CN113783184B - Power distribution network multistage network reconstruction method based on weighted index optimization - Google Patents

Abstract

The invention belongs to power system simulation, and relates to a power distribution network multistage network reconstruction method based on weighted index optimization. Starting from a power distribution network operation problem device, adopting a topology analysis method aiming at a power distribution network feeder to which the problem device belongs, and generating a transfer scheme aiming at each problem device by carrying out topology search on specific problem devices; through reverse topology search of the disconnection switch, support to carry out transfer path search on a large-range power-losing area; through the combined transfer scheme, the multi-stage transfer of the problem equipment is supported, and the operation risk of each feeder after the transfer is effectively dispersed; the partition feeder indexes are calculated efficiently by carrying out partition combination on the equipment feeder and the transfer feeder with specific problems, and the optimal reconstruction scheme of the power distribution network capable of improving the ground state indexes is reasonably provided by adopting a weighted index optimization method. The method of the invention includes, but is not limited to, giving out a problem device transfer scheme, and can be extended to any device transfer scheme analysis and preference.

Description

A Multilevel Network Reconfiguration Method of Distribution Network Based on Weighted Index Optimization

technical field

The invention belongs to the technical field of power system simulation, and in particular relates to a multi-level network reconfiguration method of a distribution network based on weighted index optimization.

Background technique

Aiming at problems such as heavy overload of lines and low voltage of distribution transformers in the operation of distribution network, traditional dispatchers need to invest a lot of manpower and material resources in finding the cause of the problem and analyzing the transfer plan. In more and more cases, it will become increasingly difficult to find a solution to the problem and compare the safety of various transfer solutions; with the development of science and technology, the increase in social demand for electricity leads to a simultaneous increase in the load rate of the grid. Traditional knife operation with problems such as low voltage will likely lead to increased operational risk after transfer.

Contents of the invention

In view of this, the present invention proposes a distribution network multi-level network reconfiguration method based on weighted index optimization to overcome the shortcomings of the prior art.

The multi-level network reconfiguration method of distribution network based on weighted index optimization proposed by the present invention includes:

(1) Read the problem equipment information in the distribution network. The problem equipment information includes equipment number, equipment name, fault type and equipment type, and store the problem equipment information in a problem equipment list;

(2) Read the distribution network equipment model. The distribution network equipment model includes equipment node information, double-ended equipment information, and single-ended equipment information. The power grid model is simplified into nodes, single-ended equipment, and double-ended equipment. According to the equipment node number , store single-ended devices in a device list associated with one node, store double-ended devices in a device list associated with two nodes, and generate an associated node device list for each node;

(3) Read the remote signaling status of circuit breakers and switch devices in the distribution network, and store the circuit breakers and switch switches disconnected in the remote signaling state in a disconnect switch list;

(4) According to the node type of the distribution network, the root node of the main transformer bus bar on the high voltage side is stored in an unsearched node list in turn, and a feeder is created for each root node of the main transformer bus bar on the high voltage side; the unsearched node list is judged, If the list of unsearched nodes is empty, then jump to step (5), if the list of unsearched nodes is not empty, then obtain the first root node from the list of unsearched nodes;

(5) Perform topology search from the forward direction of the unsearched node list, and use breadth-first search logic to sequentially obtain child nodes, node-associated single-ended devices, and node-associated double-ended devices according to the association relationship between devices and nodes, and The feeder to which the corresponding equipment belongs is set as the feeder to which the current node belongs, and the traversed nodes, single-ended equipment, and double-ended equipment are recorded as the charged state until the end of the power grid or the switching equipment whose remote signaling status is disconnected is searched;

(6) Perform a reverse topology search starting from the disconnect switch list, and adopt breadth-first search logic according to the association relationship between nodes and devices to obtain sub-nodes and disconnect switch devices associated with nodes in sequence until the end of the power grid is searched or Until the node in the charged state, create a local topology search tree; set the searched node and the searched disconnect switch device to belong to the local topology search tree, and store the local topology search tree in a local topology search tree tree list;

(7) According to the feeder to which the associated node of the equipment in the problem equipment list belongs, combined with the feeder to which the node belongs to the forward topology search mark in step (5) and the live state of the node, and the disconnect switch marked in step (6) reverse topology search Local topology search tree to find the transfer solution for the problematic equipment;

(8) Traversing the transfer plan list of the equipment in the problem equipment list, taking the feeder to which the open switch belongs and the feeder to which the closed switch belongs in the transfer plan as associations, constructing a network reconstruction partition, and including the transfer of the same feeder The supply plan is stored in a transfer plan list of the same partition, the feeder included in the transfer plan is stored in a partition feeder list, and all partitions are stored in a network reconstruction partition list;

个多级转供方案，将多级转供方案添加至馈线所属的一个网络重构分区转供方案列表；(9) According to the feeder to which the problematic equipment belongs in the problematic equipment list, group the problematic equipment, group the problematic equipment belonging to the same feeder in the problematic equipment list into a group, and merge the transfer scheme lists of all problematic equipment under the same feeder For a feeder temporary transfer plan list for this feeder, the transfer plans in the feeder temporary transfer plan list are arranged and combined to form a multi-level transfer plan, assuming that the length of the feeder temporary transfer plan list is NR, Calculated by permutation and combination, forming

multi-level transfer scheme, add the multi-level transfer scheme to a network reconstruction partition transfer scheme list to which the feeder belongs;

(10) Statistically calculate the base state load rate index and voltage index of the distribution network before the transfer, and calculate the final score of the base state according to the weight of each index set, and judge the network reconstruction partition list. If the network reconstruction partition list is Empty, jump to step (11), if the network reconstruction partition list is not empty, take out the first network reconstruction partition;

(11) Operate the action switches corresponding to each transfer scheme in the network reconfiguration partition in turn, and calculate the feeder power flow of the partition, count the load rate index and voltage index after transfer, and calculate the weight of each index according to the weight of each index. The final score of the transfer plan;

(12) By comparing the distribution network base state with the reconstructed distribution network line average load rate, line maximum load rate, distribution transformer average per unit voltage, distribution transformer minimum per unit voltage, and compare the scores of each transfer scheme, screen out the network Reconstruct the optimal sub-supply transfer scheme and complete the multi-level network reconstruction of the distribution network.

The present invention proposes a distribution network multi-level network reconfiguration method based on weighted index optimization, and its advantages are as follows:

This method starts from the problems of heavy overload and low voltage in the operation of the distribution network, and uses the forward and reverse topology analysis method for the feeder of the distribution network to which the problematic equipment belongs to, to generate a transfer plan for each problematic device; the transfer plan involves In the case of transferring in and out of multiple feeders, several network reconfiguration partitions are generated according to the feeder relationship, and the reconfiguration partition is the minimum set of transfer schemes that affect the power flow distribution; there are multiple transfer schemes for specific problem equipment Under the premise of ensuring the safety of operation, a new transfer plan is generated by merging multiple transfer plans to realize multi-level transfer of problematic equipment feeders; recalculate the power flow of each reconfigured partition according to the transfer plan, and obtain the transfer The scheme is aimed at the weighted indicators of different types of problematic equipment, and the optimal supply scheme is obtained by comparing the base state indicators with the weighted indicators of all the supply schemes. This method efficiently finds all transfer solutions by performing forward and reverse topology searches on specific problematic devices, and generates multi-level transfer solutions by analyzing the routes of the transfer solutions. The weighted index optimization method is used to reasonably give the optimal reconstruction scheme that can improve the base state index considering the multi-level network reconstruction.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some of the embodiments of the application, not all of them. Based on the embodiments in the present application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present application.

Fig. 1 is a flowchart of a multi-level network reconfiguration method of a distribution network based on weighted index optimization according to an embodiment of the method of the present invention.

Fig. 2 is a flowchart of topology search in step (5) in one embodiment of the method.

Fig. 3 is a flow chart of the reverse topology search in step (6) in one embodiment of the method.

Fig. 4 is a flow chart of step (11) network reconfiguration partition index calculation in an embodiment of the method.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present application, not all of them. Based on the embodiments in the present application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present application.

Fig. 1 is a schematic flowchart of a multi-level network reconfiguration method of distribution network based on weighted index optimization according to an embodiment of the present invention. A multi-level network reconfiguration method of a distribution network based on weighted index optimization in this embodiment can be applied to user equipment, such as mobile phones and tablet computers.

Below in conjunction with Fig. 1, introduce an embodiment of the method of the present invention in detail, can comprise the following steps:

In one embodiment of the present invention, some lists can be established first, for example:

Construct a list of problem devices to store problem devices in the distribution network; construct a list of disconnected switches to store switch devices disconnected by remote signaling in the distribution network; construct a local topology search tree list to store The result of topological search for devices in the disconnect switch list; construct a traversed disconnect switch list for storing traversed disconnect switches during the generation of local topology search tree; construct a list of unsearched nodes for temporary storage Nodes to be searched in the topology search process; construct a network reconstruction partition list to store the network reconstruction partition constructed according to the topology search results; construct a network reconstruction partition feeder list to store the feeders contained in the network reconstruction partition ; Construct a network reconfiguration partition transfer plan list, which is used to store the transfer proposals contained in the network reconfiguration partition.

Build a problem device list to store problem devices in the distribution network; build a disconnect switch list to store remote signaling disconnected switch devices in the distribution network; build a local topology search tree list to store disconnected The results of the topology search of the devices in the switch list; construct the traversed disconnect switch list, which is used to store the traversed disconnect switches in the process of generating the local topology search tree; construct the unsearched node list, which is used to temporarily store the disconnected switches during the topology search process Nodes to be searched; build a network reconstruction partition list for storing network reconstruction partitions constructed according to topology search results; construct a network reconstruction partition feeder list for storing feeders contained in network reconstruction partitions; construct network reconstruction partition transfer Provider scheme list, used to store the transfer schemes contained in the network reconstruction partition.

In step 1, read the problem equipment information such as heavy overload lines and low voltage distribution transformers in the distribution network from the power flow calculation results of the distribution network or other platform systems. The problem equipment information includes equipment number, equipment name, fault type and equipment type , storing the problematic device information in the problematic device list, and performing a topology search;

In step 2, the distribution network equipment model is read from the database or other platform systems. The distribution network equipment model includes but not limited to equipment node information (mainly including node number, node name, node type information), double-ended equipment information, (mainly including equipment number, equipment name, equipment type, feeder, node 1 number, node 2 number) such as line segment, circuit breaker, knife switch, distribution transformer winding, and single-ended equipment information (mainly including equipment number, equipment name, Equipment type, feeder, node 1 number) such as load, distributed power supply, capacitive reactor, where single-ended equipment is associated with a single equipment node, double-ended equipment is associated with two equipment nodes, the power grid model is simplified as nodes, single-ended equipment and double-ended devices, according to the device node number, add the single-ended device to the device list of its associated node, add the double-ended device to the device list of the two associated nodes, and generate its associated node device for each node list;

In step 3, the remote signaling status of circuit breakers and switch devices in the distribution network (mainly including switch number, switch name, switch open or closed status information) is read from the database or other platform systems, and the remote signaling The disconnected circuit breaker and knife switch are stored in the disconnected switch list, and the remote signaling status is mainly used to stop the search when encountering a disconnected circuit breaker and knife switch in the remote signaling state during topology search;

In step 4, according to the node type of the distribution network, the root node of the main transformer busbar on the high voltage side is stored in an unsearched node list in turn, and a feeder is created for each root node of the main transformer busbar on the high voltage side; the unsearched node list is Judgment, if the list of unsearched nodes is empty, then jump to step (5), if the list of unsearched nodes is not empty, then obtain the first root node from the list of unsearched nodes;

In one embodiment of the present invention, step 4 includes:

(1) Create a new feeder, set the current root node to belong to this feeder, and set the current root node to be charged;

(2) judge the current root node, if the current root node is not the last node of the unsearched node list, then obtain the next root node from the unsearched node list, repeat step (1), if the current root node is the last node in the list of unsearched nodes, complete this step.

In step 5, start from the forward direction of the unsearched node list to perform a topology search, and use breadth-first search logic to sequentially obtain child nodes, node-associated single-ended devices, and node-associated double-ended devices according to the association relationship between devices and nodes, And set the feeder to which the corresponding equipment belongs to the feeder to which the current node belongs, until the end of the power grid or the switchgear whose remote signaling status is disconnected is searched, and the traversed nodes, single-ended equipment, and double-ended equipment are recorded as live status.

In one embodiment of the present invention, the flowchart of step 5 is shown in Figure 2, including:

(1) Judging the list of unsearched nodes, if the list of unsearched nodes is empty, then jump to step (5), if the list of unsearched nodes is not empty, then let the length of the list of unsearched nodes be NS, and initialize The search node serial number is 1, proceed to step (2);

(2) Set the search node count position node of the unsearched node list in step (1) as the current node, make the feeder to which the current node belongs to the current feeder, and judge the node device list of the current node, if the node device list of the current node If it is empty, skip to step (3). If the node device list of the current node is not empty, traverse the node device list of the current node and perform the following steps:

(2-1) Obtain the first node device in the node device list of the current node, and set the node device as the current node device;

(2-2) Judging the current node device, if the current node device has been traversed, then jump to step (2-6), if the current node device has not been traversed, then proceed to step (2-3);

(2-3) mark that the current node equipment belongs to the current feeder, and mark that the current node equipment has been traversed;

(2-4) Determine the type of the current node device, if the type of the current node device is a single-ended device, then jump to step (2-6), if the type of the current node device is a double-ended device, then start from the double-ended device Obtain the peer node of the dual-end device from the two associated nodes of the end device, and perform steps (2-5);

(2-5) Judging the peer node, if the peer node has been traversed, then jump to step (2-6), if the peer node has not been traversed, mark the peer node as belonging to the current feeder, and mark the peer node For traversed, mark the peer node as charged, mark the parent node of the peer node as the current node, add the peer node to the end of the unsearched node list, and continue to step (2-6);

(2-6) Judging the node device list of the current node, if the current node device is not the last device in the node device list of the current node, then obtain the next device in the node device list of the current node, and set the device Determined as the current node device, return to step (2-2), if the current node device is the last device in the node device list of the current node, then proceed to step (3);

(3) Judging the search node serial number, if the search node serial number is less than the length NS of the node list without searching, then the search node serial number counts plus 1, and returns to step (2), if the search node serial number is equal to NS, proceed to step (4);

(4) Remove the first NS traversed nodes from the unsearched node list, and return to step (1);

(5) The list of unsearched nodes is empty, the forward topology search ends, and this step is completed.

In step 6, starting from the disconnection switch list, a reverse topology search is performed, and according to the association relationship between nodes and devices, breadth-first search logic is used to sequentially obtain subnodes and disconnection switch devices associated with nodes until the power grid is searched Create a local topology search tree until the end or the node in the charged state; set the searched node and the searched disconnect switch device to belong to the local topology search tree, and store the local topology search tree in a local List of topological search trees.

In one embodiment of the present invention, the flowchart of step 6 is shown in Figure 3, including:

(1) Judge the disconnect switch list, if the disconnect switch list is empty, then complete this step, if the disconnect switch list is not empty, take out the first switch in the disconnect switch list, and perform the step ( 2);

(2) Judging the current disconnect switch device, if the current disconnect switch device exists in the traversed disconnect switch list, then jump to step (3), if the current disconnect switch device does not exist in the traversed switch list Traversing the disconnected switch list creates a local topology search tree, stores the local topology search tree in a local topology search tree list, sets the current disconnected switch as the root switch of the current partial topology search tree, and sets the current disconnected switch The nodes at the first and last ends are added to the list of unsearched nodes and marked as traversed, and a topology search is performed on the current disconnected switch. The specific steps are as follows:

(2-1) Judging the list of unsearched nodes, if the list of unsearched nodes is empty, then jump to step (3), if the list of unsearched nodes is not empty, set the current length of the list of unsearched nodes to be NLS, build the search node serial number and set its initial value to 1, proceed to step (2-2);

(2-2) Set the search node serial number position node of the unsearched node list as the current node, and judge the charged state of the current node. If the current node is in the charged state, store the current node in the charged node list of the current topology search tree , and jump to step (2-4), if the current node is not charged, then proceed to step (2-3);

(2-3) Judging the node device list of the current node, if the node device list of the current node is empty, jump to step (2-4), if the node device list of the current node is not empty, continue to reverse Topology search, the specific steps are as follows:

(2-3-1) Obtain the first node device in the node device list of the current node, and set the node device as the current node device;

(2-3-2) Judging the current node device, if the current node device is a single-ended device or the current device has been traversed, then jump to step (2-3-6), if the current node device is a double-ended device and The current device has not been traversed, then continue to step (2-3-3);

(2-3-3) Mark the current node device as traversed, add the current node device to the traversed disconnect switch list, obtain the peer node of the current node from the two associated nodes of the current node device, right The end node judges, if the peer node has been traversed, jump to step (2-3-6), if the peer node has not been traversed, continue to step (2-3-4);

(2-3-4) mark that the peer node has been traversed, and set the current node as the parent node of the peer node;

(2-3-5) Judge the peer node. If the peer node is charged, add the peer node to the charged node list of the current local topology search tree. If the peer node is not charged, add the peer node Add to the end of the list of unsearched nodes;

(2-3-6) Judging the node device list of the current node, if the current node device is not the last device in the node device list of the current node, then obtain the next device in the node device list of the current node, and set the The device is set as the current node device, repeat step (2-3-2), if the current node device is the last device in the node device list of the current node, then continue to step (2-4);

(2-4) Judging the serial number of the searched node, if the serial number of the searched node is less than the length of the list of unsearched nodes NLS, then add 1 to the serial number of the searched node, return to step (2-2), if the serial number of the searched node is equal to NLS, then remove NLS traversed nodes at the head end of the unsearched node list, repeat step (2-1);

(3) judge the disconnect switch list, if the current disconnect switch is not the last switch in the disconnect switch list, then obtain the next disconnect switch from the disconnect switch list, repeat step (2), if If the current disconnect switch is the last switch in the disconnect switch list, all disconnect switches in the disconnect switch list have been associated with the local topology search tree, and the reverse topology search is completed, and this step is completed.

In step 7, according to the feeder to which the associated node of the equipment in the problem equipment list belongs, in combination with the feeder to which the node belongs to the forward topology search mark and the electrified state of the node in step (5), the off switch of the reverse topology search mark in step (6) The composed local topology search tree to find the transfer scheme for the problematic equipment.

In one embodiment of the present invention, step 7 includes:

(1) Judging the local topology search tree list, if the local topology search tree list is empty, then complete this step, if the local topology search tree list is not empty, then search for the problem equipment transfer scheme in the problem equipment list, Specific steps are as follows:

(2) Set the length of the local topology search tree list to be NT, judge the problem equipment list, if the problem equipment list is empty, then complete this step, if the problem equipment list is not empty, then take out the problem equipment list The first problematic device in and set as the current device, continue to step (3);

(3) According to the forward topology search results of live distribution network equipment, obtain the feeder to which the current equipment belongs and set it as the current feeder, construct the live node list of the current feeder, and store the feeder as the live state node of the current feeder in The live node list of the current feeder, obtaining the first local topology search tree in the local topology search tree list, and setting the first local topology search tree as the current local topology search tree;

(4) Obtain the live node list of the current local topology search tree according to the reverse topology search results of the power-off state distribution network equipment, and judge the live node list of the current local topology search tree, if the current local topology search tree If the list of charged nodes in the current local topology search tree is empty, then jump to step (12). If the list of charged nodes in the current local topology search tree is not empty, construct the connection fault node serial number and set its initial value to 1, and proceed to step (5) ;

(5) Judging the sequence number of the connection failure node, if the connection failure node sequence number is greater than or equal to the length of the live node list of the current local topology search tree, then jump to step (12), if the connection failure node sequence number is less than the current local topology search tree The length of the live node list is obtained from the live node list of the current local topology search tree to obtain the node at the position of the connection fault node serial number, and set the node as the connection fault node, set the connection fault node serial number plus 1, and proceed to step (6 );

(6) Judging the live node list of the current feeder, if the live node list of the current feeder does not contain the connection fault node, return to step (5), if the current live node list of the feeder contains the connection fault node, then construct the transfer fault Node serial number, set the initial value of the serial number to 1, and proceed to step (7);

(7) Judging the sequence number of the faulty node, if the sequence number of the faulty node is greater than or equal to the length of the live node list of the current local topology search tree, return to step (5), if the sequence number of the faulty node is less than the current local topology search tree The length of the live node list of the tree is obtained from the live node list of the current local topology search tree, and the node at the position of the transfer fault node number is obtained, and the node is set as the transfer fault node, and the number of the transfer fault node is set plus 1 , proceed to step (8);

(8) Judging the live node list of the current feeder, if the live node list of the current feeder includes the transfer fault node, jump to step (7), if the current live node list of the feeder does not include the transfer fault node, continue step (9);

(9) According to the reverse topology search results of the power-off state distribution network equipment, two different nodes on the same local topology search tree have a common parent node, or two parent nodes connected by the root switch, temporarily construct A list of closed switches for transfer, searching for the parent nodes connected to the faulty node and the parent node of the faulty node, and storing the switch connected to the parent node in the list of closed switches for transfer;

(10) According to the step (6), the connection failure node exists in the live node list of the feeder to which the current equipment belongs, and through topology search, it is judged whether there is a common parent node between the connection failure node and the current equipment node, if there is no common parent node, then Return to step (7), if there is a common parent node, proceed to step (11);

(11) According to the forward topology search results of the distribution network equipment in the charged state, search for the power supply disconnect switch on the upstream power supply path of the common parent node, construct a power supply scheme for the current equipment, and disconnect the power supply switch Opening the switch and adding the closing switch in the transfer closing switch list described in step (9) to the transfer plan, storing the transfer plan to the transfer plan list of the current device, and returning to step (7);

(12) Judging the local topology search tree list, if the current local topology search tree is not the last one in the local topology search tree list, then obtain the next local topology search tree from the local topology search tree list and set it as the current local topology search tree , jump to step (4), if the current local topology search tree is the last one in the local topology search tree list, then continue to step (13);

(13) Judging the list of problem devices, if the current problem device is not the last one in the problem device list, then obtain the next problem device from the problem device list, and set the problem device as the current device, and return to step (3) , if the current problematic device is the last one in the problematic device list, the transfer plan of each problematic device in the problematic device list has been found, and all the transfer plans are stored in the list of transfer plan of the problematic device, and this step is completed .

In step 8, traverse the transfer scheme list of the equipment in the problem equipment list, and use the feeder to which the open switch belongs and the feeder to which the closed switch belongs to in the transfer scheme as associations to construct a network reconstruction partition, which will include the same feeder The transfer plan is stored in a transfer plan list for the same partition, the feeder included in the transfer plan is stored in a partition feeder list, and all partitions are stored in a network reconstruction partition list;

个多级(例如二级)转供方案，将多级(例如二级)转供方案添加至馈线所属的一个网络重构分区转供方案列表。In step 9, according to the feeder to which the problematic equipment belongs in the problematic equipment list, the problematic equipment is grouped, the problematic equipment in the problematic equipment list belonging to the same feeder is grouped into one group, and the transfer scheme of all problematic equipment under the same feeder The list is combined into a list of temporary feeder transfer schemes for this feeder, and the transfer schemes in the feeder temporary transfer scheme list are arranged and combined to form a multi-level transfer scheme, which can reduce the possibility of each feeder transfer while improving problematic equipment. Increased risk, realize feeder-level multi-level transfer; assuming that the length of the feeder temporary transfer plan list is NR, considering the number of switching operations and calculation efficiency, this method only takes the combination of two transfer plans as an example, by arranging Combine calculations to form

A multi-level (for example, two-level) transfer scheme is added, and the multi-level (for example, two-level) transfer scheme is added to a network reconstruction partition transfer scheme list to which the feeder belongs.

In step 10, count the base state load rate index and voltage index of the distribution network before power transfer, and calculate the final score of the base state according to the weight of each index set, and judge the list of network reconstruction partitions. If the network reconstruction partition If the list is empty, skip to step (11). If the list of network reconstruction partitions is not empty, take out the first network reconstruction partition.

In one embodiment of the present invention, step 10 includes:

(1) Obtain the network reconstruction partition feeder list from the current network reconstruction partition;

(2) Obtain all lines and distribution transformers of the feeder in the feeder list of the network reconfiguration partition according to the forward topology search of the distribution network equipment in the charged state, and obtain all the lines and distribution transformers of the feeder, and calculate the base state of the distribution network according to the base state power flow results The average load rate of the line, the maximum load rate of the base state line, the average voltage of the base state distribution transformer, and the minimum voltage of the base state distribution transformer;

(3) Calculate the line load rate score, set the load rate of the distribution network line is usually less than 40% as light load, and higher than 80% as heavy load, the average load rate reflects the overall average level of the load, and the maximum load rate reflects the extreme load The lower limit of the reasonable range of the load rate is 0.4, the upper limit of the reasonable range of the load rate is 0.8, the slope of the score within the reasonable range is 0.8, and the slope of the score outside the reasonable range is 1.2, and the average load rate score of the base state line and the maximum load rate score of the line are calculated respectively. The mean value of the line average load rate score and the line maximum load rate score is the base state line load rate score;

(4) Calculate the voltage score of the distribution transformer, set the reasonable fluctuation range of the distribution network equipment voltage as ±7%, the average voltage reflects the overall average level of the voltage, and the minimum voltage reflects the extreme situation of the voltage, so that the lower limit of the reasonable range of the voltage is 0.93p.u., the voltage The upper limit of the reasonable range is 1.07p.u., the scoring slope within the reasonable range is 0.8, and the scoring slope outside the reasonable range is 1.2. The average p.u. voltage score of the distribution transformer in the base state and the minimum p.u. The average value of the lowest unit voltage score of the distribution transformer and the distribution transformer is the base state voltage score;

In one embodiment of the present invention, the process of calculating the scores of various indicators is as follows: construct a scoring method for percentage-type indicators with a reasonable range, construct a segmented continuous scoring method, and set the midpoint of a reasonable range as The maximum value of the percentage type index is 1.0, assuming that the input index is x, the lower limit of the reasonable range is min, the upper limit of the reasonable range is max, the slope within the reasonable range is r1, and the slope outside the reasonable range is r2, then the midpoint of the reasonable range is mid=(min+max )/2, the score is defined as follows:

When x<min, score score=1-(mid-min)×r1-(min-x)×r2;

When min≤x≤max, score score=1-|x-mid|×r1;

When max<x, score score=1-(mid-min)×r1-(x-max)×r2.

(5) Set the score weight of line load rate and the score weight of distribution transformer voltage respectively, and calculate the base state comprehensive score of the current network reconstruction partition in a weighted manner: base state line load rate score × line load rate score weight + base state voltage score × distribution Variable voltage scoring weight;

(6) Judging the network reconstruction partition list, if the current network reconstruction partition is not the last one in the network reconstruction partition list, take out the next network reconstruction partition, and return to step (1), if the current network reconstruction partition is The network reconstruction partition list is the last one, complete this step.

In step 11, operate the action switches corresponding to each transfer scheme in the network reconfiguration partition in sequence, calculate the feeder power flow in this partition, and count the load rate index and voltage index after transfer, and according to the weight of each index set, Calculate the final score of each transfer scheme.

In one embodiment of the present invention, the flowchart of step 11 is shown in Figure 4, including:

(1) Judging the network reconstruction partition list, if the network reconstruction partition list is empty, then complete this step, if the network reconstruction partition list is not empty, then take out the first network reconstruction partition;

(2) Take out the network reconfiguration partition transfer plan list from the current network reconfiguration partition, judge the network reconfiguration partition transfer plan list, if the network reconfiguration partition transfer plan list is empty, then jump to Step (3), if the list of current network reconfiguration partition transfer schemes is not empty, then calculate the index score of the current network reconfiguration partition transfer scheme, the specific steps are as follows:

(2-1) Take out the first transfer scheme in the current network reconstruction partition;

(2-2) Close the disconnect switch of the current transfer scheme, disconnect the close switch of the current transfer scheme, and calculate the feeder power flow of the current network reconfiguration zone;

(2-3) According to the forward topology search of the live distribution network equipment, the marked equipment belongs to the feeder, obtain all the lines and distribution transformers of the feeder in the feeder list of the network reconstruction partition, and calculate the power flow according to the step (2-2) The load rate of each line and the voltage of each distribution transformer in the statistics, the average load rate of the reconstructed line, the maximum load rate of the reconstructed line, the average voltage of the reconstructed distribution transformer and the minimum voltage of the reconstructed distribution transformer;

(2-4) Calculate the load rate score of the line, set the lower limit of the reasonable range of the load rate to 0.4, the upper limit of the reasonable range of the load rate to 0.8, the score slope within the reasonable range to 0.8, and the score slope outside the reasonable range to 1.2, respectively. After reconstruction The average load rate score of the line, the maximum load rate score of the line after reconstruction, the average load rate score of the line after reconstruction and the maximum load rate score of the line after reconstruction are the load rate score of the line after reconstruction; The method can adopt the method in the above-mentioned step 10;

(2-5) Calculate the voltage score of the distribution transformer, set the lower limit of the reasonable range of voltage to 0.93p.u., the upper limit of the reasonable range of voltage to 1.07p.u., the slope of the score within the reasonable range is 0.8, and the slope of the score outside the reasonable range is 1.2, respectively. After reconstruction The average per-unit voltage score of the distribution transformer and the minimum per-unit voltage score of the distribution transformer after reconstruction, the average of the average per-unit voltage score of the distribution transformer after reconstruction and the minimum per-unit voltage score of the distribution transformer after reconstruction is the post-reconstruction voltage score;

(2-6) The score weight of line load rate and the score weight of distribution transformer voltage consistent with the base state are used to calculate the comprehensive score of the current network reconfiguration partition and current transfer scheme reconstruction in a weighted manner: the line load rate score after reconstruction × Score weight of line load rate + voltage score after reconstruction × weight of distribution transformer voltage score;

(2-7) Make the disconnect switch of the current transfer scheme in the step (2-2) return to the disconnected state, make the closing switch of the current transfer scheme in the step (2-2) return to the closed state;

(2-8) Judgment is made to the network reconfiguration partition transfer plan list, if the current transfer plan is not the last one in the network reconfiguration partition transfer plan list, then take out the next transfer plan and return to step (2 -1), if the current transfer scheme is the last one in the network reconfiguration partition transfer scheme list, proceed to step (3);

(3) Judging the network reconstruction partition list, if the current network reconstruction partition is not the last one in the network reconstruction partition list, then take out the next network reconstruction partition and return to step (1), if the current network reconstruction partition If the configuration partition is the last one in the network reconstruction partition list, complete this step.

In step 12, by comparing the distribution network base state with the reconstructed distribution network line average load rate, line maximum load rate, distribution transformer average per unit voltage, and distribution transformer minimum per unit voltage, compare the scores of each transfer scheme, and screen Outgoing network reconfiguration partition optimal transfer scheme, complete multi-level network reconfiguration of distribution network.

In one embodiment of the present invention, step 12 includes:

(1) From the network reconfiguration partition, select the transfer scheme that satisfies the conditions for improving the base state index. The conditions for improving the base state index include: the average load rate of the line after reconstruction is less than the average load rate of the line in the base state of the distribution network; The maximum load rate is less than the maximum load rate of the base state line of the distribution network, the average per unit voltage of the distribution transformer after reconstruction is greater than the average per unit voltage of the base state distribution transformer of the distribution network, and the minimum per unit voltage of the distribution transformer after reconfiguration is greater than the base state distribution transformer of the distribution network Minimum p.u. voltage;

(2) Select the transfer plan with the highest reconstruction comprehensive score as the optimal transfer plan corresponding to the network reconstruction partition from the transfer plan for improving the base state index of the distribution network;

(3) The optimal transfer schemes of all network reconfiguration partitions are combined to form a complete transfer scheme, and the multi-level network reconfiguration of distribution network based on weighted index optimization is completed.

The above are preferred embodiments of the present disclosure, which can be understood and implemented by those skilled in the art without creative efforts. It should be pointed out that those skilled in the art can make some improvements and modifications without departing from the principle of the present invention, and these improvements and modifications are also considered as the protection scope of the present invention.

Claims (9)

1. The utility model provides a distribution network multistage network reconstruction method based on weighted index optimization, which is characterized by comprising the following steps:

(1) The method comprises the steps of reading problem equipment information in a power distribution network, wherein the problem equipment information comprises equipment numbers, equipment names, fault types and equipment types, and storing the problem equipment information in a problem equipment list;

(2) Reading a power distribution network equipment model, wherein the power distribution network equipment model comprises equipment node information, double-end equipment information and single-end equipment information, simplifying the power grid model into nodes, single-end equipment and double-end equipment, storing the single-end equipment in an equipment list associated with one node according to equipment node numbers, respectively storing the double-end equipment in an equipment list associated with two nodes, and generating an associated node equipment list for each node;

(3) Reading remote signaling states of a breaker and a disconnecting link device in the power distribution network, and storing the breaker and the disconnecting link which are disconnected in the remote signaling states in a disconnection switch list;

(4) According to the node type of the power distribution network, the high-voltage side main transformer bus root nodes are sequentially stored in an unsearched node list, and a feeder line is created for each high-voltage side main transformer bus root node; judging the unsearched node list, if the unsearched node list is empty, jumping to the step (5), and if the unsearched node list is not empty, acquiring a first root node from the unsearched node list;

(5) Performing topology search from the forward direction of the unsearched node list, sequentially obtaining sub-nodes, node-associated single-end devices and node-associated double-end devices by adopting breadth-first search logic according to the association relation between the devices and the nodes, setting feeder lines to which the corresponding devices belong as the feeder lines to which the current nodes belong until the power grid end or the switching device with the remote signaling state being disconnected is searched, and marking the traversed nodes, the single-end devices and the double-end devices as electrified states;

(6) Performing reverse topology search from the disconnection switch list, sequentially acquiring sub-nodes and disconnection switch equipment associated with the nodes by adopting breadth-first search logic according to the association relation between the nodes and the equipment until the nodes reaching the tail end of the power grid or in a charged state are searched, and creating a local topology search tree; setting the node searched at present and the disconnection switch equipment searched at present to belong to the local topology search tree, and storing the local topology search tree in a local topology search tree list;

(7) According to the feeder line to which the equipment associated node belongs in the problem equipment list, a local topology search tree consisting of the feeder line to which the node of the forward topology search mark in the step (5) belongs and the node electrification state and the disconnection switch of the reverse topology search mark in the step (6) is combined, and a transfer scheme aiming at the problem equipment is searched;

(8) Traversing a transfer scheme list of equipment in the problem equipment list, constructing a network reconstruction partition by taking a feeder line of an opening switch and a feeder line of a closing switch in the transfer scheme as a correlation, storing the transfer scheme containing the same feeder line in the same partition transfer scheme list, storing the feeder line contained in the transfer scheme in a partition feeder line list, and storing all the partitions in a network reconstruction partition list;

(9) Grouping problem equipment according to feeder lines to which the problem equipment belongs in the problem equipment list, grouping the problem equipment belonging to the same feeder line in the problem equipment list into a group, merging all transfer scheme lists of the problem equipment under the same feeder line into one feeder line temporary transfer scheme list of the feeder line, forming a multi-stage transfer scheme by arranging and combining transfer schemes in the feeder line temporary transfer scheme list, and calculating by arranging and combining assuming that the length of the feeder line temporary transfer scheme list is NR to form a multi-stage transfer scheme

The multi-stage transfer scheme is added to a network reconstruction partition transfer scheme list to which the feeder belongs;

(10) Counting the base state load rate index and the voltage index of the power distribution network before power supply transfer, calculating the base state final score according to the set index weights, judging the network reconstruction partition list, jumping to the step (11) if the network reconstruction partition list is empty, and taking out the first network reconstruction partition if the network reconstruction partition list is not empty;

(11) Sequentially operating action switches corresponding to each transfer scheme in the network reconstruction partition, calculating the feeder power flow of the partition, counting load rate indexes and voltage indexes after transfer, and calculating the final score of each transfer scheme according to the set weight of each index;

(12) And comparing the ground state of the power distribution network with the average load rate, the maximum load rate, the average per unit voltage and the minimum per unit voltage of the distribution transformer of the power distribution network after reconstruction, grading the conversion schemes, screening out the optimal conversion scheme of the network reconstruction partition, and completing the multistage network reconstruction of the power distribution network.

2. The multi-stage network reconstruction method for a power distribution network according to claim 1, wherein the step (4) includes:

(1) Creating a new feeder line, setting the current root node to belong to the feeder line, and setting the current root node to be in a charged state;

(2) Judging the current root node, if the current root node is not the last node of the unsearched node list, acquiring the next root node from the unsearched node list, repeating the step (1), and if the current root node is the last node of the unsearched node list, completing the step.

3. The multi-stage network reconstruction method for a power distribution network according to claim 1, wherein the step (5) includes:

(1) Judging the unsearched node list, if the unsearched node list is empty, jumping to the step (5), if the unsearched node list is not empty, enabling the length of the unsearched node list to be NS, enabling the serial number of the searched node to be 1 during initialization, and performing the step (2);

(2) Setting the node of the searching node counting position of the unsearched node list in the step (1) as a current node, enabling a feeder line to which the current node belongs to be the current feeder line, judging a node equipment list of the current node, jumping to the step (3) if the node equipment list of the current node is empty, traversing the node equipment list of the current node if the node equipment list of the current node is not empty, and carrying out the following steps:

(2-1) acquiring a first node device in a node device list of a current node, and setting the node device as the current node device;

(2-2) judging the current node equipment, if the current node equipment is traversed, jumping to the step (2-6), and if the current node equipment is not traversed, performing the step (2-3);

(2-3) marking that the current node device belongs to the current feeder line, and marking that the current node device has traversed;

(2-4) judging the type of the current node equipment, if the type of the current node equipment is single-ended equipment, jumping to the step (2-6), and if the type of the current node equipment is double-ended equipment, acquiring opposite-end nodes of the double-ended equipment from two associated nodes of the double-ended equipment, and performing the step (2-5);

(2-5) judging the opposite end node, if the opposite end node is traversed, jumping to the step (2-6), if the opposite end node is not traversed, marking the opposite end node as belonging to a current feeder line, marking the opposite end node as traversed, marking the opposite end node as a charged state, marking a father node of the opposite end node as the current node, adding the opposite end node to the tail of the unsearched node list, and continuing the step (2-6);

(2-6) judging the node equipment list of the current node, if the current node equipment is not the last equipment in the node equipment list of the current node, acquiring the next equipment in the node equipment list of the current node, setting the equipment as the current node equipment, returning to the step (2-2), and if the current node equipment is the last equipment in the node equipment list of the current node, executing the step (3);

(3) Judging the search node sequence number, if the search node sequence number is smaller than the non-search node list length NS, adding 1 to the search node sequence number count, returning to the step (2), and if the search node sequence number is equal to NS, executing the step (4);

(4) Removing the first NS traversed nodes from the unsearched node list, returning to step (1);

(5) And the list of the unsearched nodes is empty, the forward topology search is finished, and the step is completed.

4. The multi-stage network reconstruction method for a power distribution network according to claim 1, wherein the step (6) includes:

(1) Judging the disconnection switch list, if the disconnection switch list is empty, completing the step, and if the disconnection switch list is not empty, taking out the first switch in the disconnection switch list, and performing the step (2);

(2) Judging the current disconnection switch equipment, if the current disconnection switch equipment exists in the traversed disconnection switch list, jumping to the step (3), if the current disconnection switch equipment does not exist in the traversed disconnection switch list, creating a local topology search tree, storing the local topology search tree in a local topology search tree list, setting the current disconnection switch as a root switch of the current local topology search tree, adding nodes at the first end and the last end of the current disconnection switch into the unsearched node list and marking the nodes as traversed, and performing topology search on the current disconnection switch, wherein the specific steps are as follows:

(2-1) judging an unsearched node list, if the unsearched node list is empty, jumping to the step (3), if the unsearched node list is not empty, setting the current length of the unsearched node list as NLS, constructing a search node sequence number, setting the initial value as 1, and performing the step (2-2);

(2-2) setting a searching node serial number position node of an unsearched node list as a current node, judging the electrified state of the current node, storing the current node in the electrified node list of the current topology searching tree if the current node is in the electrified state, jumping to the step (2-4), and performing the step (2-3) if the current node is in the non-electrified state;

(2-3) judging the node equipment list of the current node, if the node equipment list of the current node is empty, jumping to the step (2-4), and if the node equipment list of the current node is not empty, continuing the reverse topology search, wherein the specific steps are as follows:

(2-3-1) acquiring a first node device in a node device list of the current node, and setting the node device as the current node device;

(2-3-2) judging the current node equipment, if the current node equipment is single-ended equipment or the current equipment is traversed, jumping to the step (2-3-6), and if the current node equipment is double-ended equipment and the current equipment is not traversed, continuing the step (2-3-3);

(2-3-3) marking the current node equipment as traversed, adding the current node equipment to the traversed disconnection switch list, acquiring opposite end nodes of the current node from two associated nodes of the current node equipment, judging the opposite end nodes, jumping to the step (2-3-6) if the opposite end nodes are traversed, and continuing the step (2-3-4) if the opposite end nodes are not traversed;

(2-3-4) marking that the opposite node has traversed, setting the current node as the parent node of the opposite node;

(2-3-5) judging the opposite node, if the opposite node is in a live state, adding the opposite node to a live node list of the current local topology search tree, and if the opposite node is in a non-live state, adding the opposite node to the tail of the non-searched node list;

(2-3-6) judging a node equipment list of the current node, if the current node equipment is not the last equipment in the node equipment list of the current node, acquiring the next equipment in the node equipment list of the current node, setting the equipment as the current node equipment, repeating the step (2-3-2), and if the current node equipment is the last equipment in the node equipment list of the current node, continuing the step (2-4);

(2-4) judging the sequence number of the searched node, if the sequence number of the searched node is smaller than the NLS of the length of the non-searched node list, adding 1 to the count of the sequence number of the searched node, returning to the step (2-2), and if the sequence number of the searched node is equal to the NLS, removing the traversed nodes of the head end NLS of the non-searched node list, and repeating the step (2-1);

(3) Judging the disconnection switch list, if the current disconnection switch is not the last switch in the disconnection switch list, acquiring the next disconnection switch from the disconnection switch list, repeating the step (2), and if the current disconnection switch is the last switch in the disconnection switch list, associating all the disconnection switches in the disconnection switch list to a local topology search tree, and finishing the reverse topology search.

5. The multi-stage network reconstruction method for a power distribution network according to claim 1, wherein the step (7) includes:

(1) Judging the local topology search tree list, if the local topology search tree list is empty, completing the step, if the local topology search tree list is not empty, searching a problem equipment conversion scheme in the problem equipment list, wherein the specific steps are as follows:

(2) Setting the length of the local topology search tree list as NT, judging the problem equipment list, if the problem equipment list is empty, completing the step, and if the problem equipment list is not empty, taking out the first problem equipment in the problem equipment list and setting the first problem equipment as current equipment, and continuing the step (3);

(3) According to a forward topology search result of the power distribution network equipment in a charged state, acquiring a feeder line to which the current equipment belongs and setting the feeder line as a current feeder line, constructing a charged node list of the current feeder line, storing charged state nodes of the feeder line to which the current feeder line belongs as the current feeder line into the charged node list of the current feeder line, acquiring a first local topology search tree in a local topology search tree list, and setting the first local topology search tree as a current local topology search tree;

(4) According to a reverse topology search result of the power-losing state power distribution network equipment, acquiring a live node list of a current local topology search tree, judging the live node list of the current local topology search tree, if the live node list of the current local topology search tree is empty, jumping to the step (12), if the live node list of the current local topology search tree is not empty, constructing a connection fault node serial number and setting an initial value of the connection fault node serial number to be 1, and performing the step (5);

(5) Judging the serial number of the connection fault node, if the serial number of the connection fault node is greater than or equal to the length of the live node list of the current local topology search tree, jumping to the step (12), if the serial number of the connection fault node is smaller than the length of the live node list of the current local topology search tree, acquiring the node at the serial number position of the connection fault node from the live node list of the current local topology search tree, setting the node as the connection fault node, setting the serial number of the connection fault node to be 1, and performing the step (6);

(6) Judging a live node list of the current feeder line, returning to the step (5) if the live node list of the current feeder line does not contain a connection fault node, constructing a transfer fault node sequence number if the live node list of the current feeder line contains the connection fault node, setting a sequence number initial value to be 1, and performing the step (7);

(7) Judging the sequence number of the transfer fault node, returning to the step (5) if the sequence number of the transfer fault node is greater than or equal to the length of the live node list of the current local topology search tree, acquiring a node at the sequence number position of the transfer fault node from the live node list of the current local topology search tree if the sequence number of the transfer fault node is smaller than the length of the live node list of the current local topology search tree, setting the node as the transfer fault node, setting the sequence number of the transfer fault node to be 1, and performing the step (8);

(8) Judging the live node list of the current feeder line, if the live node list of the current feeder line contains a transfer fault node, jumping to the step (7), and if the live node list of the current feeder line does not contain the transfer fault node, continuing the step (9);

(9) According to a reverse topology search result of power-losing power distribution network equipment, a transfer closed switch list is temporarily constructed, upper parent nodes of connection fault nodes and transfer fault nodes are searched, and switches of the connection parent nodes are stored in the transfer closed switch list;

(10) Judging whether a common father node exists between the connection fault node and the current equipment node or not through topology searching according to the electrified node list of the feeder line to which the current equipment belongs in the step (6), returning to the step (7) if the common father node does not exist, and carrying out the step (11) if the common father node exists;

(11) According to a forward topology search result of the power distribution network equipment in a charged state, finding a transfer disconnection switch on an upstream power supply path of the common father node, constructing a transfer scheme of the current equipment, adding the transfer disconnection switch and a closed switch in the transfer closed switch list in the step (9) to the transfer scheme, storing the transfer scheme to a transfer scheme list of the current equipment, and returning to the step (7);

(12) Judging a local topology search tree list, if the current local topology search tree is not the last local topology search tree list, acquiring the next local topology search tree from the local topology search tree list and setting the next local topology search tree as the current local topology search tree, jumping to the step (4), and if the current local topology search tree is the last local topology search tree list, continuing the step (13);

(13) Judging the problem equipment list, if the current problem equipment is not the last one in the problem equipment list, acquiring the next problem equipment from the problem equipment list, setting the problem equipment as the current equipment, returning to the step (3), if the current problem equipment is the last one in the problem equipment list, searching a transfer scheme of each problem equipment in the problem equipment list, and storing all transfer schemes into a transfer scheme list of the problem equipment to finish the step.

6. The multi-stage network reconstruction method for a power distribution network according to claim 1, wherein the step (10) includes:

(1) Acquiring a feeder line list of a network reconstruction partition from a current network reconstruction partition;

(2) According to the feeder line to which the marked equipment belongs in the forward topology search of the charged state distribution network equipment, all lines and distribution transformers of the feeder lines in a network reconstruction partition feeder line list are obtained, and according to a ground state power flow result, the average load rate of the ground state lines, the maximum load rate of the ground state lines, the average ground state distribution voltage and the lowest ground state distribution transformer voltage of the distribution network are counted;

(3) Calculating a line load rate score, setting that the line load rate of a power distribution network is usually lower than 40% and is light load, and higher than 80% and is heavy load, wherein the average load rate represents the overall average level of load, the maximum load rate represents the severe extreme condition of load, the lower limit of a reasonable range of the load rate is 0.4, the upper limit of the reasonable range of the load rate is 0.8, the score gradient in a reasonable interval is 0.8, the score gradient outside the reasonable range is 1.2, and calculating the average load rate score and the maximum load rate score of the line respectively, wherein the average value of the average load rate score and the maximum load rate score of the line is the base state line load rate score;

(4) Calculating the grading of the distribution voltage, setting the reasonable fluctuation range of the voltage of the distribution network equipment to be +/-7%, wherein the average voltage represents the overall average level of the voltage, the lowest voltage represents the extreme case of severe voltage, the lower limit of the reasonable range of the voltage is 0.93p.u., the upper limit of the reasonable range of the voltage is 1.07p.u., the grading gradient in the reasonable interval is 0.8, the grading gradient outside the reasonable range is 1.2, and calculating the grading of the average per unit voltage of the distribution transformer and the grading of the lowest per unit voltage of the distribution transformer respectively, so that the average of the grading of the average per unit voltage of the distribution transformer and the grading of the lowest per unit voltage of the distribution transformer is the grading of the ground state voltage;

(5) The method comprises the steps of respectively setting a line load rate scoring weight and a distribution voltage scoring weight, and calculating in a weighted manner to obtain a current network reconstruction partition ground state comprehensive score as follows: ground state line load rating score x line load rating score weight + ground state voltage score x distribution voltage score weight;

(6) Judging the network reconstruction partition list, if the current network reconstruction partition is not the last network reconstruction partition list, taking out the next network reconstruction partition, returning to the step (1), and if the current network reconstruction partition is the last network reconstruction partition list, completing the step.

7. The multi-stage network reconstruction method for a power distribution network according to claim 1, wherein the step (11) includes:

(1) Judging the network reconstruction partition list, if the network reconstruction partition list is empty, completing the step, and if the network reconstruction partition list is not empty, taking out the first network reconstruction partition;

(2) And (3) taking out the network reconfiguration partition transfer scheme list from the current network reconfiguration partition, judging the network reconfiguration partition transfer scheme list, jumping to the step (3) if the network reconfiguration partition transfer scheme list is empty, and calculating the index score of the current network reconfiguration partition transfer scheme if the current network reconfiguration partition transfer scheme list is not empty, wherein the specific steps are as follows:

(2-1) retrieving a first forwarding scheme in the current network reconfiguration partition;

(2-2) closing an opening switch of the current transfer scheme, opening a closing switch of the current transfer scheme, and calculating feeder power flow of a reconstruction partition of the current network;

(2-3) according to the feeder line to which the equipment of the forward topology search mark of the charged state distribution network equipment belongs, acquiring all lines and distribution transformers of the feeder lines in a network reconstruction partition feeder line list, and according to the load rate of each line and the voltage of each distribution transformer in the load flow calculation result of the step (2-2), counting the average load rate of the line after reconstruction, the maximum load rate of the line after reconstruction, the distribution average voltage after reconstruction and the distribution minimum voltage after reconstruction;

(2-4) calculating a line load rate score, setting the lower limit of a reasonable range of the load rate to be 0.4, setting the upper limit of the reasonable range of the load rate to be 0.8, setting the gradient of the score in a reasonable interval to be 0.8, setting the gradient of the score out of the reasonable range to be 1.2, respectively calculating an average load rate score of the line after reconstruction and a maximum load rate score of the line after reconstruction, and calculating the average load rate score of the line after reconstruction and the maximum load rate score of the line after reconstruction according to the average value of the average load rate score of the line after reconstruction and the maximum load rate score of the line after reconstruction;

(2-5) calculating a distribution voltage score, setting the lower limit of a reasonable voltage range to be 0.93p.u., setting the upper limit of the reasonable voltage range to be 1.07p.u., setting the gradient of the score in a reasonable interval to be 0.8, and setting the gradient of the score out of the reasonable range to be 1.2, respectively calculating an average per unit voltage score of the distribution after reconstruction and a lowest per unit voltage score of the distribution after reconstruction, and calculating a mean value of the average per unit voltage score of the distribution after reconstruction and the lowest per unit voltage score of the distribution after reconstruction;

and (2-6) calculating a current transfer scheme reconstruction comprehensive score of the current network reconstruction partition in a weighted manner by adopting a line load rate scoring weight and a distribution voltage scoring weight consistent with the ground state, wherein the current transfer scheme reconstruction comprehensive score is as follows: the circuit load rate score after reconstruction is multiplied by the circuit load rate score weight+the voltage score after reconstruction is multiplied by the distribution voltage score weight;

(2-7) restoring the opening switch of the current transferring scheme in the step (2-2) to an opening state, and restoring the closing switch of the current transferring scheme in the step (2-2) to a closing state;

(2-8) judging the network reconfiguration partition transfer scheme list, if the current transfer scheme is not the last one in the network reconfiguration partition transfer scheme list, taking out the next transfer scheme, returning to the step (2-1), and if the current transfer scheme is the last one in the network reconfiguration partition transfer scheme list, carrying out the step (3);

(3) And (3) judging the network reconfiguration partition list, if the current network reconfiguration partition is not the last one in the network reconfiguration partition list, taking out the next network reconfiguration partition, returning to the step (1), and if the current network reconfiguration partition is the last one in the network reconfiguration partition list, completing the step.

8. The multi-level network reconstruction method for a power distribution network according to claim 6 or 7, wherein the process of calculating the scores of the indexes is as follows: the method comprises the steps of constructing a grading method for percentage type indexes with reasonable ranges, setting the midpoint of the reasonable ranges as the maximum value 1.0 of the percentage type indexes, setting the input index as x, setting the lower limit of the reasonable ranges as min, setting the upper limit of the reasonable ranges as max, setting the gradient in the reasonable ranges as r1, setting the gradient out of the reasonable ranges as r2, and setting the midpoint mid= (min+max)/2 of the reasonable ranges as follows:

Score=1- (mid-min) x r1- (min-x) x r2 when x < min;

when min is less than or equal to x is less than or equal to max, scoring score=1- |x-mid|xr 1;

when max < x, score=1- (mid-min) ×r1- (x-max) ×r2.

9. The method of multilevel network reconstruction of a power distribution network according to claim 1, wherein the step (12) comprises:

(1) Screening a transfer scheme meeting the condition of improving the ground state index from the network reconstruction partition, wherein the condition of improving the ground state index comprises the following steps: the average load rate of the reconstructed line is smaller than the average load rate of the ground state line of the power distribution network, the maximum load rate of the reconstructed line is smaller than the maximum load rate of the ground state line of the power distribution network, the average per unit voltage of the reconstructed distribution transformer is larger than the average per unit voltage of the ground state distribution transformer of the power distribution network, and the lowest per unit voltage of the reconstructed distribution transformer is larger than the lowest per unit voltage of the ground state distribution transformer of the power distribution network;

(2) Selecting a transfer scheme with the highest reconstruction comprehensive score from the transfer schemes for improving the power distribution network ground state indexes as an optimal transfer scheme of a corresponding network reconstruction partition;

(3) And forming a complete transfer scheme by the optimal transfer scheme of all the network reconstruction partitions, and completing the multi-stage network reconstruction of the power distribution network based on the weighted index optimization.

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