, M is a capacity-load ratio coefficient, and can be 2.1; NT is the total number of the transformers, and the calculation result is carried and rounded. Main transformer capacity S_MTDirectly taking the main transformer capacity of a 110kV transformer substation, and the number NT (NT) of 100kV transformers¹¹⁰。

S112: and calculating to obtain the number of the 110kV transformer substation seats corresponding to the power supply capacity according to the number of the 110kV transformers corresponding to the power supply capacity and by combining the corresponding relation between the number of the transformers and the number of the transformer substation seats.

In the embodiment of the invention, the ratio of the number of the transformers to the number of the transformer substation seats is 2:1, namely the number of the transformer substation seats in the power supply area is 2 main transformers in each transformer substationWherein,the number of the transformer substation seats is 110 kV.

S113: determining the number of 110kV transformers and the number of 110kV transformer substation bases corresponding to the power supply capacity as the 110/10kV transformer substation scale corresponding to the power supply capacity;

the transformer substation scale mainly comprises two parts, namely the number of transformer substations and the number of transformer substations, each transformer substation comprises 1 or more transformers, and under the condition that the 110/10kV transformer substation scale is confirmed, the investment cost corresponding to the transformer substation scale can be calculated according to the scale of the 110kV transformer substation, so that a proper power supply mode can be selected.

Or,

s114: calculating the power supply area of a single 110kV transformer substation according to the power supply radius of the single 110kV transformer substation, and calculating the number of 110kV transformer substation seats corresponding to the power supply radius according to the relation between the power supply area of the single 110kV transformer substation and the total area of a power supply area;

the power supply radius reflects the power supply range of the transformer substation, the power supply area of each 110kV transformer substation can be determined according to the power supply radius of each 110kV transformer substation, and then the number of the 110kV transformer substations calculated according to the power supply radius can be determined according to the total area of the power supply area and the power supply area of each 110kV transformer substation. If the load density of the power supply area is low, the power supply capacity of the main transformer is not the main constraint of the scale of the transformer substation due to the low load density, and the main constraint of the scale of the transformer substation is the power supply radius of the transformer substation.

For example: for the 110/10kV direct-falling scheme, the power supply radius of a single substation is considered according to 10km of power supply capacity of a 10kV line. According to the constraint, the number of the transformer substation seats of the 110kV/10kV direct-falling scheme is as follows:wherein,the number of corresponding 110kV transformer substation seats under the constraint of power supply radius, S is the total area of a power supply area, and is 200km²Namely the power supply area of a single 110kV substation. In the embodiment of the invention, the power supply area of the transformer substation is considered as a square, and the power supply radius of a circular area is considered as a diagonal line of an inscribed square, so that the power supply area of a 110kV transformer substation with the power supply radius of 10km is determined as

S115: and calculating to obtain the number of 110kV transformers corresponding to the power supply radius according to the number of 110kV transformer substation seats corresponding to the power supply radius by combining the corresponding relation between the number of transformers and the number of transformer substation seats.

The corresponding relation between the number of the transformers and the number of the transformer substation seats is 2:1, and the number of the 110kV transformer substation seats corresponding to the power supply radius can be obtained according to the relation and the calculated number of the 110kV transformer substation seats corresponding to the power supply radius.

S116: and determining the number of 110kV transformers and the number of 110kV substation seats corresponding to the power supply radius as the 110/10kV substation scale corresponding to the power supply radius.

The transformer substation scale mainly comprises two parts, namely the number of transformer substations and the number of transformer substations, each transformer substation comprises 1 or more transformers, and under the condition that the 110/10kV transformer substation scale is confirmed, the investment cost corresponding to the transformer substation scale can be calculated according to the scale of the 110kV transformer substation, and then a proper power supply mode is selected, so that the investment cost is reduced.

S117: and selecting 110/10kV substation scale corresponding to the power supply capacity or selecting 110/10kV substation scale corresponding to the power supply radius as the substation scale corresponding to the 110/10kV power supply mode according to the number of the 110kV substation seats.

For areas with lower load density, such as rural areas, the power supply radius of a transformer substation is about 10km, the power supply radius constraint is the main constraint, and the constraint gradually changes into the constraint of the transformation capacity of the transformer substation along with the increase of the load density. In the concrete calculation process, the number NS of the transformer substation seats_110/10GetAndmaximum value of (2). In addition, it is necessary to ensure that each transformer station has at least 1 main transformer, so the number of the main transformers is more than or equal to that of the transformer stations, namely NT_110/10≥NS_110/10。

In selecting the power supply mode, the line size needs to be considered in addition to the substation size. In calculating the line scale, the rack structure needs to be considered.

S120: and calculating the line scale corresponding to the 110/10kV power supply mode according to the substation scale corresponding to the 110/10kV power supply mode.

As shown in fig. 3, the step S120: calculating the line scale corresponding to the 110/10kV power supply mode according to the substation scale corresponding to the 110/10kV power supply mode, and specifically comprising the following substeps:

s121: determining a grid structure corresponding to an 110/10kV power supply mode according to the load density of a power supply area;

the grid structure is related to load density, when the load density is less than 0.1MW/km2, the 110kV high-voltage power distribution network adopts a double-side power supply single-loop chain grid structure, and when the load density is greater than or equal to 0.1MW/km2, the 110kV high-voltage power distribution network adopts an incomplete double-loop chain grid structure.

And planning the 10kV medium-voltage power distribution network according to single radiation.

S122: calculating the total length of the 110kV high-voltage distribution line according to the number of the 110kV transformer substation seats and the grid structure corresponding to the 110/10kV power supply mode;

for a 110kV high-voltage distribution network line, firstly, determining the average distance d110 of a 110kV high-voltage transformer substation as follows:in the formula, s is the total area of the region, NS¹¹⁰The number of the transformer substation seats.

In determining d¹¹⁰And then, selecting the number of 110kV incomplete double-circuit chains according to the number of the 110kV transformer substation seats:

and if the number of the 110kV transformer substation seats is not more than 3, adopting 1 110kV incomplete double-circuit chain. At this time, the 110kV line length Len¹¹⁰The estimation method of (2) is as follows: len¹¹⁰＝1×1.2×(NS¹¹⁰-1)×d¹¹⁰+2×2×d_out(ii) a In the formula, the 1 st coefficient '1' of the two terms on the right side of the equal sign represents a single loop; the 2 nd coefficient "1.2" of the right-side item 1 is a line meandering coefficient; the 1 st coefficient "2" of the right-hand item 2 indicates that the terminal station has 2-loop access to the external power supply, and if a single-loop link is used, the coefficient isSelecting 1, wherein the 2 nd coefficient of 2 represents 2 substations at two ends of 1 chain; d_outAnd the distance between the 110kV transformer substations at two ends of the chain and an external access point is represented.

If the number of the 110kV transformer substation seats is 4-6, 2 110kV double-loop chains are adopted, and at the moment, the length of a 110kV line Len²²⁰The estimation method is as follows: len²²⁰＝1×1.2×(NS¹¹⁰-2)×d¹¹⁰+2×4×d_out(ii) a In the formula, the 1 st coefficient '1' of the two terms on the right side of the equal sign represents a single loop; the 2 nd coefficient "1.2" of the right-hand item 1 represents a line meandering coefficient; the 1 st coefficient "2" of the right-side item 2 indicates that the terminal station accesses an external power supply through a 2-loop line, if a single-loop chain is adopted, the coefficient is selected to be "1", and the 2 nd coefficient "4" indicates that the substations of 4 terminals in total of 2 chains need to access an external power supply point.

S123: determining the power supply radius of the 10kV medium-voltage distribution line according to the number of the 110kV transformer substation seats, and calculating the total length of the 10kV medium-voltage distribution line according to the power supply radius and the number of loops of the 10kV medium-voltage distribution line;

regarding the calculation of the scale of the medium-voltage distribution line in the 110/10kV direct drop scheme, the method for estimating the power supply radius of the 10kV medium-voltage distribution line comprises the following steps:wherein d is^MVFor the power supply radius, s is the area of the power supply area where the medium-voltage distribution line is located, and NS represents the number of 110kV substation seats.

Because the '2-1' ring network is adopted for design, the normal power supply load of each loop of the medium-voltage line is as follows:

in the formula, PL represents the normal power supply load of each circuit of the medium-voltage line, I represents current, and V represents voltage; the coefficient 0.5 is the normal load rate allowed by the 2-1 looped network, and the coefficient 0.9 is the power factor.

Medium voltage in 110/10kV power supply modeThe line backlog is estimated as follows:wherein, P is the total load of the area; PL is the normal power supply load of each return medium voltage line; the result is carried and rounded.

The total length of the medium voltage line is estimated as follows:in the formula, a coefficient α is a main line bending coefficient, and a coefficient β is an amplification factor after a branch line is designed, the main line bending coefficient of the medium-voltage line and the amplification factor after the branch line is considered are determined according to different voltage grades, wherein the main line bending coefficient of the 10kV overhead line is 1.3, the branch coefficient is 1.5, the main line bending coefficient of the 10kV cable is 1.3, and the branch coefficient is 1.2.

S124: and calculating the sum of the total length of the 110kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line as the line scale corresponding to the 110/10kV power supply mode.

S130: and determining the substation scale corresponding to the 110/35/10kV power supply mode according to 110/35/10kV substation scale obtained by calculation according to the relation between the total load of the power supply area and the main transformer capacity of the 110kV transformer and 35/10kV substation scale, wherein the 35/10kV substation scale is obtained by calculation according to the relation between the load density of the power supply area and the main transformer capacity of the 35/10kV transformer or according to the power supply radius of the 35/10kV substation. In the 110/35/10kV supply mode a 110kV substation is used to convert 110kV voltage to 35kV voltage, and the 110kV substation also has a 10kV outlet to provide the 10kV voltage directly.

As a preferred embodiment, as shown in fig. 4, step S130: determining the substation scale corresponding to a 110/35/10kV power supply mode according to 110/35/10kV substation scale calculated according to the total load of a power supply area and the main variable capacity of a 110kV transformer and 35/10kV substation scale calculated according to the load density of the power supply area or the power supply radius of a 35/10kV substation, wherein the method comprises the following steps:

s131: calculating the ratio of the total load of a power supply area to the main transformer capacity of the 110kV transformer, and calculating the number of the 110kV transformers according to the product of the ratio and the capacity-load ratio of the 110kV transformer;

in an 110/35/10kV transformer substation, a 110/35/10kV transformer for reducing the voltage of 110kV to 35kV and a 35/10kV transformer for reducing the voltage of 35kV to 10kV are included, wherein the 110kV transformer can be directly selected as the 110kV transformer. Under the 110/35/10kV power supply mode, the power supply radius of a 110kV transformer substation is 45km, and the construction scale of the transformer substation is mainly restricted by the power supply capacity of the transformer substation, so the construction scale of the transformer substation can be carried out according to the scheme of the total load of a power supply area and the main transformer capacity of the 110kV transformer under the 110/10kV power supply mode.

S132: calculating the number of the 110kV transformer substation seats according to the number of the 110kV transformers and the corresponding relation between the number of the transformers and the number of the transformer substation seats;

s133: and determining the number of the 110kV transformers and the number of the 110kV substation bases as the 110/35/10kV substation scale.

The scale of an 110/35/10kV transformer substation under the constraint of power supply capacity is mainly determined by the main transformer capacity of a 110kV transformer and the total load of a power supply area, and the scale of the transformer substation comprises two parts, namely the number of transformer stations and the number of transformers. When the 110/35/10kV substation scale is confirmed, the investment cost can be calculated according to the 110/35/10kV substation scale, and an appropriate power supply mode can be selected. In addition, because the 110/35/10kV power supply mode mainly comprises two parts, namely a 110kV transformer substation and a 35/10kV transformer substation, each 110kV transformer substation corresponds to one or more 35/10kV transformer substations, and the 110kV transformer substations can calculate according to the power supply capacity, namely the main transformer capacity of the 110kV transformer and the total load of a power supply area. However, the power supply scale of the 35/10kV substation needs to be selected according to the power supply capacity or the power supply radius.

As a preferred embodiment, as shown in fig. 5, step S130: determining the substation scale corresponding to the 110/35/10kV power supply mode according to 110/35/10kV substation scale calculated by the total load of the power supply area and the main variable capacity of the 110kV transformer and 35/10kV substation scale, and further comprising:

s134: calculating the number of 35/10kV transformers corresponding to power supply capacity in the power supply range of each 110kV transformer substation according to the power supply area and the load density corresponding to the power supply range of each 110kV transformer substation, and the capacity-to-load ratio and the main transformer capacity of the 35/10kV transformer;

according to the power supply area and the load density corresponding to the power supply range of each 110kV transformer substation, the total load in the power supply range of the 110kV transformer substation can be calculated; according to the capacity-load ratio and the main transformer capacity of the 35/10kV transformers, the load which can be borne by each 35/10kV transformer can be calculated, and the number of 35/10kV transformers corresponding to the power supply capacity in the power supply range of each 110kV transformer substation can be determined according to the total load in the power supply range and the load which can be borne by each 35/10kV transformer.

For example: in the power supply range of each 110kV transformer substation, the calculation method for the number of 35/10kV transformers is as follows:

wherein,the number of 35/10kV transformers is rho_Load(s)In order to be the load density,is the main transformer capacity, NS, of 35/10kV transformer_110/35/10The number of the transformer substations of 110kV is the same as that of the transformer substations of 110/35/10kV, and the 110kV transformer substations can provide 35kV leads and 10kV leads for direct power supply in an 110/35/10kV power supply mode; when the number of 35/10kV transformers is calculated, the power supply area of a single 110kV transformer substation needs to be eliminated, namely 314km in a formula. In the specific calculation process, in the area with low load density, the guarantee is neededIn a region with a high load density, the following conditions are satisfied The main transformer capacity of the 110kV transformer is achieved; then

S135: calculating the number of 35/10kV transformer substation seats corresponding to the power supply capacity in the power supply range of each 110kV transformer substation according to the number of 35/10kV transformers corresponding to the power supply capacity and by combining the corresponding relation between the number of transformers and the number of transformer substation seats;

the calculation can be carried out according to 1 transformer substation corresponding to each 2 transformers, and the 35/10kV transformer substation number corresponding to the power supply capacity in the power supply range of each 110kV transformer substation is obtained. The calculation formula is as follows:wherein,the average number of 35/10kV substations within the supply range of each 110kV substation,the average number of 35/10kV transformers in the power supply range of each 110kV transformer substation is calculated.

S136: determining the number of 35/10kV transformers and the number of 35/10kV transformer substations corresponding to the power supply capacity in the power supply range of the 110kV transformer substations as the scale of the 35/10kV transformer substations corresponding to the power supply capacity in the power supply range of each 110kV transformer substation.

The number of 35/10kV transformers and the number of 35/10kV transformer substation seats corresponding to the power supply capacity in the power supply range of each 110kV transformer substation are determined, namely the scale of the 35/10kV transformer substation corresponding to the power supply capacity can be determined, so that the investment cost corresponding to the scale of the transformer substation can be calculated according to the scale of the 35/10kV transformer substation, and a proper power supply mode can be selected.

And the number of the first and second groups,

s137: and calculating the number of 35/10kV transformer substation seats corresponding to the power supply radius in the power supply range of each 110kV transformer substation according to the power supply area corresponding to the power supply range of each 110kV transformer substation and the power supply radius of each 35/10kV transformer substation.

In the 110/35/10kV power supply mode, the transformer substation comprises a 110kV transformer substation and a 35/10kV transformer substation. Subtracting the power supply area of all 110kV transformer substations from the power supply area of the power supply region, and dividing the power supply area of each 35/10kV transformer substation to obtain the total number of 35/10kV transformer substations in the power supply region, wherein the power supply radius of each 35/10kV transformer substation is 10km, and the corresponding power supply area is 314km². The calculation formula of the number of seats of the 35/10kV transformer substation is as follows:wherein,number of 35/10kV transformer substation seats, NS, corresponding to power supply capacity in power supply area_110/35/10The number of seats of a 110kV transformer substation in a power supply area is calculated.

The calculation formula of the average seat number of 35/10kV substations corresponding to the power supply radius in the power supply range of each 110kV substation is as follows:wherein,the number of 35/10kV transformer substation seats corresponding to the power supply capacity in the power supply range of each 110kV transformer substation, NS_110/35/10The number of the 110kV transformer substation seats and S are the total surface of a power supply areaAnd (4) accumulating.

S138: and calculating the number of 35/10kV transformers corresponding to the power supply radius in the power supply range of each 110kV transformer substation according to the number of 35/10kV transformer substation seats corresponding to the power supply radius and by combining the corresponding relation between the number of transformers and the number of transformer substation seats. Each 35/10kV transformer substation can have 2 35/10kV transformers, and the number of the 35/10kV transformers corresponding to the power supply radius in the power supply range of each 110kV transformer substation can be calculated according to the number of the 35/10kV transformer substations corresponding to the power supply radius through the corresponding relation.

S139: and determining the number of 35/10kV transformer substation seats and the number of 35/10kV transformers corresponding to the power supply radius as the 35/10kV transformer substation scale corresponding to the power supply radius in the power supply range of each 110kV transformer substation. According to the 35/10kV transformer substation scale corresponding to the power supply radius, the investment cost corresponding to the 35/10kV transformer substation scale can be determined, and then the corresponding power supply mode is selected according to the investment cost.

S1310: and selecting 35/10kV substation scale corresponding to the power supply capacity or 35/10kV substation scale corresponding to the power supply radius as 35/10kV substation scale in a 110/35/10kV power supply mode according to the number of 35/10kV substation seats.

Generally, the 35/10kV substation scale with the least 35/10kV substation bases is selected as the 35/10kV substation scale in the 110/35/10kV power supply mode. For example: in the course of the specific calculation process,selectingAndthe largest one.

S1311: and determining the substation scale corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale and the 35/10kV substation scale in the 110/35/10kV power supply mode. When the number of the 110kV transformer substations and the 35/10kV transformer substation scale in the power supply range of each 110kV transformer substation are known, the 35/10kV transformer substation scale in the total power supply area can be obtained.

By calculating the scale of the 110/35/10kV transformer substation, including the number of the 110kV transformer substations and the number of the 110kV transformers, and the scale of the 35/10kV transformer substation in the power supply range of each 110kV transformer substation, the number of the transformer substations and the number of the transformer substations in the 110/35/10kV power supply mode, namely the scale of the transformer substation corresponding to the 110/35/10kV power supply mode, can be obtained. The power supply mode of the high-voltage distribution network can be selected and obtained by comparing the scale of the substation corresponding to the 110/35/10kV power supply mode with the scale of the substation corresponding to the 110/10kV power supply mode, including the comparison of the cost of the corresponding high-voltage substation.

S140: and calculating the line scale corresponding to the 110/35/10kV power supply mode according to the scale of the substation corresponding to the 110/35/10kV power supply mode.

As shown in fig. 6, the step S140: according to the substation scale corresponding to the 110/35/10kV power supply mode, calculating the line scale corresponding to the 110/35/10kV power supply mode comprises the following steps:

s141: and determining the grid structure corresponding to the 110/35/10kV power supply mode according to the load density of the power supply area.

For a 35kV high-voltage power distribution network, grid structure wiring such as 2T wiring, single-side power supply single-return chain or double-side power supply single-return chain can be adopted.

S142: and calculating the total length of the 110kV high-voltage distribution line according to the number of the 110kV transformer substation seats and the grid structure corresponding to the 110/35/10kV power supply mode.

Please refer to step S122 in fig. 3 for a formula for calculating the total length of the 110kV high-voltage distribution line in the 110/35/10kV power supply mode.

S143: and calculating the average distance and the circuit number of 35/10kV transformer substations in the power supply range of each 110kV transformer substation according to the number of 35/10kV transformer substations in the power supply range of each 110kV transformer substation and the number of the transformer substations.

S144: and calculating the total length of the 35kV high-voltage distribution line according to the average distance of the 35/10kV transformer substation and the number of lines.

For the calculation of the total length of the 35kV high-voltage distribution line, the following formula is involved:

firstly, determining the number of 35kV transformer substation seats in the power supply range of each 110kV transformer substationAnd the number of stationsThe calculation formula is as follows:

carrying and rounding the calculation result, and secondly, determining the power supply area of each 110kV transformer substation: s₁₁₀＝S/NS¹¹⁰。

Then, the average distance of 35kV transformer substations in the power supply range of each 110kV transformer substation is determinedThe following were used:the 35kV target connection can be selected as incomplete chain connection or 2T connection, the calculation method of the circuit loop number and the circuit length is the same as the 110kV voltage level, and for comparison, the 35kV target connection in the research scheme is adoptedAnd 2T wiring is used for calculating the number and the length of the circuit loops, and the method specifically comprises the following steps:

since 2T wiring is used, the 35kV line length is estimated as follows. Firstly, determining the number of 35kV lines in the power supply range of each 110kV transformer substation:wherein,the number of 35kV lines in the power supply range of each 110kV transformer substation is counted, and k is the number of 35kV transformers connected with one line T, and is considered according to 2T main transformers. And carrying out carry rounding on the calculation result. The estimated 35kV total line length is:wherein Len³⁵Total length of 35kV line, NS¹¹⁰The number of the transformer substation seats is 110 kV.

S145: and calculating the total length of the 10kV medium-voltage distribution line according to the main transformer capacity and the number of 35/10kV transformers.

In the 110kV/35/10kV power supply mode, the calculation formula of the 10kV medium-voltage distribution line scale is as follows:

wherein,in the 110/35/10kV supply mode, the total length of the medium voltage distribution line,configuring the number of main transformers in each 35kV transformer substation,the capacity of the 35kV main transformer is obtained.

S146: and calculating the sum of the total length of the 110kV high-voltage distribution line, the total length of the 35kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line as the line scale corresponding to the 110/35/10kV power supply mode.

By calculating the line scale corresponding to the 110/35/10kV power supply mode, the investment cost of the line scale in the 110/35/10kV power supply mode can be calculated according to the line scale, and therefore the investment cost corresponding to the 110/35/10kV power supply mode is calculated by combining the investment cost of the transformer substation.

S150: according to the relationship among the scale of the transformer substation, the scale of the line and the investment cost of the power distribution network, respectively calculating the investment cost of the power distribution network corresponding to the 110/10kV power supply mode and the investment cost of the power distribution network corresponding to the 110/35/10kV power supply mode under the same load density within the load density range; wherein, the investment cost of the power distribution network comprises the investment cost of a line scale and the investment cost of a transformer substation scale.

Preferably, step S150: according to the relationship among the load density, the transformer substation scale and the high-voltage transformer substation cost, respectively calculating the high-voltage transformer substation cost corresponding to the 110/10kV power supply mode and the high-voltage transformer substation cost corresponding to the 110/35/10kV power supply mode under the load density, wherein the method comprises the following steps: according to the relationship model:respectively calculating the investment cost of a power distribution network corresponding to an 110/10kV power supply mode and the investment cost of the power distribution network corresponding to a 110/35/10kV power supply mode; wherein, C_munRepresents the investment cost of the distribution network, C_SUBRepresents the investment cost of the transformer substation scale, C_lenRepresents the investment cost of the line scale, C^kThe cost of each high-voltage substation is expressed, and k is expressed as a voltage grade; NS (server)^kExpressed as the number of seats of the substation corresponding to the voltage class, NT^kExpressed as the number of transformers corresponding to the voltage class,expressed as the maximum number of transformers corresponding to the voltage class, Mo represents the unit price of the line, Len^kIndicating voltage level correspondenceThe total length of the line, λ, is the proportion of the investment cost corresponding to the number of the substation seats in the investment cost of the substation scale, λ may be 30 to 80, and preferably λ is 60.

The voltage class k comprises 110 and 35, for example, in an 110/35/10kV power supply mode, the voltage class corresponding to a 110/35/10kV transformer is 110, and the voltage class of a 35/10kV transformer is 35; when the scale of the substation corresponding to the power supply mode is calculated, the transformer and the substation corresponding to each voltage class in the power supply mode need to be calculated. Number of transformers NT^kThe number of the transformers may be singular, and each transformer station corresponds to 2 transformers according to the corresponding relation between the number of the transformers and the number of the transformer stations, so that the maximum number of the transformersGreater than or equal to NT^k(ii) a E.g. number of transformers NT^kAnd (9) rounding the corresponding substation seat number carry NS^kMaximum number of transformers 5

The power supply scale corresponding to the 110/10kV power supply mode or the 110/35/10kV power supply mode is calculated according to the power supply capacity or the power supply radius, and the method for calculating the power supply scale according to the power supply capacity and the method for calculating the power supply scale according to the power supply radius are related to the load density of a power supply area. Under different load densities, the cost of a high-voltage substation corresponding to the 110/10kV power supply mode is different from the cost of a high-voltage substation corresponding to the 110/35/10kV power supply mode. Calculating to obtain that the cost of the high-voltage transformer substation corresponding to the 110/35/10kV power supply mode is less than the cost of the high-voltage transformer substation corresponding to the 110/10kV power supply mode when the load density of the power supply area is less than a certain load density threshold; when the load density of the power supply area is larger than or equal to the load density threshold value, the cost of the high-voltage transformer substation corresponding to the 110/35/10kV power supply mode is larger than or equal to the cost of the high-voltage transformer substation corresponding to the 110/10kV power supply mode, and therefore after the load density is confirmed, which power supply mode is selected can be determined.

S160: according to the investment cost of the power distribution network, an 110/10kV power supply mode or a 110/35/10kV power supply mode is selected as the power supply mode of the high-voltage power distribution network.

According to the method for selecting the power supply mode of the high-voltage distribution network, provided by the embodiment of the invention, the transformer substation scale corresponding to the 110/10kV power supply mode and the transformer substation scale corresponding to the 110/35/10kV power supply mode are respectively determined according to the relation among the total load and the load density of a power supply area and the main transformer capacity of a transformer, or the relation between the power supply radius of the transformer substation and the total area of the power supply area, the line scale corresponding to the power supply mode is calculated according to the transformer substation scale, and the transformer substation scale with lower investment cost under the same load density is selected as the power supply mode of the distribution network according to the relation model among the transformer substation scale, the line scale and the investment cost of the distribution network. The scheme has a mature power supply mode selection strategy of the power distribution network, so that the situations of unreasonable voltage level setting, repeated construction and investment waste can be reduced in the actual power grid planning and construction process. Wherein the investment cost of the power distribution network comprises the investment cost of a transformer substation and the investment cost of a line scale.

Based on the same inventive concept, the embodiment of the present application further provides a system for selecting a power supply mode of a high voltage distribution network, and as the method corresponding to the system is the method for selecting the power supply mode of the high voltage distribution network in the embodiment of the present application, and the principle of the system for solving the problem is similar to that of the method, the implementation of the system can refer to the implementation of the method, and repeated parts are not described again.

Fig. 7 shows a system for selecting a power supply mode of a high-voltage distribution network according to an exemplary embodiment of the present invention, where as shown in fig. 7, the system for selecting a power supply mode of a high-voltage distribution network includes:

the first substation scale determining module 701 is configured to determine the substation scale corresponding to the 110/10kV power supply mode according to the total load of the power supply area and the main transformer capacity of the 110kV transformer, or according to the power supply radius of the 110kV substation and the total area of the power supply area.

The first line scale calculation module 702 is configured to calculate a line scale corresponding to a 110/10kV power supply mode according to a substation scale corresponding to an 110/10kV power supply mode;

the second substation scale determining module 703 is configured to determine a substation scale corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale calculated according to the total load of the power supply area and the main variable capacitance of the 110kV transformer and the 35/10kV substation scale, where the 35/10kV substation scale is calculated according to a relationship between the load density of the power supply area and the main transformer capacity of the 35/10kV transformer or according to the power supply radius of the 35/10kV substation.

And the second line scale calculating module 704 is used for calculating the line scale corresponding to the 110/35/10kV power supply mode according to the substation scale corresponding to the 110/35/10kV power supply mode.

The cost calculation module 705 is configured to calculate, according to a relationship between the scale of the substation and the cost of the high-voltage substation, the cost of the high-voltage substation corresponding to the 110/10kV power supply mode and the cost of the high-voltage substation corresponding to the 110/35/10kV power supply mode under the load density, respectively. Preferably, the cost calculation module 103 is specifically configured to:respectively calculating the investment cost of a power distribution network corresponding to an 110/10kV power supply mode and the investment cost of the power distribution network corresponding to a 110/35/10kV power supply mode; wherein, C_munRepresents the investment cost of the distribution network, C_SUBRepresents the investment cost of the transformer substation scale, C_lenRepresents the investment cost of the line scale, C^kThe cost of each high-voltage substation is expressed, and k is expressed as a voltage grade; NS (server)^kExpressed as the number of seats of the substation corresponding to the voltage class, NT^kExpressed as the number of transformers corresponding to the voltage class,expressed as the maximum number of transformers corresponding to the voltage class, Mo represents the unit price of the line, Len^kThe total length of the line is shown,and lambda is the investment cost ratio corresponding to the number of the transformer substation seats.

And the power supply mode selection module 706 is used for selecting an 110/10kV power supply mode or a 110/35/10kV power supply mode as a power supply mode of the high-voltage distribution network according to the cost of the high-voltage substation.

According to the system for selecting the power supply mode of the high-voltage distribution network, provided by the embodiment of the invention, the transformer substation scale corresponding to the 110/10kV power supply mode and the transformer substation scale corresponding to the 110/35/10kV power supply mode are respectively determined according to the relation among the total load and the load density of a power supply area and the main transformer capacity of a transformer, or the relation between the power supply radius of the transformer substation and the total area of the power supply area, the line scale corresponding to the power supply mode is calculated according to the transformer substation scale, and the transformer substation scale with lower investment cost under the same load density is selected as the power supply mode of the distribution network according to the relation model among the transformer substation scale, the line scale and the investment cost of the distribution network. The scheme has a mature power supply mode selection strategy of the power distribution network, so that the situations of unreasonable voltage level setting, repeated construction and investment waste can be reduced in the actual power grid planning and construction process. Wherein the investment cost of the power distribution network comprises the investment cost of a transformer substation and the investment cost of a line scale.

Preferably, as shown in fig. 8, the first substation scale determining module 701 in the embodiment of fig. 7 includes:

the first transformer number calculating submodule 7011 is configured to calculate a ratio of a total load of a power supply area to a main transformer capacity of a 110kV transformer, and calculate the number of 110kV transformers corresponding to a power supply capacity according to a product of the ratio and a capacity-to-load ratio of the 110kV transformer;

the first substation seat number calculating submodule 7012 is configured to calculate, according to the number of 110kV transformers corresponding to the power supply capacity, the number of 110kV substations corresponding to the power supply capacity by combining the corresponding relationship between the number of transformers and the number of substations;

the first substation scale determining submodule 7013 is configured to determine that the number of 110kV transformers and the number of 110kV substation bases corresponding to the power supply capacity are 110/10kV substation scales corresponding to the power supply capacity;

or,

the second substation seat number calculating submodule 7014 is configured to calculate the power supply area of a single 110kV substation according to the power supply radius of the single 110kV substation, and calculate the seat number of the single 110kV substation corresponding to the power supply radius according to the relationship between the power supply area of the single 110kV substation and the total area of the power supply area;

the second transformer number calculating submodule 7015 is configured to calculate, according to the number of 110kV substation seats corresponding to the power supply radius, the number of 110kV transformers corresponding to the power supply radius by combining the correspondence between the number of transformers and the number of substation seats;

the second substation scale determining submodule 7016 is configured to determine that the number of 110kV transformers and the number of 110kV substation bases corresponding to the power supply radius are 110/35/10kV substation scales corresponding to the power supply radius;

the first substation scale selection submodule 7017 is configured to select, according to the number of 110kV substations, an 110/35/10kV substation scale corresponding to the power supply capacity or a 110/10kV substation scale corresponding to the power supply radius as the substation scale corresponding to the 110/10kV power supply mode.

As shown in fig. 9, the first line size calculating module 702 in the embodiment shown in fig. 7 specifically includes:

the first grid structure determining submodule 7021 is configured to determine a grid structure corresponding to the 110/10kV power supply mode according to the load density of the power supply area;

the first line length calculating submodule 7022 is configured to calculate the total length of the 110kV high-voltage distribution line according to the number of 110kV substation seats and the grid structure corresponding to the 110/10kV power supply mode;

the second line length calculating submodule 7023 is configured to determine the power supply radius of the 10kV medium-voltage distribution line according to the number of the 110kV substation bases, and calculate the total length of the 10kV medium-voltage distribution line according to the power supply radius and the number of returns of the 10kV medium-voltage distribution line;

and the first line scale determining sub-module 7024 is configured to calculate a sum of the total length of the 110kV high-voltage distribution line and the total length of the 10kV medium-voltage distribution line, as the line scale corresponding to the 110/10kV power supply mode.

As shown in fig. 10, the second substation scale determining module 703 in the embodiment shown in fig. 7 includes:

the third transformer number calculating submodule 7031 is configured to calculate a ratio of a total load of a power supply area to a main transformer capacity of the 110kV transformer, and calculate the number of the 110kV transformers according to a product of the ratio and a capacity-to-load ratio of the 110kV transformers;

the third substation seat number calculating submodule 7032 is configured to calculate the number of seats of the 110kV substation according to the number of 110kV transformers and by combining the corresponding relationship between the number of transformers and the number of seats of the substation;

and the third substation scale determining submodule 7033 is used for determining the scale of the substations of the 110kV transformers and the 110kV substations as 110/35/10 kV.

As a preferred embodiment, as shown in fig. 11, the second substation size determining module 703 in the embodiment shown in fig. 7 further includes:

the fourth transformer number calculating submodule 7034 is configured to calculate the number of 35/10kV transformers corresponding to power supply capacity in the power supply range of each 110kV substation according to the power supply area and load density corresponding to the power supply range of each 110kV substation, and the capacity-to-load ratio and main transformer capacity of the 35/10kV transformer;

the fourth substation seat number calculation submodule 7035 is configured to calculate, according to the 35/10kV transformer seat numbers corresponding to the power supply capacity, the 35/10kV substation seat numbers corresponding to the power supply capacity within the power supply range of each 110kV substation in combination with the correspondence between the transformer seat numbers and the transformer substation seat numbers;

the fourth substation scale determining submodule 7036 is used for determining the number of 35/10kV transformers and the number of 35/10kV substations corresponding to the power supply capacity as the 35/10kV substation scale corresponding to the power supply capacity in the power supply range of each 110kV substation;

the fifth substation seat number calculating submodule 7037 is used for calculating the seat number of the 35/10kV substation corresponding to the power supply radius in the power supply range of each 110kV substation according to the power supply area corresponding to the power supply range of each 110kV substation and the power supply radius of each 35/10kV substation;

the fifth transformer station number calculating submodule 7038 is configured to calculate, according to the 35/10kV substation station number corresponding to the power supply radius, the 35/10kV transformer station number corresponding to the power supply radius in the power supply range of each 110kV substation in combination with the correspondence between the substation station number and the transformer station number;

the fifth substation scale determining submodule 7039 is used for determining the number of 35/10kV substations corresponding to the power supply radius and the number of 35/10kV transformers as the scale of 35/10kV substations corresponding to the power supply radius in the power supply range of each 110kV substation;

the second substation scale selection submodule 70310 is used for selecting the 35/10kV substation scale corresponding to the power supply capacity or the 35/10kV substation scale corresponding to the power supply radius as the 35/10kV substation scale in the 110/35/10kV power supply mode according to the number of the 35/10kV substations;

and the sixth substation scale determining submodule 70311 is used for determining the substation scale corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale and the 35/10kV substation scale.

As shown in fig. 12, the second line size calculation module 704 in the embodiment shown in fig. 7 includes:

the second grid structure determining submodule 7041 is configured to determine, according to the load density of the power supply area, a grid structure corresponding to the 110/35/10kV power supply mode;

the third line length calculating submodule 7042 is configured to calculate the total length of the 110kV high-voltage distribution line according to the number of seats and the grid structure of the 110kV substation corresponding to the 110/35/10kV power supply mode;

the distance and return number calculating submodule 7043 is used for calculating the average distance and the line return number of the 35/10kV transformer substation in the power supply range of each 110kV transformer substation according to the number of 35/10kV transformer substation seats and the number of transformer substations in the power supply range of each 110kV transformer substation;

the fourth line length calculating submodule 7044 is used for calculating the total length of the 35kV high-voltage distribution line according to the average distance and the number of lines of the 35/10kV substation;

a fifth line length calculating submodule 7045, configured to calculate the total length of the 10kV medium-voltage distribution line according to the main transformer capacity and the number of 35/10kV transformers;

and the second line scale determining submodule 7046 is configured to calculate a sum of the total length of the 110kV high-voltage distribution line, the total length of the 35kV high-voltage distribution line, and the total length of the 10kV medium-voltage distribution line, as a line scale corresponding to the 110/35/10kV power supply mode.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above-described embodiments of the present invention do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for selecting a power supply mode of a high-voltage distribution network is characterized by comprising the following steps:

determining the substation scale corresponding to the 110/35/10kV power supply mode according to 110/35/10kV substation scale obtained by calculating the relation between the total load of a power supply area and the main transformer capacity of a 110kV transformer and 35/10kV substation scale, wherein the 35/10kV substation scale is obtained by calculating according to the relation between the load density of the power supply area and the main transformer capacity of a 35/10kV transformer or according to the power supply radius of a 35/10kV substation;

according to the relationship among the scale of the transformer substation, the scale of the line and the investment cost of the power distribution network, respectively calculating the investment cost of the power distribution network corresponding to the 110/10kV power supply mode and the investment cost of the power distribution network corresponding to the 110/35/10kV power supply mode under the same load density;

2. The method for selecting the power supply mode of the high-voltage power distribution network according to claim 1, wherein the determining the scale of the substation corresponding to the 110/10kV power supply mode according to the relation between the total load of the power supply area and the main transformer capacity of the 110kV transformer or according to the relation between the power supply radius of the 110kV substation and the total area of the power supply area comprises:

according to the number of the 110kV transformer substation seats corresponding to the power supply radius, the number of the 110kV transformers corresponding to the power supply radius is obtained through calculation by combining the corresponding relation between the number of the transformers and the number of the transformer substation seats;

3. The method for selecting the power supply mode of the high-voltage distribution network according to claim 2, wherein the step of determining the scale of the substation corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale and the 35/10kV substation scale calculated according to the relation between the total load of the power supply area and the main transformer capacity of the 110kV transformer comprises the following steps:

4. The method for selecting the power supply mode of the high-voltage distribution network according to claim 3, wherein the determining of the scale of the substation corresponding to the 110/35/10kV power supply mode according to the 110/35/10kV substation scale and the 35/10kV substation scale calculated according to the relationship between the total load of the power supply area and the main transformer capacity of the 110kV transformer further comprises:

and the number of the first and second groups,

5. The method for selecting the power supply mode of the high-voltage power distribution network according to claim 1, wherein the step of calculating the investment cost of the power distribution network corresponding to the 110/10kV power supply mode and the investment cost of the power distribution network corresponding to the 110/35/10kV power supply mode under the same load density according to the relationship among the substation scale, the line scale and the investment cost of the power distribution network comprises the following steps:

according to the relationship model:respectively calculating the investment cost of a power distribution network corresponding to an 110/10kV power supply mode and the investment cost of the power distribution network corresponding to a 110/35/10kV power supply mode; wherein, C_munRepresents the investment cost of the distribution network, C_SUBRepresents the investment cost of the transformer substation scale, C_lenRepresents the investment cost of the line scale, C^kThe cost of each high-voltage substation is expressed, and k is expressed as a voltage grade; NS (server)^kExpressed as the number of seats of the substation corresponding to the voltage class, NT^kExpressed as the number of transformers corresponding to the voltage class,expressed as the maximum number of transformers corresponding to the voltage class, Mo represents the unit price of the line, Len^kAnd the total line length corresponding to the voltage grade is shown, and lambda is the investment cost ratio corresponding to the number of the transformer substation seats.

6. The method for selecting the power supply mode of the high-voltage power distribution network according to claim 1, wherein the calculating the line size corresponding to the 110/10kV power supply mode according to the substation size corresponding to the 110/10kV power supply mode comprises:

7. A system for selecting a power supply mode of a high voltage distribution network, comprising:

the cost calculation module is used for respectively calculating the investment cost of the power distribution network corresponding to the 110/10kV power supply mode and the investment cost of the power distribution network corresponding to the 110/35/10kV power supply mode under the same load density within the load density range according to a relation model among the scale of the transformer substation, the scale of the line and the investment cost of the power distribution network;

8. The system for selecting a supply mode of a high voltage distribution network according to claim 7, wherein the first substation size determination module comprises:

9. The system for selecting a supply mode of a high voltage distribution network according to claim 8, wherein the second substation dimensioning module comprises:

the fourth substation scale determining submodule is used for determining the 35/10kV transformer station number and the 35/10kV substation seat number corresponding to the power supply capacity in the power supply range of the 110kV substation as the 35/10kV substation scale corresponding to the power supply capacity in the power supply range of each 110kV substation; and the number of the first and second groups,

10. The system for selecting a power supply mode of a high-voltage distribution network according to claim 7, wherein the first line scale calculation module comprises:

the second line length calculation submodule is used for determining the power supply radius of the 10kV medium-voltage distribution line according to the number of the 110kV transformer substation seats and calculating the total length of the 10kV medium-voltage distribution line according to the power supply radius and the number of the 10kV medium-voltage distribution line;