A method for topology identification of distribution network containing distributed generation

Abstract

The present invention relates to a method for identifying the topology of a distribution network containing distributed power sources, which includes two parts: topology division and topology information identification. The topology division part constructs the topology structure of the distribution network containing distributed power sources, including nodes, units, regions, and fault action port information. The topology information identification part identifies the topology information of the distribution network by a traversal method through communication between distributed control terminals and stores it in the distributed control terminals. The method is conducive to simplifying the topology of the distribution network containing distributed power sources and obtaining accurate distribution network structure information.

Description

Technical Field

[0001] The present invention belongs to the field of power distribution networks, and in particular relates to a topology identification method for a power distribution network containing distributed power sources. Background Art

[0002] In recent years, State Grid Corporation of China has actively built a strong and intelligent power grid to improve the inherent safety level of the power grid. Today, the development of the distribution network is mainly reflected in the following three aspects and is in rapid development: 1) Distributed power sources continue to penetrate into the distribution network, resulting in significant changes in the source-grid-load structure of the distribution network. The proportion of distributed power sources incorporated into the distribution network continues to increase, and it will occupy an irreplaceable position in urban power supply. 2) With the continuous development of transportation electrification and the continuous penetration of energy storage equipment, loads with source / load duality will have an important impact on the distribution network. In addition, the regenerative braking energy feedback mode of urban rail transit and the discharge mode of electric vehicles and energy storage equipment will have a serious impact on the distribution network at the load end. 3) The rapid development of large-scale distributed power grid connection, flexible AC / DC transmission and distribution, AC variable frequency drive and energy storage applications has driven power conversion equipment to gradually develop towards high technology, diversification and strong nonlinearity, resulting in the deepening of power electronics and DC.

[0003] The new form of distribution network has the characteristics of multiple voltage levels, complex branches, variable operation modes, and frequent feeder switching. Its topological structure is difficult to identify, and topological information is difficult to accurately describe the structural characteristics of the distribution network. In addition, a high proportion of devices with source / load duality, such as distributed power sources, electrified transportation, and energy storage equipment, are connected, and traditional distribution network topology division schemes and topological information identification are difficult to meet the needs. Summary of the invention

[0004] The object of the present invention is to provide a method for identifying the topology of a distribution network containing distributed power sources, which is conducive to simplifying the topology of the distribution network containing distributed power sources and obtaining accurate distribution network structure information.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for identifying the topology of a distribution network containing distributed power sources, comprising:

[0006] Topology division: construct the topology of the distribution network containing distributed power sources, including nodes, units, areas and fault action port information;

[0007] Topology information identification: Through communication between distributed control terminals, the distribution network topology information is identified by a traversal method and stored in the distributed control terminals.

[0008] Furthermore, the node is a switch controlled by a control terminal or an electric power device with switching capability.

[0009] Furthermore, the unit is composed of all adjacent nodes connected by the transmission line. If there is no adjacent node on one side of the node, it does not constitute a unit; the adjacent units have a common part, and the terminals of the common part work in two adjacent units respectively.

[0010] Furthermore, the area is composed of units connected by closed switches, and the power flow of the distribution network flows in one area.

[0011] Furthermore, the fault-affected port information is switch information of a port node affected after a unit is disconnected, including a switch serial number, a control terminal IP and a switch type, and the fault-affected port node switch information is stored in the unit.

[0012] Furthermore, the topology information identification includes area identification and fault-affecting port identification.

[0013] Furthermore, the region identification process includes:

[0014] Select the starting node and start regional topology recognition; according to the recognition direction, the upper unit sends a recognition command to the lower unit. In the unit, the common node with the upper unit (or the starting node) is the upper node, and the common node with the lower unit (or the node without a lower unit, i.e., the end node) is the lower node;

[0015] If the unit is the starting unit, the unit number is set as the regional attribute; otherwise, the unit inherits the attributes of the previous unit;

[0016] If there is an adjacent lower-level unit in the lower-level node of the unit, when the switch of the lower-level node is closed, the regional attributes and identification command are sent to it; when the switch of the lower-level node is disconnected and the adjacent lower-level unit has not performed the identification process, the adjacent lower-level unit is set as the starting unit and the identification command is sent to it;

[0017] If there are no adjacent lower-level units for the lower-level nodes in the unit, the region identification is terminated.

[0018] Furthermore, the fault-affected port identification process includes a primary identification process and a secondary identification process.

[0019] Furthermore, the one-time identification process includes:

[0020] After the region is identified, the end node initiates an identification;

[0021] In a unit, if the lower-level node is an end node, or the lower-level node receives the return information from the adjacent lower-level unit, it sends the return information to the upper-level node, and the return information contains the switch information of the downstream port node; the upper-level node processes the return information of each lower-level node, and if the switch type of the port node is not a substation exit, the returned port node switch information is stored in groups; if there is a substation exit, it is not stored; after the upper-level node receives the return information of all lower-level nodes, it merges them as the lower-level node of the upper-level unit and repeats the above process;

[0022] After receiving the return information, the starting unit stores the switch information of the port node and sends the information to the port node. The terminals where all port nodes in the same area are located have the port node information of the area. Among them, communication channels are established between the substation outgoing line and the connecting switch, the load outgoing line and the connecting switch, the distributed power supply and the connecting switch, and the connecting switch.

[0023] Furthermore, the secondary identification process includes:

[0024] If the starting node is not the substation exit, after the first identification is completed, the starting node is used as the end node to initiate a secondary identification process;

[0025] In the unit, the node that returns the information through secondary identification is regarded as the only subordinate node. If there is only one node among the other nodes that does not have a corresponding faulty port node group, it is regarded as the superior node, and the return information of the only subordinate node is combined with the switch information of the faulty port node stored in the unit group and sent to the superior node. The superior unit repeats the above process until there is no superior unit; otherwise, the secondary identification process ends.

[0026] Compared with the prior art, the present invention has the following beneficial effects: a method for topology identification of a distribution network containing distributed power sources is provided, which simplifies the topology information of the distribution network containing distributed power sources, can accurately describe the structural characteristics of the distribution network, and based on the topology traversal method, can automatically perform topology information identification through node terminal communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of a topological division scheme of a distribution network containing distributed power sources in an embodiment of the present invention.

[0028] Figure 2 This is the region identification data transmission process in the embodiment of the present invention.

[0029] Figure 3 This is a process of transmitting identification information of a fault-affecting port in an embodiment of the present invention.

[0030] Figure 4 This is the secondary identification information transmission process of the fault-affecting port in the embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] This embodiment provides a method for identifying topology of a distribution network including distributed power sources, including two parts: topology division and topology information identification.

[0035] The topology division constructs a distribution network topology structure containing distributed power sources, including node, unit, area and fault action port information.

[0036] The topology information is identified through communication between distributed control terminals, and the distribution network topology information is identified by a traversal method and stored in the distributed control terminals.

[0037] Figure 1 This is a topology division scheme of a distribution network containing distributed power sources in this embodiment, which plans the topology structure of a distribution network containing distributed power sources, including information on nodes, units, areas, and fault action ports;

[0038] In this embodiment, the node is a switch (or an electric device with switching capability) controlled by a control terminal; the unit is composed of all adjacent nodes connected by the transmission line. If there is no adjacent node on one side of the node, it does not constitute a unit; the adjacent units have a common part, and the terminals of the common part work in two adjacent units respectively; the area is composed of units connected by closed switches, and the distribution network flow flows in an area; the fault action port information represents the switch information of the port node affected after a unit is disconnected, including the switch serial number, the IP of the control terminal where it is located, and the switch type, and the switch information of the fault action port node is stored in the unit.

[0039] Specifically, nodes K2, K3 and K9 form unit U2. Units U1-4 and U8 form area Z1, which is the shaded part in the figure. After unit U2 is disconnected due to fault, nodes K5, K12, K10 and node K9 are disconnected from the substation busbar respectively, which is the fault action port information.

[0040] This embodiment provides a topology information identification process of a distributed power distribution network based on 5G communication. The topology information identification includes area identification, primary identification of fault-affected ports, and secondary identification of fault-affected ports.

[0041] In this embodiment, the distributed control terminals communicate with each other through a 5G communication network, and the communication messages use the GOOSE protocol encapsulated in TCP.

[0042] In this embodiment, region identification includes the following steps:

[0043] S1. Select the starting node and start regional topology identification. According to the identification direction, the upper unit sends an identification command to the lower unit. Within the unit, the common node with the upper unit (or the starting node) is the upper node, and the common node with the lower unit (or the node without a lower unit, i.e., the end node) is the lower node.

[0044] S2. If the unit is the starting unit, set the unit number as the regional attribute; otherwise, inherit the attributes of the previous unit.

[0045] S3. If there is an adjacent lower-level unit in the lower-level node of the unit, when the switch of the lower-level node is closed, the regional attributes and identification command are sent to it; when the switch of the lower-level node is disconnected and the adjacent lower-level unit has not performed the identification process, the adjacent lower-level unit is set as the starting unit and the identification command is sent to it.

[0046] S4. If there are no adjacent lower-level units for the lower-level nodes in the unit, the region identification is terminated.

[0047] Specifically, Figure 2As shown, CB1 is selected as the starting node and U1 as the starting unit. CB1 in U1 sets the area to Z1 and sends it to the lower switch K2 terminal. K2 terminal stores it after receiving the U1 area attribute. Since K2 is closed, the area attribute of unit U2 is set to Z1. In unit U2, K2 terminal acts as the upper switch and sends the U2 area attribute Z1 to the lower switches K3 and K9. K3 follows the same step as K2 and sets the area attribute of unit U3 to Z1. K9 is the end switch, and the area identification ends. Similarly, the area attributes of U3, U4, and U8 are set to Z1, and K10, K12, and K5 end the area identification. During the initial area identification, K5 is the connecting switch and is disconnected. Since the adjacent unit U5 has not been identified, K5 is set as the starting switch of the next area, U5 is the starting unit, and the area number is set to Z5. Similarly, the identification of area Z5 starts from U5.

[0048] In this embodiment, the primary identification of the faulty active port includes the following steps:

[0049] S1. After the region is identified, the end node initiates an identification;

[0050] S2. Within a unit, if the lower-level node is an end node, or the lower-level node receives return information from an adjacent lower-level unit, it sends return information to the upper-level node, and the return information includes the switch information of the downstream port node.

[0051] S3, the upper node processes the return information of each lower node. If the switch type of the port node is not a substation exit, the returned port node switch information is stored in groups; if there is a substation exit, it is not stored. After the upper node receives the return information of all lower nodes, it merges them as the lower node of the upper unit and repeats the above S2 and S3 processes;

[0052] S4. After receiving the return information, the starting unit stores the switch information of the port node and sends the information to the port node. The terminals where all the port nodes in the same area are located have the port node information of the area. Among them, a TCP communication channel is established between the substation outgoing line and the connecting switch, the load outgoing line and the connecting switch, the distributed power supply and the connecting switch, and the connecting switch.

[0053] Specifically, Figure 3As shown, after the area identification is completed, in area Z1, K9, K10, K12, and K5 return port switch information to the upper switch in the unit respectively. U8 has only one lower switch K12, so its fault action port only contains K12. After receiving the return information, the upper switch K11 returns the switch information of K12 to the upper switch K4 in unit U4. After receiving the return information from all lower switches K5 and K11, K4 determines that none of them contain substation outgoing lines, and stores the switch information of K5 and K12 in groups of K5 and K11, and returns all fault action ports to the upper switch K3 of U3. Similarly, the upper switches of U3, U2, and U1 receive the return information in turn and store the fault action ports. The starting switch CB1 sends the port switch information to the port switches K5, K12, K10, and K9. Then, the substation outgoing switch CB1, the distributed power outgoing switches K9, K10, and the user outgoing switch K12 respectively establish a TCP communication channel with the tie switch K5 and send power and load information regularly. Since the port switch in area 1 contains only one tie switch, there is no need to establish an AC communication channel between the tie switches.

[0054] Specifically, Figure 3 As shown, after the area identification is completed, in area Z5, CB8, K15, and K14 return the port switch information to the upper switch in the unit respectively. U7 has only one lower switch CB8, and it is the outgoing line of the substation, so its fault action port is none, and it sends the CB8 switch information to the upper unit. Similarly, the K7 group in the fault action port of U6 is none, and the K15 group stores the switch information of K15; the K6 group in the fault action port of U5 is none, and the K13 group stores the switch information of K14. In the same area Z1, the outgoing line switch CB1 of the substation, the outgoing line switch K15 of the distributed power source, and the outgoing line switch K14 of the user respectively establish TCP communication channels with the contact switch K5, and send power and load information regularly.

[0055] In this embodiment, the secondary identification of the fault-affected port includes the following steps:

[0056] S1. If the starting node is not the substation exit, after the first identification is completed, the starting node is used as the end node to initiate a secondary identification process;

[0057] S2. In the unit, the node that returns the information of the secondary identification is regarded as the only subordinate node. If there is only one node among the other nodes that does not have the corresponding faulty port node group, it is regarded as the superior node, and the return information of the only subordinate node is combined with the switch information of the faulty port node stored in the unit group, and sent to the superior node. The superior unit repeats the above S2 process until there is no superior unit. Otherwise, the secondary identification process ends;

[0058] Specifically, Figure 4As shown, after the first identification process of the fault impact information is completed, the starting switch CB1 type of area Z1 is a transformer outlet, and no secondary identification is performed; the starting switch K5 type of area Z5 is a non-transformer outlet, and secondary identification is performed. In the secondary identification, only the K6 group information of U5 is None, K6 is selected as the upper switch, and the lower switch K5 information is stored in the affected end switch information of U5 according to group K5, and group K6 is not saved. Similarly, the affected end switch information of U6 and U7 is modified. U7 has no upper unit, and the secondary identification process is terminated.

[0059] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for identifying topology of a distribution network containing distributed power sources, characterized in that: include: Topology division: construct the topology of the distribution network containing distributed power sources, including nodes, units, areas and fault action port information; Topology information identification: through the communication between distributed control terminals, the distribution network topology information is identified by traversal method and stored in the distributed control terminal; The topology information identification includes area identification and fault-affected port identification; The region identification process includes: Select the starting node and start regional topology recognition; according to the recognition direction, the upper unit sends a recognition command to the lower unit. In the unit, the common node or the starting node with the upper unit is the upper node, and the common node or the end node with the lower unit is the lower node; If the unit is the starting unit, the unit number is set as the regional attribute; otherwise, the unit inherits the attributes of the previous unit; If there is an adjacent lower-level unit in the lower-level node of the unit, when the switch of the lower-level node is closed, the regional attributes and identification command are sent to it; when the switch of the lower-level node is disconnected and the adjacent lower-level unit has not performed the identification process, the adjacent lower-level unit is set as the starting unit and the identification command is sent to it; If there are no adjacent lower-level units for the lower-level nodes in the unit, the region identification ends; The fault-affected port identification process includes a primary identification process and a secondary identification process; The one-time identification process includes: After the region is identified, the end node initiates an identification; In a unit, if the lower-level node is an end node, or the lower-level node receives the return information from the adjacent lower-level unit, it sends the return information to the upper-level node, and the return information contains the switch information of the downstream port node; the upper-level node processes the return information of each lower-level node, and if the switch type of the port node is not a substation exit, the returned port node switch information is stored in groups; if there is a substation exit, it is not stored; after the upper-level node receives the return information of all lower-level nodes, it merges them as the lower-level node of the upper-level unit and repeats the above process; After receiving the return information, the starting unit stores the switch information of the port node and sends the information to the port node. The terminals where all the port nodes in the same area are located have the port node information of the area. Among them, the substation outgoing line and the connecting switch, the load outgoing line and the connecting switch, the distributed power supply and the connecting switch, and the connecting switch establish a communication channel; The secondary identification process includes: If the starting node is not the substation exit, after the first identification is completed, the starting node is used as the end node to initiate a secondary identification process; In the unit, the node that returns the information through secondary identification is regarded as the only subordinate node. If there is only one node among the other nodes that does not have a corresponding faulty port node group, it is regarded as the superior node, and the return information of the only subordinate node is combined with the switch information of the faulty port node stored in the unit group and sent to the superior node. The superior unit repeats the above process until there is no superior unit; otherwise, the secondary identification process ends.

2. A method for identifying topology of a distribution network containing distributed power sources according to claim 1, characterized in that: The node is a switch controlled by a control terminal or an electric device with switching capability.

3. A method for identifying topology of a distribution network containing distributed power sources according to claim 1, characterized in that: The unit is composed of all adjacent nodes connected by the transmission line. If there is no adjacent node on one side of the node, it does not constitute a unit; adjacent units have a common part, and the terminals of the common part work in two adjacent units respectively.

4. The method for identifying the topology of a distribution network containing distributed power sources according to claim 1, characterized in that: The area is composed of cells connected by closed switches, and the power flow of the distribution network flows in an area.

5. The method for identifying the topology of a distribution network containing distributed power sources according to claim 1, characterized in that: The fault action port information is the switch information of the port node affected after a unit is disconnected, including the switch serial number, the control terminal IP and the switch type, and the fault action port node switch information is stored in the unit.

Images