Low-voltage flexible interconnection diversified power distribution area line loss evaluation method and related equipment

Abstract

The invention belongs to the technical field of power systems and automation thereof, and discloses a low-voltage flexible interconnection diversified power distribution area line loss assessment method and related equipment, and the method can be used for a power distribution area under the access of diversified resources such as low-voltage flexible interconnection, distributed power supplies, charging piles, energy storage and the like through obtaining the input variables of a to-be-assessed area, and evaluating the line loss of the to-be-assessed area. Inputting the data into a pre-constructed diversified power distribution area line loss evaluation model, so as to accurately output an alternating current area line loss rate and a direct current micro-grid line loss rate; according to the method, line loss calculation is detailedly divided into the alternating-current transformer area line loss rate and the direct-current micro-network line loss rate, the prominent problems that the transformer area line loss rate is suddenly increased and suddenly decreased and the transformer area line loss is larger along with more photovoltaic and charging piles are connected are effectively solved, the accuracy of line loss evaluation is improved, the working efficiency of statistical analysis personnel is improved, and the working efficiency of the statistical analysis personnel is improved. And the authenticity and reliability of the assessment indexes are ensured, and an accurate and efficient assessment mode is provided for line loss management of the low-voltage flexible interconnection power distribution area.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems and automation thereof, and specifically relates to a line loss assessment method for a low-voltage flexible interconnected diversified distribution station area and related equipment. Background Art

[0002] With the grid connection of large-scale distributed photovoltaic power generation, and the widespread popularity of new loads represented by electric vehicles, electric heating and other electric energy replacement loads, the diversification trend of distribution substations has become prominent, and the power quality and operation control of existing distribution substations have also been affected. On the other hand, the inconsistent economic structure in the same region has led to a large difference in substation loads. Therefore, the interconnection and mutual supply of multiple substations through flexible DC technology in the low-voltage substation system will be a new solution to change the current status of substation operations, improve the power supply level of substations in multiple dimensions, and realize advanced application functions of substations. Line loss is the abbreviation of power loss in the power grid, which mainly refers to the power loss and loss generated in various links such as transmission, transformation, distribution and marketing during the transmission of electricity from power plants to power users.

[0003] In terms of line loss assessment, with the large-scale access of a large number of distributed power sources, electric vehicles, distributed energy storage and other diversified resources, as well as the interconnection and mutual supply of multiple substations by low-voltage substation systems through flexible DC technology, the difficulty of line loss assessment has increased. At present, there is no unified substation line loss assessment method that considers the access of diversified resources such as low-voltage substation flexible interconnection, distributed power sources, charging piles, and energy storage. The existing line loss statistical analysis method is prone to cause a sudden increase or decrease in the substation line loss rate, or the prominent problem that the more photovoltaic and charging piles are connected, the greater the substation line loss, resulting in poor accuracy of line loss assessment, reducing the work efficiency of statistical analysts, and also affecting the authenticity and reliability of assessment indicators.

[0004] It can be seen from this that for distribution stations with access to diversified resources such as low-voltage flexible interconnection, distributed power sources, charging piles, and energy storage, there is a prominent problem of sudden increase or decrease in line loss rate, or the line loss in the station area increases with the increase in the number of photovoltaic and charging pile connections. There is a lack of accurate and efficient line loss assessment methods. Summary of the invention

[0005] The purpose of the present invention is to provide a line loss assessment method and related equipment for diversified distribution station areas with low-voltage flexible interconnection, so as to solve the prominent problem that the line loss rate of distribution stations under the access of diversified resources such as low-voltage flexible interconnection, distributed power sources, charging piles, energy storage, etc. suddenly increases or decreases, or the line loss in the station area increases with the increase of photovoltaic and charging pile access, and the technical problem of the lack of accurate and efficient line loss assessment method.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A line loss assessment method for a low-voltage flexible interconnected diversified distribution area, comprising: Obtain input variables of the low voltage flexible interconnected diversified distribution substation to be evaluated; The input variables of the diversified distribution station area with low-voltage flexible interconnection to be evaluated are input into a pre-built diversified distribution station area line loss evaluation model, and the AC station area line loss rate and the DC microgrid line loss rate are output to realize the line loss evaluation of the diversified distribution station area with low-voltage flexible interconnection according to the AC station area line loss rate and the DC microgrid line loss rate.

[0007] Furthermore, the diversified distribution area line loss assessment model includes a low-voltage flexible interconnected AC area line loss calculation model and a flexible interconnected DC microgrid line loss calculation model; wherein, The AC transformer area line loss calculation model for low voltage flexible interconnection is constructed in three ways: The first type: The line loss construction method of installing ordinary charging piles in the AC area with low-voltage flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area )﹣(The outflow of AC bidirectional electric energy meter connected to the flexible interconnection device in this area + The AC energy meter of the charging pile in this area and + Other AC energy meters in this area and ); The specific formula for the line loss rate in the AC station area is as follows: AC station area line loss rate = (1- )×100%=(1- )×100% The second method: The line loss construction method of installing V2G charging piles in the AC area with low-voltage flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area + The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in this area and )﹣(The outflow of AC bidirectional electric energy meter connected to the flexible interconnection device in this area + The outflow of AC bidirectional electric energy meter of V2G charging pile in this area and + Other AC energy meters in this area and ); The specific formula for the line loss rate in the AC station area is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The third method: Install V2G charging piles and photovoltaic line loss in the flexible interconnected AC area at the same time: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area + The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in this area and + The amount of electricity flowing into the photovoltaic AC bidirectional energy meter in this area and )﹣(The outflow of AC bidirectional electric energy meter connected to the flexible interconnection device in this area + The outflow of AC bidirectional electric energy meter of V2G charging pile in this area and + The outflow of photovoltaic AC bidirectional electric energy meter in this area and + Other AC energy meters in this area and ), the specific formula of AC line loss rate is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The DC microgrid line loss calculation model based on flexible interconnection is divided into three construction methods: The first one: The DC microgrid installation method based on flexible interconnection and the line loss construction method of ordinary charging piles: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and )﹣(DC microgrid charging pile DC energy meter power and + Based on flexible interconnection of DC microgrid other DC energy meters and ); The specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100% The second method: The line loss construction method of installing V2G charging piles in DC microgrid based on flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ), the specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100% The third method: A flexible interconnected DC microgrid with V2G charging piles and photovoltaic line loss installed at the same time: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and + Based on flexible interconnection, DC microgrid photovoltaic AC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + DC microgrid photovoltaic AC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ), the specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100%.

[0008] Furthermore, the AC bidirectional electric energy meter on the low-voltage side of the transformer outputs electric power The amount of electricity flowing from the low-voltage side of the transformer to the grid, and the amount of electricity flowing out of the AC bidirectional energy meter on the low-voltage side of the transformer The amount of electricity flowing from the power grid to the low-voltage side of the transformer; the amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device The amount of electricity flowing from the flexible interconnection device to the AC station area, and the amount of electricity flowing out of the AC bidirectional energy meter connected to the flexible interconnection device is the amount of electricity flowing to the flexible interconnection device in this AC area; the amount of electricity flowing into the AC bidirectional energy meter of each V2G charging pile and is the sum of the power flowing from each V2G charging pile in this area to the AC area, and the sum of the power flowing out of the AC bidirectional power meter of the V2G charging pile is the sum of the electricity flowing to each V2G charging pile in this AC area; the sum of the electricity flowing into the photovoltaic AC bidirectional energy meter The sum of the power supplied by each photovoltaic power generation system in this area to the AC area, and the sum of the power outflow from the photovoltaic AC bidirectional energy meter It is the total amount of electricity consumed by each photovoltaic user in this area.

[0009] Furthermore, the DC microgrid based on flexible interconnection connects the DC bidirectional electric energy meters of each flexible interconnection device to flow in and is the sum of the amount of electricity flowing from the flexible interconnected DC microgrid to each flexible interconnected device, and the sum of the amount of electricity flowing out of the DC bidirectional electric energy meter connected to each flexible interconnected device of the flexible interconnected DC microgrid is the sum of the electricity flowing from each flexible interconnection device to the DC microgrid based on flexible interconnection; the sum of the electricity flowing into the DC bidirectional electric energy meter of the V2G charging pile based on flexible interconnection is the sum of the power flowing from each V2G charging pile to the DC microgrid based on flexible interconnection, and the sum of the power flowing out of the DC bidirectional electric energy meter of the DC microgrid charging pile based on flexible interconnection is the sum of the electricity flowing from the flexible interconnected DC microgrid to each V2G charging pile; the sum of the electricity flowing into the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid The sum of the power supplied by each photovoltaic power generation system to the flexible interconnected DC microgrid, and the sum of the power outflow from the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid It is the total electricity consumption of each photovoltaic user in the DC microgrid based on flexible interconnection.

[0010] Furthermore, the AC bidirectional energy meter on the low-voltage side of the transformer is installed at the outlet port on the low-voltage side of the transformer; the AC bidirectional energy meters connected to the flexible interconnection device are respectively installed at the AC incoming ports of the flexible interconnection device; the AC energy meters of the charging piles are respectively installed at the incoming ports of the AC station area connecting each charging pile; the AC bidirectional energy meters of the V2G charging piles are respectively installed at the incoming ports of the AC station area connecting each V2G charging pile; the photovoltaic AC bidirectional energy meters are respectively installed at each photovoltaic access point in the AC station area; and the other AC energy meters are installed at the incoming ports of other loads in the AC station area except for charging piles and photovoltaics.

[0011] Furthermore, the DC bidirectional energy meters connected to each flexible interconnection device of the DC microgrid based on flexible interconnection are respectively installed at the DC outlet ports of each flexible interconnection device, and the DC energy meters of the charging piles are respectively installed at the incoming ports of each charging pile connected to the DC microgrid based on flexible interconnection; the DC bidirectional energy meters of the V2G charging piles are respectively installed at the incoming ports of each V2G charging pile connected to the DC microgrid based on flexible interconnection; the photovoltaic DC bidirectional energy meters are respectively installed at each photovoltaic access point of the DC microgrid based on flexible interconnection; and the other DC energy meters are installed at the incoming ports of other loads of the DC microgrid based on flexible interconnection except for charging piles and photovoltaics.

[0012] A low-voltage flexible interconnected diversified distribution area line loss assessment system, comprising: A data acquisition module, used to obtain input variables of the low-voltage flexible interconnected diversified distribution substation to be evaluated; The line loss assessment module is used to input the input variables of the low-voltage flexible interconnected diversified distribution station area to be evaluated into a pre-built diversified distribution station area line loss assessment model, and output the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the low-voltage flexible interconnected diversified distribution station area according to the AC station area line loss rate and the DC microgrid line loss rate.

[0013] A device comprising: Memory for storing computer programs; A processor is used to implement the steps of the above-mentioned low-voltage flexible interconnected diversified distribution station area line loss assessment method when executing the computer program.

[0014] A computer-readable storage medium stores a computer program, which, when executed by a processor, is used to implement the steps of the above-mentioned low-voltage flexible interconnected diversified distribution area line loss assessment method.

[0015] A computer program product includes a computer program, which, when executed by a processor, implements the steps of the above-mentioned low-voltage flexible interconnected diversified distribution station area line loss assessment method.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a line loss assessment method for a diversified distribution station area with low-voltage flexible interconnection. The method can obtain input variables of the station area to be assessed and input them into a pre-built diversified distribution station area line loss assessment model for the distribution station area with diversified resources such as low-voltage flexible interconnection, distributed power sources, charging piles, and energy storage, thereby accurately outputting the AC station area line loss rate and the DC microgrid line loss rate. In the method, the line loss calculation is divided into the AC station area line loss rate and the DC microgrid line loss rate in detail, which effectively solves the prominent problems of sudden increase or decrease in the station area line loss rate and greater station area line loss as more photovoltaic and charging piles are connected, improves the accuracy of line loss assessment, not only improves the work efficiency of statistical analysts, but also ensures the authenticity and reliability of assessment indicators, and provides an accurate and efficient assessment method for line loss management of low-voltage flexible interconnected distribution stations.

[0017] Preferably, in the present invention, the construction method of the diversified distribution station area line loss assessment model is refined, including a low-voltage flexible interconnected AC station area line loss calculation model and a flexible interconnected DC microgrid line loss calculation model, and is respectively refined for ordinary charging piles, V2G charging piles, and the simultaneous installation of V2G charging piles and photovoltaics. This refined construction method can more accurately reflect the line loss conditions of distribution stations in different scenarios, and provides a diversified distribution station area line loss calculation method when connected to different loads and distributed power sources such as photovoltaics for line loss assessment of diversified distribution stations, which brings convenience to station managers (grid members) and improves the accuracy of calculation and the authenticity and reliability of assessment indicators.

[0018] Preferably, in the present invention, a line loss calculation model for an AC substation area with low voltage flexible interconnection and a method for obtaining input variables of a DC microgrid line loss calculation model based on flexible interconnection are provided, which provide a basis for accurately calculating the line loss rate of the AC substation area.

[0019] Preferably, in the present invention, the installation locations of the AC bidirectional electric energy meter on the low-voltage side of the transformer, the AC bidirectional electric energy meter connected to the flexible interconnection device, the charging pile AC electric energy meter, the V2G charging pile AC bidirectional electric energy meter, the photovoltaic AC bidirectional electric energy meter and other AC electric energy meters are specified; this ensures the accuracy and reliability of the data and provides strong support for the precise assessment of line losses in the substation area.

[0020] Preferably, in the present invention, the installation locations of the DC bidirectional energy meters, charging pile DC energy meters, V2G charging pile DC bidirectional energy meters, photovoltaic DC bidirectional energy meters and other DC energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid are specified; this also ensures the accuracy and reliability of the data, and provides strong support for the accurate assessment of the DC microgrid line loss; in addition, the clear provisions of these installation locations also help to improve the efficiency and accuracy of the assessment work. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of installing a common charging pile in a low-voltage flexible interconnected AC station area provided by an embodiment of the present invention; Figure 2 A schematic diagram of installing a V2G charging pile in a low-voltage flexible interconnected AC station area provided by an embodiment of the present invention; Figure 3 A schematic diagram of simultaneously installing V2G charging piles and photovoltaics in a low-voltage flexible interconnected AC station area provided by an embodiment of the present invention; Figure 4 A schematic diagram of installing a common charging pile in a DC microgrid based on flexible interconnection provided by an embodiment of the present invention; Figure 5 A schematic diagram of installing a V2G charging pile in a DC microgrid based on flexible interconnection provided in an embodiment of the present invention; Figure 6 A schematic diagram of simultaneously installing V2G charging piles and photovoltaics in a DC microgrid based on flexible interconnection provided by an embodiment of the present invention; Figure 7 A flow chart of a line loss assessment method for a low-voltage flexible interconnected diversified distribution area provided by the present invention; Figure 8 A schematic diagram of the structure of a low-voltage flexible interconnected diversified distribution area line loss assessment system provided by the present invention. DETAILED DESCRIPTION

[0022] Example 1 The present invention provides a method for evaluating line loss in a low-voltage flexible interconnected diversified distribution area. Figure 7 As shown, the following steps are included: S1: Obtain input variables of the low-voltage flexible interconnected diversified distribution substation to be evaluated; S2: Input the input variables of the diversified distribution station area with low voltage flexible interconnection to be evaluated into the pre-built diversified distribution station area line loss assessment model, and output the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the diversified distribution station area with low voltage flexible interconnection according to the AC station area line loss rate and the DC microgrid line loss rate.

[0023] Specifically, the diversified distribution area line loss assessment model includes a low-voltage flexible interconnected AC area line loss calculation model and a flexible interconnected DC microgrid line loss calculation model; wherein, The AC transformer area line loss calculation model for low voltage flexible interconnection is constructed in three ways: The first type: The line loss construction method of installing ordinary charging piles in the AC area with low-voltage flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area )﹣(The outflow of AC bidirectional electric energy meter connected to the flexible interconnection device in this area + The AC energy meter of the charging pile in this area and + Other AC energy meters in this area and ); The specific formula for the line loss rate in the AC station area is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The second method: The line loss construction method of installing V2G charging piles in the AC area with low-voltage flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area + The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in this area and )﹣(The outflow of AC bidirectional electric energy meter connected to the flexible interconnection device in this area + The outflow of AC bidirectional electric energy meter of V2G charging pile in this area and + Other AC energy meters in this area and ); The specific formula for the line loss rate in the AC station area is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The third method: Install V2G charging piles and photovoltaic line loss in the flexible interconnected AC area at the same time: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area + The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in this area and + The amount of electricity flowing into the photovoltaic AC bidirectional energy meter in this area and )﹣(The outflow of AC bidirectional electric energy meter connected to the flexible interconnection device in this area + The outflow of AC bidirectional electric energy meter of V2G charging pile in this area and + The outflow of photovoltaic AC bidirectional electric energy meter in this area and + Other AC energy meters in this area and ), the specific formula of AC line loss rate is as follows: AC station area line loss rate = (1- )×100%=(1- )×100% The DC microgrid line loss calculation model based on flexible interconnection is divided into three construction methods: The first one: The DC microgrid installation method based on flexible interconnection and the line loss construction method of ordinary charging piles: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and )﹣(DC microgrid charging pile DC energy meter power and + Based on flexible interconnection of DC microgrid other DC energy meters and ); The specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100% The second method: The line loss construction method of installing V2G charging piles in DC microgrid based on flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ), the specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100% The third method: A flexible interconnected DC microgrid with V2G charging piles and photovoltaic line loss installed at the same time: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and + Based on flexible interconnection, DC microgrid photovoltaic AC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + DC microgrid photovoltaic AC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ), the specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100%.

[0024] Here, the AC bidirectional electric energy meter on the low-voltage side of the transformer outputs the electric energy The amount of electricity flowing from the low-voltage side of the transformer to the grid, and the amount of electricity flowing out of the AC bidirectional energy meter on the low-voltage side of the transformer The amount of electricity flowing from the power grid to the low-voltage side of the transformer; the amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device The amount of electricity flowing from the flexible interconnection device to the AC station area, and the amount of electricity flowing out of the AC bidirectional energy meter connected to the flexible interconnection device is the amount of electricity flowing to the flexible interconnection device in this AC area; the amount of electricity flowing into the AC bidirectional energy meter of each V2G charging pile and is the sum of the power flowing from each V2G charging pile in this area to the AC area, and the sum of the power flowing out of the AC bidirectional power meter of the V2G charging pile is the sum of the electricity flowing to each V2G charging pile in this AC area; the sum of the electricity flowing into the photovoltaic AC bidirectional energy meter The sum of the power supplied by each photovoltaic power generation system in this area to the AC area, and the sum of the power outflow from the photovoltaic AC bidirectional energy meter It is the total amount of electricity consumed by each photovoltaic user in this area.

[0025] In addition, the DC microgrid based on flexible interconnection connects the DC bidirectional electric energy meters of each flexible interconnection device to flow in and is the sum of the amount of electricity flowing from the flexible interconnected DC microgrid to each flexible interconnected device, and the sum of the amount of electricity flowing out of the DC bidirectional electric energy meter connected to each flexible interconnected device of the flexible interconnected DC microgrid is the sum of the electricity flowing from each flexible interconnection device to the DC microgrid based on flexible interconnection; the sum of the electricity flowing into the DC bidirectional electric energy meter of the V2G charging pile based on flexible interconnection is the sum of the power flowing from each V2G charging pile to the DC microgrid based on flexible interconnection, and the sum of the power flowing out of the DC bidirectional electric energy meter of the DC microgrid charging pile based on flexible interconnection is the sum of the electricity flowing from the flexible interconnected DC microgrid to each V2G charging pile; the sum of the electricity flowing into the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid The sum of the power supplied by each photovoltaic power generation system to the flexible interconnected DC microgrid, and the sum of the power outflow from the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid It is the total electricity consumption of each photovoltaic user in the DC microgrid based on flexible interconnection.

[0026] Among them, the AC bidirectional electric energy meter on the low-voltage side of the transformer is installed at the outlet port on the low-voltage side of the transformer; the AC bidirectional electric energy meters connected to the flexible interconnection device are respectively installed at the AC incoming ports of the flexible interconnection device; the AC electric energy meters of the charging piles are respectively installed at the incoming ports of the AC station area connecting each charging pile; the AC bidirectional electric energy meters of the V2G charging piles are respectively installed at the incoming ports of the AC station area connecting each V2G charging pile; the photovoltaic AC bidirectional electric energy meters are respectively installed at each photovoltaic access point in the AC station area; and the other AC electric energy meters are installed at the incoming ports of other loads in the AC station area except charging piles and photovoltaics.

[0027] Among them, the DC bidirectional electric energy meters connected to each flexible interconnection device of the DC microgrid based on flexible interconnection are respectively installed at the DC outlet ports of each flexible interconnection device, and the DC electric energy meters of the charging piles are respectively installed at the incoming ports of each charging pile connected to the DC microgrid based on flexible interconnection; the DC bidirectional electric energy meters of the V2G charging piles are respectively installed at the incoming ports of each V2G charging pile connected to the DC microgrid based on flexible interconnection; the photovoltaic DC bidirectional electric energy meters are respectively installed at each photovoltaic access point of the DC microgrid based on flexible interconnection; and the other DC electric energy meters are installed at the incoming ports of other loads of the DC microgrid based on flexible interconnection except for charging piles and photovoltaics.

[0028] like Figure 8 As shown, the present invention also provides a line loss assessment system for a low-voltage flexible interconnected diversified distribution station area, comprising: a data acquisition module, used to obtain input variables of the low-voltage flexible interconnected diversified distribution station area to be evaluated; a line loss assessment module, used to input the input variables of the low-voltage flexible interconnected diversified distribution station area to be evaluated into a pre-built diversified distribution station area line loss assessment model, and output the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the low-voltage flexible interconnected diversified distribution station area according to the AC station area line loss rate and the DC microgrid line loss rate.

[0029] The present invention also provides a device, comprising: a memory for storing a computer program; a processor for implementing the steps of the line loss assessment method for a diversified distribution area with low-voltage flexible interconnection when executing the computer program.

[0030] When the processor executes the computer program, the steps of implementing the above-mentioned low-voltage flexible interconnected diversified distribution station area line loss assessment steps are implemented, for example: obtaining the input variables of the low-voltage flexible interconnected diversified distribution station area to be assessed; inputting the input variables of the low-voltage flexible interconnected diversified distribution station area to be assessed into a pre-built diversified distribution station area line loss assessment model, and outputting the AC station area line loss rate and the DC microgrid line loss rate, so as to implement the line loss assessment of the low-voltage flexible interconnected diversified distribution station area according to the AC station area line loss rate and the DC microgrid line loss rate.

[0031] Alternatively, the processor implements the functions of each module in the above system when executing the computer program, for example: a data acquisition module for acquiring input variables of the diversified distribution station area with low-voltage flexible interconnection to be evaluated; a line loss assessment module for inputting the input variables of the diversified distribution station area with low-voltage flexible interconnection to be evaluated into a pre-built diversified distribution station area line loss assessment model, and outputting the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the diversified distribution station area with low-voltage flexible interconnection according to the AC station area line loss rate and the DC microgrid line loss rate.

[0032] Exemplarily, the computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments that can complete preset functions, and the instruction segments are used to describe the execution process of the computer program in the line loss assessment device of the low-voltage flexible interconnected diversified distribution station area. For example, the computer program can be divided into a data acquisition module and a line loss assessment module; the specific functions of each module are as follows: a data acquisition module, which is used to obtain the input variables of the low-voltage flexible interconnected diversified distribution station area to be evaluated; a line loss assessment module, which is used to input the input variables of the low-voltage flexible interconnected diversified distribution station area to be evaluated into a pre-built diversified distribution station area line loss assessment model, and output the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the low-voltage flexible interconnected diversified distribution station area according to the AC station area line loss rate and the DC microgrid line loss rate.

[0033] The line loss assessment device for the diversified distribution area with low voltage flexible interconnection can be a computing device such as a desktop computer, a notebook, a PDA, and a cloud server. The line loss assessment device for the diversified distribution area with low voltage flexible interconnection can include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the above is an example of a line loss assessment device for the diversified distribution area with low voltage flexible interconnection, and does not constitute a limitation on the line loss assessment device for the diversified distribution area with low voltage flexible interconnection, and may include more components than the above, or a combination of certain components, or different components. For example, the line loss assessment device for the diversified distribution area with low voltage flexible interconnection can also include input and output devices, network access devices, buses, etc.

[0034] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The processor is the control center of the line loss assessment of the low-voltage flexible interconnected diversified distribution area, and uses various interfaces and lines to connect various parts of the entire low-voltage flexible interconnected diversified distribution area line loss assessment equipment.

[0035] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the low-voltage flexible interconnected diversified distribution area line loss assessment device by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory.

[0036] The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0037] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the method for evaluating line loss in a diversified distribution area with low-voltage flexible interconnection are implemented.

[0038] If the module / unit integrated in the low-voltage flexible interconnected diversified distribution area line loss assessment system is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0039] Based on this understanding, the present invention implements all or part of the processes in the above-mentioned low-voltage flexible interconnected diversified distribution area line loss assessment method, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned low-voltage flexible interconnected diversified distribution area line loss assessment method can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or preset intermediate form, etc.

[0040] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0041] It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electrical carrier signals and telecommunication signals.

[0042] The present invention will be further described below in conjunction with the embodiments and drawings: Example 2 As described in the background technology, in terms of line loss assessment, with the large-scale access of a large number of distributed power sources, electric vehicles, distributed energy storage and other diversified resources, and the application of low-voltage substation systems to interconnect and supply multiple substations through flexible DC technology, the difficulty of line loss assessment has increased. At present, there is no unified substation line loss assessment method that considers the access of diversified resources such as low-voltage substation flexible interconnection, distributed power sources, charging piles, and energy storage. The use of existing line loss statistical analysis methods is prone to cause a sudden increase or decrease in the substation line loss rate, or the prominent problem that the more photovoltaic and charging piles are connected, the greater the substation line loss, resulting in poor accuracy in line loss assessment, reducing the work efficiency of statistical analysts, and also affecting the authenticity and reliability of assessment indicators.

[0043] In order to solve the above problems, the present invention provides a line loss assessment method for a diversified distribution station area with low-voltage flexible interconnection. This method can solve the prominent problems of the lack of line loss calculation method for distribution station areas under the access of diversified resources such as low-voltage flexible interconnection, distributed power sources, charging piles, energy storage, etc., the sudden increase or decrease in line loss rate, or the increase in line loss in the area with the increase in photovoltaic and charging pile access, thereby improving the accuracy of line loss assessment.

[0044] This embodiment provides a line loss assessment method for a low-voltage flexible interconnected diversified distribution area, specifically including: The first step is to obtain the input variables of the diversified distribution station area of ​​the low-voltage flexible interconnection to be evaluated, where the input variables include the AC station area input variables of the low-voltage flexible interconnection and the DC microgrid line input variables based on the flexible interconnection.

[0045] Among them, the input variables of the AC substation of the low-voltage flexible interconnection include the outflow of the AC two-way electric energy meter on the low-voltage side of the transformer in this substation, the inflow of the AC two-way electric energy meter on the low-voltage side of the transformer in this substation, the inflow of the AC two-way electric energy meter connected to the flexible interconnection device in this substation, the outflow of the AC two-way electric energy meter connected to the flexible interconnection device in this substation, the power of the AC two-way electric energy meter of the charging pile in this substation, and the power of other AC electric energy meters in this substation; or include the outflow of the AC two-way electric energy meter on the low-voltage side of the transformer in this substation, the inflow of the AC two-way electric energy meter on the low-voltage side of the transformer in this substation, the inflow of the AC two-way electric energy meter connected to the flexible interconnection device in this substation, the inflow of the AC two-way electric energy meter of the V2G charging pile in this substation, and the power of the AC two-way electric energy meter connected to the flexible interconnection device in this substation. The outflow amount of the AC bidirectional energy meter of the device, the sum of the outflow amount of the AC bidirectional energy meter of the V2G charging pile in this area, and the sum of the amounts of other AC energy meters in this area; or including the outflow amount of the AC bidirectional energy meter on the low-voltage side of the transformer in this area, the inflow amount of the AC bidirectional energy meter on the low-voltage side of the transformer in this area, the inflow amount of the AC bidirectional energy meter connected to the flexible interconnection device in this area, the sum of the inflow amount of the AC bidirectional energy meter of the V2G charging pile in this area, the sum of the inflow amount of the photovoltaic AC bidirectional energy meter in this area, the outflow amount of the AC bidirectional energy meter connected to the flexible interconnection device in this area, the sum of the outflow amount of the AC bidirectional energy meter of the V2G charging pile in this area, the sum of the outflow amount of the photovoltaic AC bidirectional energy meter in this area, and the sum of the amounts of other AC energy meters in this area.

[0046] The input variables of the DC microgrid based on flexible interconnection include the sum of outflow electricity of the DC bidirectional electric energy meters of the flexible interconnection devices connected to the DC microgrid based on flexible interconnection, the sum of inflow electricity of the DC bidirectional electric energy meters of the flexible interconnection devices connected to the DC microgrid based on flexible interconnection, the sum of electricity of the DC electric energy meters of the DC microgrid charging piles based on flexible interconnection, and the sum of electricity of other DC electric energy meters of the DC microgrid based on flexible interconnection; or include the sum of outflow electricity of the DC bidirectional electric energy meters of the flexible interconnection devices connected to the DC microgrid based on flexible interconnection, the sum of inflow electricity of the DC bidirectional electric energy meters of the DC microgrid V2G charging piles based on flexible interconnection, and the sum of electricity of other DC electric energy meters of the DC microgrid based on flexible interconnection. The sum of the outflow of DC bidirectional energy meters of 2G charging piles, and the sum of the energy of other DC energy meters in the DC microgrid based on flexible interconnection; or the sum of the outflow of DC bidirectional energy meters of each flexible interconnected device connected to the DC microgrid based on flexible interconnection, the sum of the inflow of DC bidirectional energy meters of each flexible interconnected device connected to the DC microgrid based on flexible interconnection, the sum of the inflow of DC bidirectional energy meters of V2G charging piles in the DC microgrid based on flexible interconnection, the sum of the inflow of photovoltaic AC bidirectional energy meters in the DC microgrid based on flexible interconnection, the sum of the outflow of DC bidirectional energy meters of V2G charging piles in the DC microgrid based on flexible interconnection, the sum of the outflow of photovoltaic AC bidirectional energy meters in the DC microgrid based on flexible interconnection, and the sum of other DC energy meters in the DC microgrid based on flexible interconnection.

[0047] The second step is to input the input variables of the diversified distribution station area with low-voltage flexible interconnection to be evaluated into the pre-built diversified distribution station area line loss assessment model, and output the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the diversified distribution station area with low-voltage flexible interconnection according to the AC station area line loss rate and the DC microgrid line loss rate.

[0048] It should be noted that the above-mentioned input variables can be collected through relevant devices and input into the overall large model, namely the diversified distribution station area line loss assessment model; the AC substation area line loss rate and the DC microgrid line loss rate can be directly input; the input variables can also be input into the corresponding low-voltage flexible interconnected AC substation area line loss calculation model and the DC microgrid line loss calculation model based on flexible interconnection, and the AC substation area line loss rate and the DC microgrid line loss rate can be output respectively.

[0049] For the line loss calculation of the diversified distribution area of ​​low-voltage flexible interconnection, the specific calculation method is further explained below with reference to the attached figure: In this embodiment, the line loss calculation of the diversified distribution area of ​​low-voltage flexible interconnection includes the line loss calculation of the AC area of ​​low-voltage flexible interconnection and the line loss calculation of the DC microgrid based on flexible interconnection, which is as follows: The line loss calculation method for the AC station area with low voltage flexible interconnection includes: the line loss calculation method for the installation of ordinary charging piles in the AC station area with low voltage flexible interconnection, the line loss calculation method for the installation of V2G charging piles in the AC station area with low voltage flexible interconnection, and the line loss calculation method for the installation of V2G charging piles and photovoltaics in the AC station area with low voltage flexible interconnection at the same time.

[0050] A line loss calculation method for a DC microgrid based on flexible interconnection includes: a line loss calculation method for a DC microgrid installed with ordinary charging piles based on flexible interconnection, a line loss calculation method for a DC microgrid installed with V2G charging piles based on flexible interconnection, and a line loss calculation method for a DC microgrid installed with V2G charging piles and photovoltaics at the same time based on flexible interconnection.

[0051] First, the calculation method of line loss in the AC area of ​​low-voltage flexible interconnection: (1) Calculation method for line loss of ordinary charging piles installed in low-voltage flexible interconnected AC stations: Take the No. 1 transformer AC station area as an example. Figure 1 As shown, the AC bidirectional energy meter on the low-voltage side of the transformer is installed at the outlet port on the low-voltage side of transformer No. 1, the AC bidirectional energy meter connected to the flexible interconnection device is installed on the incoming line connecting the AC station area of ​​transformer No. 1 and the flexible interconnection device, the AC energy meters for charging piles are respectively installed at the incoming ports of the AC station area of ​​transformer No. 1 connecting each charging pile, and other AC energy meters are installed at the incoming ports of other loads except the charging piles in the AC station area of ​​transformer No. 1.

[0052] No. 1 transformer area power loss = power supply - power sales = (power outflow from the AC bidirectional electric energy meter on the low voltage side of No. 1 transformer - The amount of electricity flowing into the AC bidirectional energy meter on the low voltage side of No. 1 transformer + No. 1 transformer area connected to the AC bidirectional energy meter of the flexible interconnection device flowing into the )﹣(Outflow of AC bidirectional energy meter connected to flexible interconnection device in transformer area No. 1 + No. 1 transformer area charging pile AC energy meter power and +Other AC energy meters in the No. 1 transformer area and ); Line loss rate of transformer area No. 1 = (1- )×100%=(1- )×100% The outflow of AC bidirectional electric energy meter on the low voltage side of No. 1 transformer The amount of electricity flowing from the low-voltage side of transformer No. 1 to the grid and the amount of electricity flowing out of the AC bidirectional energy meter on the low-voltage side of transformer No. 1 The amount of electricity flowing from the power grid to the low-voltage side of transformer No. 1; the amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in the transformer No. 1 area The amount of electricity flowing from the flexible interconnection device to this AC area, and the amount of electricity flowing out of the AC bidirectional energy meter connected to the flexible interconnection device in the No. 1 transformer area It is the amount of electricity flowing to the flexible interconnection device in this AC section.

[0053] The line loss calculation method for installing ordinary charging piles in other low-voltage flexible interconnected AC substations is the same as the line loss calculation method for installing ordinary charging piles in the No. 1 transformer substation.

[0054] (2) Calculation method for line loss of V2G charging piles installed in low-voltage flexible interconnected AC stations: Take the No. 1 transformer AC station area as an example. Figure 2 As shown, the AC bidirectional energy meter on the low-voltage side of transformer No. 1 is installed at the outlet port on the low-voltage side of transformer No. 1, the AC bidirectional energy meter connecting the flexible interconnection device in the transformer No. 1 area is installed on the incoming line connecting the transformer No. 1 area and the flexible interconnection device, the AC bidirectional energy meters for V2G charging piles are respectively installed at the incoming ports of the transformer No. 1 area connected to each V2G charging pile, and other AC energy meters are installed at the incoming ports of other loads in the transformer No. 1 area except the V2G charging piles.

[0055] No. 1 transformer area power loss = power supply - power sales = (power outflow from the AC bidirectional electric energy meter on the low voltage side of No. 1 transformer - The amount of electricity flowing into the AC bidirectional energy meter on the low voltage side of No. 1 transformer + No. 1 transformer area connected to the AC bidirectional energy meter of the flexible interconnection device flowing into the + No. 1 transformer area V2G charging pile AC bidirectional energy meter inflow and )﹣(Outflow of AC bidirectional energy meter connected to flexible interconnection device in transformer area No. 1 + No. 1 transformer area V2G charging pile AC bidirectional energy meter outflow and +Other AC energy meters in the No. 1 transformer area and ); Line loss rate of transformer area No. 1 = (1- )×100%=(1- )×100% The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in the No. 1 transformer area and is the sum of the power flowing from each V2G charging pile in the No. 1 transformer area to the AC area, and the sum of the power flowing out of the AC bidirectional electric energy meter of the V2G charging pile in the No. 1 transformer area It is the sum of the electricity flowing to each V2G charging pile in this AC area.

[0056] The line loss calculation method for installing V2G charging piles in other low-voltage flexible interconnected AC areas is the same as the line loss calculation method for installing V2G charging piles in transformer area No. 1. At the same time, the calculation method for connecting energy storage to low-voltage flexible interconnected AC areas is the same as the line loss calculation method for installing V2G charging piles.

[0057] (3) Calculation method for line loss when V2G charging piles and photovoltaic power generation are installed simultaneously in low-voltage flexible interconnected AC stations: Take the No. 1 transformer AC station area as an example. Figure 3 As shown, the AC bidirectional energy meter on the low-voltage side of transformer No. 1 is installed at the outlet port on the low-voltage side of transformer No. 1, the AC bidirectional energy meter connected to the flexible interconnection device in the transformer area No. 1 is installed on the incoming line connecting the transformer area No. 1 and the flexible interconnection device, the AC bidirectional energy meters for V2G charging piles are respectively installed at the incoming ports of the transformer area No. 1 connecting each V2G charging pile, the AC bidirectional energy meters for photovoltaic are respectively installed at each photovoltaic access point in the transformer area No. 1, and other AC energy meters are installed at the incoming ports of other loads in the transformer area No. 1 except V2G charging piles and photovoltaics.

[0058] No. 1 transformer area power loss = power supply - power sales = (power outflow from the AC bidirectional electric energy meter on the low voltage side of No. 1 transformer - The amount of electricity flowing into the AC bidirectional energy meter on the low voltage side of No. 1 transformer + No. 1 transformer area connected to the AC bidirectional energy meter of the flexible interconnection device flowing into the + No. 1 transformer area V2G charging pile AC bidirectional energy meter inflow and +1 transformer area photovoltaic AC bidirectional energy meter inflow and )﹣(Outflow of AC bidirectional energy meter connected to flexible interconnection device in transformer area No. 1 + No. 1 transformer area V2G charging pile AC bidirectional energy meter outflow and +1 transformer area photovoltaic AC bidirectional energy meter outflow and +Other AC energy meters in the No. 1 transformer area and ); Line loss rate of transformer area No. 1 = (1- )×100%=(1- )×100% The amount of electricity flowing into the photovoltaic AC bidirectional energy meter in the No. 1 transformer area and The sum of the power supplied by each photovoltaic power generation system in the No. 1 transformer area to the AC area, and the sum of the power outflow from the photovoltaic AC bidirectional electric energy meter in the No. 1 transformer area It is the total amount of electricity consumed by each photovoltaic user in this AC station area.

[0059] The calculation method for the line loss of other low-voltage flexible interconnected AC areas with V2G charging piles and photovoltaic power installed at the same time is the same as the calculation method for the line loss of the No. 1 transformer area with V2G charging piles and photovoltaic power installed at the same time. At the same time, the calculation method for the connection of energy storage to the low-voltage flexible interconnected AC area is the same as the calculation method for the line loss of the V2G charging pile installed.

[0060] Second, the DC microgrid line loss calculation method based on flexible interconnection: (1) Calculation method of line loss of ordinary charging piles installed in DC microgrid based on flexible interconnection: by Figure 4 For example, the DC bidirectional energy meters connected to each flexible interconnection device of the DC microgrid based on flexible interconnection are respectively installed at the DC outlet ports connected to the flexible interconnection device of the AC station area of ​​transformer No. 1 and the flexible interconnection device of the AC station area of ​​transformer No. 2, the DC energy meters of the charging piles are respectively installed at the incoming ports of each charging pile connected to the DC microgrid based on flexible interconnection, and other DC energy meters are installed at other load incoming ports of the DC microgrid based on flexible interconnection except the charging piles.

[0061] The power loss of DC microgrid based on flexible interconnection = power supply - power sales = (the power outflow of DC bidirectional electric energy meter at the DC outlet port connected to the flexible interconnection device of AC station area of ​​transformer No. 1 and the flexible interconnection device of AC station area of ​​transformer No. 2 and - The amount of electricity flowing into the DC bidirectional energy meter at the DC outlet port connected to the flexible interconnection device of the AC station area of ​​the No. 1 transformer and the flexible interconnection device of the AC station area of ​​the No. 2 transformer and )﹣(DC microgrid charging pile DC energy meter power and + Based on flexible interconnection of DC microgrid other DC energy meters and ); Line loss rate of DC microgrid based on flexible interconnection = (1- )×100%=(1- )×100% The amount of electricity flowing into the DC bidirectional energy meter at the DC outlet port connected to the flexible interconnection device of the AC station area of ​​the No. 1 transformer and the flexible interconnection device of the AC station area of ​​the No. 2 transformer and The sum of the electricity flowing to the DC microgrid based on flexible interconnection by connecting the flexible interconnection device of the AC station area of ​​transformer No. 1 and the flexible interconnection device of the AC station area of ​​transformer No. 2, and the sum of the electricity flowing out of the DC bidirectional electric energy meter at the DC outlet port connecting the flexible interconnection device of the AC station area of ​​transformer No. 1 and the flexible interconnection device of the AC station area of ​​transformer No. 2 It is the sum of the electric quantity connected to the flexible interconnection device of the AC station area of ​​transformer No. 1 and the flexible interconnection device of the AC station area of ​​transformer No. 2 in the DC microgrid based on flexible interconnection.

[0062] Other methods for calculating line losses of ordinary charging piles installed in DC microgrids based on flexible interconnection Figure 4 The line loss calculation method for installing ordinary charging piles in a DC microgrid based on flexible interconnection is the same.

[0063] (2) Calculation method of line loss of V2G charging piles installed in DC microgrid based on flexible interconnection: by Figure 5 For example, the DC bidirectional energy meters connected to each flexible interconnection device of the DC microgrid based on flexible interconnection are respectively installed at the DC outlet ports connected to the flexible interconnection device of the AC station area of ​​transformer No. 1 and the flexible interconnection device of the AC station area of ​​transformer No. 2, the DC bidirectional energy meters of the V2G charging piles are respectively installed at the incoming ports of the DC microgrid based on flexible interconnection connecting each V2G charging pile, and other DC energy meters are installed at other load incoming ports of the DC microgrid based on flexible interconnection except the V2G charging piles.

[0064] The power loss of DC microgrid based on flexible interconnection = power supply - power sales = (the power outflow of DC bidirectional electric energy meter at the DC outlet port connected to the flexible interconnection device of AC station area of ​​transformer No. 1 and the flexible interconnection device of AC station area of ​​transformer No. 2 and - The amount of electricity flowing into the DC bidirectional energy meter at the DC outlet port connected to the flexible interconnection device of the AC station area of ​​the No. 1 transformer and the flexible interconnection device of the AC station area of ​​the No. 2 transformer and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ); Line loss rate of DC microgrid based on flexible interconnection = (1- )×100%=(1- )×100% DC microgrid V2G charging pile DC bidirectional energy meter inflow and is the sum of the power flowing from each V2G charging pile of the DC microgrid based on flexible interconnection to the DC microgrid based on flexible interconnection, and the sum of the power flowing out of the DC bidirectional electric energy meter of the DC microgrid charging pile based on flexible interconnection It is the sum of the electricity flowing to each V2G charging pile based on the flexible interconnected DC microgrid.

[0065] Other methods for calculating line loss of V2G charging piles installed in DC microgrids based on flexible interconnection Figure 5 The calculation method for line loss of V2G charging piles installed in a DC microgrid based on flexible interconnection is the same. At the same time, the calculation method for connecting energy storage to a DC microgrid based on flexible interconnection is the same as the calculation method for line loss of V2G charging piles installed.

[0066] (3) Calculation method of line loss when V2G charging piles and photovoltaic power generation are installed simultaneously in a DC microgrid based on flexible interconnection: by Figure 6 For example, the DC bidirectional energy meters connected to each flexible interconnection device of the DC microgrid based on flexible interconnection are respectively installed at the DC outlet ports connected to the flexible interconnection device of the AC station area of ​​transformer No. 1 and the flexible interconnection device of the AC station area of ​​transformer No. 2, the DC bidirectional energy meters of V2G charging piles are respectively installed at the incoming ports of each V2G charging pile connected to the DC microgrid based on flexible interconnection, the DC bidirectional energy meters of photovoltaic are respectively installed at each photovoltaic access point of the DC microgrid based on flexible interconnection, and other DC energy meters are installed at other load incoming ports of the DC microgrid based on flexible interconnection except V2G charging piles and photovoltaics.

[0067] The power loss of DC microgrid based on flexible interconnection = power supply - power sales = (the power outflow of DC bidirectional electric energy meter at the DC outlet port connected to the flexible interconnection device of AC station area of ​​transformer No. 1 and the flexible interconnection device of AC station area of ​​transformer No. 2 and - The amount of electricity flowing into the DC bidirectional energy meter at the DC outlet port connected to the flexible interconnection device of the AC station area of ​​the No. 1 transformer and the flexible interconnection device of the AC station area of ​​the No. 2 transformer and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and + Based on flexible interconnection, DC microgrid photovoltaic AC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + DC microgrid photovoltaic AC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ); Line loss rate of DC microgrid based on flexible interconnection = (1- )×100%=(1- )×100% The inflow and flow of photovoltaic and AC bidirectional electric energy meters in DC microgrids based on flexible interconnection The sum of the power supplied by each photovoltaic power generation system to the flexible interconnected DC microgrid, and the sum of the power outflow from the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid It is the total electricity consumption of each photovoltaic user in the DC microgrid based on flexible interconnection.

[0068] Other methods for calculating line losses when V2G charging piles and photovoltaic power are installed simultaneously in DC microgrids based on flexible interconnection Figure 6 The line loss calculation method for installing V2G charging piles and photovoltaics in a DC microgrid based on flexible interconnection is the same. At the same time, the calculation method for connecting energy storage to a DC microgrid based on flexible interconnection is the same as the line loss calculation method for installing V2G charging piles.

[0069] In summary, the present invention provides a line loss assessment method for a low-voltage flexible interconnected diversified distribution area, which has the following advantages over existing line loss calculation or assessment methods: Firstly, by obtaining the input variables of the distribution area to be evaluated and inputting them into the pre-built diversified distribution area line loss evaluation model, this method can accurately calculate the line loss rate of the AC area and the line loss rate of the DC microgrid, thereby realizing the accurate evaluation of the line loss of the diversified distribution area with low-voltage flexible interconnection, which is of great significance for improving the operation efficiency and energy utilization efficiency of the power system; secondly, the diversified distribution area line loss evaluation model constructed by this method includes the AC area line loss calculation model of low-voltage flexible interconnection and the DC microgrid line loss calculation model based on flexible interconnection, and each model considers different construction methods, such as ordinary charging piles, V2G charging piles and photovoltaic access, which makes this method flexible to adapt to distribution areas with different configurations and needs, and has strong practicality and adaptability; finally, this method gives a detailed description of the installation location of the electric energy meter and the calculation method of the power quantity, ensuring the accuracy and reliability of the power quantity data, and providing a solid foundation for line loss evaluation. It can be seen that the use of this evaluation method not only improves the accuracy and efficiency of line loss evaluation, but also provides strong support for the optimized operation and energy conservation and emission reduction of the power system.

[0070] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A line loss assessment method for a low-voltage flexible interconnected diversified distribution area, characterized in that: include: Obtain input variables of the low voltage flexible interconnected diversified distribution substation to be evaluated; The input variables of the diversified distribution station area with low-voltage flexible interconnection to be evaluated are input into a pre-built diversified distribution station area line loss evaluation model, and the AC station area line loss rate and the DC microgrid line loss rate are output to realize the line loss evaluation of the diversified distribution station area with low-voltage flexible interconnection according to the AC station area line loss rate and the DC microgrid line loss rate.

2. The line loss assessment method for low-voltage flexible interconnected diversified distribution area according to claim 1 is characterized in that: The diversified distribution area line loss assessment model includes a low-voltage flexible interconnected AC area line loss calculation model and a flexible interconnected DC microgrid line loss calculation model; wherein, The AC transformer area line loss calculation model for low voltage flexible interconnection is constructed in three ways: The first type: The line loss construction method of installing ordinary charging piles in the AC area with low-voltage flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area )﹣(Outflow of AC bidirectional energy meter connected to flexible interconnection device in this area + The AC energy meter of the charging pile in this area and + Other AC energy meters in this area and ); The specific formula for the line loss rate in the AC station area is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The second method: The line loss construction method of installing V2G charging piles in the AC area with low-voltage flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area + The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in this area and )﹣(Outflow of AC bidirectional energy meter connected to flexible interconnection device in this area + The outflow of AC bidirectional electric energy meter of V2G charging pile in this area and + Other AC energy meters in this area and ); The specific formula for the line loss rate in the AC station area is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The third method: Install V2G charging piles and photovoltaic line loss in the flexible interconnected AC area at the same time: Loss of electricity = power supply - electricity sales = (the amount of electricity flowing out of the AC bidirectional electric energy meter on the low-voltage side of the transformer in this area ﹣Amount of electricity flowing into the AC bidirectional energy meter on the low-voltage side of the transformer in this area + The amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device in this area + The amount of electricity flowing into the AC bidirectional energy meter of the V2G charging pile in this area and + The amount of electricity flowing into the photovoltaic AC bidirectional energy meter in this area and )﹣(Outflow of AC bidirectional energy meter connected to flexible interconnection device in this area + The outflow of AC bidirectional electric energy meter of V2G charging pile in this area and + The outflow of photovoltaic AC bidirectional electric energy meter in this area and + Other AC energy meters in this area and ), the specific formula of AC line loss rate is as follows: AC station line loss rate = (1- )×100%=(1- )×100% The DC microgrid line loss calculation model based on flexible interconnection is divided into three construction methods: The first one: The DC microgrid installation method based on flexible interconnection and the line loss construction method of ordinary charging piles: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and )﹣(DC microgrid charging pile DC energy meter power and + Based on flexible interconnection of DC microgrid other DC energy meters and ); The specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100% The second method: The line loss construction method of installing V2G charging piles in DC microgrid based on flexible interconnection: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ), the specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100% The third method: A flexible interconnected DC microgrid with V2G charging piles and photovoltaic line loss installed at the same time: Loss of electricity = power supply - electricity sales = (the amount of electricity outflow from the DC bidirectional electric energy meters connected to each flexible interconnection device based on the flexible interconnection DC microgrid and ﹣The DC microgrid based on flexible interconnection connects the DC bidirectional energy meters of each flexible interconnection device with the inflow of electricity and +DC microgrid V2G charging pile DC bidirectional energy meter inflow and + Based on flexible interconnection, DC microgrid photovoltaic AC bidirectional energy meter inflow and )﹣(DC microgrid V2G charging pile DC bidirectional energy meter outflow and + DC microgrid photovoltaic AC bidirectional energy meter outflow and + Based on flexible interconnection of DC microgrid other DC energy meters and ), the specific formula of DC microgrid line loss rate is as follows: DC microgrid line loss rate = (1- )×100%=(1- )×100%.

3. The line loss assessment method for low-voltage flexible interconnected diversified distribution area according to claim 2 is characterized in that: The AC bidirectional electric energy meter on the low voltage side of the transformer outputs the amount of electricity The amount of electricity flowing from the low-voltage side of the transformer to the grid, and the amount of electricity flowing out of the AC bidirectional energy meter on the low-voltage side of the transformer The amount of electricity flowing from the power grid to the low-voltage side of the transformer; the amount of electricity flowing into the AC bidirectional energy meter connected to the flexible interconnection device The amount of electricity flowing from the flexible interconnection device to the AC station area, and the amount of electricity flowing out of the AC bidirectional energy meter connected to the flexible interconnection device is the amount of electricity flowing to the flexible interconnection device in this AC area; the amount of electricity flowing into the AC bidirectional energy meter of each V2G charging pile and is the sum of the power flowing from each V2G charging pile in this area to the AC area, and the sum of the power flowing out of the AC bidirectional power meter of the V2G charging pile is the sum of the electricity flowing to each V2G charging pile in this AC area; the sum of the electricity flowing into the photovoltaic AC bidirectional energy meter The sum of the power supplied by each photovoltaic power generation system in this area to the AC area, and the sum of the power outflow from the photovoltaic AC bidirectional energy meter It is the total amount of electricity consumed by each photovoltaic user in this area.

4. The line loss assessment method for low-voltage flexible interconnected diversified distribution area according to claim 2 is characterized in that: The DC microgrid based on flexible interconnection connects the DC bidirectional electric energy meters of each flexible interconnection device with the inflow of electric quantity and is the sum of the amount of electricity flowing from the flexible interconnected DC microgrid to each flexible interconnected device, and the sum of the amount of electricity flowing out of the DC bidirectional electric energy meter connected to each flexible interconnected device of the flexible interconnected DC microgrid is the sum of the electricity flowing from each flexible interconnection device to the DC microgrid based on flexible interconnection; the sum of the electricity flowing into the DC bidirectional electric energy meter of the V2G charging pile based on flexible interconnection is the sum of the power flowing from each V2G charging pile to the DC microgrid based on flexible interconnection, and the sum of the power flowing out of the DC bidirectional electric energy meter of the DC microgrid charging pile based on flexible interconnection is the sum of the electricity flowing from the flexible interconnected DC microgrid to each V2G charging pile; the sum of the electricity flowing into the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid The sum of the power supplied by each photovoltaic power generation system to the flexible interconnected DC microgrid, and the sum of the power outflow from the photovoltaic AC bidirectional electric energy meter of the flexible interconnected DC microgrid It is the total electricity consumption of each photovoltaic user in the DC microgrid based on flexible interconnection.

5. The line loss assessment method for low-voltage flexible interconnected diversified distribution area according to claim 2 is characterized in that: The AC bidirectional energy meter on the low-voltage side of the transformer is installed at the outlet port on the low-voltage side of the transformer; the AC bidirectional energy meters connected to the flexible interconnection device are respectively installed at the AC incoming ports of the flexible interconnection device; the AC energy meters for charging piles are respectively installed at the incoming ports connecting each charging pile in the AC station area; the AC bidirectional energy meters for V2G charging piles are respectively installed at the incoming ports connecting each V2G charging pile in the AC station area; the photovoltaic AC bidirectional energy meters are respectively installed at each photovoltaic access point in the AC station area; and the other AC energy meters are installed at the incoming ports of other loads in the AC station area except charging piles and photovoltaics.

6. The line loss assessment method for low voltage flexible interconnected diversified distribution area according to claim 2 is characterized in that: The DC bidirectional electric energy meters connected to each flexible interconnection device of the flexible interconnection-based DC microgrid are respectively installed at the DC outlet ports of each flexible interconnection device; the DC electric energy meters of the charging piles are respectively installed at the incoming ports of each charging pile connected to the DC microgrid based on flexible interconnection; the DC bidirectional electric energy meters of the V2G charging piles are respectively installed at the incoming ports of each V2G charging pile connected to the DC microgrid based on flexible interconnection; the photovoltaic DC bidirectional electric energy meters are respectively installed at each photovoltaic access point of the DC microgrid based on flexible interconnection; and the other DC electric energy meters are installed at the incoming ports of other loads of the DC microgrid based on flexible interconnection except for charging piles and photovoltaics.

7. A low-voltage flexible interconnected diversified distribution area line loss assessment system, characterized in that: include: A data acquisition module, used to obtain input variables of the low-voltage flexible interconnected diversified distribution substation to be evaluated; The line loss assessment module is used to input the input variables of the diversified distribution station area with low-voltage flexible interconnection to be evaluated into a pre-built diversified distribution station area line loss assessment model, and output the AC station area line loss rate and the DC microgrid line loss rate, so as to realize the line loss assessment of the diversified distribution station area with low-voltage flexible interconnection according to the AC station area line loss rate and the DC microgrid line loss rate.

8. A device, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of the line loss assessment method for a diversified distribution station area with low-voltage flexible interconnection as described in any one of claims 1-6 when executing the computer program.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it is used to implement the steps of the line loss assessment method for a diversified distribution area with low-voltage flexible interconnection as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for evaluating line loss in a diversified distribution area with low-voltage flexible interconnection as described in any one of claims 1 to 6 are implemented.

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