CN105469316B

CN105469316B - Method and system for calculating theoretical line loss between any two points of power distribution network

Info

Publication number: CN105469316B
Application number: CN201410437762.8A
Authority: CN
Inventors: 刘自发; 刘斌; 李柯; 王萌; 王威; 李梦渔; 李韦姝
Original assignee: Shaanxi Regional Electric Power Group Co ltd; North China Electric Power University
Current assignee: Shaanxi Regional Electric Power Group Co ltd; North China Electric Power University
Priority date: 2014-08-29
Filing date: 2014-08-29
Publication date: 2020-05-15
Anticipated expiration: 2034-08-29
Also published as: CN105469316A

Abstract

A method and a system for calculating theoretical line loss between any two points of a power distribution network are provided, wherein the method comprises the following steps: obtaining element branches and loss; forming a road matrix; obtaining the branch and node contained in the road between any node A and any node B; acquiring nodes and branches on non-roads between any nodes A and B; a judgment step; and a step of counting loss. The method and the system for calculating the theoretical line loss between any two points of the power distribution network are based on the road matrix and the depth-first search algorithm, can help distribution network dispatchers to quickly calculate the loss of the area between any two nodes of the distribution network, master the distribution situation of the line loss, are favorable for finding weak links of the network, further take optimization measures, reduce the network loss, improve the economy and have high practical value.

Description

Method and system for calculating theoretical line loss between any two points of power distribution network

Technical Field

The invention relates to a method and a system for calculating loss of a power distribution network. In particular to a method and a system for calculating theoretical line loss between any two points of a power distribution network.

Background

The line loss rate of the distribution network is an important technical index of the operation of the distribution network, and theoretical line loss calculation refers to calculation of electric energy loss in a transformer winding, a transmission line wire and a series reactor coil which are in direct proportion to the square of current; transformer cores, capacitors, cable insulation, shunt reactors, corona losses, etc. related to the operating voltage. The transformer loss and the line loss can be effectively determined through theoretical line loss calculation, and line loss management is facilitated. Furthermore, a line with large loss can be reconstructed, so that the loss is reduced; and the theoretical line loss is compared with the statistical line loss, so that the line loss management work can be guided.

At present, with the improvement of the automation level of the distribution network and the increase of real-time measuring devices, a matching load flow calculation method is mainly adopted for theoretical line loss calculation, and the method comprises the following steps:

1) calculating equivalent injection power of the root node and each load by adopting a head end power coefficient method, and calculating load mismatching distribution coefficients;

2) the active power and reactive power mismatch amount of the root node is obtained through primary load flow calculation, and the active power and reactive power mismatch amount is distributed to each load according to the load mismatch amount distribution coefficient;

3) repeating the step 2) until the difference of the voltages of the two adjacent load flow calculation nodes is smaller than a given threshold value;

4) and calculating the total loss of the bus according to the node voltage, and counting the total loss of each branch, the total loss of each distribution transformer, the total loss of each capacitor and the like.

However, the problems with this technique are: only line losses of elements such as lines, transformers and capacitors can be classified and counted, only total losses can be obtained, and a certain region, specifically, loss distribution between certain two nodes cannot be obtained. Thus, the work efficiency of field scheduling personnel is reduced.

Therefore, how to rapidly perform theoretical calculation on the loss of the region between any two points and obtain an accurate result becomes a technical problem to be solved in the prior art.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a statistical calculation algorithm for the line loss of a power distribution network, which can calculate the loss distribution between any two points and improve the common-group efficiency of dispatching personnel.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for calculating theoretical line loss between any two points of a power distribution network comprises the following steps:

step S110, obtaining element branches and loss step: acquiring a topology data table and a topology relation table of actual equipment and elements operated by a distribution network according to the operation condition of the distribution network, forming node and branch data required by power flow calculation of the distribution network according to the two tables, and calculating the loss of each element and branch by adopting a matching power flow technology;

step S120, forming a road matrix: for a radial distribution network, firstly forming a radial distribution network node branch incidence matrix, calculating and transposing an inverse matrix of the incidence matrix to form a road matrix, wherein the horizontal axis of the two matrixes is a branch and the vertical axis is a node;

step S130, obtaining the branch and node contained in the road between any node A and any node B: taking out the corresponding rows of the given two nodes A and B from the road matrix, and comparing the data of the two rows one by one according to the columns; if the numerical values of the rows corresponding to the nodes A and B are different for a certain column, the branch set omega included in the road of the node A and the node B is counted by the branch number corresponding to the column_bAccording to the branches contained in the road A and the road B, all the node sets between the road A and the road B can be obtained by utilizing the incidence matrix and are marked as omega_nThe number of elements is n, and the node set omega_nDoes not contain the starting and ending nodes A and B;

step S140, acquiring nodes and branches on non-roads between any nodes A and B: set of nodes omega_nI is not less than 1<N is less than or equal to n, all the branches connected with the incidence matrix are obtained according to the incidence matrix, and the branches do not belong to the set omega_bThe correspondent node of each connected leg in the set starts depth-first search not at omega_nAnd nodes in the first and the last nodes A and B until the ith node is returned, and adding the newly searched branch into the set omega_biNewly searched nodes join the set omega_niPerforming the following steps;

step 150, the judging step: determine omega_nWhether all the nodes are searched in the step S140 or not is judged, if yes, the step S160 is turned to, and if not, the step S140 is turned to, and the searching is continued;

step S160, a loss statistics step: statistical set omega_bAnd Ω_biN, and the loss of the branch is denoted as P_loss,bStatistics of Ω_nAnd Ω_niN, and the losses of the distribution transformer, the parallel capacitor and the series reactor connected to the node are denoted as P_loss,nThe total loss between any given two nodes is P_loss＝P_loss,b+P_loss,n。

Preferably, in step S110, the step of obtaining the component branch and the step of loss specifically include: according to the operation condition of the distribution network, the numbers of nodes at two ends of a feeder section, a distribution transformer and a load element of an actual distribution network operation feeder line are obtained, the parameters of each element and the power of a load are obtained, the power of a feeder root node is obtained, a node and branch data table required by power flow calculation of the distribution network is formed, the load pseudo measurement estimation of each non-measurement node is realized by adopting a matching power flow technology, the voltage and the branch current of each node are calculated by adopting a forward-backward push power flow technology, the branch loss is calculated, and the distribution transformer active loss of each node is calculated according to the node voltage.

Preferably, in the step of obtaining the branch and loss of the element, the method for calculating the line loss of each branch and the transformer adopts a root mean square current method or a square current method.

Preferably, in the step of acquiring nodes and branches on the non-road between any nodes a and B, the depth-first searching for nodes not included in the road is performed until the ith node is returned, that is, the ith node is searched for the second time.

The invention also discloses a system for calculating the theoretical line loss between any two points of the power distribution network, which comprises the following units:

element branch, loss acquisition unit: acquiring a topology data table and a topology relation table of actual equipment and elements operated by a distribution network according to the operation condition of the distribution network, forming node and branch data required by power flow calculation of the distribution network according to the two tables, and calculating the loss of each element and branch by adopting a matching power flow technology;

a road matrix forming unit: for a radial distribution network, firstly forming a radial distribution network node branch incidence matrix, calculating and transposing an inverse matrix of the incidence matrix to form a road matrix, wherein the horizontal axis of the two matrixes is a branch and the vertical axis is a node;

branches and nodes contained in path between any node A and any node BA point acquisition unit: taking out the corresponding rows of the given two nodes A and B from the road matrix, and comparing the data of the two rows one by one according to the columns; if the numerical values of the rows corresponding to the nodes A and B are different for a certain column, the branch set omega included in the road of the node A and the node B is counted by the branch number corresponding to the column_bAccording to the branches contained in the road A and the road B, all the node sets between the road A and the road B can be obtained by utilizing the incidence matrix and are marked as omega_nThe number of elements is n, and the node set omega_nDoes not contain the starting and ending nodes A and B;

a node and branch acquisition unit on a non-road between any node A and any node B: set of nodes omega_nI is not less than 1<N is less than or equal to n, all the branches connected with the incidence matrix are obtained according to the incidence matrix, and the branches do not belong to the set omega_bThe correspondent node of each connected leg in the set starts depth-first search not at omega_nAnd nodes in the first and the last nodes A and B until the ith node is returned, and adding the newly searched branch into the set omega_biNewly searched nodes join the set omega_niPerforming the following steps;

search completion judging unit: determine omega_nWhether all the nodes are searched in the step S140 or not is judged, if yes, the step S160 is turned to, and if not, the step S140 is turned to, and the searching is continued;

a loss statistics unit: statistical set omega_bAnd Ω_biN, and the loss of the branch is denoted as P_loss,bStatistics of Ω_nAnd Ω_niN, and the losses of the distribution transformer, the parallel capacitor and the series reactor connected to the node are denoted as P_loss,nThe total loss between any given two nodes is P_loss＝P_loss,b+P_loss,n。

Preferably, the element branch and the loss obtaining unit are specifically: according to the operation condition of the distribution network, the numbers of nodes at two ends of a feeder section, a distribution transformer and a load element of an actual distribution network operation feeder line are obtained, the parameters of each element and the power of a load are obtained, the power of a feeder root node is obtained, a node and branch data table required by power flow calculation of the distribution network is formed, the load pseudo measurement estimation of each non-measurement node is realized by adopting a matching power flow technology, the voltage and the branch current of each node are calculated by adopting a forward-backward push power flow technology, the branch loss is calculated, and the distribution transformer active loss of each node is calculated according to the node voltage.

Preferably, in the element branches and the loss acquisition unit, the method for calculating the line loss of each branch and the transformer adopts a root mean square current method or a square current method.

Preferably, in the node on the non-road between any node a and any node B and the branch obtaining unit, the depth-first searching for the node not included in the road until the ith node is returned means that the ith node is searched for the second time.

Therefore, the method and the system for calculating the theoretical line loss between any two points of the power distribution network are based on the road matrix and the depth-first search algorithm, can help distribution network dispatchers to quickly calculate the loss of the area between any two nodes of the distribution network, master the distribution situation of the line loss, are favorable for finding weak links of the network, further take optimization measures, reduce the network loss and have high practical value.

Drawings

FIG. 1 is a flow chart of a method for calculating theoretical line loss between two points according to an embodiment of the present invention;

fig. 2 is a schematic diagram of an 11-node distribution network according to an embodiment of the present invention;

fig. 3 is a block diagram of a theoretical line loss calculation system between two points, according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

The distribution network refers to radial running distribution and comprises a topological relation table and a data table among various distribution devices, and the specific calculated line loss devices comprise branches, distribution transformers, parallel capacitors, series reactors and the like.

Referring to fig. 1, a flowchart of a method for calculating theoretical line loss between two nodes according to an embodiment of the present invention is disclosed, where the calculation of the line loss in the area between any two nodes includes the following steps:

step S130, obtaining the branch and node contained in the road between any node A and any node B: taking out the corresponding rows of the given two nodes A and B from the road matrix, and comparing the data of the two rows one by one according to the columns; if the numerical values of the rows corresponding to the nodes A and B are different for a certain column, the branch set omega included in the road of the node A and the node B is counted by the branch number corresponding to the column_bAccording to the branches contained in the road A and the road B, all the node sets between the road A and the road B can be obtained by utilizing the incidence matrix and are marked as omega_nThe number of elements is n, and the node set omega_nDoes not contain the starting and ending nodes A and B; this step is used to obtain the set of nodes and branches directly connected between the nodes A, B through the road matrix.

Step S140, acquiring nodes and branches on non-roads between any nodes A and B: set of nodes omega_nI is not less than 1<N is less than or equal to n, all the branches connected with the incidence matrix are obtained according to the incidence matrix, and the branches do not belong to the set omega_bStarting a depth-first search for nodes not included in the road, i.e. not included in Ω, for the opposite end node of each connected leg in (b)_nAnd nodes in the first and the last nodes A and B until the ith node is returned, and adding the newly searched branch into the set omega_biNewly searched nodeJoin set omega_niPerforming the following steps; this step is used to obtain other nodes and branches between nodes A, B that are not directly connected by means of a depth first search, to be used as a complement to step S130.

Step 150, the judging step: determine omega_nWhether all the nodes are searched in the step S140 or not is judged, if yes, the step S160 is turned to, and if not, the step S140 is turned to, and the searching is continued; by the judging step, other nodes and branches which are not directly connected are prevented from being obtained by omitting the nodes and branches which are directly connected.

Upon completion of steps S140 and S150, this step is used to account for the loss of all nodes and branches between nodes A, B, resulting in a theoretical line loss between any two nodes A, B.

Preferably, in step S110, the method for calculating the line loss of each branch and the transformer is based on a root mean square current method or a square current method.

Preferably, in step S140, the depth-first search is performed on nodes that are not included in the road until the ith node is returned, that is, the ith node is searched for the second time.

Example 1:

the embodiment specifically discloses the calculation of the theoretical loss between two nodes.

Referring to fig. 2, a schematic diagram of a distribution network with 11 nodes is disclosed.

Step S110, obtaining element branches and loss step: according to the operation condition of a distribution network, acquiring node numbers of two ends of a feeder line section of an actual distribution network operation feeder line, node numbers of a distribution transformer and a load element, parameters of each element and power of a load, acquiring power of a feeder line root node, forming a node and branch data table required by power flow calculation of the distribution network, realizing load pseudo measurement estimation of each non-measurement node by adopting a matching power flow technology, calculating voltage and branch current of each node by adopting a forward-backward push power flow technology, further calculating loss of each branch, and calculating active loss of each node distribution transformer according to the node voltage;

according to the node distribution network of fig. 2, step S110 is utilized to obtain an original topology data table and a relationship table, i.e., the node and branch data table shown in table 1.

TABLE 1 node and tributary data sheet

For an actual distribution network as shown in fig. 2, the actual load power of the system is calculated to obtain the power values at the head ends of lines 1-2 and 2-3 as branch measurements for state estimation, and the power measurement at the 1-2 section is the active power P_1-2569.944kW, reactive power Q_1-2243.636 kW; 2-3 segment power measurement as active power P_2-3305.407kW, reactive power Q_2-3Distribution data for distribution transformers at 129.937kvar are shown in table 2:

table 2 distribution transformer data table

The non-measured load pseudo-measurement of nodes 2 to 11 according to the matched load flow is shown in Table 3

TABLE 3 non-measurement load pseudo-measurement table

Node number	Active pseudo measurement (kW)	Reactive measurement (kvar)
			2	50.1	19.7
3	0.00	0.00
			4	80.1	31.9
5	0.00	0.00
			6	40.2	16.3
7	63.5	25.1
			8	0.00	0.00
9	50.5	19.2
			10	89.2	36.3
11	180	71.5

On the basis of pseudo measurement of each node of matched power flow estimation, the forward-backward push power flow technology is adopted to calculate the loss of each branch and the loss of each point, wherein the loss of each branch is shown in a table 4, and the distribution and transformation loss of each node is shown in a table 5:

table 4 distribution loss table for each branch

TABLE 5 distribution transformer loss table for each node

Node number	1	2	3	4	5	6	7	8	9	10	11
												Loss (kW)	0	1.24	0	1.71	0	1.05	1.43	0	1.25	2.3	3.91

Step S120, obtaining the following node branch relationship matrix according to fig. 2:

node/branch	1	2	3	4	5	6	7	8	9	10
											2	-1	1	0	0	0	0	0	0	0	0
3	0	-1	1	1	0	0	0	0	0	0
											4	0	0	-1	0	1	0	0	0	0	0
5	0	0	0	0	-1	1	1	0	0	0
											6	0	0	0	0	0	-1	0	0	0	0
7	0	0	0	-1	0	0	0	1	0	0
											8	0	0	0	0	0	0	0	-1	1	1
9	0	0	0	0	0	0	0	0	-1	0
											10	0	0	0	0	0	0	0	0	0	-1
11	0	0	0	0	0	0	-1	0	0	0

The horizontal axis is a branch and the vertical axis is a node.

In the above matrix, 1 indicates that a branch k is associated with a node j and the direction deviates from the node; -1 indicates that branch k is associated with node j, the direction pointing to the node.

And solving an inverse matrix according to the node branch incidence matrix, and forming the following road matrix through transposition.

Node/branch	1	2	3	4	5	6	7	8	9	10
											2	-1	0	0	0	0	0	0	0	0	0
3	-1	-1	0	0	0	0	0	0	0	0
											4	-1	-1	-1	0	0	0	0	0	0	0
5	-1	-1	-1	0	-1	0	0	0	0	0
											6	-1	-1	-1	0	-1	-1	0	0	0	0
7	-1	-1	0	-1	0	0	0	0	0	0
											8	-1	-1	0	-1	0	0	0	-1	0	0
9	-1	-1	0	-1	0	0	0	-1	-1	0
											10	-1	-1	0	-1	0	0	0	-1	0	-1
11	-1	-1	-1	0	-1	0	-1	0	0	0

In the above matrix, if a certain branch exists on a path from a node to a root node, a point corresponding to the node and the branch is not 0; for example, node 2 has only branch 1 to root node 1, so the column corresponding to only branch 1 in the second row in the table above is not 0.

Step S3: searching nodes and branches of a road array between

nodes

5 and 9 by comparing columns between the

nodes

5 and 9, if the two columns are different, the corresponding branch is a branch on the road, and the result is as follows: the branches corresponding to the node 5 are respectively:

-1

0

-1

0

the branches corresponding to the node 9 are respectively:

-1

0

-1

0

-1

0

obviously, the values of the

corresponding branches

3, 4, 5, 8, 9 are different.

Therefore, the road directly connected between the nodes 5 to 9 is the branch set Ω_b：3、4、5、8、9。

According to the branch, the roads directly connected between the

nodes

5 and 9 include

nodes

3, 4, 5, 7, 8 and 9 by using the incidence matrix. Removing the first node 5 and the last node 9 to obtain a node set omega_n: 3. 4, 7 and 8, wherein n is 4.

Steps S140 and S150: starting from

nodes

3, 4, 7, 8, respectively, a depth-first search is performed for nodes other than

nodes

3, 4, 5, 7, 8, 9 until the node is returned.

Taking the first node 3 as an example, the depth-first search algorithm is adopted to search the node 2 first, and the node 2 is not included in the node set omega_nIn, add node 2 to Ω_n1And starting the deep search from the node 2 and then searching the

nodes

1 and 3, wherein the node 3 is searched for the first time without stopping the search, and the node 1 is not contained in the node set omega_nThus adding node 1 to Ω_n1Starting from node 1, the deep search is performed, and then the

nodes

2 and 2 are searched back to be in the set omega_n1And finally searching back to the node 3, wherein the node 3 is searched for the 2 nd time, and the search is terminated. And then in the set omega_n1The searched nodes are

nodes

1 and 2, and

branches

1 and 2 connected with the

nodes

1 and 2 are added into omega_b1. By analogy, the node 10 is searched by the node 8 with depth first, and then the node 10 is searched, the searched node is the node 10, the branch connected with the node 10 is 10, and the nodes are not searched by the other nodes.

Finally, the area between

nodes

5 and 9 contains

branches

1,2, 3, 4, 5, 8, 9, 10

The area between

nodes

5 and 9 contains

nodes

1,2, 3, 4, 7, 8, 10.

According to the step, all nodes and branches between the

nodes

5 and 9 except the road array in the step 3 are obtained.

Step S160: and (5) counting the line loss between the

nodes

5 and 9.

According to the result of step 130, the loss on the direct link between

nodes

5 and 9 is: 5.28kW

The calculation process is as follows: the losses on

branches

3, 4, 8, 9 plus the losses on

nodes

4, 7, 9, i.e.

0.499+0.095+0.226+0.061+0.0127+1.71+1.43+1.25 ═ 5.28kW (rounding)

According to the results of steps 140 and 150, the loss in the area between

nodes

5 and 9 is: 12.96

The calculation process is as follows: loss on the road at nodes 5-9 plus loss on

legs

1,2, 10 plus loss on

nodes

1,2, 10, i.e. loss on the road at nodes 5-9

5.28+2.04+2.08+0.018+1.24+2.3 ═ 12.96kW (rounding)

As a comparative example, if only matching power flow calculation is used, only the total loss can be given as: 18.07 kW; the branch loss is 5.18 kW: and the loss on the node transformer is 12.89 kW.

element branch, loss acquisition unit 210: acquiring a topology data table and a topology relation table of actual equipment and elements operated by a distribution network according to the operation condition of the distribution network, forming node and branch data required by power flow calculation of the distribution network according to the two tables, and calculating the loss of each element and branch by adopting a matching power flow technology;

the road matrix forming unit 220: for a radial distribution network, firstly forming a radial distribution network node branch incidence matrix, calculating and transposing an inverse matrix of the incidence matrix to form a road matrix, wherein the horizontal axis of the two matrixes is a branch and the vertical axis is a node;

the node acquisition unit 230 and the branch included in the path between any node a and any node B: taking out the corresponding rows of the given two nodes A and B from the road matrix, and comparing the data of the two rows one by one according to the columns; if the numerical values of the rows corresponding to the nodes A and B are different for a certain column, the branch set omega included in the road of the node A and the node B is counted by the branch number corresponding to the column_bAccording to the branches contained in the road A and the road B, all the node sets between the road A and the road B can be obtained by utilizing the incidence matrix and are marked as omega_nThe number of elements is n, and the node set omega_nDoes not contain the starting and ending nodes A and B;

node and branch acquisition unit 240 on the non-road between any nodes a, B: set of nodes omega_nI is not less than 1<N is less than or equal to n, all the branches connected with the incidence matrix are obtained according to the incidence matrix, and the branches do not belong to the set omega_bThe correspondent node of each connected leg in the set starts depth-first search not at omega_nAnd nodes in the first and the last nodes A and B until the ith node is returned, and adding the newly searched branch into the set omega_biNewly searched nodes join the set omega_niPerforming the following steps;

search completion determination unit 250: determine omega_nWhether all the nodes are searched in the step S140 or not is judged, if yes, the step S160 is turned to, and if not, the step S140 is turned to, and the searching is continued;

loss statistics unit 260: statistical set omega_bAnd Ω_biN, and the loss of the branch is denoted as P_loss,bStatistics of Ω_nAnd Ω_niN, and the losses of the distribution transformer, the parallel capacitor and the series reactor connected to the node are denoted as P_loss,nThe total loss between any given two nodes is P_loss＝P_loss,b+P_loss,n。

Preferably, the element branch and loss obtaining unit 210 specifically includes: according to the operation condition of the distribution network, the numbers of nodes at two ends of a feeder section, a distribution transformer and a load element of an actual distribution network operation feeder line are obtained, the parameters of each element and the power of a load are obtained, the power of a feeder root node is obtained, a node and branch data table required by power flow calculation of the distribution network is formed, the load pseudo measurement estimation of each non-measurement node is realized by adopting a matching power flow technology, the voltage and the branch current of each node are calculated by adopting a forward-backward push power flow technology, the branch loss is calculated, and the distribution transformer active loss of each node is calculated according to the node voltage.

Preferably, in the element branch and loss obtaining unit 210, the method for calculating line loss of each branch and the transformer adopts a root mean square method or a square current method.

Therefore, the method and the system for calculating the theoretical line loss between any two points of the power distribution network are based on the road matrix and the depth-first search algorithm, can help distribution network dispatchers to quickly calculate the loss of the area between any two nodes of the distribution network, master the distribution situation of the line loss, are favorable for finding weak links of the network, further take optimization measures, reduce the network loss and have high practical value. ,

while the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for calculating theoretical line loss between any two points of a power distribution network comprises the following steps:

step S140, acquiring nodes and branches on non-roads between any nodes A and B: set of nodes omega_nI is not less than 1<N is less than or equal to n, according to the correlation momentThe array acquires all the branches connected to it, never belonging to the set omega_bThe correspondent node of each connected leg in the set starts depth-first search not at omega_nAnd nodes in the first and the last nodes A and B until the ith node is returned, and adding the newly searched branch into the set omega_biNewly searched nodes join the set omega_niPerforming the following steps;

step S160, a loss statistics step: statistical set omega_bAnd Ω_biN, and the loss of the branch is denoted as P_loss，bStatistics of Ω_nAnd Ω_niN, and the losses of the distribution transformer, the parallel capacitor and the series reactor connected to the node are denoted as P_loss，nThe total loss between any given two nodes is P_loss＝P_loss，b+P_loss，n。

2. The method for calculating the theoretical line loss between any two points of the power distribution network according to claim 1, wherein the method comprises the following steps:

step S110, the step of obtaining the component branch and the step of loss specifically include: according to the operation condition of the distribution network, the numbers of nodes at two ends of a feeder section, a distribution transformer and a load element of an actual distribution network operation feeder line are obtained, the power of a root node of the feeder line is obtained according to the parameters of each element and the power of the load, a node and branch data table required by power flow calculation of the distribution network is formed, wherein the node and branch data table is a topological data table and a relation table, the pseudo-load measurement estimation of each non-measurement node is realized by adopting a matching power flow technology, the voltage of each node and the current of each branch are calculated by adopting a forward-push-back power flow technology, the loss of each branch is further calculated, and the active loss of each node.

3. The method for calculating the theoretical line loss between any two points of the power distribution network according to claim 2, wherein the method comprises the following steps:

in the step of obtaining the branch circuit and the loss of the element, the loss of each branch circuit is calculated by adopting a method based on root mean square current or a method based on square current.

4. The method for calculating the theoretical line loss between any two points of the power distribution network according to claim 1, wherein the method comprises the following steps:

in the step of acquiring nodes and branches on the non-road between any node A and any node B, the step until the ith node is returned means that the ith node is searched for the second time.

5. A system for calculating theoretical line loss between any two points of a power distribution network comprises the following units:

the path between any node A and any node B comprises a branch and a node acquisition unit: taking out the corresponding rows of the given two nodes A and B from the road matrix, and comparing the data of the two rows one by one according to the columns; if the numerical values of the rows corresponding to the nodes A and B are different for a certain column, the branch set omega included in the road of the node A and the node B is counted by the branch number corresponding to the column_bAccording to the branches contained in the road A and the road B, all the node sets between the road A and the road B can be obtained by utilizing the incidence matrix and are marked as omega_nThe number of elements is n, and the node set omega_nDoes not contain the starting and ending nodes A and B;

a node and branch acquisition unit on a non-road between any node A and any node B: set of nodes omega_nI is not less than 1<N is less than or equal to n, all the branches connected with the correlation matrix are obtained according to the correlation matrix and never belong toSet omega_bThe correspondent node of each connected leg in the set starts depth-first search not at omega_nAnd nodes in the first and the last nodes A and B until the ith node is returned, and adding the newly searched branch into the set omega_biNewly searched nodes join the set omega_niPerforming the following steps;

search completion judging unit: determine omega_nIf all the nodes in the system are searched by the node and branch acquisition unit on the non-road between the node A and the node B, if so, turning to the loss statistical unit, otherwise, turning to the node and branch acquisition unit on the non-road between the node A and the node B to acquire any node A, and continuing searching;

a loss statistics unit: statistical set omega_bAnd Ω_biN, and the loss of the branch is denoted as P_loss，bStatistics of Ω_nAnd Ω_niN, and the losses of the distribution transformer, the parallel capacitor and the series reactor connected to the node are denoted as P_loss，nThe total loss between any given two nodes is P_loss＝P_loss，b+P_loss，n。

6. The system according to claim 5, wherein the system comprises:

the element branch and loss acquisition unit specifically comprises: according to the operation condition of the distribution network, the numbers of nodes at two ends of a feeder section, a distribution transformer and a load element of an actual distribution network operation feeder line are obtained, the power of a root node of the feeder line is obtained according to the parameters of each element and the power of the load, a node and branch data table required by power flow calculation of the distribution network is formed, wherein the node and branch data table is a topological data table and a relation table, the pseudo-load measurement estimation of each non-measurement node is realized by adopting a matching power flow technology, the voltage of each node and the current of each branch are calculated by adopting a forward-push-back power flow technology, the loss of each branch is further calculated, and the active loss of each node.

7. The system according to claim 6, wherein the system comprises:

in the element branch circuit and the loss obtaining unit, the method for calculating the loss of each branch circuit adopts a method based on root mean square current or a method based on square current.

8. The system according to claim 5, wherein the system comprises:

in the node and branch acquiring unit on the non-road between any node a and any node B, the point until the ith node is returned means that the ith node is searched for the second time.