Distribution network protection and wide-area adaptive protection method for distributed power generation

Abstract

The invention provides a distributed power generation power distribution network protection and wide-area adaptive protection method, which comprises the following steps of: introducing a multi-level system, and accurately positioning a fault section according to fault direction criteria of different branch types in a distributed power generation power distribution network; carrying out topology analysis on the fault section, setting a hierarchical point at a port, and solving the position of a fault point by adopting an impedance method according to fault information obtained by the hierarchical point; according to the position of the fault point, establishing an optimization model of independent region division according to the load priority by utilizing a depth and breadth-first search algorithm; establishing an objective function of a distribution characteristic curve between a distributed power generation power supply and a load, and adopting a particle swarm optimization algorithm to realize dynamic matching between the power generation power supply and the load; on the basis of realizing dynamic matching between a power generation power supply and a load, the central hierarchy sends a decision to the execution hierarchy to realize protection of the power distribution network, and the method provided by the invention can realize all-around distributed power generation power distribution network protection and wide-area self-adaptive protection.

Description

Technical Field

[0001] The present invention relates to the field of intelligent distribution networks, and in particular to a distribution network protection and wide-area adaptive protection method for distributed power generation. Background Art

[0002] With the increasing prominence of environmental problems and energy crises, the continuous development and improvement of new energy and its control technology, the capacity of distributed generation in the distribution system is increasing. After the distributed power source is connected to the distribution system, clean energy can be used more effectively, the construction investment of transmission and distribution equipment can be reduced, and the reliability of power supply can be improved. However, distributed generation has different power generation characteristics from traditional power plants such as thermal power plants, hydropower plants, and nuclear power plants, and its access point is the original radial distribution network. Its access has brought many impacts on the operation of the original distribution network, among which relay protection is an important technical issue for the access of distributed generation to the distribution network.

[0003] Traditional distribution networks are generally powered by only a single power source, operate in a radial manner, and have a fixed power flow direction. When a fault occurs, the direction of the short-circuit current is also basically determined. The protection scheme is relatively simple, and from an economic perspective, the protection configuration is also relatively simple. However, as the types, quantity, and capacity of distributed power sources in the distribution network increase, the topology of the distribution network will become more and more complex, and the direction of the power flow in the network will no longer be single, and will change accordingly as the distributed power source operation mode switches. When a fault occurs, the direction of the short-circuit current cannot be determined, which brings many problems to the setting and operation of relay protection. The original simple protection scheme can no longer meet the protection requirements of the distribution network with distributed power sources connected. Summary of the invention

[0004] The main purpose of the present invention is to overcome the above-mentioned defects in the prior art, propose a distribution network protection and wide-area adaptive protection method for distributed power generation, introduce a multi-level system, which can quickly and accurately determine the fault location and form a complete fault location strategy. On the basis of determining the fault location, an optimization model for independent area division is established, and a high degree of adaptation between load power and power generation is ensured, which effectively improves the self-healing ability of the power grid, thereby realizing all-round distribution network protection and wide-area adaptive protection for distributed power generation.

[0005] The present invention adopts the following technical solution:

[0006] A distribution network protection and wide-area adaptive protection method for distributed generation includes the following steps:

[0007] Introducing a multi-level system to accurately locate the fault section in the distributed generation distribution network based on the fault direction criteria of different branch types;

[0008] Perform topological analysis on the fault section and set hierarchical points at the ports. Use the impedance method to solve the fault point location based on the fault information obtained from the hierarchical points.

[0009] Based on the location of the fault point, the optimization model of independent area division is established according to the load priority level using depth and breadth first search algorithms;

[0010] Establish the objective function of the distribution characteristic curve between distributed power generation and load, and use particle swarm optimization algorithm to achieve dynamic matching between power generation and load;

[0011] On the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to implement distribution network protection.

[0012] Specifically, the multi-level system is introduced to accurately locate the fault section in the distributed power distribution network according to the fault direction judgment criteria of different branch types, specifically including:

[0013] Active node: Determine whether the fault occurs on the upstream or downstream side of the node based on whether the current directions of the two branches of the node are consistent; determine the specific fault section based on Kirchhoff's current law, which states that the current flowing through the fault line is the sum of the currents of the other two lines;

[0014] Passive node: If the current flowing through the line changes suddenly, the line is judged to be a fault section;

[0015] Combined node: There are both lines with distributed power sources and lines without distributed power sources. The passive branches are analyzed for criteria. If the fault is determined to occur in the passive branch, the positioning is completed. Otherwise, the active branch is topologically analyzed, and the corresponding criteria are used to determine the fault section.

[0016] Specifically, a topological analysis is performed on the fault section, and a hierarchical point is set at the port. The impedance method is used to solve the fault point location based on the fault information obtained from the hierarchical point. Specifically,

[0017] Perform topological analysis on the fault section and divide the fault section into two-terminal fault section, three-terminal fault section and four-terminal fault section;

[0018] Set the hierarchical points A1 and A2 at the port, and the voltage and current equations of the hierarchical points are:

[0019] U 1f =λI 1f Z+I f R f

[0020] U 2f =(1-λ)I 2f Z+I f Rf

[0021] I f =I 1f +I 2f

[0022] U 1f , U 2f ,I 1f ,I 2f are the information of voltage and current measured at the port level points respectively; λ is the ratio of the distance from the starting point of the section to the fault point to the total length of the section, f is the short-circuit point of the fault line, and Z is the impedance of the fault line.

[0023] Specifically, the impedance method is used to solve the fault point location based on the fault information obtained from the hierarchical point. Specifically, after calculation and reasoning, the voltage and current equations of the fault point at the two-end fault section are obtained:

[0024] U 1fi -U 2f sinα2-λ[(I 1fr +I 2f cosβ2)Z i -(I 1fr +I 2f sinβ2)Z r ]+(I 2f cosβ2Z i -I 2f sinβ2Z r )=0

[0025] Among them: α1 and α2 are the voltage phase angle values ​​measured at the port level points, β1 and β2 are

[0026] The current phase angle value measured at the port level point, Z = (Z r +jZ i ).

[0027] The location of the fault point:

[0028] D1=λL

[0029] D 12 =(1-λ)L

[0030] Where D1 is the distance from the fault point to the level point A1, D2 is the distance from the fault point to the level point A2, and L is the length of the fault branch;

[0031] Thereby determining the location of the fault point.

[0032] Specifically, according to the location of the fault point, the optimization model of independent area division is established according to the load priority level by using the depth and breadth first search algorithm. The optimization model is:

[0033]

[0034] in:

[0035]

[0036] ω1,ω2,ω3,ω4≥0

[0037] st|Δε|≤|Δε| max

[0038] Among them, p s is the rated power of the photovoltaic power source; n is the number of important loads that the photovoltaic power source must supply; p i is the rated power value of each important load; ω1, ω2, ω3, ω4 are the rated power values ​​of the primary industry, secondary industry, tertiary industry, and life industry that the photovoltaic power source should supply to the non-important loads, respectively. s (t) is the analytical expression of the daily output power curve function of the photovoltaic power source, f c (t), f l (t), f h (t), f r (t) are the analytical expressions of the comprehensive daily load curve functions of the primary industry, secondary industry, tertiary industry and living industry in the region; f i (t) is the analytical expression of the daily load curve function of the industry to which each important load belongs, Δε is the instantaneous deviation between the output power of the photovoltaic power source and the planned load power supply, F represents the deviation between the total power output of the photovoltaic power source and the planned load power supply in the time period [t1, t2], and |Δε|max is the set maximum power deviation.

[0039] Specifically, the objective function of the distribution characteristic curve between the distributed power generation source and the load is established, and the particle swarm optimization algorithm is used to achieve the dynamic matching between the power generation source and the load, specifically:

[0040] Establish the objective function of the distribution characteristic curve between distributed generation and load,

[0041] The particle swarm optimization algorithm is used to dynamically optimize the power supplied by each photovoltaic power source to each load, so that the adaptability between load demand and power generation output is maximized;

[0042] The block power supply area of ​​each power generation source is dynamically divided according to the supplied power value.

[0043] Specifically, a multi-level system is introduced to accurately locate the fault section in the distribution network of distributed power generation according to the fault direction judgment criteria of different branch types. The multi-level system includes:

[0044] The multi-level system includes information collection level points, a central level and an execution level. The information collection level points send the collected information to the central level. The central level receives the information and makes a decision, and sends it to the execution level for execution. The central level is a neural network including three neural sub-networks.

[0045] Another embodiment of the present invention further provides a distribution network protection and wide-area adaptive protection system based on distributed generation, comprising:

[0046] Fault section location unit: introduces a multi-level system to accurately locate the fault section in the distributed power distribution network according to the fault direction judgment criteria of different branch types;

[0047] Fault point solving unit: Perform topological analysis on the fault section, set hierarchical points at the ports, and use impedance method to solve the fault point location based on the fault information obtained from the hierarchical points;

[0048] Optimization model building unit: Based on the location of the fault point, using depth and breadth first search algorithms, an optimization model for independent area division is established according to load priority levels;

[0049] Dynamic matching realization unit: establish the objective function of the distribution characteristic curve between the distributed power generation source and the load, and use the particle swarm optimization algorithm to realize the dynamic matching between the power generation source and the load;

[0050] Protection execution unit: On the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to implement distribution network protection.

[0051] Specifically, the fault point solving unit performs topological analysis on the fault section, sets a hierarchical point at the port, and uses the impedance method to solve the fault point location according to the fault information obtained by the hierarchical point, specifically:

[0052] Perform topological analysis on the fault section and divide the fault section into two-terminal fault section, three-terminal fault section and four-terminal fault section;

[0053] Set the hierarchical points A1 and A2 at the port, and the voltage and current equations of the hierarchical points are:

[0054] U 1f =λI 1f Z+I f R f

[0055] U 2f =(1-λ)I 2f Z+I f R f

[0056] If =I 1f +I 2f

[0057] U 1f , U 2f ,I 1f ,I 2f are the information of voltage and current measured at the port level points respectively; λ is the ratio of the distance from the starting point of the section to the fault point to the total length of the section, f is the short-circuit point of the fault line, and Z is the impedance of the fault line.

[0058] Specifically, the fault point solving unit uses the impedance method to solve the fault point location according to the fault information obtained from the hierarchical point. Specifically, after calculation and reasoning, the voltage and current equations of the fault points of the fault sections at both ends are obtained:

[0059] U 1fi -U 2f sinα2-λ[(I 1fr +I 2f cosβ2)Z i -(I 1fr +I 2f sinβ2)Z r ]+(I 2f cosβ2Z i -I 2f sinβ2Z r )=0

[0060] Among them: α1 and α2 are the voltage phase angle values ​​measured at the port level points, β1 and β2 are

[0061] The current phase angle value measured at the port level point, Z = (Z r +jZ i ).

[0062] The location of the fault point:

[0063] D1=λL

[0064] D 12 =(1-λ)L

[0065] Where D1 is the distance from the fault point to the level point A1, D2 is the distance from the fault point to the level point A2, and L is the length of the fault branch;

[0066] Thereby determining the location of the fault point.

[0067] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following beneficial effects:

[0068] 1) The present invention provides a distribution network protection and wide-area adaptive protection method based on distributed power generation, comprising: introducing a multi-level system, accurately locating the fault section in the distributed power generation distribution network according to the fault direction judgment criteria of different branch types; performing topological analysis on the fault section, setting level points at the ports, and solving the fault point location by impedance method according to the fault information obtained by the level points; according to the fault point location, using depth and breadth first search algorithms, establishing an optimization model for independent area division according to load priority levels; establishing an objective function of the distribution characteristic curve between distributed power generation sources and loads, and using a particle swarm optimization algorithm to achieve dynamic matching between power generation sources and loads; on the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to achieve distribution network protection; the method provided by the present invention can achieve all-round distributed power generation distribution network protection and wide-area adaptive protection.

[0069] 2) The present invention introduces a multi-level system. In the distribution network of distributed power generation, the fault section is accurately located according to the fault direction judgment criteria of different branch types; a topological analysis is performed on the fault section, and a hierarchical point is set at the port. The impedance method is used to solve the fault point position based on the fault information obtained from the hierarchical point. The fault location can be determined quickly and accurately, forming a complete fault location strategy, which provides a basis for further realizing the protection of the distribution network.

[0070] 3) The present invention establishes an optimization model for independent area division according to the location of the fault point; establishes an objective function of the distribution characteristic curve between the distributed power generation source and the load, and adopts a particle swarm optimization algorithm to achieve dynamic matching between the power generation source and the load; on the basis of determining the fault location, establishes an optimization model for independent area division, and ensures a high degree of adaptation between the load power and the power generation, thereby effectively improving the self-healing ability of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 A flow chart of a distribution network protection and wide-area adaptive protection method based on distributed generation provided by an embodiment of the present invention;

[0072] Figure 2 Schematic diagrams of different types of nodes are provided for embodiments of the present invention, wherein Figure (a) is a schematic diagram of an active node, Figure (b) is a schematic diagram of a passive node, and Figure (c) is a schematic diagram of a combined node;

[0073] Figure 3 A schematic diagram of the principle of fault point location provided by an embodiment of the present invention;

[0074] Figure 4 A structural diagram of a distribution network protection and wide-area adaptive protection method based on distributed generation provided in an embodiment of the present invention.

[0075] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0076] The present invention proposes a distribution network protection and wide-area adaptive protection method for distributed power generation, introduces a multi-level system, can quickly and accurately determine the fault location, form a complete fault location strategy, and establish an optimization model for independent area division on the basis of determining the fault location, and ensure a high degree of adaptation between load power and power generation, effectively improving the self-healing ability of the power grid, thereby realizing all-round distribution network protection and wide-area adaptive protection for distributed power generation.

[0077] like Figure 1 , the embodiment of the present invention provides a flow chart of a distribution network protection and wide-area adaptive protection method for distributed generation, including the following steps:

[0078] S101: Introducing a multi-level system to accurately locate the fault section in the distributed generation distribution network based on the fault direction criteria of different branch types;

[0079] Specifically, the multi-level system is introduced to accurately locate the fault section in the distribution network of distributed power generation according to the fault direction judgment criteria of different branch types, specifically including:

[0080] Active node: Determine whether the fault occurs on the upstream or downstream side of the node based on whether the current directions of the two branches of the node are consistent; determine the specific fault section based on Kirchhoff's current law, which states that the current flowing through the fault line is the sum of the currents of the other two lines;

[0081] Passive node: If the current flowing through the line changes suddenly, the line is judged to be a fault section;

[0082] Combined node: There are both lines with distributed power sources and lines without distributed power sources. The passive branches are analyzed for criteria. If the fault is determined to occur in the passive branch, the positioning is completed. Otherwise, the active branch is topologically analyzed, and the corresponding criteria are used to determine the fault section.

[0083] Among them, about active nodes, passive nodes and combined nodes; such as Figure 2 , are schematic diagrams of different types of nodes, where (a) is a schematic diagram of an active node, (b) is a schematic diagram of a passive node, and (c) is a schematic diagram of a combined node; an active node is a line whose lines all contain distributed power sources; a passive node is a line whose lines all do not contain distributed power sources; a combined node is a line that has both lines containing distributed power sources and lines without distributed power sources.

[0084] S102: Perform topological analysis on the fault section, set a hierarchical point at the port, and use an impedance method to solve the fault point location based on the fault information obtained from the hierarchical point;

[0085] Specifically, a topological analysis is performed on the fault section, and a hierarchical point is set at the port. The impedance method is used to solve the fault point location based on the fault information obtained from the hierarchical point. Specifically,

[0086] Perform topological analysis on the fault section and divide the fault section into two-terminal fault section, three-terminal fault section and four-terminal fault section;

[0087] Set the hierarchical points A1 and A2 at the port, and the voltage and current equations of the hierarchical points are:

[0088] U 1f =λI 1f Z+I f R f

[0089] U 2f =(1-λ)I 2f Z+I f R f

[0090] I f =I 1f +I 2f

[0091] U 1f , U 2f ,I 1f ,I 2f are the information of voltage and current measured at the port level points respectively; λ is the ratio of the distance from the starting point of the section to the fault point to the total length of the section, f is the short-circuit point of the fault line, and Z is the impedance of the fault line.

[0092] Specifically, the impedance method is used to solve the fault point location based on the fault information obtained from the hierarchical point. Specifically, after calculation and reasoning, the voltage and current equations of the fault point at the two-end fault section are obtained:

[0093] U 1fi -U 2f sinα2-λ[(I 1fr +I 2f cosβ2)Z i -(I 1fr +I 2f sinβ2)Z r ]+(I 2f cosβ2Z i -I 2f sinβ2Z r )=0

[0094] Where: α1 and α2 are the voltage phase angle values ​​measured at the port level points, β1 and β2 are the current phase angle values ​​measured at the port level points, Z = (Z r +jZ i ).

[0095] The location of the fault point:

[0096] D1=λL

[0097] D 12 =(1-λ)L

[0098] Where D1 is the distance from the fault point to the level point A1, D2 is the distance from the fault point to the level point A2, and L is the length of the fault branch;

[0099] So as to determine the location of the fault point, such as Figure 3 Schematic diagram of the principle of fault point location.

[0100] Similarly, the specific fault point locations of the three-terminal fault section and the four-segment fault section can be inferred and calculated, which will not be repeated here.

[0101] S103: Based on the location of the fault point, using the depth and breadth first search algorithm, an optimization model for independent area division is established according to the load priority level;

[0102] Specifically, according to the location of the fault point, the optimization model of independent area division is established according to the load priority level by using the depth and breadth first search algorithm. The optimization model is:

[0103]

[0104] in:

[0105]

[0106] Among them, p s is the rated power of the photovoltaic power source; n is the number of important loads that the photovoltaic power source must supply; p i is the rated power value of each important load; ω1, ω2, ω3, ω4 are the rated power values ​​of the primary industry, secondary industry, tertiary industry, and life industry that the photovoltaic power source should supply to the non-important loads, respectively. s (t) is the analytical expression of the daily output power curve function of the photovoltaic power source, f c (t), f l (t), f h (t), f r (t) are the analytical expressions of the comprehensive daily load curve functions of the primary industry, secondary industry, tertiary industry and living industry in the region; f i(t) is the analytical expression of the daily load curve function of the industry to which each important load belongs, Δε is the instantaneous deviation between the output power of the photovoltaic power source and the planned load power supply, F represents the deviation between the total power output of the photovoltaic power source and the planned load power supply in the time period [t1, t2], |Δε| max This is the maximum power deviation that is set.

[0107] S104: establishing an objective function of a distribution characteristic curve between distributed generation sources and loads, and using a particle swarm optimization algorithm to achieve dynamic matching between the generation sources and loads;

[0108] Specifically, the objective function of the distribution characteristic curve between the distributed power generation source and the load is established, and the particle swarm optimization algorithm is used to achieve the dynamic matching between the power generation source and the load, specifically:

[0109] Establish the objective function of the distribution characteristic curve between distributed generation and load,

[0110] The particle swarm optimization algorithm is used to dynamically optimize the power supplied by each photovoltaic power source to each load, so that the adaptability between load demand and power generation output is maximized;

[0111] The block power supply area of ​​each power generation source is dynamically divided according to the supplied power value.

[0112] S105: On the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to implement distribution network protection.

[0113] In addition, it should be noted that a multi-level system is introduced to accurately locate the fault section in the distribution network of distributed power generation according to the fault direction judgment criteria of different branch types. The multi-level system includes:

[0114] The multi-level system includes information collection level points, a central level and an execution level. The information collection level points send the collected information to the central level. The central level receives the information and makes a decision, and sends it to the execution level for execution. The central level is a neural network including three neural sub-networks.

[0115] like Figure 4 Another embodiment of the present invention further provides a distribution network protection and wide-area adaptive protection method based on distributed generation, comprising:

[0116] Fault section location unit 401: introduces a multi-level system to accurately locate the fault section in the distribution network of distributed generation according to the fault direction judgment criteria of different branch types;

[0117] Fault point solving unit 402: performs topological analysis on the fault section, sets a hierarchical point at the port, and solves the fault point location using an impedance method based on the fault information obtained from the hierarchical point;

[0118] Specifically, the fault point solving unit 402 performs topological analysis on the fault section, sets a hierarchical point at the port, and solves the fault point location using an impedance method according to the fault information obtained by the hierarchical point, specifically:

[0119] Perform topological analysis on the fault section and divide the fault section into two-terminal fault section, three-terminal fault section and four-terminal fault section;

[0120] Set the hierarchical points A1 and A2 at the port, and the voltage and current equations of the hierarchical points are:

[0121] U 1f =λI 1f Z+I f R f

[0122] U 2f =(1-λ)I 2f Z+I f R f

[0123] I f =I 1f +I 2f

[0124] U 1f , U 2f ,I 1f ,I 2f are the information of voltage and current measured at the port level points respectively; λ is the ratio of the distance from the starting point of the section to the fault point to the total length of the section, f is the short-circuit point of the fault line, and Z is the impedance of the fault line.

[0125] Specifically, the fault point solving unit 402 uses the impedance method to solve the fault point location according to the fault information obtained from the hierarchical point, specifically: after calculation and reasoning, the voltage and current equations of the fault point of the fault section at both ends are obtained:

[0126] U 1fi -U 2f sinα2-λ[(I 1fr +I 2f cosβ2)Z i -(I 1fr +I 2f sinβ2)Z r ]+(I 2f cosβ2Z i -I 2f sinβ2Zr )=0

[0127] Among them: α1 and α2 are the voltage phase angle values ​​measured at the port level points, β1 and β2 are

[0128] The current phase angle value measured at the port level point, Z = (Z r +jZ i ).

[0129] The location of the fault point:

[0130] D1=λL

[0131] D 12 =(1-λ)L

[0132] Where D1 is the distance from the fault point to the level point A1, D2 is the distance from the fault point to the level point A2, and L is the length of the fault branch;

[0133] Thereby determining the location of the fault point.

[0134] Optimization model building unit 403: based on the location of the fault point, using depth and breadth first search algorithms, building an optimization model for independent area division according to load priority levels;

[0135] Dynamic matching realization unit 404: establishes an objective function of a distribution characteristic curve between a distributed power generation source and a load, and uses a particle swarm optimization algorithm to realize dynamic matching between the power generation source and the load;

[0136] Protection execution unit 405: On the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to implement the protection of the distribution network.

[0137] The present invention provides a distribution network protection and wide-area adaptive protection method based on distributed power generation, comprising: introducing a multi-level system, accurately locating the fault section in the distribution network of distributed power generation according to the fault direction judgment criteria of different branch types; performing topological analysis on the fault section, setting a level point at the port, and solving the fault point position by using an impedance method according to the fault information obtained by the level point; according to the fault point position, using a depth-first and breadth-first search algorithm, and establishing an optimization model for independent area division according to load priority level; establishing an objective function of a distribution characteristic curve between a distributed power source and a load, and using a particle swarm optimization algorithm to achieve dynamic matching between the power source and the load; on the basis of achieving dynamic matching between the power source and the load, the central level sends the decision to the execution level to achieve distribution network protection; the method provided by the present invention can achieve all-round distributed power distribution network protection and wide-area adaptive protection.

[0138] The present invention introduces a multi-level system. In the distribution network of distributed power generation, the fault section is accurately located according to the fault direction judgment criteria of different branch types; a topological analysis is performed on the fault section, and a hierarchical point is set at the port. The impedance method is used to solve the fault point position according to the fault information obtained from the hierarchical point. The fault position can be determined quickly and accurately, forming a complete fault location strategy, which provides a basis for further realizing the protection of the distribution network.

[0139] The present invention establishes an optimization model for independent area division according to the location of the fault point; establishes an objective function of the distribution characteristic curve between the distributed power generation source and the load, and adopts a particle swarm optimization algorithm to achieve dynamic matching between the power generation source and the load; on the basis of determining the fault location, establishes an optimization model for independent area division, and ensures a high degree of adaptation between the load power and the power generation, thereby effectively improving the self-healing ability of the power grid.

[0140] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A distribution network protection and wide-area adaptive protection method for distributed generation, characterized in that: The steps include: Introducing a multi-level system to accurately locate the fault section in the distributed generation distribution network based on the fault direction criteria of different branch types; Perform topological analysis on the fault section and set hierarchical points at the ports. Use the impedance method to solve the fault point location based on the fault information obtained from the hierarchical points. Based on the location of the fault point, the optimization model of independent area division is established according to the load priority level using depth and breadth first search algorithms; Establish the objective function of the distribution characteristic curve between distributed power generation and load, and use particle swarm optimization algorithm to achieve dynamic matching between power generation and load; On the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to implement distribution network protection.

2. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 1, characterized in that: The multi-level system is introduced to accurately locate the fault section in the distributed power distribution network according to the fault direction judgment criteria of different branch types, specifically including: Active node: Determine whether the fault occurs on the upstream or downstream side of the node based on whether the current directions of the two branches of the node are consistent; determine the specific fault section based on Kirchhoff's current law, which states that the current flowing through the fault line is the sum of the currents of the other two lines; Passive node: If the current flowing through the line changes suddenly, the line is judged to be a fault section; Combined node: There are both lines with distributed power sources and lines without distributed power sources. The passive branches are analyzed for criteria. If the fault is determined to occur in the passive branch, the positioning is completed. Otherwise, the active branch is topologically analyzed, and the corresponding criteria are used to determine the fault section.

3. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 1, characterized in that: Perform topological analysis on the fault section and set hierarchical points at the ports. The impedance method is used to solve the fault point location based on the fault information obtained from the hierarchical points. Specifically: Perform topological analysis on the fault section and divide the fault section into two-terminal fault section, three-terminal fault section and four-terminal fault section; Set the hierarchical points A1 and A2 at the port, and the voltage and current equations of the hierarchical points are: U 1f =λI 1f Z+I f R f U 2f =(1-λ)I 2f Z+I f R f I f =I 1f +I 2f U 1f , U 2f ,I 1f ,I 2f are the information amounts of voltage and current measured at the port level points respectively; λ is the ratio of the distance from the starting point of the section to the fault point to the total length of the section, f is the short-circuit point of the fault line, and Z is the impedance of the fault line.

4. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 3, characterized in that: According to the fault information obtained from the hierarchical points, the impedance method is used to solve the fault point location. Specifically, after calculation and reasoning, the voltage and current equations of the fault points in the fault sections at both ends are obtained: AT 1fi -AT 2f sinα2-λ[(I 1fr +I 2f cosβ2)Z i -(AND 1fr +I 2f sinβ2)Z r ]+(I 2f cosβ2Z i -AND 2f sinβ2Z r )=0 Where: α1 and α2 are the voltage phase angle values ​​measured at the port level points, β1 and β2 are the current phase angle values ​​measured at the port level points, Z = (Z r +jZ i ). The location of the fault point: D1=λL D 12 =(1-λ)L Where D1 is the distance from the fault point to the level point A1, D2 is the distance from the fault point to the level point A2, and L is the length of the fault branch; Thereby determining the location of the fault point.

5. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 1, characterized in that: According to the location of the fault point, the optimization model of independent area division is established according to the load priority level by using the depth and breadth first search algorithm. The optimization model is: in: ω1,ω2,ω3,ω4≥0 st|Not|≤|Not| max Among them, p s is the rated power of the photovoltaic power source; n is the number of important loads that the photovoltaic power source must supply; p i is the rated power value of each important load; ω1, ω2, ω3, ω4 are the rated power values ​​of the primary industry, secondary industry, tertiary industry, and life industry that the photovoltaic power source should supply to the non-important loads, respectively. s (t) is the analytical expression of the daily output power curve function of the photovoltaic power source, f c (t), f l (t), f h (t), f r (t) are the analytical expressions of the comprehensive daily load curve functions of the primary industry, secondary industry, tertiary industry and living industry in the region; f i (t) is the analytical expression of the daily load curve function of the industry to which each important load belongs, Δε is the instantaneous deviation between the output power of the photovoltaic power source and the planned load power supply, F represents the deviation between the total power output of the photovoltaic power source and the planned load power supply in the time period [t1, t2], |Δε| max This is the maximum power deviation that is set.

6. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 1, characterized in that: The objective function of the distribution characteristic curve between distributed power generation and load is established, and the particle swarm optimization algorithm is used to achieve dynamic matching between power generation and load, specifically: Establish the objective function of the distribution characteristic curve between distributed generation and load, The particle swarm optimization algorithm is used to dynamically optimize the power supplied by each photovoltaic power source to each load, so that the adaptability between load demand and power generation output is maximized; According to the power value supplied, the block power supply area of ​​each power generation source is dynamically divided.

7. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 1, characterized in that: A multi-level system is introduced to accurately locate the fault section in the distribution network of distributed generation according to the fault direction judgment criteria of different branch types. The multi-level system includes: The multi-level system includes information collection level points, a central level and an execution level. The information collection level points send the collected information to the central level. The central level receives the information and makes a decision, and sends it to the execution level for execution. The central level is a neural network including three neural sub-networks.

8. A distribution network protection and wide-area adaptive protection method based on distributed generation, characterized in that: include: Fault section location unit: introduces a multi-level system to accurately locate the fault section in the distributed power distribution network according to the fault direction judgment criteria of different branch types; Fault point solving unit: Perform topological analysis on the fault section, set hierarchical points at the ports, and use the impedance method to solve the fault point location based on the fault information obtained from the hierarchical points; Optimization model building unit: Based on the location of the fault point, using the depth and breadth first search algorithm, an optimization model for independent area division is established according to the load priority level; Dynamic matching realization unit: establish the objective function of the distribution characteristic curve between the distributed power generation source and the load, and use the particle swarm optimization algorithm to realize the dynamic matching between the power generation source and the load; Protection execution unit: On the basis of achieving dynamic matching between power generation sources and loads, the central level sends the decision to the execution level to implement distribution network protection.

9. The distributed power generation distribution network protection and wide area adaptive protection system according to claim 8, characterized in that: The fault point solving unit performs topological analysis on the fault section and sets a hierarchical point at the port. The impedance method is used to solve the fault point location based on the fault information obtained from the hierarchical point. Specifically: Perform topological analysis on the fault section and divide the fault section into two-terminal fault section, three-terminal fault section and four-terminal fault section; Set the hierarchical points A1 and A2 at the port, and the voltage and current equations of the hierarchical points are: U 1f =λI 1f Z+I f R f U 2f =(1-λ)I 2f Z+I f R f I f =I 1f +I 2f U 1f , U 2f ,I 1f ,I 2f are the information amounts of voltage and current measured at the port level points respectively; λ is the ratio of the distance from the starting point of the section to the fault point to the total length of the section, f is the short-circuit point of the fault line, and Z is the impedance of the fault line.

10. The method for distribution network protection and wide-area adaptive protection of distributed generation according to claim 8, characterized in that: The fault point solving unit uses the impedance method to solve the fault point location according to the fault information obtained from the hierarchical point. Specifically, after calculation and reasoning, the voltage and current equations of the fault points of the fault sections at both ends are obtained: AT 1fi -AT 2f sinα2-λ[(I 1fr +I 2f cosβ2)Z i -(AND 1fr +I 2f sinβ2)Z r ]+(I 2f cosβ2Z i -AND 2f sinβ2Z r )=0 Where: α1 and α2 are the voltage phase angle values ​​measured at the port level points, β1 and β2 are the current phase angle values ​​measured at the port level points, Z = (Z r +jZ i ). The location of the fault point: D1=λL D 12 =(1-λ)L Where D1 is the distance from the fault point to the level point A1, D2 is the distance from the fault point to the level point A2, and L is the length of the fault branch; Thereby determining the location of the fault point.

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