Distributed relay protection test method and system for smart substation

Abstract

The present application relates to the technical field of electrical sensor, in particular to a distributed relay protection test method and system for smart substation, comprising: acquiring current signals, voltage signals of nodes, spatial distances between nodes, spatial distances between nodes and busbars; according to current signals and voltage signals of nodes at adjacent time, acquiring current mutation degree, voltage mutation degree and fault characteristics of each node at each time, so as to acquire influencing time and each suspected fault node; according to current mutation degree of suspected fault nodes at all influencing time, combining fault characteristics of each suspected fault node at each fault time, acquiring possibility of each suspected fault node to occur fault at each fault time, and combining spatial distances between nodes and busbars, giving priority to each node. The present application gives priority to each node by analyzing the node most likely to occur fault first, so as to improve fault response speed.

Description

Technical Field

[0001] This invention relates to the field of electrical sensor technology, and more specifically to a method and system for testing distributed relay protection in smart substations. Background Technology

[0002] Substations are places in power systems that transform voltage and current, receive electrical energy, and distribute electrical energy. When a fault occurs in the power system, if the faulty part is not removed from the power system in time, it may lead to equipment burnout, damage to the synchronous stability between generator sets, power angle instability or voltage collapse, and in severe cases, it may cause system vibration or even paralysis, leading to large-scale power outages and grid collapse. Therefore, when a fault occurs in the power system, it is necessary to quickly and accurately detect and disconnect the faulty part to protect equipment safety and maintain stable system operation.

[0003] In traditional distributed relay protection monitoring systems, when a fault occurs, the electrical characteristics of several nodes need to be uploaded to a merging unit. The merging unit analyzes the electrical characteristics of each node to determine whether a fault has occurred in each node. However, since the merging unit does not directly analyze the electrical characteristics of nodes without faults, and does not analyze the probability of fault occurrence at each node, it is not conducive to the rapid response of each node to faults and independent relay protection in smart substations. At the same time, there is a certain degree of interference between nodes, which needs to be eliminated to achieve distributed relay protection. Summary of the Invention

[0004] This invention provides a distributed relay protection testing method and system for smart substations to solve the existing problem: in traditional distributed relay protection monitoring systems, no analysis and judgment priority is assigned to the nodes when a fault occurs, which reduces the response speed to the fault.

[0005] The distributed relay protection testing method and system for smart substations of the present invention adopts the following technical solution: One embodiment of the present invention provides a method for testing distributed relay protection in smart substations, the method comprising the following steps: Acquire current signals, voltage signals, spatial distances between nodes, and spatial distances between nodes and buses at each node in the power system of a smart substation; Based on the current and voltage signals of nodes at adjacent time points, the degree of current and voltage fluctuations of each node at each time point is obtained; based on the degree of current and voltage fluctuations of each node at each time point, the importance weight of the electrical data of each node at each time point is obtained; combined with the temporal changes of the degree of current and voltage fluctuations in the period preceding each time point, the electrical synchronicity of each node at each time point is obtained; based on the degree of current and voltage fluctuations and the electrical synchronicity of each node at each time point, the fault characteristics of each node at each time point are obtained, and then the fault time and fault node, as well as the affected time and each suspected fault node are obtained. Based on the degree of current change of the suspected fault node at all affected times, combined with the spatial distance between the suspected fault node and the fault node, the degree of interference of the fault node on each suspected fault node is obtained. Combined with the fault characteristics of each suspected fault node at each fault time, the probability of each suspected fault node failing at each fault time is obtained. Based on the probability of a node failing at the time of the fault, and combined with the spatial distance between the node and the bus, each node is assigned a priority and distributed relay protection is implemented.

[0006] Preferably, the specific method for obtaining the degree of current change and voltage change of each node at each time step based on the current and voltage signals of the nodes at adjacent time steps includes: Preset an analysis range For the first At the moment, the first Before the moment All moments within a millisecond, as the first The analysis of each moment; For the The first moment at the moment Get the nth node, The moment and the The analysis of the first moment at the second moment The slope of the current signal in the nth node; the nth At the moment of the first The slope of the current signal at the nth node, and the slope of the current signal at the nth node. All analysis times at time n, the i-th time The ratio between the standard deviations of the current signal slopes at each node is used as the ratio of the standard deviations of the current signal slopes at the nth node. At the moment of the first The degree of current abrupt change at each node; Obtain the degree of voltage fluctuation at each node at each time point.

[0007] Preferably, the method for obtaining the importance weight of the electrical data of each node at each time point based on the degree of current and voltage change at each time point includes: For the The moment of the first The first analysis time point The node, for the node The moment of the first At the analysis time point, the first The product of the current change rate and the voltage change rate at each node is weighted and normalized, and the weighted normalization result is used as the weighted normalization result of the node. The moment of the first At the analysis time point, the first The importance weight of each node's electrical data.

[0008] Preferably, the specific method for obtaining the electrical synchronization of each node at each time point is as follows:

[0009] In the formula, Indicates the first The moment of the first At the analysis time point, the first The degree of coordinated change between the voltage and current mutation rates at each node; Indicates the first The moment of the first At the analysis time point, the first The degree of voltage fluctuation at each node; Indicates the first All analysis times at time n, the i-th time The average voltage fluctuation level of each node; Indicates the first The moment of the first At the analysis time point, the first The degree of current abrupt change at each node; Indicates the first All analysis times at time n, the i-th time The average degree of current abrupt change at each node; Indicates the first At each analysis time of time n, the first... The importance weight of electrical data for each node; Indicates the first All analysis times at time n, the i-th time Standard deviation of the degree of current abrupt change at each node; Indicates the first All analysis times at time n, the i-th time Standard deviation of voltage fluctuation at each node; Indicates the first The number of analysis moments per moment; Indicates the first At the moment of the first Electrical synchronization of each node.

[0010] Preferably, the method for obtaining the fault characteristics of each node at each time point based on the degree of current change, voltage change, and electrical synchronization at each time point includes the following specific methods: For the The first moment at the moment The node; for the node At the moment of the first The product of the current mutation rate, voltage mutation rate, and electrical synchronization of each node is normalized, and the normalization result is used as the product of the current mutation rate, voltage mutation rate, and electrical synchronization of each node. At the moment of the first Fault characteristics of each node.

[0011] Preferably, the specific method for obtaining the fault time and fault node, as well as the impact time and each suspected fault node, includes: Preset a fault characteristic threshold Obtain the fault characteristics of all nodes at each time step. For the first time step... At the moment, if the first The fault characteristics of any node at any given time are greater than And the first The analysis at each time point shows that no node has a fault characteristic greater than [a certain value]. Then the first The fault time is the nth time. At any given time, the fault characteristic is greater than The node is the faulty node; and the first After that moment All moments within a millisecond, as the first The impact of each moment; If the first The fault characteristics of any node at any time of any influence moment are greater than [the value of the fault characteristics of any node at any time of any influence moment]. Then the first The node at the time of the impact mentioned above is denoted as a suspected fault node.

[0012] Preferably, the method for obtaining the interference level of a fault node on each suspected fault node based on the degree of current change of the suspected fault node at all influencing times, combined with the spatial distance between the suspected fault nodes and the fault node, includes the following specific methods: For the One suspected faulty node, and all affected times are recorded. The maximum value of the current surge at the suspected fault node is used as the first... The extent of impact on the suspected faulty node; the impact on the first The degree of impact of each suspected faulty node and the time of the fault. The difference in the degree of current change at the first suspected fault node, and the difference in the degree of current change at the second suspected fault node. The ratio of the spatial distance between each suspected faulty node and the faulty node is mapped to a range of -1 to 1, and the mapping result of the ratio is used as the distance between the faulty node and the first faulty node. The degree of interference from a suspected faulty node.

[0013] Preferably, the specific method for obtaining the probability of each suspected fault node failing at each fault time is as follows: For the i-th at any time of influence The first suspected faulty node will be linked to the faulty node. The sum of the interference levels of each suspected faulty node and 1, multiplied by the value at the time of the influence. The product of the fault characteristics of the suspected faulty nodes is used as the product of the fault characteristics of the first node at the time of influence. The possibility of a suspected faulty node failing.

[0014] Preferably, the method for assigning priorities to each node based on the probability of a node failing at the time of failure, combined with the spatial distance between the node and the bus, includes the following specific methods: For any suspected fault node at any time of influence, the ratio of the probability of the suspected fault node at that time of influence to the spatial distance between the suspected fault node and the model is used as the priority of the suspected fault node.

[0015] Another embodiment of the present invention provides a distributed relay protection testing system for smart substations, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of any of the above-described distributed relay protection testing methods for smart substations.

[0016] The beneficial effects of the technical solution of the present invention are as follows: When a circuit in a power system fails, the faulty circuit will have a certain impact on the normal circuit in the power system, causing a certain abrupt change in the current signal and voltage signal of the normal circuit. Therefore, this application obtains the degree of current change and voltage change of each node at each moment by analyzing the current signal and voltage signal of the node at adjacent moments. However, since the current change and voltage signal change in the faulty circuit are caused by the fault in the power system, the current change and voltage signal change in the faulty circuit are highly synchronized. When the degree of voltage change and current change in the node is greater, and the electrical synchronization of the node is greater, the current circuit corresponding to the node is more likely to fail. In this way, the fault characteristics of each node at each moment are obtained, and the fault time and faulty node, as well as the affected time and each suspected faulty node, are obtained, realizing the distributed identification of the fault characteristics of each node.

[0017] Furthermore, since faults in the current system can affect normal circuits in the power system, to avoid incorrect fault identification due to faults in faulty nodes, and because fault characteristics in a node may originate from its own fault or be caused by disturbances propagated through the system from adjacent faults, further distributed analysis of suspected faulty nodes is required. This involves quantifying the interference level of a faulty node on suspected faulty nodes, adjusting the suspected faulty nodes at each fault moment based on this interference level, obtaining the probability of each suspected faulty node failing at each fault moment, and assigning priorities to each node based on the spatial distance between the node and the bus. This allows the merging unit in the distributed relay protection device to prioritize analyzing suspected faulty nodes with higher probability, followed by those with lower probability. This avoids the merging unit potentially analyzing and judging nodes that are not faulty first and then analyzing and judging nodes that are faulty, thereby improving the fault response speed of the distributed relay protection device and ensuring that the fault handling process of distributed nodes can independently achieve relay protection without excessive interference to other distributed nodes, further guaranteeing the independent operation of relay protection for multiple nodes in the smart substation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the steps of the distributed relay protection testing method for smart substations according to the present invention. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the distributed relay protection testing method and system for smart substations proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] The following description, in conjunction with the accompanying drawings, details the specific scheme of the distributed relay protection testing method and system for smart substations provided by this invention.

[0023] Please see Figure 1 The diagram illustrates a flowchart of a distributed relay protection testing method for smart substations according to an embodiment of the present invention. The method includes the following steps: Step S001: Obtain the current signal, voltage signal, spatial distance between nodes, and spatial distance between nodes and busbars at each node in the power system of the intelligent substation.

[0024] It should be noted that the execution logic of distributed relay protection is as follows: acquiring fault signals, collaborative decision-making by distributed relay protection devices, and execution of relay protection actions. This embodiment, as a distributed relay protection testing method for smart substations, requires the cooperation of various intelligent electronic components to achieve distributed relay protection. These various intelligent electronic components include, but are not limited to, merging units, intelligent terminals, relay protection devices, busbar protection devices, and transformer protection devices. Based on the collaborative cooperation of these various intelligent electronic components, distributed relay protection is performed on the substation.

[0025] Specifically, a preset electrical signal sampling frequency is used. The The specific value can be set according to the actual situation. This embodiment does not make a hard requirement. In this embodiment, it is used as... The description will be based on Hertz (in this embodiment, Hertz is used as an example). (A second is considered a moment in time), so that the current transformer and voltage transformer are... The sampling frequency is used to collect the current and voltage signals in each node; at the same time, the spatial distance between the nodes is obtained.

[0026] Thus, the current signal, voltage signal, and spatial distance between nodes at each time point are obtained.

[0027] Step S002: Based on the current and voltage signals of nodes at adjacent time points, obtain the degree of current and voltage fluctuations of each node at each time point; based on the degree of current and voltage fluctuations of each node at each time point, obtain the importance weight of the electrical data of each node at each time point; combined with the temporal changes of the degree of current and voltage fluctuations in the period preceding each time point, obtain the electrical synchronicity of each node at each time point; based on the degree of current and voltage fluctuations and the electrical synchronicity of nodes at each time point, obtain the fault characteristics of each node at each time point, and then obtain the fault time and fault node, as well as the affected time and each suspected fault node.

[0028] It should be noted that distributed relay protection mainly involves collecting electrical signals from each node, calculating the electrical characteristics of each node, integrating the electrical signals from each node, analyzing and determining whether a fault has occurred in the circuit corresponding to each node. When a fault occurs in the circuit corresponding to a node, the circuit corresponding to the node is immediately isolated from the power system, thereby completing the distributed relay protection of the power system.

[0029] It should be further explained that when a circuit in a substation's power system experiences a fault, both the current and voltage signals in the circuit will change abruptly. Therefore, the degree of current and voltage fluctuations received by a node can be used to determine whether the circuit corresponding to that node has experienced a fault. When a circuit in the power system experiences a fault, the faulty circuit will have a certain impact on the normal circuits in the power system, causing certain abrupt changes in the current and voltage signals of the normal circuits. However, since the current and voltage signal fluctuations in the faulty circuit are caused by the fault in the power system, the current and voltage signal fluctuations in the faulty circuit are highly synchronized. In contrast, the current and voltage signal fluctuations in the normal circuit are caused by the fault in the faulty circuit, and the current and voltage signal fluctuations in the normal circuit are less synchronized. Therefore, the fault characteristics of each node at each moment can be accurately obtained.

[0030] Specifically, a pre-defined analysis range is set. The The specific value can be set according to the actual situation. This embodiment does not make a hard requirement. In this embodiment, the value is taken as follows: For example, the following description will be given; regarding the first At the moment, the first Before the moment All moments within a millisecond, as the first The analysis of each moment; Furthermore, regarding the first The first moment at the moment Get the nth node, The moment and the The analysis of the first moment at the second moment The slope of the current signal at each node (obtained by considering the current signal at each time step, the current signal at the previous time step, and the time interval between adjacent time steps); the slope of the current signal at each node. At the moment of the first The slope of the current signal at the nth node, and the slope of the current signal at the nth node. All analysis times at time n, the i-th time The ratio between the standard deviations of the current signal slopes at each node is used as the ratio of the standard deviations of the current signal slopes at the nth node. At the moment of the first The degree of current abrupt change at each node; Similarly, the slope of the voltage signal at each node at each time moment is obtained, thereby obtaining the degree of voltage change at each node at each time moment.

[0031] It should be noted that when a circuit in a power system fails, the faulty circuit will have a certain impact on the normal circuit in the power system, causing a certain sudden change in the current signal of the normal circuit. However, the current change and voltage signal change in the faulty circuit are highly synchronized, while the current change and voltage signal change in the normal circuit are not. Therefore, this can be used as a basis to obtain the electrical synchronization of each node at each moment, so as to correct the fault characteristics of each node at each moment, thereby accurately identifying the faulty circuit in the cable system.

[0032] Preferably, in a specific embodiment of the present invention, for the first The moment of the first The first analysis time point The node, for the node The moment of the first At the analysis time point, the first The product of the current change rate and the voltage change rate at each node is weighted and normalized (its normalization range is the 1st node). At each analysis time of time n, the first... The product of the current change rate and the voltage change rate of each node is used as the weight normalization result. The moment of the first At the analysis time point, the first The importance weight of electrical data for each node; For the The first moment at the moment The node; according to the first node; At each analysis time of time n, the first... The degree of current change and voltage change at each node, combined with the degree of voltage change at the first node. At each analysis time of time n, the first... The importance weight of the electrical data of each node is obtained to determine the importance weight of the first node. At the moment of the first The electrical synchronization of each node is calculated using the following formula:

[0033] In the formula, Indicates the first The moment of the first At the analysis time point, the first The degree of coordinated change between the voltage and current mutation rates at each node; Indicates the first The moment of the first At the analysis time point, the first The degree of voltage fluctuation at each node; Indicates the first All analysis times at time n, the i-th time The average voltage fluctuation degree of each node; Indicates the first The moment of the first At the analysis time point, the first The degree of current abrupt change at each node; Indicates the first All analysis times at time n, the i-th time The average degree of current abrupt change at each node; Indicates the first At each analysis time of time n, the first... The importance weight of electrical data for each node; Indicates the first All analysis times at time n, the i-th time Standard deviation of the degree of current abrupt change at each node; Indicates the first All analysis times at time n, the i-th time Standard deviation of voltage fluctuation at each node; Indicates the first The number of analysis moments per moment; Indicates the first At the moment of the first Electrical synchronization of each node.

[0034] It should be noted that current and voltage signal mutations in faulty circuits exhibit strong synchronization, while those in normal circuits show weak synchronization. Therefore, the fault characteristics of the corresponding circuit at a node are quantified by calculating the degree of coordinated change in the timing of current and voltage signal mutations. When quantifying the fault characteristics of a node's corresponding circuit using this time-series coordination, moments with large voltage and current mutations are more representative of actual fault impacts on the system. Therefore, moments with large voltage and current mutations should be given a high weight to more accurately distinguish faulty nodes from normal nodes and obtain the electrical synchronicity of each node at each moment. The greater the voltage and current mutations and the greater the electrical synchronicity of a node, the more likely the current circuit corresponding to that node is to fail, thus obtaining the fault characteristics of each node at each moment.

[0035] Specifically, for the first The first moment at the moment The node; for the node At the moment of the first The product of the current mutation rate, voltage mutation rate, and electrical synchronicity of each node is normalized (using the sigmoid function), and the normalization result is used as the product of the current mutation rate, voltage mutation rate, and electrical synchronicity of the nodes. At the moment of the first Fault characteristics of each node.

[0036] It should be noted that the larger the fault characteristics of a node, the more likely the circuit corresponding to the node is to fail. Therefore, this is used as a basis to determine whether a fault has occurred in the circuit corresponding to the node. When a fault occurs in the circuit corresponding to the node, the circuit corresponding to the node is immediately isolated from the power system to provide distributed relay protection for the power system.

[0037] Specifically, a fault characteristic threshold is preset. The The specific value can be set according to the actual situation. This embodiment does not make a hard requirement. In this embodiment, it is used as... Let's take an example to illustrate; Obtain the fault characteristics of all nodes at each time step. For the first time step... At the moment, if the first The fault characteristics of any node at any given time are greater than And the first The analysis at each time point shows that no node has a fault characteristic greater than [a certain value]. Then the first The fault time is the nth time. At any given time, the fault characteristic is greater than The node is the faulty node; and the first After that moment All moments within a millisecond, as the first The impact of each moment; If the first The fault characteristics of any node at any time of any influence moment are greater than [the value of the fault characteristics of any node at any time of any influence moment]. Then the first The node at the time of the impact mentioned above is denoted as a suspected fault node.

[0038] At this point, we have obtained the time of the fault, the fault node, and the suspected fault node.

[0039] Step S003: Based on the degree of current change of the suspected fault node at all affected times, and combined with the spatial distance between the suspected fault node and the fault node, obtain the degree of interference of the fault node on each suspected fault node. Combined with the fault characteristics of each suspected fault node at each fault time, obtain the probability of each suspected fault node failing at each fault time.

[0040] It should be noted that faults in the current system can affect normal circuits in the power system, causing abrupt changes in the current signal of normal circuits. To avoid incorrect fault identification due to faults in faulty nodes, further analysis of suspected faulty nodes is necessary. Fault characteristics appearing in a node may originate from its own fault or from disturbances caused by adjacent faults propagating through the system. Since fault current disturbances gradually decrease with distance, this embodiment extracts the maximum current mutation value of the normal node within a set delay time window and calculates the disturbance intensity per unit distance based on the electrical distance between the node and the faulty node. Through normalization, the obtained interference level index can quantify the strength of the impact of fault propagation on the node, thus providing a basis for subsequent correction of node fault characteristics.

[0041] Specifically, for the first One suspected faulty node, and all affected times are recorded. The maximum value of the current surge at the suspected fault node is used as the first... The extent of impact on the suspected faulty node; the impact on the first The degree of impact of each suspected faulty node and the time of the fault. The difference in the degree of current change at the first suspected fault node, and the difference in the degree of current change at the second suspected fault node. The ratio of the spatial distance between each suspected faulty node and the faulty node is mapped to a range of -1 to 1, and the mapping result of the ratio is used as the distance between the faulty node and the first faulty node. The degree of interference from a suspected faulty node.

[0042] As an example, obtain the faulty node pair. The specific formula for calculating the interference level of a suspected faulty node is as follows:

[0043] In the formula, Indicates the faulty node to the first The degree of interference from a suspected faulty node; Indicates the first The extent to which each suspected faulty node is affected; Indicates the time of failure. The degree of current change at each suspected fault node; Indicates the first The spatial distance between suspected faulty nodes and faulty nodes; This represents the `premnmx` function, which maps the calculation result to the range of -1 to 1.

[0044] It should be noted that when the first The smaller the spatial distance between suspected faulty nodes and the faulty nodes, the better the impact at all times. The greater the degree of change in current at the suspected fault node, the more likely the fault will be. The more likely a suspected faulty node is to be affected by a real fault in the circuit corresponding to the faulty node, the more likely it is to fail. Based on this, the fault characteristics of the suspected faulty node at the time of influence can be corrected, thus obtaining the probability of the suspected faulty node failing at the time of influence.

[0045] Specifically, for the first moment under any influence... The first suspected faulty node will be linked to the faulty node. The sum of the interference levels of each suspected faulty node and 1, multiplied by the value at the time of the influence. The product of the fault characteristics of the suspected faulty nodes is used as the product of the fault characteristics of the first node at the time of influence. The possibility of a suspected faulty node failing.

[0046] As an example, the first time at the time of influence is obtained. The specific formula for calculating the probability of a suspected faulty node failing is as follows:

[0047] In the formula, Indicates the time of influence at the time of the event. The probability that a suspected faulty node will fail; Indicates the faulty node to the first The degree of interference from a suspected faulty node; Indicates the time of influence at the time of the event. Fault characteristics of a suspected faulty node.

[0048] It should be noted that the original characteristics of a suspected faulty node may be amplified for two reasons: first, the node itself may experience a real fault; second, it may be affected by disturbances propagated from adjacent faults, thus forming a false anomaly. To achieve accurate identification, this embodiment introduces an interference level index and adjusts the feature intensity based on this value. If the interference level is weak, it indicates that the node is less affected by real faults in the corresponding circuits of other nodes, and the observed anomaly is more likely to originate from its own fault. In this case, the fault characteristics of the original suspected faulty node should be retained or even amplified; conversely, the fault characteristics of the suspected faulty node should be reduced.

[0049] At this point, the probability of each suspected faulty node failing at all affected moments is obtained.

[0050] Step S004: Based on the probability of a node failing at the time of the fault, and combined with the spatial distance between the node and the bus, assign priorities to each node and perform distributed relay protection.

[0051] It should be noted that after obtaining the probability of a fault occurring in the corresponding circuit of all suspected fault nodes through step S003, the various electrical signals of the suspected fault nodes can be uploaded to the merging unit. Furthermore, based on the probability of a suspected fault node occurring, a priority can be assigned to the suspected fault node, so that the merging unit analyzes the suspected fault nodes with a high probability first and then analyzes the suspected fault nodes with a low probability. This avoids the possibility that the merging unit might analyze and judge the nodes that have not occurred first and then analyze and judge the nodes that have occurred, thereby improving the fault response speed of the distributed relay protection device.

[0052] It should be further explained that, since the closer a node is to the bus, the faster the fault propagates within the node, the greater the threat it poses to the system, and the more it should be dealt with first, it is also necessary to assign priority to suspected faulty nodes by combining the probability of the suspected faulty node failing with the distance between the suspected faulty node and the bus.

[0053] Specifically, for any suspected fault node at any influencing moment, the ratio of the probability of the suspected fault node at the influencing moment to the spatial distance between the suspected fault node and the model is used as the priority of the suspected fault node. All suspected fault nodes at the fault moment are sorted in descending order according to their priorities to obtain a sequence of suspected fault nodes at the fault moment. The merging unit analyzes all fault nodes at the influencing moment according to the sequence of suspected fault nodes at the fault moment to determine whether a fault exists in the circuit corresponding to each suspected fault node at the fault moment. Since analyzing whether a fault exists in the circuit corresponding to a node through the merging unit is a known prior art, it will not be elaborated upon in this embodiment.

[0054] Another embodiment of the present invention provides a distributed relay protection test system for smart substations, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the distributed relay protection test method for smart substations in steps S001 to S004.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test method for distributed relay protection in smart substations, characterized in that, The method includes the following steps: Acquire current signals, voltage signals, spatial distances between nodes, and spatial distances between nodes and buses at each node in the power system of a smart substation; Based on the current and voltage signals of nodes at adjacent time points, the degree of current and voltage fluctuations of each node at each time point is obtained; based on the degree of current and voltage fluctuations of each node at each time point, the importance weight of the electrical data of each node at each time point is obtained; combined with the temporal changes of the degree of current and voltage fluctuations in the period preceding each time point, the electrical synchronicity of each node at each time point is obtained; based on the degree of current and voltage fluctuations and the electrical synchronicity of each node at each time point, the fault characteristics of each node at each time point are obtained, and then the fault time and fault node, as well as the affected time and each suspected fault node are obtained. Based on the degree of current change of the suspected fault node at all affected times, combined with the spatial distance between the suspected fault node and the fault node, the degree of interference of the fault node on each suspected fault node is obtained. Combined with the fault characteristics of each suspected fault node at each fault time, the probability of each suspected fault node failing at each fault time is obtained. Based on the probability of a node failing at the time of the fault, and combined with the spatial distance between the node and the bus, each node is assigned a priority and distributed relay protection is implemented. The method for obtaining the degree of current and voltage change at each node at each time point is as follows: a pre-defined analysis range is used. For the first At the moment, the first Before the moment All moments within a millisecond, as the first The analysis time at time n; for the nth time... The first moment at the moment Get the nth node, The moment and the The analysis of the first moment at the second moment The slope of the current signal in the nth node; the nth At the moment of the first The slope of the current signal at the nth node, and the slope of the current signal at the nth node. All analysis times at time n, the i-th time The ratio between the standard deviations of the current signal slopes at each node is used as the ratio of the standard deviations of the current signal slopes at the nth node. At the moment of the first The degree of current change at each node; the degree of voltage change at each node at each time step; The method for determining the importance weight of the electrical data of each node at each time point is as follows: For the The moment of the first The first analysis time point The node, for the node The moment of the first At the analysis time point, the first The product of the current change rate and the voltage change rate at each node is weighted and normalized, and the weighted normalization result is used as the weighted normalization result of the node. The moment of the first At the analysis time point, the first The importance weight of each node's electrical data.

2. The test method for distributed relay protection in smart substations according to claim 1, characterized in that, The specific method for obtaining the electrical synchronization of each node at each time point is as follows: In the formula, Indicates the first The moment of the first At the analysis time point, the first The degree of coordinated change between the voltage and current mutation rates at each node; Indicates the first The moment of the first At the analysis time point, the first The degree of voltage fluctuation at each node; Indicates the first All analysis times at time n, the i-th time The average voltage fluctuation level of each node; Indicates the first The moment of the first At the analysis time point, the first The degree of current abrupt change at each node; Indicates the first All analysis times at time n, the i-th time The average degree of current abrupt change at each node; Indicates the first At each analysis time of time n, the first... The importance weight of electrical data for each node; Indicates the first All analysis times at time n, the i-th time Standard deviation of the degree of current abrupt change at each node; Indicates the first All analysis times at time n, the i-th time Standard deviation of voltage fluctuation at each node; Indicates the first The number of analysis moments per moment; Indicates the first At the moment of the first Electrical synchronization of each node.

3. The test method for distributed relay protection in smart substations according to claim 1, characterized in that, The method for obtaining the fault characteristics of each node at each time point based on the degree of current change, voltage change, and electrical synchronization at each time point includes the following specific methods: For the The first moment at the moment The node; for the node At the moment of the first The product of the current mutation rate, voltage mutation rate, and electrical synchronization of each node is normalized, and the normalization result is used as the product of the current mutation rate, voltage mutation rate, and electrical synchronization of each node. At the moment of the first Fault characteristics of each node.

4. The test method for distributed relay protection in smart substations according to claim 1, characterized in that, The specific methods for obtaining the fault time and fault node, as well as the impact time and each suspected fault node, are as follows: Preset a fault characteristic threshold Obtain the fault characteristics of all nodes at each time step. For the first time step... At the moment, if the first The fault characteristics of any node at any given time are greater than And the first The analysis at each time point shows that no node has a fault characteristic greater than [a certain value]. Then the first The fault time is the nth time. At any given time, the fault characteristic is greater than The node is the faulty node; and the first After that moment All moments within a millisecond, as the first The impact of each moment; If the first The fault characteristics of any node at any time of any influence moment are greater than [the value of the fault characteristics of any node at any time of any influence moment]. Then the first The node at the time of the impact mentioned above is denoted as a suspected fault node.

5. The test method for distributed relay protection in smart substations according to claim 1, characterized in that, The method for obtaining the interference level of a fault node on each suspected fault node based on the degree of current change of the suspected fault node at all influencing times, combined with the spatial distance between the suspected fault nodes and the fault nodes, includes the following specific methods: For the One suspected faulty node, and all affected times are recorded. The maximum value of the current surge at the suspected fault node is used as the first... The extent of impact on the suspected faulty node; the impact on the first The degree of impact of each suspected faulty node and the time of the fault. The difference in the degree of current change at the first suspected fault node, and the difference in the degree of current change at the second suspected fault node. The ratio of the spatial distance between each suspected faulty node and the faulty node is mapped to a range of -1 to 1, and the mapping result of the ratio is used as the distance between the faulty node and the first faulty node. The degree of interference from a suspected faulty node.

6. The test method for distributed relay protection in smart substations according to claim 1, characterized in that, The specific method for obtaining the probability of each suspected fault node failing at each fault time is as follows: For the i-th at any time of influence The first suspected faulty node will be linked to the faulty node. The sum of the interference levels of each suspected faulty node and 1, multiplied by the value at the time of the influence. The product of the fault characteristics of the suspected faulty nodes is used as the product of the fault characteristics of the first node at the time of influence. The possibility of a suspected faulty node failing.

7. The test method for distributed relay protection in smart substations according to claim 1, characterized in that, The method for assigning priorities to each node based on the probability of a node failing at the time of failure, combined with the spatial distance between the node and the bus, includes the following specific methods: For any suspected fault node at any time of influence, the ratio of the probability of the suspected fault node at that time of influence to the spatial distance between the suspected fault node and the bus is used as the priority of the suspected fault node.

8. A distributed relay protection testing system for intelligent substations, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed by the processor, it implements the steps of the distributed relay protection test method for smart substations as described in any one of claims 1-7.

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