Expandable power distribution network frame structure with high power supply reliability

Abstract

The invention discloses an expandable power distribution network grid structure with high power supply reliability, and relates to the technical field of power distribution networks, the expandable power distribution network grid structure comprises a simple windmill type networking structure, and the simple windmill type networking structure comprises a three-station three-group single-ring network structure and a four-station four-group single-ring network structure. The power supply reliability is remarkably improved, power failure events caused by power grid faults are reduced, the expansibility of the grid structure enables the power grid to flexibly adapt to future load increase and power supply changes, diversified application scenes and investment level selection can meet the requirements and budgets of different users, and the power grid structure is suitable for popularization and application. The design of the grid structure considers the environmental adaptability, the influence of reasonable distribution on the geographical environment and space resources, the modernization and intellectualization development of the power distribution network is promoted, and a foundation is laid for the construction of a digital and intelligent power system.

Description

Technical Field

[0001] The present application relates to the technical field of power distribution networks, and in particular to an expandable power distribution network grid structure with high power supply reliability. Background Art

[0002] With the development of social economy and changes in energy consumption structure, the source-load characteristics of the power system have become more and more complex. The existing grid structure is single and cannot meet the diverse needs of source-load characteristics in different regions.

[0003] First, the source-load characteristics are becoming increasingly complex: the access of new loads such as distributed power sources, electric vehicle charging stations, and energy storage equipment makes the source-load characteristics of the power system more variable and uncertain.

[0004] Secondly, the existing grid structure is of a single form: the traditional distribution network grid structure often adopts a fixed topology, lacks flexibility and scalability, and is difficult to adapt to rapid changes in source and load characteristics.

[0005] Finally, the matching of source-load characteristics is poor: there are significant differences in source-load characteristics in different regions, and the existing grid structure is difficult to achieve accurate matching with regional characteristics, which affects the operating efficiency and power supply reliability of the power grid. Summary of the invention

[0006] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes an expandable distribution network grid structure with high power supply reliability, including a simple windmill type networking structure, the simple windmill type networking structure includes a three-station three-group single-ring network structure and a four-station four-group single-ring network structure; each group of the single-ring network structure includes a substation and two lines drawn from the substation, and a plurality of ring network boxes are respectively arranged on the two lines drawn from the substation, wherein the two lines drawn from the substation form a connection line at the first corresponding ring network box and constitute an intra-station connection; the two adjacent substations form a connection line through the ring network boxes arranged on the adjacent lines of the two substations and constitute an inter-station connection.

[0007] In addition, a scalable distribution network grid structure with high power supply reliability according to an embodiment of the present application also has the following additional technical features:

[0008] Preferably, the substation has a single bus segment structure, and the single bus segment structure includes bus segment 1 and bus segment 2.

[0009] Preferably, the line drawn out from the busbar segment 1 is line A, and the line drawn out from the busbar segment 2 is line B.

[0010] Preferably, three new intra-station connections are built in the three-station three-group single-ring network structure to form a three-station windmill type networking structure.

[0011] Preferably, in the three-station windmill type networking structure, one communication line in each of the two double-ring network structures is disconnected, and two inter-station connections and four intra-station connections are newly established between the two double-ring network structures to form a four-station windmill type networking structure.

[0012] Preferably, the communication line of any side in the three-station windmill type ring network structure is disconnected, and one intra-station communication and two inter-station communications are newly built to form the four-station windmill type networking structure.

[0013] Preferably, an expandable distribution network grid structure with high power supply reliability also includes a chain windmill type networking structure, the chain windmill type networking structure includes a simple windmill type networking structure, and a traditional switch station is used in the simple windmill type networking structure to access two nearby lines, wherein each of the traditional switch stations is not interconnected.

[0014] Preferably, a scalable distribution network grid structure with high power supply reliability also includes a two-way ring windmill type networking structure, which uses two independent single bus switch stations for networking, wherein each of the traditional switch stations is interconnected.

[0015] Preferably, a scalable distribution network grid structure with high power supply reliability also includes a multi-ring windmill type networking structure, which adopts a single bus three-segment wiring type switch station for networking, wherein each of the traditional switch stations is interconnected.

[0016] Preferably, a scalable distribution network grid structure with high power supply reliability also includes a windmill-type SOP mode networking structure, in which the traditional switch is replaced with an intelligent soft switch SOP.

[0017] Beneficial Effects

[0018] According to an expandable distribution network framework structure with high power supply reliability according to an embodiment of the present application, the beneficial effects are:

[0019] 1. The distribution network structure of the present invention significantly improves the reliability of power supply and reduces power outages caused by power grid failures.

[0020] 2. The scalability of the grid structure enables the power grid to flexibly adapt to future load growth and power supply changes.

[0021] 3. Diverse application scenarios and investment level options enable the present invention to meet the needs and budgets of different users.

[0022] 4. The design of the grid structure takes into account environmental adaptability and rationally allocates the impact on the geographical environment and space resources.

[0023] 5. The implementation of this invention will help promote the modernization and intelligent development of the distribution network and lay the foundation for the construction of a digital and intelligent power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the implementation methods of the present application, the drawings required for use in the implementation methods will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a schematic diagram of a simple wind turbine unitized design of a distribution network grid structure according to an embodiment of the present application;

[0026] Figure 2 is a schematic diagram of a three-station three-group single ring network according to an embodiment of the present application;

[0027] Figure 3 is a schematic diagram of a four-station four-group single ring network according to an embodiment of the present application;

[0028] Figure 4 is a schematic diagram of a three-station wind turbine type network according to an embodiment of the present application;

[0029] Figure 5 is a schematic diagram of a four-station wind turbine type network according to an embodiment of the present application;

[0030] Figure 6 is a schematic diagram of a chain windmill type topology according to an embodiment of the present application;

[0031] Figure 7 is a system configuration diagram KB-1-A according to an embodiment of the present application;

[0032] Figure 8 is a system configuration diagram KB-1-B according to an embodiment of the present application;

[0033] Fig. 9 is a schematic diagram of a two-way ring windmill type topology according to an embodiment of the present application;

[0034] Fig.10 is a system configuration diagram KB-2 according to an embodiment of the present application;

[0035] Fig.11 is a schematic diagram of a multi-way ring wind turbine type topology according to an embodiment of the present application;

[0036] Fig.12is a schematic diagram of a single connection grid transition solution according to an embodiment of the present application;

[0037] Fig.13 is a three-station transition networking topology diagram according to an embodiment of the present application;

[0038] Fig.14 is a four-station transition networking topology diagram according to an embodiment of the present application;

[0039] Fig.15 is a diagram showing the reliability analysis results of a wind turbine type four-station structure according to an embodiment of the present application;

[0040] Fig.16 It is a result diagram of the reliability rate of the four-station structure of the windmill type according to the embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the implementation methods of this application clearer, the technical solutions in the implementation methods of this application will be clearly and completely described below in conjunction with the drawings in the implementation methods of this application. Obviously, the described implementation methods are part of the implementation methods of this application, not all of the implementation methods. Based on the implementation methods in this application, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] The distribution network framework structure of the present invention is described in detail below through specific implementation methods.

[0043] The following expansion modes have been studied based on reliability, space resources, and investment levels. As shown in Table 1, a simple comparison of different expansion modes is made, mainly from the perspectives of reliability, economy, usage scenarios, networking methods, and space resource occupancy.

[0044] Table 1 Wind turbine expansion mode

[0045]

[0046]

[0047] Embodiment 1:

[0048] like Figure 1-Figure 5 As shown, in the old city distribution network, the simple windmill type topology of the present invention is adopted. Only by setting up a trunk ring network cabinet and utilizing a unique networking method, only less space resources are occupied, which can greatly improve the self-healing ability and power supply reliability of the power grid.

[0049] Among them, each substation (taking substation A as an example) is a single busbar (busbar segment 1, busbar segment 2) segmented structure, and a line is connected from each of the two busbars, namely line a and line b. Line a and line b are connected at the first ring network box (i.e. ring network box No. 1 and ring network box No. 2) after the substation busbar is connected to form a connecting line; at the same time, line a and line c are connected through the ring network box. The remaining substations are networked in the same way, and finally form a three-station three-group single ring network and a four-station four-group single ring network.

[0050] Three stations and three groups of single ring networks, three new station connections can form a three-station wind type wiring mode. Disconnect one of the connection lines of the two groups of double ring networks, build two new station connections in the two groups of double ring networks, and build four new station connections, which can form a four-station wind type wiring mode.

[0051] A three-station wind turbine type wiring pattern is formed. If there is load growth and substation line spacing, corridors and other conditions, the connection line on any side of a wind turbine type wiring pattern can be interrupted, two new lines can be added from the substation, one intra-station connection and two inter-station connections can be added, and a three-station wind turbine type wiring pattern can be expanded to a four-station wind turbine type wiring pattern.

[0052] For old urban areas, where space site resources are insufficient, ring network boxes are suitable for areas with narrow terrain and difficult site selection. The main layer uses ring network boxes, and users are directly connected without a secondary trunk layer.

[0053] Single and double ring networks can be gradually transitioned to the windmill type basic mode. There are two main transition strategies for the windmill type basic mode. One is the transition from single and double ring networks to three stations and six lines, and the other is the transition from single and double ring networks to four stations and eight lines.

[0054] Embodiment 2:

[0055] like Figure 6 As shown, in the distribution network of a new urban area with rapidly developing loads, the chain topology of the present invention is selected according to the requirements of the urban power grid for high power supply reliability, load development distribution, and the abundance of spatial corridor resources, thereby achieving the high reliability requirements of the regional power grid.

[0056] Specifically, the chain wind turbine type wiring mode can be transitioned from the simple wind turbine type wiring mode. It can first transition from the single and double ring network to the simple wind turbine type wiring mode, and then use the chain wind turbine type wiring mode for networking according to the load development level.

[0057] Each substation (taking substation A as an example) is a single busbar (busbar segment 1, busbar segment 2) segmented structure, with one line connected from each of the two busbars, namely line a and line b. Line a and line b are connected at the first ring network box (i.e., ring network box No. 1 and ring network box No. 2) after the substation busbar is connected to form a connecting line; at the same time, line a and line c are connected through the ring network box. The remaining substations are networked in the same way, and finally form a backbone layer of four stations and four groups of single ring networks. The secondary backbone layer uses traditional switch stations, and each switch station is not interconnected. Each switch station is connected to two nearby lines through the secondary network.

[0058] like Figure 7 As shown, the first expansion mode adopts KB-1, single busbar segmentation, 2 incoming lines and 12 outgoing lines. Each switch station has dual power supplies, the switch station goes deep into the load center, and users can access the switch station to achieve dual power supply. One power supply is the main power supply, and the other power supply is the backup power supply.

[0059] like Figure 8 and Fig. 9 As shown, the two-way ring wind turbine type wiring mode can be transitioned from the simple wind turbine type wiring mode. It can first transition from the single and double ring network to the simple wind turbine type wiring mode, and then according to the load development level, two independent single bus switch stations are used for networking, and the secondary trunk layer forms a ring network.

[0060] Each substation (taking substation A as an example) is a single busbar (busbar segment 1, busbar segment 2) segmented structure, with one line connected from each of the two busbars, namely line a and line b. Line a and line b are connected at the first ring network box (i.e., ring network box No. 1 and ring network box No. 2) after the substation busbar is connected to form a connecting line; at the same time, line a and line c are connected through the ring network box. The remaining substations are networked in the same way, and finally form a backbone layer of four stations and four groups of single ring networks. The secondary backbone layer uses traditional switch stations, each switch station is interconnected, and each switch station is connected to two nearby lines through the secondary network.

[0061] The second expansion mode of the switch station adopts KB-1-B, two independent single busbars, 4 incoming lines and 12 outgoing lines. Each switch station has dual power supplies, the switch station goes deep into the load center, and the user accesses the switch station. Each switch station is interconnected to form a ring network. Each busbar has one main power supply and one backup power supply. The backup intervals between the switch stations are connected to form a ring network, which can realize dual power supply.

[0062] like Fig.10 and Fig.11 As shown, the multi-way ring wind turbine type wiring mode can be transitioned from the simple wind turbine type wiring mode. It can first transition from the single and double ring network to the simple wind turbine type wiring mode, and then according to the load development level, a single busbar three-section wiring form switch station is used for networking, and the secondary trunk layer forms a ring network.

[0063] Each substation (taking substation A as an example) is a single busbar (busbar segment 1, busbar segment 2) segmented structure, with one line connected from each of the two busbars, namely line a and line b. Line a and line b are connected at the first ring network box (i.e., ring network box No. 1 and ring network box No. 2) after the substation busbar is connected to form a connecting line; at the same time, line a and line c are connected through the ring network box. The remaining substations are networked in the same way, and finally form a backbone layer of four stations and four groups of single ring networks. The secondary backbone layer uses traditional switch stations, each switch station is interconnected, and each switch station is connected to two nearby lines through the secondary network.

[0064] The expansion mode adopts KB-2, single busbar three-section wiring form, 4 incoming lines and 12 outgoing lines. Each switch station has dual power supplies, the switch station goes deep into the load center, and the user accesses the switch station. One power supply enters one busbar, and the other power supply enters three busbars. Each switch station uses the ring network between the two busbars to interconnect, which can realize dual power supply or even multiple power supply for users.

[0065] Embodiment 3:

[0066] like Figure 9-10 As shown, in the distribution network with extremely high power supply reliability requirements, taking into account the investment level and space resource conditions, the windmill-type SOP topology of the present invention is adopted to optimize the spatial layout of the power grid and greatly improve the power supply reliability of the power grid.

[0067] Each substation (taking substation A as an example) is a single busbar (busbar segment 1, busbar segment 2) segmented structure, with one line connected from each of the two busbars, namely line a and line b. Line a and line b are connected at the first ring network box (i.e., ring network box No. 1 and ring network box No. 2) after the substation busbar is connected to form a connecting line; at the same time, line a and line c are connected through the ring network box. The remaining substations are networked in the same way, and finally form a backbone layer of a single ring network with three stations and three groups, or four stations and four groups. The secondary backbone layer uses traditional switch stations, each of which is interconnected, and each switch station is connected to two nearby lines through the secondary network.

[0068] It should be noted that the soft open point (SOP) in the specific embodiment of the present application is a new type of power electronic device, which can replace the traditional contact switch in the distribution network as a new means of regulation and control, and has the functions of real-time adjustment of power size, flow direction and reactive power compensation. SOP can reduce the forecast error of renewable energy output through real-time power control, effectively control the current and voltage over-limit problems caused by the access of high-penetration renewable energy, and play an important role in the economic and safe operation of active distribution networks containing high-penetration DG.

[0069] The basic concept of the intelligent soft switch SOP is to use fully controlled power electronic devices to form a normalized "flexible connection" between feeders, adjust the power exchange of connected feeders in real time according to control instructions, and thus change the overall power flow distribution of the system.

[0070] Compared with traditional switches, SOP has higher control accuracy, stronger regulation capability, faster action speed, and less impact of faults, which significantly improves the controllability of distribution networks. Especially for the issue of distribution network flexibility, SOP's real-time dynamic response, fine flow regulation, and multi-time scale operation capabilities enable it to serve as a bridge for coordinating and coordinating multi-source, multi-type, and multi-scale flexibility resources in the distribution network, effectively improving the distribution network's ability to coordinate and optimize flexibility resources.

[0071] There are two main transition modes for wind turbine SOP mode networking. One is to implement SOP first and then gradually build the network; the other is to build the network first and then implement SOP transition strategy.

[0072] First, Figure 4 and Fig.12 As shown in the figure, the strategy of installing SOP first and then gradually networking is to install SOP on the lines that need to be modified first, and gradually form a windmill-type grid. Taking the overhead single contact line as an example, the contact switch is replaced with SOP to achieve flexible networking of 2 circuits, and in the long term, a windmill-type structure of 3 stations and 6 lines or a windmill-type structure of 4 stations and 8 lines is constructed.

[0073] Secondly, if Fig.13 and Fig.14 As shown in the figure, the strategy of networking first and then implementing SOP is to optimize and adjust the existing grid first, for example, 3 groups of single interconnection lines form a windmill-type structure with 3 stations and 6 lines, or 2 groups of double-ring networks form a windmill-type structure with 4 stations and 8 lines. In the long term, the interconnection switches will be replaced with SOP to realize flexible networking.

[0074] In the embodiment of the present application, a windmill-shaped wiring group simulation calculation is provided:

[0075] 1) Distribution network reliability evaluation indicators

[0076] The distribution system uses relevant indicators to comprehensively reflect the reliability level. The existing reliability indicators are mainly divided into two categories: load point reliability indicators and system reliability indicators.

[0077] Load point reliability indicators are used to characterize the ability of different load points in the distribution network to provide continuous power supply, mainly including the annual failure rate of the load point, the annual average power outage time of the load point and the average power outage duration of the load point.

[0078] System reliability index is used to reflect the severity of the load power outage caused by system failure, which can be calculated through relevant formulas. Commonly used system reliability indicators at this stage are: system average power outage frequency, user average power outage time, system average power outage duration, and system average power supply availability.

[0079] According to the set parameter boundary conditions, assuming that the circuit breakers, fuses and switchgear operate reliably, and the lines are all equipped with distribution automation, the bus and line fault parameter information is shown in Table 2.

[0080] Table 2 Busbar and line fault information

[0081] Equipment parameters Numeric Cable failure rate ( / times ( / hundred km·a)) 0.02 Cable repair time / h 5.5 10kV bus failure rate ( / times / a) 0.0015 10kV busbar repair time / h 20 Distribution automation action time / s 30

[0082] 2) Distribution network reliability software

[0083] This simulation calculation and analysis uses the "Intelligent Distribution Network Analysis Simulation System" independently developed by Tianjin University. The software analyzes and calculates the power grid by constructing the power grid structure and configuring equipment parameters. This system can realize power grid topology verification, power flow calculation, time series power flow, short circuit calculation, and reliability calculation by constructing scheme groups, entering equipment parameters, and drawing graphics.

[0084] 3) Distribution network reliability evaluation indicators

[0085] Using the intelligent distribution network analysis and simulation system, the reliability analysis and simulation of the wind turbine type four-station structure is carried out. The results are as follows: Fig.15 , Fig.16 And as shown in Table 3.

[0086] Table 3 Power supply reliability of different structures

[0087] Grid structure Power supply reliability Windmill type structure 99.9996％ Double ring network structure 99.9993％ Diamond-shaped structure 99.9996％ Petal structure 99.9997％ Snowflake network structure 99.9996％

[0088] The above embodiments are only used to illustrate the specific embodiments of the present invention and are not limited thereto. For those skilled in the art, various similar deformations and changes can be made according to the concept of the present invention, and these deformations and changes should be regarded as the protection scope of the present invention.

Claims

1. A scalable distribution network structure with high power supply reliability, characterized in that: include: A simple windmill type networking structure, the simple windmill type networking structure includes a three-station three-group single ring network structure and a four-station four-group single ring network structure; Each group of the single ring network structure includes a substation and two lines drawn from the substation, and a plurality of ring network boxes are respectively arranged on the two lines drawn from the substation, wherein the two lines drawn from the substation form a connection line at the first corresponding ring network box and constitute in-station connection; A connection line is formed between two adjacent substations through the ring network boxes arranged on the adjacent lines of the two substations, thereby forming inter-station connection.

2. According to claim 1, a scalable power distribution network structure with high power supply reliability is characterized in that: The substation has a single busbar segment structure, and the single busbar segment structure includes busbar segment 1 and busbar segment 2.

3. The expandable power distribution network structure with high power supply reliability according to claim 2 is characterized in that: The line drawn out from the busbar segment 1 is line A, and the line drawn out from the busbar segment 2 is line B.

4. The expandable power distribution network structure with high power supply reliability according to claim 1, characterized in that: Three new intra-station connections are built in the three-station three-group single-ring network structure to form a three-station windmill type networking structure.

5. The expandable power distribution network structure with high power supply reliability according to claim 4, characterized in that: In the three-station windmill type networking structure, one communication line in two sets of double-ring network structures is disconnected respectively, and two inter-station communications and four intra-station communications are newly built between the two sets of double-ring network structures to form a four-station windmill type networking structure.

6. The expandable power distribution network structure with high power supply reliability according to claim 5, characterized in that: In the three-station windmill type ring network structure, the communication line of any side is disconnected, and one intra-station communication and two inter-station communications are newly built to form the four-station windmill type networking structure.

7. The expandable power distribution network grid structure with high power supply reliability according to claim 1, characterized in that: It also includes a chain windmill type networking structure, wherein the chain windmill type networking structure includes a simple windmill type networking structure, and a traditional switch station is used in the simple windmill type networking structure to access two nearby lines; Each of the conventional switch stations is not interconnected.

8. The expandable power distribution network structure with high power supply reliability according to claim 7, characterized in that: It also includes a two-way ring windmill type networking structure, which uses two independent single bus switch stations for networking, wherein each of the traditional switch stations is interconnected.

9. The expandable power distribution network structure with high power supply reliability according to claim 8, characterized in that: It also includes a multi-ring windmill type networking structure, which adopts a single busbar three-section wiring form switch station for networking, wherein each of the traditional switch stations is interconnected.

10. The expandable power distribution network frame structure with high power supply reliability according to claim 9, characterized in that: It also includes a windmill-type SOP mode networking structure, in which the traditional switch is replaced with an intelligent soft switch SOP.

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