Single degree of freedom active open power line transmission efficiency evaluation method and system

Abstract

The present application relates to power distribution line transmission technical field, specifically relates to a kind of single degree of freedom active ringless power distribution line transmission efficiency evaluation method and system, the method includes: obtaining certain section containing bus and main line power distribution line, and multiple power supplies and several loads are distributed on the two sides of main line;According to the direction of each power supply and load, the overall power flow direction of the power distribution line is confirmed, the power from the power supply to each load in the power distribution line is obtained, and the equivalent load distance of the overall power distribution network is calculated by arranging the power supply at different positions to meet the power demand of all loads;Find the equivalent load distance with the minimum equivalent load distance value, and the power distribution line after its corresponding arrangement is used as the topology structure with the minimum transmission cost.The present application is based on the optimal network topology power supply mode of distribution network structure, and the load can evaluate the advantages and disadvantages of different topology power supply characteristics, and the equivalent load distance method is used to evaluate network topology, with the advantages of comprehensiveness and convenience.

Description

Technical Field

[0001] This invention relates to the field of power distribution line transmission technology, specifically to a method and system for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line. Background Technology

[0002] The transmission efficiency of distribution network lines is an important indicator reflecting the network topology. However, the current main technological direction is to improve transmission efficiency. For example, application number CN201310701284.2 improves transmission efficiency by adding identifiers at the sending and receiving ends. Currently, the parameters used to evaluate transmission efficiency are too complex and cannot clearly reflect the structural advantages, transmission efficiency, and network transmission costs of the network topology.

[0003] The invention patent application with publication number CN116915690A discloses a method and system for evaluating the transmission efficiency of a passive tree topology power distribution line. This method discloses a method for evaluating the network topology based on the fact that there is an optimal network topology power supply mode in the distribution network structure and that the load can evaluate the advantages and disadvantages of different topology power supply. However, this prior art is only used for passive structures and does not provide a specific solution for active structures, thus limiting its application scope. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention provides a method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line, which is used to evaluate the transmission efficiency of the power distribution line. Based on this, the present invention also provides a system for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line.

[0005] Technical solution: On the one hand, the present invention provides a method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line, the method comprising the following steps:

[0006] S1 acquires a power distribution line containing a busbar and a main line, wherein the main line is directly connected to the busbar, and multiple power sources and several loads are distributed on both sides of the main line, wherein the power sources are used to transmit power to the loads;

[0007] S2 determines the overall power flow direction of the distribution line based on the tree-like line structure described above, and determines the length of each power source and load to the main line.

[0008] S3 obtains the power from the power source to each load in the power distribution line, and calculates the equivalent load distance of the power source and equivalent arrangement in different locations to meet the power demand of all loads in order to meet the power demand of all loads.

[0009] S4 compares the calculated equivalent load distances, finds the equivalent load distance with the smallest value, and uses the corresponding power distribution line as the topology with the lowest transmission cost.

[0010] Furthermore, including:

[0011] In step S2, the direction of the power supply is defined as the direction pointing towards the bus and is positive; the direction of the load is defined as the direction away from the bus and is negative. Therefore, the overall power flow direction of the distribution line is obtained.

[0012] Furthermore, including:

[0013] According to the principle of directional superposition, based on the power provided by each power source and the power required by the load, as well as the corresponding direction, the remaining or missing power is obtained. If the result of the vector summation is negative, it means that a certain amount of power is missing and power is supplied from the direction of the bus. If the result of the vector summation is positive, it means that a certain amount of power is remaining and power is supplied to the direction of the bus. Therefore, the corresponding current passing through each power source and load is obtained.

[0014] Furthermore, including:

[0015] In step S3, the equivalent load distance of the overall distribution network is calculated by arranging the power source and load in different locations to meet the power demand of all loads, including:

[0016] Starting from any load, if the power required by the current load is L1, first determine whether the power p1 that any power source can provide satisfies p1≥L1. If it does, then first supply power to the current load, and allocate the remaining power p1-L1 to the second load.

[0017] Then, the power L2 required by the second load is compared with the remaining power p1-L1. If p1-L1≥L2,

[0018] After satisfying the power requirements of the second load, the remaining power p1-L1-L2 is allocated to the third load.

[0019] otherwise,

[0020] If p1 < L1, then iterate through other power sources, select one power source, confirm the amount of electricity p2 it provides, and confirm whether p1 + p2 ≥ L1. If it is satisfied, then supply power to the current load and allocate the remaining power p1 + p2 - L1 to the second load. Otherwise, continue to iterate through other power sources until the power supply to the current load is completed.

[0021] Repeat the above method to power all loads.

[0022] Furthermore, including:

[0023] After powering all loads, calculate the corresponding equivalent load distance, which is specifically expressed as follows:

[0024]

[0025] Where P1 is the power provided by the first power source, P m The power supplied by the m-th power source, P M The power supplied to the Mth power source, where M is the total number of power sources, L1 is the power required by the first load, and L... n For the power required by the nth load, L N The power required for the Nth load; T1 is the power supplied / required on the first main line segment, q1 is the length of the first main line segment, T s Provide / required power to the s-th segment of the main line.

[0026] It is used to characterize the power flow direction of the distribution line; U is the total output value, d1 is the line length corresponding to the power flow from the first power source to the main line, and d m Let d be the line length corresponding to the power flow from the current of the m-th power source to the main line. M R is the line length corresponding to the power flow from the Mth power source to the main line, and R1 is the line length corresponding to the power flow from the first load to the main line. n R is the line length corresponding to the power flow from the nth load to the main line. N Let q be the line length corresponding to the power flow from the Nth load to the main line. s Let be the length of the s-th segment of the main line.

[0027] Furthermore, including:

[0028] The total output value U is expressed as:

[0029]

[0030] On the other hand, the present invention also provides a transmission efficiency evaluation system for a single-degree-of-freedom active loop-free power distribution line, the system comprising:

[0031] The line acquisition module is used to acquire a certain section of power distribution line containing a busbar and a main line. The main line is directly connected to the busbar. Multiple power sources and several loads are distributed on both sides of the main line. The power sources are used to transmit power to the loads.

[0032] The direction confirmation module is used to confirm the overall power flow direction of the distribution line based on the direction of each power source and load according to the tree-like line structure described above, and to determine the length of each power source and load to the main line.

[0033] The equivalent load distance calculation module is used to obtain the power from the power source to each load in the power distribution line, and to calculate the equivalent load distance of the power source and load at different locations to the overall power distribution network in order to meet the power demand of all loads.

[0034] The topology confirmation module is used to compare the calculated equivalent load distances, find the equivalent load distance with the smallest value, and use the corresponding power distribution lines as the topology with the lowest transmission cost.

[0035] Furthermore, including:

[0036] In the direction confirmation module, the direction of the power supply is defined as the direction pointing towards the bus and is positive; the direction of the load is defined as the direction away from the bus and is negative. Therefore, the overall power flow direction of the distribution line is obtained.

[0037] Furthermore, including:

[0038] According to the principle of directional superposition, based on the power provided by each power source and the power required by the load, as well as the corresponding direction, the remaining or missing power is obtained. If the result of the vector summation is negative, it means that a certain amount of power is missing and power is supplied from the direction of the bus. If the result of the vector summation is positive, it means that a certain amount of power is remaining and power is supplied to the direction of the bus. Therefore, the corresponding current passing through each power source and load is obtained.

[0039] Beneficial effects: This invention assumes that the power distribution line is active and loop-free under a single degree of freedom, and that multiple power sources are used to complete the power transmission to several loads. Since the power transmission capabilities of the power sources are different, from an optimization perspective, there should be an optimal network topology power supply method. Therefore, this application uses the equivalent load distance calculation method to evaluate the corresponding power distribution line, so as to clearly and accurately reflect the structural advantages, transmission efficiency and network transmission cost of the network topology. Attached Figure Description

[0040] Figure 1 This is a flowchart of the method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line according to an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of the structure of a power distribution line according to an embodiment of the present invention;

[0042] Figure 3 This is the topology formed by the first distribution method of the two power sources as described in the embodiments of the present invention;

[0043] Figure 4 This is the topology formed by the second distribution method of the two power sources as described in the embodiment of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Load represents the demand side of energy, while power distribution lines are a specific topology used to meet that demand. For a single load point, load distance represents the product of power and distance from that point to the power source, characterizing the system transmission cost required to meet that point's energy demand. In this invention, load distance is not merely an atomic-level distance but extends to complex networks. Because a specific power distribution line typically needs to simultaneously meet the energy demands of different locations with varying characteristics, multiple topologies can be used to meet these demands. Different topologies correspond to different transmission efficiencies, but the energy demand met is the same. From an input-output perspective, different topologies have varying transmission efficiencies. If we equate the multiple distributed load points to a single logical load point—meaning that the energy demand of the actual load in a certain line segment is the same as the energy demand of the equivalent load—then the equivalent load in the corresponding topology corresponds to different load distances. This is similar in principle to the composition of torque. Similarly, different topologies correspond to different lengths of equivalent load distance. Therefore, equivalent load distance can be used to characterize the transmission efficiency of different topologies.

[0046] Therefore, as Figure 1 As shown, on one hand, the present invention provides a method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line, the method comprising the following steps:

[0047] S1 acquires a single-degree-of-freedom active loop-free power distribution line containing a busbar and a main line. The main line is directly connected to the busbar. Multiple power sources and several loads are distributed on both sides of the main line. The power sources are used to transmit power to the loads.

[0048] The circuit in this invention is a constant voltage network and satisfies... And U and I are the line voltage and line current, The power factor is a metric that measures the ratio of active power consumed by a load to apparent power. When the load is purely resistive, the power factor is 1; when the load includes inductance or capacitance, the power factor is less than 1. Therefore, when U is a constant... When the differences are not significant, P is directly proportional to I. Therefore, in calculating energy loss, this invention uniformly uses i... 2 d is equivalent to p 2Therefore, for the "series" case, the equivalent load distance for two loads P1 and P2 can be calculated as follows, where the arrow direction indicates the power flow direction.

[0049] (i1+i2) 2 d = (i1 + i2) 2 d1+i2 2 d2

[0050]

[0051] Specifically, the right side of the first formula represents the actual total energy demand. The current from the power source to P1 is i1 + i2, while the current flowing through P2 is i2. Therefore, the total demand on the right side is (i1 + i2). 2 d1+i2 2 d2, the corresponding left side is the equivalent state, because two charges are equivalent to one, and the current flowing through it is (i1+i2). Therefore, the energy demand represented on the left side is expressed as: (i1+i2). 2 Therefore, the equivalent line d is expressed as: Correspondingly, in this invention, i is replaced with the corresponding power p.

[0052] Therefore, the calculation formula is:

[0053]

[0054] Where d1 is the line length between the first load and the power source, i.e., the corresponding load distance; d2 is the line length between the second load and the power source, i.e., the load distance corresponding to the second load; p2 is the power corresponding to the second load; and p1 is the power corresponding to the first load.

[0055] Based on the tree-like circuit structure described above, S2 determines the overall power flow direction of the distribution line according to the direction of each power source and load, and determines the length of each power source and load to the main line.

[0056] Specifically: In step S2, the direction of the power supply is defined as the direction pointing towards the bus and is positive; the direction of the load is defined as the direction away from the bus and is negative. Therefore, the overall power flow direction of the distribution line can be obtained based on the direction of the power supply and the direction of the load.

[0057] In this embodiment, for any tree-like structure, the tree-like structure includes a busbar and a main line. The power supply and load are distributed on both sides of the main line, and the main line is directly connected to the busbar. Therefore, the length from each power supply or load to the main line can be measured. To simplify the calculation, the present invention assumes that the length from each power supply or load to the main line is the same. According to the principle of directional superposition, based on the power provided by each power supply and the power required by the load and the corresponding direction, the remaining or missing power is obtained. If the result of the vector summation is negative, it means that a certain amount of power is missing and power is supplied from the direction of the busbar. If the result of the vector summation is positive, it means that a certain amount of power is remaining and power is supplied to the direction of the busbar. Therefore, the corresponding current passing through each power supply and load is obtained.

[0058] First, consider the individual effects of each element. For example, if there are power sources 1, 2, 3, ..., M, the number of power sources they can provide can be represented as: P1, P2, ..., P... M The load includes load 1, load 2, load 3, ..., load N, and the required number of loads are represented as: L1, L2, ..., L N In embodiments of the present invention, the direction of a single power source is towards the bus, denoted as positive, while the direction of a single load is away from the bus, denoted as negative. Therefore, the overall power flow direction can be determined, and based on the superposition of the directions, the remaining or missing power can also be obtained.

[0059] P1+P2+,...,+P M -L1-L2-,...,-L N If the result is negative, it means there is a shortage of certain electrical energy, and power is supplied from the busbar direction. If the result is positive, it means there is a remaining electrical energy, and power is supplied to the busbar. Based on this, the current passing through each line can be determined.

[0060] S3 obtains the power from the power source to each load in the power distribution line, and calculates the equivalent load distance of the overall power distribution network by arranging the power source in different locations to meet the power demand of all loads.

[0061] In this embodiment, the calculation of the equivalent load distance of the overall distribution network by arranging power sources and loads in different locations to meet the power demand of all loads includes:

[0062] Starting from any load, if the power required by the current load is L1, first determine whether the power P1 that any power source can provide satisfies P1≥L1. If it does, then power is supplied to the current load first, and the remaining power P1-L1 is allocated to the second load.

[0063] Then, the power L2 required by the second load is compared with the remaining power P1-L1. If P1-L1≥L2, the power of the second load is satisfied, and the remaining power P1-L1-L2 is allocated to the third load.

[0064] otherwise,

[0065] If P1 < L1, then iterate through other power sources, select one power source, confirm the amount of electricity it provides P2, and confirm whether P1 + P2 ≥ L1 is satisfied. If satisfied, then power the current load and allocate the remaining power P1 + P2 - L1 to the second load. Otherwise, continue to iterate through other power sources until power supply to the current load is completed.

[0066] Repeat the above method to power all loads.

[0067] Furthermore, including:

[0068] After powering all loads, calculate the corresponding equivalent load distance, which is specifically expressed as follows:

[0069]

[0070] That is, the numerator of the equivalent load distance is the sum of the energy consumed by the power flowing through each segment, and the denominator is the maximum value of the power demand or power generation demand that the entire network needs to meet, i.e., the total output value.

[0071] Where p1 is the power provided by the first power source, p m The power supplied by the m-th power source, p M The power supplied to the Mth power source, where M is the total number of power sources, L1 is the power required by the first load, and L... n For the power required by the nth load, L N The power required for the Nth load; T1 is the power supplied / required on the first main line segment, q1 is the length of the first main line segment, T s Provide / required power to the s-th segment of the main line.

[0072] It is used to characterize the power flow direction of the distribution line; U is the total output value, d1 is the line length corresponding to the power flow from the first power source to the main line, and d m Let d be the line length corresponding to the power flow from the current of the m-th power source to the main line. M R is the line length corresponding to the power flow from the Mth power source to the main line, and R1 is the line length corresponding to the power flow from the first load to the main line. n R is the line length corresponding to the power flow from the nth load to the main line. N Let q be the line length corresponding to the power flow from the Nth load to the main line.s Let be the length of the s-th segment of the main line.

[0073] Furthermore, the total output value U in this embodiment is expressed as:

[0074]

[0075] S4 compares the calculated equivalent load distances, finds the equivalent load distance with the smallest value, and uses the corresponding power distribution line as the topology with the lowest transmission cost.

[0076] As shown in the appendix of this embodiment Figure 2 In the power distribution network, there are two power sources, denoted as the first power source and the second power source, and a first load and a second load. The first power source can provide 9 units of electricity, the second power source can provide 3 units of electricity, the first load needs 6 units of electricity, and the second load needs 1 unit of electricity. The busbar is connected to the power sources and the loads via lines, including the main line. The power sources and loads are distributed on both sides of the main line. Starting from any load, if the first load needs 6 units of electricity, the first power source will provide 6 units of electricity, and there will be 3 units remaining, which will be returned to the main line. The direction of charge flow is from the first power source to the load. The second load needs 1 unit of charge, so the first power source will provide 1 unit of charge, and there will be 2 units remaining, which will be returned to the main line. Therefore, the main line receives 5 units of charge and returns them to the busbar, i.e., h(x) = -1.

[0077] Furthermore, for the sake of simplicity, in the example of this embodiment, the length of each main line segment is set to 1. In the example of this embodiment, the distance between each power source and load and the main line is the same, denoted as d. That is, the length from the power source or load to the main line is also set to 1. The main line of this application has 4 segments because the main line is divided by the power sources and loads on both sides. In order to simplify the calculation, the division in this application is equal distance division.

[0078] The corresponding equivalent load distance is expressed as: Where U is max{total power output of the power supply, total power output of the load}, and the power output of the power supply is (3+9). 2 The total load demand is (1+6). 2 Therefore, U = 144. At this point... Figure 3 The calculated equivalent load distance is 1.479.

[0079] If the first power supply has a charge of 3 and the second power supply has a charge of 9, then according to the above description, the corresponding equivalent load distance can be expressed as:

[0080] Right now

[0081]

[0082] It should be noted that the examples in this embodiment are only two cases. In actual applications, the number of power sources and loads is not limited to these few, and their arrangement positions can be anywhere. However, the corresponding equivalent load distance can be calculated using the above formula of this invention.

[0083] Therefore, to meet the power demand of 12 units, the lower the cost to the power grid as described above, the better. Thus, the second power supply configuration incurs a lower cost and has higher transmission efficiency.

[0084] This invention also provides a system for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line, the system comprising:

[0085] The line acquisition module is used to acquire a certain section of power distribution line containing a busbar and a main line. The main line is directly connected to the busbar. Multiple power sources and several loads are distributed on both sides of the main line. The power sources are used to transmit power to the loads.

[0086] The direction confirmation module is used to confirm the overall power flow direction of the distribution line based on the direction of each power source and load according to the tree-like line structure described above, and to determine the length of each power source and load to the main line.

[0087] The equivalent load distance calculation module is used to obtain the power from the power source to each load in the power distribution line, and to calculate the equivalent load distance of the power source at different locations to the overall power distribution network in order to meet the power demand of all loads.

[0088] The topology confirmation module is used to compare the calculated equivalent load distances, find the equivalent load distance with the smallest value, and use the corresponding power distribution lines as the topology with the lowest transmission cost.

[0089] Furthermore, including:

[0090] In the direction confirmation module, the direction of the power supply is defined as the direction pointing towards the bus and is positive; the direction of the load is defined as the direction away from the bus and is negative. Therefore, the overall power flow direction of the distribution line is obtained.

[0091] Furthermore, including:

[0092] According to the principle of directional superposition, based on the power provided by each power source and the power required by the load, as well as the corresponding direction, the remaining or missing power is obtained. If the result of the vector summation is negative, it means that a certain amount of power is missing and power is supplied from the direction of the bus. If the result of the vector summation is positive, it means that a certain amount of power is remaining and power is supplied to the direction of the bus. Therefore, the corresponding current passing through each power source and load is obtained.

[0093] The other technical features of the evaluation system described in this invention are the same as those of the corresponding single-degree-of-freedom active loopless distribution line transmission efficiency evaluation method, and will not be repeated here.

[0094] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0095] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations to the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line, characterized in that, The method includes the following steps: S1 obtains a segment of a tree-like power distribution line, which is a power distribution line containing at least a busbar and a main line. The main line is directly connected to the busbar, and multiple power sources and several loads are distributed on both sides of the main line. The power sources are used to transmit power to the loads. S2 determines the overall power flow direction of the distribution line based on the tree-like line structure described above, combined with the direction of each power source and load, and determines the length of each power source and load to the main line. S3 obtains the power from the power source to each load in the power distribution line, and calculates the equivalent load distance of the overall power distribution network by arranging the power source and load in different locations to meet the power demand of all loads. S4 compares the calculated equivalent load distances, finds the equivalent load distance with the smallest value, and uses the corresponding power distribution line as the topology with the lowest transmission cost. In step S3, calculating the equivalent load distance of the overall distribution network by arranging power sources in different locations to meet the power demand of all loads includes: Starting from any load, if the power required by the current load is First, determine the power that any power source can provide. Does it meet the requirements? If the conditions are met, power will first be supplied to the current load, and the remaining power will be diverted to the appropriate source. Assigned to the second load, Then, the power required by the second load. With remaining power Compare, if satisfied , After satisfying the power requirement of the second load, the remaining power will be... Assigned to the third load; otherwise, like Then iterate through the other power sources, randomly select one of them, and confirm the amount of electricity it provides. And confirm whether it meets the requirements. If the conditions are met, power will be supplied to the current load, and the remaining power will be used for other purposes. If the power supply is not assigned to the second load, then continue iterating through other power sources until the current load is fully powered. Repeat the above equivalent load distance calculation to complete the power supply for all loads; After powering all loads, calculate the corresponding equivalent load distance, which is specifically expressed as follows: ; in, The power supplied to the first power source For the first m The power supplied by each power source The power supplied to the Mth power source, where M is the total number of power sources. The power required for the first load, For the first n The power required by the load The power required for the Nth load; Provide / required power to the first main line. The length of the first main line. For the first s The power supplied / required on the main line; It is used to characterize the power flow direction of the distribution line; U is the total output value. This represents the line length corresponding to the power flow from the first power source to the main line. For the first m The current from the power source to the power flow of the main line corresponds to the line length. Let be the line length corresponding to the power flow from the Mth power source to the main line. The line length corresponding to the power flow from the first load to the main line. For the first n The line length corresponding to the power flow from the load to the main line. Let N be the line length corresponding to the power flow from the Nth load to the main line. For the first s The length of the main line section; The total output value U is expressed as: .

2. The method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line according to claim 1, characterized in that, In step S2, the direction of the power supply is defined as the direction pointing towards the bus and is positive; the direction of the load is defined as the direction away from the bus and is negative. Therefore, the overall power flow direction of the distribution line is obtained.

3. The method for evaluating the transmission efficiency of a single-degree-of-freedom active loop-free power distribution line according to claim 2, characterized in that, According to the principle of directional superposition, based on the power provided by each power source and the power required by the load, as well as the corresponding direction, the remaining or missing power is obtained. If the result of the vector summation is negative, it means that a certain amount of power is missing and power is supplied from the direction of the bus. If the result of the vector summation is positive, it means that a certain amount of power is remaining and power is supplied to the direction of the bus. Therefore, the corresponding current passing through each power source and load is obtained.

4. A transmission efficiency evaluation system for a single-degree-of-freedom active loop-free power distribution line, characterized in that, The system includes: The line acquisition module is used to acquire a certain tree-shaped power distribution line. The structure is a power distribution line containing at least a busbar and a main line. The main line is directly connected to the busbar. Multiple power sources and several loads are distributed on both sides of the main line. The power sources are used to transmit power to the loads. The direction confirmation module is used to confirm the overall power flow direction of the distribution line based on the tree-like line structure described above, combined with the direction of each power source and load, and to determine the length of each power source and load to the main line. The equivalent load distance calculation module is used to obtain the power from the power source to each load in the power distribution line, and to calculate the equivalent load distance of the overall power distribution network by arranging the power source and load in different locations in order to meet the power demand of all loads. The topology confirmation module is used to compare the calculated equivalent load distances, find the equivalent load distance with the smallest value, and use the corresponding power distribution lines as the topology with the lowest transmission cost. The equivalent load distance calculation module calculates the equivalent load distance of the overall distribution network when power sources are placed in different locations to meet the power demand of all loads, including: Starting from any load, if the power required by the current load is First, determine the power that any power source can provide. Does it meet the requirements? If the conditions are met, power will first be supplied to the current load, and the remaining power will be diverted to the appropriate source. Assigned to the second load, Then, the power required by the second load. With remaining power Compare, if satisfied , After satisfying the power requirement of the second load, the remaining power will be... Distribute the third load; otherwise, like Then iterate through the other power sources, randomly select one of them, and confirm the amount of electricity it provides. And confirm whether it meets the requirements. If the conditions are met, power will be supplied to the current load, and the remaining power will be used for other purposes. If the power supply is not assigned to the second load, then continue iterating through other power sources until the current load is fully powered. Repeat the above equivalent load distance calculation to complete the power supply for all loads; After powering all loads, calculate the corresponding equivalent load distance, which is specifically expressed as follows: ; in, The power supplied to the first power source For the first m The power supplied by each power source The power supplied to the Mth power source, where M is the total number of power sources. The power required for the first load, For the first n The power required by the load The power required for the Nth load; Provide / required power to the first main line. The length of the first main line. For the first s The power supplied / required on the main line; It is used to characterize the power flow direction of the distribution line; U is the total output value. This represents the line length corresponding to the power flow from the first power source to the main line. For the first m The current from the power source to the power flow of the main line corresponds to the line length. Let be the line length corresponding to the power flow from the Mth power source to the main line. The line length corresponding to the power flow from the first load to the main line. For the first n The line length corresponding to the power flow from the load to the main line. Let N be the line length corresponding to the power flow from the Nth load to the main line. For the first s The length of the main line section; The total output value U is expressed as: .

5. The single-degree-of-freedom active loop-free power distribution line transmission efficiency evaluation system according to claim 4, characterized in that, In the direction confirmation module, the direction of the power supply is defined as the direction pointing towards the bus and is positive; the direction of the load is defined as the direction away from the bus and is negative. Therefore, the overall power flow direction of the distribution line is obtained.

6. The single-degree-of-freedom active loop-free power distribution line transmission efficiency evaluation system according to claim 5, characterized in that, According to the principle of directional superposition, based on the power provided by each power source and the power required by the load, as well as the corresponding direction, the remaining or missing power is obtained. If the result of the vector summation is negative, it means that a certain amount of power is missing and power is supplied from the direction of the bus. If the result of the vector summation is positive, it means that a certain amount of power is remaining and power is supplied to the direction of the bus. Therefore, the corresponding current passing through each power source and load is obtained.

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