Method and system for checking distance protection device of new energy cluster sending-out line

Abstract

The application discloses a new energy cluster sending-out line distance protection device checking method and system, and relates to the field of new energy cluster protection device checking. The scheme comprises the following steps: a simulation model is established; a strategy is set based on a preset condition to determine the checking condition of the current round; the simulation model is controlled to run based on the checking condition to obtain electric parameter information corresponding to the target distance protection device to be checked and output by the simulation model; corresponding protection setting values are downloaded to the target distance protection device, and corresponding electric signals are output to the target distance protection device based on the electric parameter information to obtain the action condition of the target distance protection device and determine whether the target distance protection device malfunctions according to the action condition to obtain the checking result of whether the target distance protection device malfunctions, and then the checking of the next round is started and the checking condition is determined again until the preset checking end condition is reached. The scheme can efficiently and comprehensively determine the adaptability determination result of the distance protection device in the power system and clearly determine the device malfunction boundary.

Description

Technical Field

[0001] This invention relates to the field of verification technology for protection devices of new energy clusters, and in particular to a method and system for verifying distance protection devices of new energy cluster transmission lines. Background Technology

[0002] With the accelerated progress of the global energy transition, new energy power generation technologies, represented by wind power and photovoltaics, have achieved explosive growth. The power system is undergoing a transformation from traditional fossil energy-dominated to new energy-dominated. The large-scale grid connection of new energy clusters has also brought technical challenges to traditional relay protection systems.

[0003] Protection selectivity is one of the fundamental requirements of relay protection, meaning that in the event of a fault, the protection device should only disconnect the faulty component from the power system, ensuring the continued operation of the non-faulty components. However, the integration of renewable energy clusters can affect protection selectivity. Specifically, in terms of distance protection, the integration of renewable energy clusters causes changes in the system impedance characteristics, thereby affecting the measurement accuracy and operating characteristics of distance protection devices. Because the equivalent impedance of renewable energy power plants varies with operating conditions, traditional distance protection setting methods are no longer applicable, potentially leading to a narrowing or expansion of the protection range and affecting protection selectivity. Especially when a fault occurs near the outlet of a renewable energy power plant, the presence of renewable energy power sources between the fault point and the protection installation location can cause impedance distortion in the measurement, leading the distance protection device to misjudge the fault location.

[0004] Therefore, how to provide an adaptive verification scheme for the distance protection devices at the transmission lines of new energy clusters to ensure the adaptability of the distance protection devices under various actual working conditions is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention provides a method and system for verifying distance protection devices of new energy cluster transmission lines, which can efficiently and comprehensively determine the adaptability judgment results of distance protection devices under power systems, clarify the boundaries of device maloperation, and facilitate practical application.

[0006] To address the aforementioned technical problems, this application provides a method for verifying the distance protection device of a new energy cluster transmission line, applicable to a power system including a new energy cluster. The new energy cluster comprises multiple new energy power station units, and each new energy power station unit has a distance protection device installed on its transmission line at the end closest to the system side. The method for verifying the distance protection device includes: Establish a simulation model of the power system; The strategy is set based on preset conditions to determine the verification conditions for the current round; The simulation model is controlled to run based on the verification conditions to obtain the electrical parameter information output by the simulation model that corresponds to the target distance protection device currently being verified. The corresponding protection setting value is downloaded to the target distance protection device, and the corresponding electrical signal is output to the target distance protection device based on the electrical parameter information, so as to obtain the operation status of the target distance protection device and determine the verification result of whether the target distance protection device has malfunctioned based on the operation status. Then, the next round of verification is started and the step of determining the verification conditions of the current round based on the preset condition setting strategy is returned until the preset verification end condition is reached.

[0007] Furthermore, based on preset conditions, a strategy is set to determine the verification conditions for the current round, including: A five-layer nested traversal loop is adopted, arranged sequentially from the outer layer to the inner layer. The loop traverses the following layers sequentially from the outer layer to the inner layer: all operating modes in the preset power system operating mode set, all output conditions in the preset new energy output condition set, all fault locations in the preset fault location set, all fault types corresponding to the currently selected fault location, and all distance protection devices related to the currently selected fault location. In this process, each layer selects and fixes the corresponding verification conditions in a loop, so that the combination of the five selected verification conditions in the current round becomes the complete verification conditions in the current round.

[0008] Furthermore, after establishing the simulation model of the power system, the following is also included: The new energy power station bus under the new energy power station unit is used as a node and the transmission line is used as a branch. A corresponding tree structure is constructed by combining the actual connection topology of multiple new energy power station units. A distance protection device is set at the end of each branch that is closer to the system side. The steps for traversing all fault locations in the preset fault location set include: Based on the tree structure and the preset breadth-first traversal strategy, all fault locations in the preset fault location set are traversed. The steps for traversing all distance protection devices corresponding to the currently selected fault location include: Based on the tree structure and the preset dynamic priority traversal strategy, all distance protection devices corresponding to the currently selected fault location are traversed.

[0009] Furthermore, the step of constructing a tree structure corresponding to the actual connection topology of the multiple new energy power station units includes: S11: Based on the actual connection topology, construct a first-layer node group based on nodes directly connected to the AC power grid; S12: For each node in the current layer node group, based on the actual connection topology, determine the target node that is connected in series with the node via the outgoing line, and take the target node corresponding to each node as the next layer node group. S13: Corresponding to the actual connection topology, repeat step S12 along the reverse power output direction to perform layer-by-layer recursion, thereby determining the multi-layer node group to obtain a tree structure composed of the multi-layer node group.

[0010] Furthermore, based on the tree structure and the preset breadth-first traversal strategy, all fault locations in the preset fault location set are traversed, including: Based on the tree structure, all fault locations in the preset fault location set are determined to include all non-terminal nodes under the tree structure; Starting from the first layer of node groups, the process is recursively applied layer by layer, and a target node is selected in each layer of node groups to complete the traversal of all non-terminal nodes. When the current layer of node groups includes multiple target nodes, the traversal order of the multiple target nodes is determined according to a preset priority evaluation strategy.

[0011] Furthermore, the traversal order of the multiple target nodes is determined according to a preset priority evaluation strategy, including: For multiple target nodes in the current layer node group that are recursively obtained, the electrical distance of the transmission line between each target node and the corresponding node in the previous layer node group is determined. The traversal order of each target node is determined based on the sorting of the electrical distances.

[0012] Furthermore, based on the tree structure and the preset dynamic priority traversal strategy, all distance protection devices corresponding to the currently selected fault location are traversed, including: Based on the tree structure, determine all distance protection devices related to the node where the currently selected fault location is located, including distance protection devices on all lower-level outgoing lines of the node. Starting from the last branch corresponding to the last node group, the process is recursively applied layer by layer. In each branch corresponding to the node group, a target branch is selected to determine the distance protection device on the target branch as the target distance protection device. This process continues until the level of the node where the currently selected fault location is located is reached, thus completing the traversal of the distance protection devices on all the lower-level outgoing lines of the node.

[0013] Furthermore, when the current layer node group corresponds to multiple branches, it also includes: Determine the electrical distance corresponding to each of the aforementioned branches; The traversal order of the distance protection devices under each branch is determined based on the sorting of the electrical distances.

[0014] Furthermore, when the verification result of the target distance protection device determined in the current round is that a malfunction has occurred, it also includes: The level corresponding to the target distance protection device that the verification result indicates has malfunctioned will be designated as the interruption level. Based on the tree structure, a complete connection path is determined from the branch corresponding to the target distance protection device to the node where the currently selected fault location is located. The remaining distance protection devices on the complete connection path are sequentially identified as target distance protection devices for priority verification; and after all distance protection devices on the complete connection path have been verified, the process returns to the interruption level to continue the layer-by-layer verification process.

[0015] To address the aforementioned technical problems, this invention also provides a distance protection device verification system for new energy cluster transmission lines, comprising: Memory, used to store computer programs; A processor is used to execute the computer program to implement the steps of the distance protection device verification method for the new energy cluster transmission line as described above.

[0016] The beneficial effects of this invention are as follows: This application provides a method and system for verifying distance protection devices on transmission lines of new energy clusters. This solution is applied to power systems including new energy clusters, which comprise multiple new energy power station units. Each new energy power station unit has a distance protection device installed on its transmission line near the system side. The solution includes: establishing a simulation model of the power system; setting a strategy based on preset conditions to determine the verification conditions for the current cycle; controlling the simulation model to operate based on the verification conditions to obtain electrical parameter information output by the simulation model corresponding to the target distance protection device being verified; downloading the corresponding protection setting value to the target distance protection device and outputting a corresponding electrical signal to the target distance protection device based on the electrical parameter information to obtain the action status of the target distance protection device and determine whether the target distance protection device has malfunctioned based on the action status; then initiating the next cycle of verification and returning to the step of determining the verification conditions for the current cycle based on the preset condition setting strategy, until the preset verification termination condition is met. It is evident that this solution provides a standardized verification process for distance protection devices in power systems including new energy clusters. It is particularly suitable for full-condition verification of distance protection devices in large-scale multi-node power systems. It can efficiently and comprehensively determine the adaptability judgment results of distance protection devices in power systems, clarify the boundaries of device malfunction, and facilitate practical applications.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A flowchart of a distance protection device verification method for a new energy cluster transmission line provided by the present invention; Figure 2 A schematic diagram of the structure of a new energy power station unit provided by the present invention; Figure 3 This invention provides a schematic diagram of the structure of a new energy cluster; Figure 4 This is a schematic diagram of another new energy cluster structure provided by the present invention; Figure 5 A schematic diagram of a five-level nested traversal loop provided by the present invention; Figure 6 A schematic diagram of a tree structure provided by the present invention; Figure 7 This is a schematic diagram of the structure of a distance protection device verification system for a new energy cluster transmission line provided by the present invention. Detailed Implementation

[0019] The core of this invention is to provide a method and system for verifying distance protection devices on new energy cluster transmission lines. This method can efficiently and comprehensively determine the adaptability of distance protection devices under the power system, clarify the boundaries of device malfunction, and facilitate practical applications.

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, without limiting the number of objects; for example, a first object can be one or more. Furthermore, in this application, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects have an "or" relationship.

[0022] Please refer to Figure 1 , Figure 1 This invention provides a method for verifying the distance protection device of a new energy cluster transmission line.

[0023] The method for verifying the distance protection device of the transmission line of the new energy cluster is applied to a power system including a new energy cluster. The new energy cluster includes multiple new energy power station units 110, and each new energy power station unit 110 has a distance protection device 11 installed on the transmission line near the system side. The method for verifying the distance protection device includes: S21: Establish a simulation model of the power system; S22: Set a strategy based on preset conditions to determine the verification conditions for the current round; S23: Control the simulation model to run based on the verification conditions in order to obtain the electrical parameter information output by the simulation model that corresponds to the target distance protection device being verified. S24: Download the corresponding protection setting to the target distance protection device, and output the corresponding electrical signal to the target distance protection device based on the electrical parameter information, so as to obtain the operation status of the target distance protection device and determine the verification result of whether the target distance protection device has malfunctioned based on the operation status, and then start the next round of verification and return to the step of determining the verification conditions of the current round based on the preset condition setting strategy, until the preset verification end condition is reached.

[0024] In this embodiment, the access of the new energy cluster will cause distortion of the system impedance characteristics, making the distance protection device 11 prone to maloperation. To address this, a verification method for the distance protection device 11 of the new energy cluster transmission line is provided. This method provides a standard adaptive verification scheme for each distance protection device 11 at the transmission line of the new energy cluster, enabling rapid and comprehensive verification of the adaptability of each distance protection device 11 under all operating conditions. Moreover, for the purpose of verification under all operating conditions, this scheme has higher traversal efficiency than the blind sequence full verification method, and can quickly locate the maloperation boundary to ensure that the protection does not maloperate when there is an external fault, thus avoiding the risk of cascading tripping.

[0025] To elaborate, please first refer to Figure 2 , Figure 2 This is a structural schematic diagram of a new energy power station unit provided by the present invention. Specifically, each new energy power station unit 110 includes a new energy power station and a distance protection device 11. The side where the new energy power station is located is the power supply side, extending along the transmission line. The side away from the power supply side and used to connect other new energy power station units 110 or connect to the power grid according to the circuit configuration is the system side. The end closer to the system side is provided with a distance protection device 11, such as... Figure 2 As shown, taking the system side connected to a conventional AC power grid as an example; it should also be noted that the new energy power station unit 110 may also include a current transformer 13, a voltage transformer 14, and other protection devices 12, such as Figure 2 As shown, no special limitations are made here.

[0026] A regional power system includes a renewable energy cluster, which comprises multiple renewable energy power station units 110. These renewable energy power station units 110 are connected via AC lines. Specifically, the actual connection topology of the multiple renewable energy power station units 110 can be series, parallel, or a combination of series and parallel. No particular limitation is placed on the specific connection topology setting; it is determined by the actual application requirements. For example, corresponding to... Figure 2 Please refer to Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the structure of a new energy cluster provided by the present invention, wherein the actual connection topology of multiple new energy power station units 110 is in series; Figure 4 This is a schematic diagram of another new energy cluster structure provided by the present invention, wherein the actual connection topology of multiple new energy power station units 110 is a combination of series and parallel connections. In the context of large-scale new energy cluster transmission, during actual operation, the distance protection device 11 installed at the end of a transmission line closest to the system side may malfunction. This malfunction will cause the distance protection to lose its selectivity. Therefore, it is necessary to perform adaptive verification on the distance protection device 11 installed at the end of each transmission line closest to the system side.

[0027] Furthermore, based on step S21, a simulation model of the power system is constructed in the simulation software. This model is specifically an electromagnetic transient simulation model. In detail, when building the model, based on the actual situation of the power system, various new energy power stations, including wind power and photovoltaic power stations, are first added to the simulation software. The installed capacity, unit type, and control parameters of each power station are set. Then, the transmission line model of each new energy power station is built. A suitable transmission line type is selected, and parameters such as line length, resistance, reactance, and susceptance are set. Next, the new energy power stations are connected to the corresponding transmission lines to obtain new energy power station units 110. Then, based on the actual connection topology, multiple new energy power station units 110 are connected and connected to the main grid on the system side. The equivalent parameters of the main grid are set, and the time step and total duration of the electromagnetic transient simulation are defined. Then, when running the simulation model later, transient data such as voltage, current, and power of the line can be extracted for analysis. No special limitations are made here.

[0028] Based on step S22, the complete verification conditions for the current round include the currently selected power system operation mode, new energy output conditions, fault location, fault type, and the distance protection device 11 (i.e., the target distance protection device) corresponding to the fault location. Based on step S23, the electrical parameter information corresponding to the target distance protection device under the current verification conditions can be obtained. This electrical parameter information can protect the three-phase voltage and three-phase current at the installation location of the target distance protection device, and this electrical parameter information can be obtained in the waveform file output by the simulation model.

[0029] Based on step S24, the corresponding protection setting is downloaded to the target distance protection device. This protection setting can be understood as specifying the conditions (such as electrical quantity thresholds) under which the target distance protection device being verified will act, such as starting, tripping, or alarming. Based on the electrical parameter information, the corresponding electrical signal is output to the target distance protection device to reproduce the on-site fault conditions, thereby obtaining the actual action of the target distance protection device after receiving the electrical signal. The action is stored and recorded in the memory, and the verification result of whether the target distance protection device has malfunctioned is determined based on the action. The verification result can also be stored and recorded in the memory. It can be understood that the above steps are a single verification process corresponding to the current round. If the preset verification end condition is not reached, the next round of verification will continue, and the verification conditions will be re-determined to execute the above single verification process. The preset verification end condition here can be that all operating conditions have been verified, thereby determining which verification conditions will cause the distance protection device 11 at which location to malfunction. If the distance protection device 11 does not malfunction under each verification condition, it is determined that the entire new energy cluster has passed the verification.

[0030] In summary, this application provides a method for verifying the distance protection device of a new energy cluster transmission line. This method provides a standardized verification process for distance protection devices in power systems including new energy clusters. It is particularly suitable for full-condition verification of distance protection devices 11 in large-scale multi-node power systems. It can efficiently and comprehensively determine the adaptability judgment results of distance protection devices 11 in power systems, clarify the boundaries of device maloperation, and facilitate practical applications.

[0031] Based on the above embodiments: In some embodiments, a strategy is set based on preset conditions to determine the verification conditions for the current round, including: A five-layer nested traversal loop is adopted, arranged sequentially from the outer layer to the inner layer. The loop traverses the following layers sequentially from the outer layer to the inner layer: all operating modes in the preset power system operating mode set, all output conditions in the preset new energy output condition set, all fault locations in the preset fault location set, all fault types corresponding to the currently selected fault location, and all distance protection devices related to the currently selected fault location. In this process, each layer selects and fixes the corresponding verification conditions in a loop, so that the combination of the five selected verification conditions in the current round becomes the complete verification conditions in the current round.

[0032] In this embodiment, please first refer to Figure 5 , Figure 5 The diagram illustrates the loop process of a five-level nested traversal loop provided by the present invention. It can be seen that the overall idea of ​​this five-level nested traversal loop is as follows: first, fix the verification condition of the o-th level, then run the loop of the o+1 level (o=1,…4), and only when the o+1 level is completely traversed will it return to the o-th level to change the next verification condition.

[0033] Specifically, the outermost nested loop refers to: traversing all operating modes of the power system and selecting the current operating mode of the power system as the first-level verification condition; the second outermost nested loop refers to: based on the current operating mode of the power system, traversing all renewable energy output conditions (specifically, this can include the output conditions of the entire renewable energy cluster, or the output conditions of each renewable energy power station unit 110, without special limitation here), and selecting the current renewable energy output condition as the second-level verification condition; the middle nested loop refers to: based on the current operating mode of the power system and the renewable energy output conditions, traversing all fault locations and selecting the current fault location as the third-level verification condition; the inner nested loop refers to: fixing... Based on the current power system operation mode, renewable energy output, and fault location, all possible fault types at that fault location (such as single-phase ground fault, two-phase short-circuit fault, two-phase ground short-circuit fault, and three-phase short-circuit fault) are iterated, and the current fault type is selected as the fourth-level verification condition. The innermost nested loop refers to: based on the fixed current power system operation mode, renewable energy output, fault location, and fault type, all protection installation locations related to the currently selected fault location are iterated, and the current distance protection device 11 (i.e., the target distance protection device) is selected as the fifth-level verification condition. Then, the combination of the five selected verification conditions in the current cycle is the complete verification condition for the current cycle.

[0034] Understandably, once the fault location is selected, regardless of the type of fault, the corresponding distance protection devices remain fixed based on the actual connection topology of the new energy cluster. Therefore, the above settings facilitate comprehensive and efficient full-condition traversal.

[0035] In some embodiments, after establishing a simulation model of the power system, the method further includes: The new energy power station bus under the new energy power station unit 110 is used as a node and the transmission line is used as a branch. A corresponding tree structure is constructed by combining the actual connection topology of multiple new energy power station units 110. Among them, a distance protection device 11 is set at the end of each branch that is closer to the system side. The steps for traversing all fault locations in the preset fault location set include: Based on a tree structure and a preset breadth-first traversal strategy, all fault locations in the preset fault location set are traversed. The steps for traversing all distance protection devices corresponding to the currently selected fault location include: Based on a tree structure and a preset dynamic priority traversal strategy, all distance protection devices corresponding to the currently selected fault location are traversed.

[0036] Specifically, modeling is based on a graph theory tree structure, where the new energy power station busbar under the new energy power station unit 110 is used as a node and the transmission line is used as a branch. A corresponding tree structure is constructed by combining the actual connection topology of multiple new energy power station units 110. Furthermore, the nodes and branches at each level of the tree structure can be numbered. Please refer to... Figure 6 , Figure 6 This is a schematic diagram of a tree structure provided by the present invention. Node nij represents the j-th node under the node group of the i-th layer, and branch buv represents the v-th branch in the branch group of the u-th layer. It should be noted that... Figure 6 This is just an example of a tree structure for the purpose of explanation. In actual applications, the tree structure of new energy clusters is more complex, with a much larger number of nodes and branches than in this example.

[0037] More specifically, in some embodiments, the step of constructing a tree structure corresponding to the actual connection topology of multiple new energy power station units 110 includes: S11: Based on the actual connection topology, construct the first-layer node group based on nodes directly connected to the AC power grid; S12: For each node in the current layer node group, determine the target node that is connected in series with the node via the outgoing line based on the actual connection topology, and take the target node corresponding to each node as the next layer node group. S13: Corresponding to the actual connection topology, repeat step S12 along the reverse power output direction to perform layer-by-layer recursion, thereby determining the multi-layer node group to obtain a tree structure composed of the multi-layer node group.

[0038] It should be noted that in step S11, the number of nodes directly connected to the AC power grid can be one or more, and when there are multiple nodes, they are connected in parallel topology; that is, the first-layer node group can include only one node, such as... Figure 6 The node n11 in the first layer can also include multiple nodes. When multiple nodes exist, the output terminals of multiple nodes are connected to the AC power grid together, and the input terminals are led outwards to the next layer of node group, thereby reflecting the parallel topology relationship between multiple nodes in the first layer of node group.

[0039] In step S12, for each node in the current layer node group, a target node connected in series with that node via an outgoing line is determined based on the actual connection topology. The number of target nodes can be one or more, and when there are multiple target nodes, the multiple target nodes are in a parallel topology relationship. That is, the output end of each target node is connected to the corresponding node under the current layer node group, and the input ends are respectively led outwards to the next layer node group, thereby reflecting the parallel topology relationship between multiple target nodes. For example, if the current layer node group is the first layer node group, for node n11 under the first layer node group, based on the actual connection topology, the target nodes connected in series with node n11 via an outgoing line can be determined to include nodes n21 and n22. The output ends of nodes n21 and n22 are connected to node n11, and the input ends of nodes n21 and n22 are respectively led outwards to the next layer node group (i.e., the third layer node group). Then, nodes n21 and n22 are the second layer node group.

[0040] The power transmission direction refers to the direction corresponding to the new energy power plant - transmission line - AC grid, and the reverse power transmission direction refers to the opposite direction. Corresponding to the actual connection topology, step S12 is repeated along the reverse power transmission direction to perform a layer-by-layer recursion, thereby determining multi-level node groups to obtain a tree structure composed of multi-level node groups. Corresponding to the above example, when the current layer node group is the second layer node group, the second layer node group includes nodes n21 and n22. For node n21, step S12 determines its corresponding target nodes, including nodes n31 and n32; for node n22, step S12 determines its corresponding target node, including node n33. Therefore, nodes n31, n32, and n33 constitute the third layer node group. Continuing the recursion, when the current layer node group is the third layer node group, nodes n31 and n33 do not have corresponding target nodes, and the target node corresponding to node n32 is node n41. Therefore, the fourth layer node group includes node n41, ultimately obtaining... Figure 6 The tree structure shown.

[0041] In some embodiments, based on a tree structure and a preset breadth-first traversal strategy, all fault locations in a preset fault location set are traversed, including: Based on the tree structure, all fault locations in the preset fault location set are determined, including all non-terminal nodes under the tree structure; Starting from the first layer of node groups, the process is recursively applied layer by layer, and target nodes are selected in each layer of node groups to complete the traversal of all non-terminal nodes. When the current layer of node groups includes multiple target nodes, the traversal order of the multiple target nodes is determined according to a preset priority evaluation strategy.

[0042] Specifically, all fault locations are selected on the busbar. The preset fault location set includes all non-terminal nodes in the tree structure, corresponding to... Figure 6 The nodes where all fault locations are located include: node n11, node n21, node n22, and node n32. Considering that when the number of nodes is large, a preset breadth-first traversal strategy is used to assign priority to target nodes to determine the traversal order of multiple target nodes. This ensures that during the process of recursively traversing down from the first layer of node groups, the node where the distance protection device 11 is most likely to malfunction is first discovered.

[0043] More specifically, following the layer-by-layer recursive traversal process, there may be multiple nodes under the currently traversed level node group. At this time, the nodes can be directly selected as target nodes according to their numbers in ascending order to complete the node traversal under this level node group; or, based on actual operating experience, considering that the distance protection device 11 installed on the long electrical transmission line is more prone to malfunction, a preset priority evaluation strategy is set to determine the traversal order of multiple target nodes, so as to achieve efficient verification and facilitate the quick identification of the conditions under which the distance protection device 11 will malfunction.

[0044] In some embodiments, the traversal order of multiple target nodes is determined according to a preset priority evaluation strategy, including: For multiple target nodes in the current layer node group that are recursively obtained, determine the electrical distance of the transmission line between each target node and the corresponding node in the previous layer node group. The traversal order of each target node is determined based on the order of electrical distance.

[0045] Specifically, determining the traversal order of each target node based on the electrical distance can include: sorting the target nodes in descending order of electrical distance and sequentially traversing each target node starting from the target node corresponding to the highest electrical distance; or, sorting the target nodes in ascending order of electrical distance and sequentially traversing each target node starting from the target node corresponding to the lowest electrical distance.

[0046] For example, the second-level node group includes two target nodes, namely node n21 and node n22. Then, the electrical distance of the transmission line between node n21 and the corresponding node in the upper-level node group (i.e., node n11) is determined, which is the electrical distance corresponding to branch b11; the electrical distance of the transmission line between node n22 and the corresponding node in the upper-level node group (i.e., node n11) is determined, which is the electrical distance corresponding to branch b12. If the electrical distance corresponding to branch b11 is greater than the electrical distance corresponding to branch b12, then the traversal priority of node n21 is higher than the traversal priority of node n22. The traversal order of the target nodes in the second-level node group is: node n21, node n22.

[0047] Specifically, if the first-level node group includes multiple nodes, the traversal order of each node in the first-level node group can be determined based on the electrical distance between each node and the transmission line of the AC power grid, and then based on the order of the electrical distances.

[0048] In some embodiments, based on a tree structure and a preset dynamic priority traversal strategy, all distance protection devices corresponding to the currently selected fault location are traversed, including: Based on the tree structure, determine all distance protection devices related to the node where the currently selected fault location is located, including distance protection devices 11 on all lower-level outgoing lines of the node; Starting from the last branch corresponding to the last node group, the process is recursively applied layer by layer. In each branch corresponding to the node group, a target branch is selected to determine the distance protection device 11 on the target branch as the target distance protection device. This process continues until the level of the node where the currently selected fault location is located is reached, so as to complete the traversal of the distance protection devices 11 on all the lower-level outgoing lines of the node.

[0049] Specifically, for a node where a fault location is currently selected, all related protection devices include distance protection devices 11 on all downstream outgoing lines (or downstream branches) of that node; for example, if the node where the fault location is currently selected is node n21, then all related distance protection devices include: distance protection devices 11 on branch b21, distance protection devices 11 on branch b22, and distance protection devices 11 on branch b31.

[0050] Based on actual operational data, the distance protection device 11 on the end branch is most prone to malfunction. Therefore, the traversal is completed by recursively iterating from the end branch corresponding to the last layer of node groups. It should be noted that the branch corresponding to each layer of node groups refers to the branch between the nodes under that layer of node groups and the nodes under the node groups of the previous layer. For example, corresponding to Figure 6The last node group (i.e., the fourth node group) corresponds to the terminal branch b31. Assuming the current fault location is node n21, all its corresponding lower-level outgoing lines include branches b21, b22, and b31. All distance protection devices corresponding to node n21 include distance protection device 11 on branch b21, distance protection device 11 on branch b22, and distance protection device 11 on branch b31. During traversal, the verification starts from the distance protection device 11 on the terminal branch (i.e., branch b31) corresponding to the last node group, and then it is recursively applied to the branches corresponding to the third node group, i.e., branches b21 and b22. The distance protection devices 11 on branch b21 and b22 are determined as the target distance protection devices for verification. Since the verification has been recursively applied to node n21, the traversal of all distance protection devices corresponding to node n21 is completed.

[0051] Specifically, the current layer node group recursively reached may correspond to multiple branches. In this case, the branches can be traversed directly in ascending order of branch number, or they can be traversed in the manner described in the following embodiments. No special restrictions are imposed here.

[0052] Specifically, in some embodiments, when the current layer node group corresponds to multiple branches, the method further includes: Determine the electrical distances corresponding to each branch; The traversal order of the distance protection devices 11 under each branch is determined according to the sorting of electrical distances.

[0053] Specifically, determining the traversal order of the distance protection devices 11 under each branch based on the electrical distance sorting can include: sorting the electrical distances from largest to smallest, and sequentially traversing the distance protection devices 11 under each branch starting from the branch corresponding to the highest sorting; or, sorting the electrical distances from smallest to largest, and sequentially traversing the distance protection devices 11 under each branch starting from the branch corresponding to the lowest sorting, without any particular limitation here.

[0054] In some embodiments, when the verification result of the target distance protection device determined in the current round is that a false activation has occurred, the method further includes: The level corresponding to the target distance protection device that the verification result indicates has malfunctioned will be designated as the interruption level. Based on the tree structure, a complete connection path is determined from the branch corresponding to the target distance protection device to the node where the currently selected fault location is located. The remaining distance protection devices 11 on the complete connection path are identified as target distance protection devices in sequence so that they can be verified first; and after all distance protection devices 11 on the complete connection path have been verified, the process returns to the interruption level so that the verification process can continue to be carried out layer by layer.

[0055] In this embodiment, the malfunction of the distance protection device 11 on the branch is used as the basis for setting dynamic priorities. Depth-first traversal is preferred to quickly identify the conditions under which the distance protection device 11 might malfunction. Specifically, when the verification result of the target distance protection device determined in the current round is that it has malfunctioned, the level corresponding to the target distance protection device with the verification result of malfunctioning is taken as the interrupt level. Then, the complete connection path is determined based on the tree structure, and the remaining distance protection devices 11 on the complete connection path are determined as target distance protection devices in turn, so as to prioritize whether the remaining distance protection devices 11 will malfunction. It should be noted that the verification can be performed from the end of the complete connection path to the front end. And the remaining distance protection devices 11 mentioned here refer to those distance protection devices 11 remaining in the complete connection path excluding the target distance protection device.

[0056] After all distance protection devices 11 on the complete connection path have been verified, the process returns to the interruption level to continue the layer-by-layer verification process. That is, if there are other branches under the interruption level that have not been traversed, then the distance protection devices 11 under these branches are taken as target distance protection devices to continue traversing. Specifically, the traversal can be carried out according to the previously determined traversal order. If there are no branches under the interruption level that have not been traversed, then the process is carried out according to the layer-by-layer recursion setting to the level above the interruption level, so that the level above is taken as the current level, and the branches corresponding to the node group under that level are traversed.

[0057] It should also be noted that, following the layer-by-layer recursive process, the distance protection device 11 corresponding to the complete connection path does not need to be re-verified. That is, when the layer-by-layer recursive process traverses to the distance protection device 11 that has already been verified, it can be skipped directly to traverse other distance protection devices 11.

[0058] For example, assuming the currently selected fault location node is node n11, its corresponding lower-level outgoing lines include: branch b11, branch b12, branch b21, branch b22, branch b23, and branch b31. All related distance protection devices include the distance protection devices 11 on each of these branches. Starting from the last branch (i.e., branch b31) of the last layer of node groups, proceeding layer by layer, assuming the distance protection device 11 on branch b31 malfunctions, the last layer (i.e., the fourth layer) is designated as the interruption level. The complete connection path from branch b31 to node n11 is determined to be: branch b31, branch b22, and branch b11. The remaining distance protection devices 11 on the complete connection path, i.e., the distance protection devices 11 on branch b22 and branch b11, are then sequentially identified as the target distance protection devices 11 for verification. After verification, the process returns to the interruption level. Since there are no other unverified branches at the interruption level... The path (or distance protection device 11) is then processed in a layer-by-layer recursive manner, up to the third-level node group. The branches corresponding to the third-level node group include branches b21, b22, and b23. Since the distance protection device 11 on branch b21 has already been verified, it does not need to be verified again. Therefore, branches b21 and b23 can be verified separately. Of course, at this time, the verification can be performed directly according to the branch number, that is, first verify the distance protection device 11 on branch b21, and then verify the distance protection device 11 on branch b23, to complete the complete traversal of the branches corresponding to this level of node group. Alternatively, the verification can be performed according to the electrical distance order, without any special limitation here. Assuming that only the distance protection device 11 on branch b31 malfunctions, the verification order of all distance protection devices corresponding to node n11 is as follows: verify the distance protection devices 11 on branches b31, b22, b11, b21, b23, and b12 in sequence.

[0059] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the structure of a distance protection device verification system for a new energy cluster transmission line provided by the present invention.

[0060] The distance protection device verification system for the transmission line of this new energy cluster includes: Memory 31 is used to store computer programs; The processor 32 is used to execute computer programs to implement the steps of the distance protection device verification method for the new energy cluster transmission line as described above.

[0061] For an introduction to the distance protection device verification system for the new energy cluster transmission line provided in this application, please refer to the embodiment of the distance protection device verification method for the new energy cluster transmission line described above, which will not be repeated here.

[0062] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. Relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0063] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for verifying the distance protection device of a new energy cluster transmission line, characterized in that, Applied to power systems including new energy clusters, the new energy clusters include multiple new energy power station units, and each new energy power station unit has a distance protection device installed on the transmission line near the system side. The distance protection device verification method includes: Establish a simulation model of the power system; The strategy is set based on preset conditions to determine the verification conditions for the current round; The simulation model is controlled to run based on the verification conditions to obtain the electrical parameter information output by the simulation model that corresponds to the target distance protection device currently being verified. The corresponding protection setting value is downloaded to the target distance protection device, and the corresponding electrical signal is output to the target distance protection device based on the electrical parameter information, so as to obtain the operation status of the target distance protection device and determine the verification result of whether the target distance protection device has malfunctioned based on the operation status. Then, the next round of verification is started and the step of determining the verification conditions of the current round based on the preset condition setting strategy is returned until the preset verification end condition is reached.

2. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 1, characterized in that, Based on preset conditions, the strategy determines the verification conditions for the current round, including: A five-layer nested traversal loop is adopted, arranged sequentially from the outer layer to the inner layer. The loop traverses the following layers sequentially from the outer layer to the inner layer: all operating modes in the preset power system operating mode set, all output conditions in the preset new energy output condition set, all fault locations in the preset fault location set, all fault types corresponding to the currently selected fault location, and all distance protection devices related to the currently selected fault location. In this process, each layer selects and fixes the corresponding verification conditions in a loop, so that the combination of the five selected verification conditions in the current round becomes the complete verification conditions in the current round.

3. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 2, characterized in that, After establishing the simulation model of the power system, the following is also included: The new energy power station bus under the new energy power station unit is used as a node and the transmission line is used as a branch. A corresponding tree structure is constructed by combining the actual connection topology of multiple new energy power station units. A distance protection device is set at the end of each branch that is closer to the system side. The steps for traversing all fault locations in the preset fault location set include: Based on the tree structure and the preset breadth-first traversal strategy, all fault locations in the preset fault location set are traversed. The steps for traversing all distance protection devices corresponding to the currently selected fault location include: Based on the tree structure and the preset dynamic priority traversal strategy, all distance protection devices corresponding to the currently selected fault location are traversed.

4. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 3, characterized in that, The steps of constructing a tree structure corresponding to the actual connection topology of multiple new energy power station units include: S11: Based on the actual connection topology, construct a first-layer node group based on nodes directly connected to the AC power grid; S12: For each node in the current layer node group, based on the actual connection topology, determine the target node that is connected in series with the node via the outgoing line, and take the target node corresponding to each node as the next layer node group. S13: Corresponding to the actual connection topology, repeat step S12 along the reverse power output direction to perform layer-by-layer recursion, thereby determining the multi-layer node group to obtain a tree structure composed of the multi-layer node group.

5. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 4, characterized in that, Based on the tree structure and the preset breadth-first traversal strategy, all fault locations in the preset fault location set are traversed, including: Based on the tree structure, all fault locations in the preset fault location set are determined to include all non-terminal nodes under the tree structure; Starting from the first layer of node groups, the process is recursively applied layer by layer, and a target node is selected in each layer of node groups to complete the traversal of all non-terminal nodes. When the current layer of node groups includes multiple target nodes, the traversal order of the multiple target nodes is determined according to a preset priority evaluation strategy.

6. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 5, characterized in that, The traversal order of the multiple target nodes is determined according to a preset priority evaluation strategy, including: For multiple target nodes in the current layer node group that are recursively obtained, the electrical distance of the transmission line between each target node and the corresponding node in the previous layer node group is determined. The traversal order of each target node is determined based on the sorting of the electrical distances.

7. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 4, characterized in that, Based on the tree structure and the preset dynamic priority traversal strategy, all distance protection devices corresponding to the currently selected fault location are traversed, including: Based on the tree structure, determine all distance protection devices related to the node where the currently selected fault location is located, including distance protection devices on all lower-level outgoing lines of the node. Starting from the last branch corresponding to the last node group, the process is recursively applied layer by layer. In each branch corresponding to the node group, a target branch is selected to determine the distance protection device on the target branch as the target distance protection device. This process continues until the level of the node where the currently selected fault location is located is reached, thus completing the traversal of the distance protection devices on all the lower-level outgoing lines of the node.

8. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 7, characterized in that, When the current layer node group corresponds to multiple branches, it also includes: Determine the electrical distance corresponding to each of the aforementioned branches; The traversal order of the distance protection devices under each branch is determined based on the sorting of the electrical distances.

9. The method for verifying the distance protection device of the new energy cluster transmission line as described in claim 7, characterized in that, When the verification result of the target distance protection device determined in the current round is that a false trip has occurred, it also includes: The level corresponding to the target distance protection device that the verification result indicates has malfunctioned will be designated as the interruption level. Based on the tree structure, a complete connection path is determined from the branch corresponding to the target distance protection device to the node where the currently selected fault location is located. The remaining distance protection devices on the complete connection path are sequentially identified as target distance protection devices for priority verification; and after all distance protection devices on the complete connection path have been verified, the process returns to the interruption level to continue the layer-by-layer verification process.

10. A distance protection device verification system for a new energy cluster transmission line, characterized in that, include: Memory, used to store computer programs; A processor is configured to execute the computer program to implement the steps of the distance protection device verification method for the new energy cluster transmission line as described in any one of claims 1 to 9.

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