Busbar split tripping detection method and system

Abstract

The application provides a bus splitting trip detection method and system, and relates to the technical field of circuit detection. The method comprises the following steps: detecting the opening and closing state changes of a circuit breaker in real time, obtaining bus parameters when the opening and closing state changes of any circuit breaker are monitored; decoding the bus parameters, constructing a first equivalent network model and a first sparse linear equation set, constructing a second equivalent network model and a second sparse linear equation set when the solution of the sparse linear equation set is less than a threshold value; and obtaining a bus splitting trip result based on the solution of the second equivalent network model and the second sparse linear equation set. The equivalent model based on the basic law of electricity naturally adapts to all 3 / 2 wiring topologies and operation modes, reduces the omission problem of manual branch logic, can correctly distinguish in single outgoing line, double outgoing line, cross series contact and other complex working conditions, reduces protection misoperation and refusal to operate, and improves the action reliability of bus splitting protection.

Description

Technical Field

[0001] This application relates to the field of circuit testing technology, and in particular to a method and system for detecting busbar split tripping. Background Technology

[0002] With the application of digital control and protection technologies, the mainstream solution for busbar splitting in converter stations has shifted to topology traversal based on programmable logic. This method divides the electrical range of the busbar using a connected component search algorithm, counts the types and quantities of equipment on the busbar, and then determines whether tripping conditions are met. However, as the scale of AC fields in converter stations expands and the series and outgoing line combinations become increasingly complex, the topology traversal method has gradually revealed problems such as large computational delays, easy omission of logic branches, and low reuse rate across different projects. It is difficult to simultaneously meet the requirements of protection speed, operational reliability, and engineering versatility.

[0003] In related technologies, the logic coverage is incomplete and the reliability of operation is insufficient. For complex wiring conditions such as dual-outgoing-line strings, cross-string interconnections, and multiple converters in parallel, the topology traversal method requires writing a large number of branch judgment logics. Manual design is prone to omission of operating conditions, leading to false tripping or failure to trip of protection. Especially under special operating modes, the tripping logic is prone to mismatch with the actual topology, threatening the safety of the DC system.

[0004] Poor wiring adaptability, high engineering maintenance costs, and a strong binding between topology traversal logic and specific wiring make the algorithm unusable when there are significant differences in the number of strings, string types, and outgoing line types among different converter stations. When converter stations are expanded or wiring is modified, the topology needs to be re-examined and the protection logic code needs to be modified, resulting in low reusability and the possibility of introducing new logical defects through manual modification. Summary of the Invention

[0005] The main objective of this application is to propose a busbar split trip detection method and system, which aims to solve the problems in the background art.

[0006] To achieve the above objectives, one aspect of this application proposes a busbar split trip detection method, the method comprising: Real-time detection of changes in the opening and closing status of circuit breakers; when a change in the opening and closing status of any circuit breaker is detected, bus parameters are acquired. The bus parameters are decoded to construct a first equivalent network model and a first sparse linear equation system. When the solution result of the sparse linear equation system is less than a threshold, a second equivalent network model and a second sparse linear equation system are constructed. Based on the solution results of the second equivalent network model and the second sparse linear equation system, the bus split trip result is obtained.

[0007] In some embodiments, the bus parameters include the total number of series in the 3 / 2 connection AC field, the connection structure parameters of each series, and the real-time status words of each circuit breaker. After obtaining the bus parameters, the process further includes: Decode the total number of series and the wiring structure parameters of each series of the 3 / 2 wiring AC field to obtain the total number of converter valves and the total number of AC filter groups in the entire station; Based on the real-time status words of each circuit breaker, the closing circuit breaker is equivalent to a high-conductivity branch, and the opening circuit breaker is equivalent to a low-conductivity branch.

[0008] In some embodiments, constructing the first equivalent network model and the first sparse linear equation system specifically includes: Bus I, Bus II, and the interval voltage node group are defined as the voltage node set; Each string of circuit breakers is determined as an equivalent conductance branch, and a first equivalent network model is formed based on the series connection relationship of each circuit breaker between bus I and bus II. Based on the first equivalent network model and combined with Kirchhoff's current law, current conservation equations are written for each node in the voltage node set. Based on Ohm's law, the current conservation equation and voltage-current relationship equation are written for each of the equivalent conductance branches. By combining the preset first boundary conditions, the current conservation equation and the voltage-current relationship equation are put into a simultaneous system to construct the first sparse linear equation system.

[0009] In some embodiments, constructing a second equivalent network model and a second sparse linear equation system when the solution result of the sparse linear equation system is less than a threshold specifically includes: Extract the grounding current value of bus II in the first boundary condition; When the grounding current value of the II bus is less than the preset first threshold, it is determined that the bus is in a split operation state, and a second equivalent network model and a second sparse linear equation system are constructed. If the grounding current value of bus II is greater than the preset first threshold, the bus split trip condition is not met.

[0010] In some embodiments, constructing the second equivalent network model and the second sparse linear equation system specifically includes: Based on the first equivalent network model, according to the type encoding of each string connection, an equivalent grounding branch is connected to the interval voltage node of the corresponding string, and the converter valve branch current variable and the AC filter group branch current variable of the equivalent grounding branch are added accordingly to form a second equivalent network model. Based on the second equivalent network model, and in accordance with Kirchhoff's current law, the current conservation equations are rewritten for all voltage nodes, including the I bus node, the II bus node, and the interval voltage node group. Based on Ohm's law, the voltage-current relationship equations of the equivalent conductance branches are written respectively. The equivalent conductance branches include the current variables of the original circuit breaker branches, the newly added converter valve branches, and the current variables of the AC filter group branches. Pre-set second and third boundary conditions, and construct a second sparse linear equation set by combining the current conservation equation and the voltage-current relationship equation. The second sparse linear equation set includes the first linear equation set and the second linear equation set.

[0011] In some embodiments, the first boundary condition is that bus I is connected to a test power supply with a voltage of 1 via a preset first conductance, and bus II is grounded via a preset first conductance; the second boundary condition is that bus I is connected to a test power supply via a preset second conductance, and bus II is grounded via a preset second conductance; and the third boundary condition is that bus II is connected to a test power supply via a preset second conductance, and bus I is grounded via a preset second conductance.

[0012] In some embodiments, connecting an equivalent grounding branch at the interval voltage node of the corresponding string specifically includes: Determine the presence of the converter valve and AC filter group at the interval voltage node; If the interval voltage node has a converter valve, then an equivalent grounding branch connected to the ground terminal is added for the converter valve; If the interval voltage node has a large group of AC filters, then an equivalent grounding branch connected to the ground terminal is added to the large group of AC filters.

[0013] In some embodiments, obtaining the bus split trip result based on the solution results of the second equivalent network model and the second sparse linear equation system specifically includes: Solve the first and second linear equation sets respectively to obtain the branch currents of each converter valve and each AC filter group under different boundary conditions; For the converter valve or AC filter group whose branch current is greater than the preset second threshold, the affiliation result of the equipment is determined. The affiliation result is defined as the converter valve or AC filter group being electrically connected to the bus side connected to the corresponding test power supply. The attribution result is compared with the preset operating conditions to obtain the busbar split trip result.

[0014] In some embodiments, after comparing the attribution result with a preset operating condition to obtain the busbar split trip result, the method further includes: Based on the bus split trip result, execute the preset trip protection strategy; The split status of bus I and bus II, equipment distribution results, and tripping action status are synchronously sent to the station monitoring backend, and operation alarms and event records are generated.

[0015] To achieve the above objectives, another aspect of this application provides a busbar split trip detection system, the system comprising: The data acquisition module is used to detect changes in the opening and closing status of circuit breakers in real time. When a change in the opening and closing status of any circuit breaker is detected, the bus parameters are acquired. The data decoding module is used to decode the bus parameters, construct a first equivalent network model and a first sparse linear equation system, and construct a second equivalent network model and a second sparse linear equation system when the solution result of the sparse linear equation system is less than a threshold. The trip detection module is used to obtain the bus split trip result based on the solution results of the second equivalent network model and the second sparse linear equation system.

[0016] The embodiments of this application include at least the following beneficial effects: This application provides a busbar split trip detection method and system. The equivalent model based on the basic laws of circuits is naturally adapted to all 3 / 2 wiring topologies and operating modes, reducing the omission problem of manual branch logic. It can correctly identify complex operating conditions such as single outgoing line, double outgoing line, and cross-series connection, reducing protection false trips and failure to trip, and improving the reliability of busbar split protection. The trip detection in this application and the bus split interlock detection with the same architecture are based on the same equivalent modeling principle and discrimination criterion. The two have the same input parameters, the same topology model and the same threshold criterion, which ensures that the interlock warning result and the trip action result are consistent. This application can configure AC fields with different numbers of strings, different string types, and different outgoing line types simply by using structural parameters. When the converter station is expanded or the wiring is modified, there is no need to modify the core code of the protection algorithm. Only the configuration parameters need to be updated to complete the adaptation, reducing the workload of customized development and maintenance. The sparse matrix solution proposed in this application is a mature deterministic numerical computation method. It avoids the risks of stack overflow and computation timeout caused by recursive traversal, has controllable memory usage, and runs stably and reliably in resource-constrained embedded protection devices, meeting the high availability requirements of power protection devices. Attached Figure Description

[0017] Figure 1 This is a flowchart of the busbar split trip detection method provided in the embodiments of this application; Figure 2 This is an expanded diagram of the busbar split trip detection method provided in the embodiments of this application; Figure 3This is a circuit diagram of the converter valve and AC filter assembly provided in the embodiments of this application; Figure 4 This is a first equivalent network model structure diagram provided in the embodiments of this application; Figure 5 This is a solution diagram of the first sparse linear equation system provided in the embodiments of this application; Figure 6 This is a diagram of the second equivalent network model structure under a preset second boundary condition provided in the embodiments of this application; Figure 7 This is a solution diagram of the coefficient matrix H2 and the right-hand vector L2 under the preset second boundary conditions provided in the embodiments of this application; Figure 8 This is a diagram of the second equivalent network model structure under a preset third boundary condition provided in the embodiments of this application; Figure 9 This is a solution diagram of the coefficient matrix H3 and the right-hand vector L3 under the preset third boundary conditions provided in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0019] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0020] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[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 application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0022] Before providing a detailed description of the embodiments of this application, some of the nouns and terms involved in the embodiments of this application will be explained first. The nouns and terms involved in the embodiments of this application are subject to the following interpretations.

[0023] A large AC filter group refers to a filter assembly unit directly connected to the 3 / 2 connection AC field bus bay (i.e., the node between AB bays or BC bays), and exists as an independent bay device in the electrical topology.

[0024] An AC filter group refers to the basic filtering unit that makes up an AC filter group, that is, a sub-level device under the group.

[0025] Kirchhoff's Current Law, also known as Kirchhoff's First Law or the Nodal Current Law, is basically stated as follows: In a lumped-parameter circuit, at any given moment, the algebraic sum of the currents flowing into any node is equal to zero.

[0026] Ohm's Law states that in the same circuit, the current through a conductor is directly proportional to the voltage across the conductor and inversely proportional to the resistance of the conductor.

[0027] In 3 / 2 wiring, a "bay" specifically refers to a physical unit containing a particular circuit breaker and disconnector. For example, the area occupied by circuit breaker A and its surrounding disconnectors and current transformers is called "Bay A". "Bay" here is a directional word, meaning "between" or "middle position". So, "Bay AB" refers to the electrical connection point (i.e., the physical short busbar or connecting bar) between "Bay A containing circuit breaker B containing circuit breaker A".

[0028] In related technologies, some manufacturers judge sequentially , , , as well as The connection status; in The connection status between busbar I and busbar II, when A value of 1 indicates that there is no connection between busbar I and busbar II, while a value of 0 indicates that there is a connection between busbar I and busbar II. in For connecting the converter valve to the I busbar mark, when A value of 1 indicates that the converter valve corresponding to the polarity controller is connected to the I bus, while a value of 0 indicates that the converter valve corresponding to the polarity controller is not connected to the I bus. in The converter valve is connected to bus II, marked when... A value of 1 indicates that the converter valve corresponding to the polarity controller is connected to bus II, while a value of 0 indicates that the converter valve corresponding to the polarity controller is not connected to bus II. in Connect the I bus flag to the AC filter group when A value of 1 indicates that an AC filter group is connected to the I bus, while a value of 0 indicates that no AC filter group is connected to the I bus.

[0029] in Connect the AC filter group to the II bus marker, when A value of 1 indicates that an AC filter group is connected to bus II, and a value of 0 indicates that no AC filter group is connected to bus I. Then use the following formula to determine the bus split logic action.

[0030] ; in This is the output signal for the split trip. For logic, For OR logic.

[0031] However, the above methods still have similar problems to the background technology. In view of this, this application provides a busbar split trip detection method and system.

[0032] It should be noted that the implementation logic of this application is as follows: 1. Assuming there is a power source with Us=1 on bus I, and disregarding the output of the converter valve, AC filter, and AC line, ground bus II. Since grounding bus II is the only grounding point, if there is no current in the Us power source, it proves that bus I and bus II are disconnected, and we can proceed to the next step of judgment.

[0033] 2. Assuming there is a power supply with Us=1 on bus I, ground the output lines of the converter valve and AC filter. If the current of the converter valve is not 0, it means that the converter valve is connected to bus I. If the current of the AC filter is not 0, it means that the converter valve is connected to bus I. The same applies to bus II.

[0034] refer to Figures 1-3 As shown, one embodiment of this application proposes a busbar split trip detection method, including: S101: Real-time detection of changes in the opening and closing status of circuit breakers; when a change in the opening and closing status of any circuit breaker is detected, bus parameters are obtained. S102: Decode the bus parameters, construct the first equivalent network model and the first sparse linear equation system. When the solution result of the sparse linear equation system is less than the threshold, construct the second equivalent network model and the second sparse linear equation system. S103: Based on the solution results of the second equivalent network model and the second sparse linear equation system, obtain the bus split trip result.

[0035] Step S101 involves real-time detection of the status changes of the 3 / 2 connection AC circuit breaker. If any circuit breaker changes its open or closed status, the process proceeds to step S102.

[0036] In step S102, the bus parameters mainly include the total number of AC circuits in the 3 / 2 connection, N, the connection structure parameter Tn, and the real-time circuit breaker status words BRK-nA, BRK-nB, and BRK-nC.

[0037] After obtaining the bus parameters, the hexadecimal bus parameters Tn are decoded to determine the outgoing line type of each string, and the total number of converter valves NVAL and the total number of AC filter groups NACF are counted. Specifically, T1, T2, ..., TN represent the wiring structures of the first to Nth strings: 0 represents no wiring between AB bays and no wiring between BC bays; 1 represents AC output between AB bays and no wiring between BC bays; 2 represents AC filter group between AB bays and no wiring between BC bays; 3 represents AC converter valve between AB bays and no wiring between BC bays; 4 represents no wiring between AB bays and AC output between BC bays; 5 represents no wiring between AB bays and AC filter group between BC bays; 6 represents no wiring between AB bays and converter valve between BC bays; 7 represents AC output between AB bays and AC output between BC bays. Outgoing lines; 8 represents AB interval indirect AC outgoing lines and BC interval indirect AC filter group; 9 represents AB interval indirect AC outgoing lines and BC interval indirect converter valve; A represents AB interval indirect AC filter group and BC interval indirect AC outgoing lines; B represents AB interval indirect AC filter group and BC interval indirect AC filter group; C represents AB interval indirect AC filter group and BC interval indirect converter valve; D represents AB interval indirect converter valve and BC interval indirect AC outgoing lines; E represents AB interval indirect converter valve and BC interval indirect AC filter group; F represents AB interval indirect converter valve and BC interval indirect converter valve.

[0038] Map each decimal circuit breaker status word BRK to conductance: the closing circuit breaker is equivalent to a high conductance branch (1000S, approximately ideal conduction), and the opening circuit breaker is equivalent to an extremely low conductance branch (1e-6S, approximately ideal disconnection).

[0039] Among them, BRK-1A, BRK-1B, BRK-1C, ..., BRK-NA, and BRK-NC represent the switching states of the first A / B / C bay circuit breaker, ..., the Nth A / B / C bay circuit breaker, respectively. 1 represents closed, and 0 represents open.

[0040] Specifically, in step S102, the bus parameters are decoded to construct the first equivalent network model and the first sparse linear equation system, including: Bus I, Bus II, and the interval voltage node group are defined as the voltage node set, where the interval voltage node group includes the AB interval and BC interval of each string as voltage nodes. Each string of circuit breakers is determined as an equivalent conductance branch, and a first equivalent network model is formed based on the series connection relationship of each circuit breaker between bus I and bus II. The string of circuit breakers includes three circuit breakers in each string A / B / C. Based on the first equivalent network model and combined with Kirchhoff's current law, the current conservation equation is written for each node in the voltage node set. Based on Ohm's law, write the current conservation equation and voltage-current relationship equation for each equivalent conductance branch; The current conservation equations satisfy the current node equations (KCL constraints). The current conservation equations for each voltage node are as follows: I busbar node: Sum of currents of all A-bay circuit breakers - Total current of I busbar = 0; Bus II node: Sum of currents of all C-bay circuit breakers + total current of Bus II = 0; At the midpoint of each string AB: Current flowing into A interval - Current flowing out of B interval = 0; At the midpoint of each string BC: Current flowing into B interval - Current flowing out of C interval = 0.

[0041] Voltage branch equation (Ohm's law constraint): Write the voltage-current relationship for each circuit breaker branch. The voltage difference across the branch multiplied by the conductance equals the branch current.

[0042] Combining the preset first boundary conditions, the current conservation equation and the voltage-current relationship equation are combined to construct the first sparse linear equation system, which is a 5N+4 variable first-order equation system. The unknowns are all voltage nodes (2N+2), conductance branch current (3N), I bus power supply current and II bus grounding current. Specifically, in this application, the first boundary condition is that bus I is connected to a test power supply with a voltage of 1 via a preset first conductance, and bus II is grounded via a preset first conductance. In this application, the first conductance is preset to 1e-6S. Based on the first sparse linear equation system, a sparse coefficient matrix H1 with dimension 5N+4 and a right-hand vector L1 are formed. When constructing the coefficient matrix H1 and the right-hand vector L1, the voltage-current relationship equation corresponding to the first boundary condition is placed in the last two equation positions of the first sparse linear equation system (i.e., the last two rows of the matrix).

[0043] By applying the first sparse linear equation system H1 X1=L1 is numerically solved to extract the grounding current value of bus II; if the grounding current value of bus II is less than the set first threshold (1p.u.), it indicates that there is no effective conduction path between bus I and bus II, and it is determined to be a bus split operation state. The second equivalent network model and the second sparse linear equation system are constructed. If the current is greater than or equal to the threshold, it is determined that the bus is operating in parallel, which does not meet the preconditions for tripping. The tripping signal TRIP=0 is output directly, and the process ends.

[0044] Furthermore, a second equivalent network model and a second sparse linear equation system are constructed, including: Based on the first equivalent network model, according to the type coding of each string connection, equivalent grounding branches of converter valves and AC filter groups are connected to the voltage nodes in the AB and BC intervals of the corresponding strings (the branches are grounded after being connected in series with a 1000S conductance), specifically as follows: If there is a converter valve at the voltage node between the AB and BC bays, then an equivalent grounding branch connected to the ground terminal is added for the converter valve. If there is a large AC filter group at the interval voltage node (between AB and BC), then an equivalent grounding branch connected to the ground terminal is added to the large AC filter group.

[0045] An equivalent grounding branch is connected to the voltage interval node of the corresponding string, and the current variables of the converter valve branch and the AC filter group branch of the equivalent grounding branch are added accordingly to form a second equivalent network model. Based on the second equivalent network model, and in accordance with Kirchhoff's current law, the current conservation equations are rewritten for all voltage nodes, including the I bus node, the II bus node, and the interval voltage node group. Based on Ohm's law, the voltage-current relationship equations of the equivalent conductance branches are written separately. The equivalent conductance branches include the current variables of the original circuit breaker branches, the newly added converter valve branches, and the current variables of the AC filter group branches. The construction of the current conservation equation and the voltage-current relationship equation is similar to that of the first equivalent network model.

[0046] By pre-setting second and third boundary conditions, and combining the current conservation equation and the voltage-current relationship equation, a second sparse linear equation system is constructed.

[0047] The second sparse linear equation system forms an extended sparse coefficient matrix H with a dimension of 5N+4+NVAL+NACF and a right-hand vector L. The second sparse linear equation system includes the first linear equation system and the second linear equation system.

[0048] It should be noted that the first system of linear equations corresponds to the preset second boundary condition. The first system of linear equations includes a coefficient matrix H2 and a right-hand vector L2. The second linear equation system corresponds to the preset third boundary condition. The second linear equation system includes the coefficient matrix H3 and the right-hand vector L3.

[0049] refer to Figure 6 and Figure 8 As shown, the second equivalent network model also differs under different boundary conditions.

[0050] Furthermore, the voltage-current relationship equations corresponding to the second and third boundary conditions are placed in the last two equation positions of the corresponding linear equation system (i.e., the last two rows of the matrix).

[0051] Specifically, the second boundary condition is that bus I is connected to the test power supply via a preset second conductor, and bus II is grounded via a preset second conductor, wherein the second conductor is set to 1000S.

[0052] The third boundary condition is that bus II is connected to the test power supply via a preset second conductor, and bus I is grounded via a preset second conductor, wherein the second conductor is set to 1000S.

[0053] Furthermore, the first and second linear equations are solved separately to obtain the branch currents of each converter valve and each AC filter group under different boundary conditions. For converter valves or AC filter groups whose branch current exceeds the preset second threshold, determine the device's affiliation result. The affiliation result is defined as the converter valve or AC filter group being electrically connected to the bus side connected to the corresponding test power supply. The attribution result is compared with the preset operating conditions to obtain the bus split trip result; Based on the busbar split trip result, execute the preset trip protection strategy; The split status of bus I and bus II, equipment distribution results, and tripping action status are synchronously sent to the station monitoring backend, and operation alarms and event records are generated.

[0054] The preset operating conditions include: Operating Condition 1: A converter valve is connected to Bus I, and a large AC filter group is connected to Bus II. Operating Condition 2: A converter valve is connected to the II bus side, and a large AC filter group is connected to the I bus side.

[0055] Specifically, the trip protection strategy includes: 1. When a group of converter valves is connected to a bus, and another AC bus is connected to a filter group (all subgroups are out) and is not connected to a converter, a time limit is used to momentarily prohibit all subgroup filters connected to the other AC bus from automatically starting. When a group of converter valves is connected to a busbar, and another AC busbar is connected to a filter group (with a small group in operation) but not to a converter, a two-time delay is used. The first time delay instantaneously trips all filter switches connected to the other AC busbar, and the second time delay delays and locks out this converter. The second time delay starts counting after the trip output of the first time delay is met, and should avoid the return time of the busbar split judgment logic. Generally, considering the circuit breaker failure protection time (200ms), the switch opening status judgment time, and the margin time, the second time delay should not be less than 300ms; 3) When a group of converter valves is connected to a busbar, and another AC busbar is connected to a filter group (with a small group in operation) and to a converter, a one-time delay is used to instantaneously lock out this converter.

[0056] The following specific examples illustrate this application: Step 1: Real-time detection of changes in the opening and closing status of circuit breakers. When a change in the opening and closing status of any circuit breaker is detected, obtain the bus parameters. The bus parameters are as follows: total number of AC field series in 3 / 2 connection N=3, connection structure parameters T1=3, T2=B, T2=1, BRK-1A=1, BRK-1B=0, BRK-1C=1, BRK-2A=0, BRK-2B=1, BRK-2C=1, BRK-3A=1, BRK-3B=0, BRK-3C=1. After obtaining the bus parameters, proceed to step 2. Step 2: Preprocess the bus parameters and calculate the total number of converter valves (NVAL) and the total number of AC filter groups (NACF) for the entire station; where the total number of converter valves (NVAL) is 1 and the total number of AC filter groups (NACF) is 2. BRK-1A, BRK-1C, BRK-2B, BRK-2C, BRK-3A, and BRK-3C circuit breakers are equivalent to high-conductance branches (1000S, approximately ideal conduction), and BRK-1B, BRK-2A, and BRK-3B circuit breakers are equivalent to extremely low-conductance branches (1e-6S, approximately ideal disconnection).

[0057] Step 3, Reference Figures 4-5 As shown, a first equivalent network model and a first sparse linear equation system are constructed, wherein the first sparse linear equation system includes a coefficient matrix H1 and a right-hand vector L1, and the first sparse linear equation system satisfies the following: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; in The voltage of bus I, The voltage of bus II. The grounding current of bus I is... This is the grounding current of bus II. , as well as The voltage at the nodes between the AB intervals of the 1st, 2nd, and 3rd strings. , as well as The voltages between the nodes of the BC intervals in the 1st, 2nd, and 3rd strings are... , as well as The currents of the branches of the A-section circuit breakers in series 1, 2, and 3 are as follows: , as well as The currents of the branches of the b-interval circuit breakers in series 1, 2, and 3 are as follows: , as well as This refers to the branch current of the first, second, and third series c-interval circuit breakers.

[0058] in Figure 4 by" (I busbar)" as the starting point, " (II busbar) is the endpoint. Figure 4 The three parallel independent branches correspond to the first, second, and third strings, respectively.

[0059] Specifically defined as: The first string, - - - - - - Circuit breaker A current (I1a), AB bay voltage (U1ab), B circuit breaker current (I1b), BC bay voltage (U1bc), and C circuit breaker current (I1c). The second string, - - - - - - A circuit breaker current (I2a), AB bay voltage (U2ab), B circuit breaker current (I2b), BC bay voltage (U2bc), C circuit breaker current (I2c). The third string, - - - -U3bc- - Circuit breaker A current (I3a), AB bay voltage (U3ab), B circuit breaker current (I3b), BC bay voltage (U3bc), and C circuit breaker current (I3c).

[0060] It should be noted that, in Figure 4 , Figure 6 as well as Figure 8 In the diagram, the "first string" is defined by all variables with index "1" (I1a, U1ab, I1b, U1bc, I1c) and their concatenated paths; the "second string" is defined by all variables with index "2" (I2a, U2ab, I2b, U2bc, I2c); and the "third string" is defined by all variables with index "3" (I3a, U3ab, I3b, U3bc, I3c). They are connected side-by-side between bus I (UI) and bus II (UII).

[0061] The calculated grounding current value of Bus II is... =3.0000e-06<1, indicating a busbar split operation state, proceed to step four.

[0062] Step 4, Reference Figure 6 and Figure 7As shown in step three, a second boundary condition is preset. Based on the first equivalent network model, and according to the type encoding of each string connection, equivalent grounding branches of the converter valve and AC filter group are connected to the voltage nodes in the AB and BC intervals of the corresponding strings (the branches are grounded after being connected in series with a 1000S conductance). Specifically: If there is a converter valve at the voltage node between the AB and BC bays, then an equivalent grounding branch connected to the ground terminal is added for the converter valve. If there is a large AC filter group at the interval voltage node (between AB and BC), then an equivalent grounding branch connected to the ground terminal is added to the large AC filter group.

[0063] An equivalent grounding branch is connected to the voltage interval node of the corresponding string, and the current variables of the converter valve branch and the AC filter group branch of the equivalent grounding branch are added accordingly to form a second equivalent network model. Based on the second equivalent network model, and in accordance with Kirchhoff's current law, the current conservation equations are rewritten for all voltage nodes, including the I bus node, the II bus node, and the interval voltage node group. Based on Ohm's law, the voltage-current relationship equations of the equivalent conductance branches are written separately. The equivalent conductance branches include the current variables of the original circuit breaker branches, the newly added converter valve branches, and the current variables of the AC filter group branches. The construction of the current conservation equation and the voltage-current relationship equation is similar to that of the first equivalent network model.

[0064] By pre-setting a second boundary condition and combining the current conservation equation and the voltage-current relationship equation, a second sparse linear equation system is constructed. Under the pre-set second boundary condition, the second sparse linear equation system can be understood as the first linear equation system.

[0065] It should be noted that the second sparse linear equation in this application includes a first linear equation system and a second linear equation system. The first linear equation system corresponds to the second boundary condition, and the second linear equation system corresponds to the third boundary condition. Under different boundary conditions, the composition of the second equivalent model also differs. (See reference...) Figure 6 and Figure 8 As shown.

[0066] The first system of linear equations includes a coefficient matrix H2 and a right-hand vector L2, and satisfies the following: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; in This refers to the branch current connected to the equipment via the first AB interval. This refers to the branch current connected to the equipment via the second AB interval. This is the branch current connected to the equipment in the second BC interval.

[0067] Calculations show that =333.333>1, =0.5417e-6<1, =0.4167e-6<1, the converter valve is connected to the I bus side.

[0068] Similarly, refer to Figure 8 and Figure 9 As shown, with a preset third boundary condition, and referring to the construction method of the first linear equation system, a second linear equation system and a second equivalent network model are constructed. The second linear equation system includes a coefficient matrix H3 and a right-hand vector L3, and satisfies the following: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Calculations show that =0.667e-6<1, =125>1, =250>1, the two AC filter groups are connected to the I bus side.

[0069] Step 5: As can be seen, operating condition 1 is met: a converter valve is connected to the I bus side and a large AC filter group is connected to the II bus side. Proceed to step 6.

[0070] Step Six: Execute the tripping logic according to the procedure requirements. Determine if the busbar split tripping conditions are met, and set TRIP=1.

[0071] Assuming a sub-group is engaged within a large group, the following condition is met: "When a group of converter valves is connected to one busbar, and another AC busbar is connected to a filter group (with a sub-group engaged) but not to a converter," a two-time delay is used. The first time delay instantaneously trips all sub-group filter switches connected to the other AC busbar. The second time delay delay blocks the converter itself. The second time delay starts counting after the tripping output of the first time delay is met and should avoid the return time of the busbar splitting judgment logic. Generally, considering the circuit breaker failure protection time (200ms), the switch opening status judgment time, and the margin time, the second time delay should not be less than 300ms.

[0072] The methods provided in this application relate to the field of information technology. The methods provided in this application can be applied to terminals, servers, or software running on either a terminal or a server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, or in-vehicle terminal, but is not limited to these. The server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network. The software can be an application implementing the method, but is not limited to the above forms.

[0073] In another aspect of the embodiments of this application, a busbar split trip detection system is also proposed, the system comprising: The data acquisition module is used to detect changes in the opening and closing status of circuit breakers in real time. When a change in the opening and closing status of any circuit breaker is detected, the bus parameters are acquired. The data decoding module is used to decode the bus parameters, construct a first equivalent network model and a first sparse linear equation system, and construct a second equivalent network model and a second sparse linear equation system when the solution result of the sparse linear equation system is less than a threshold. The trip detection module is used to obtain the bus split trip result based on the solution results of the second equivalent network model and the second sparse linear equation system.

[0074] This application can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices. This application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0075] It should be noted that in all specific embodiments of this application, when processing data related to user identity or characteristics, such as user information, user behavior data, user historical data, and user location information, user permission or consent is obtained first. Furthermore, the collection, use, and processing of this data comply with relevant laws, regulations, and standards. In addition, when embodiments of this application require access to sensitive personal information of users, separate permission or consent from the user is obtained through pop-ups or redirection to confirmation pages. Only after obtaining the user's separate permission or consent is the necessary user-related data required for the proper functioning of these embodiments acquired.

[0076] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0077] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0078] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0079] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0080] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0081] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0082] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0083] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0084] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0085] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0086] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for detecting busbar split tripping, characterized in that, The method includes: Real-time detection of changes in the opening and closing status of circuit breakers; when a change in the opening and closing status of any circuit breaker is detected, bus parameters are acquired. The bus parameters are decoded to construct a first equivalent network model and a first sparse linear equation system. When the solution result of the sparse linear equation system is less than a threshold, a second equivalent network model and a second sparse linear equation system are constructed. Based on the solution results of the second equivalent network model and the second sparse linear equation system, the bus split trip result is obtained.

2. The busbar split trip detection method according to claim 1, characterized in that, The bus parameters include the total number of series in the 3 / 2 connection AC field, the connection structure parameters of each series, and the real-time status words of each circuit breaker. After obtaining the bus parameters, the process further includes: Decode the total number of series and the wiring structure parameters of each series of the 3 / 2 wiring AC field to obtain the total number of converter valves and the total number of AC filter groups in the entire station; Based on the real-time status words of each circuit breaker, the closing circuit breaker is equivalent to a high-conductivity branch, and the opening circuit breaker is equivalent to a low-conductivity branch.

3. The busbar split trip detection method according to claim 1, characterized in that, The construction of the first equivalent network model and the first sparse linear equation system specifically includes: Bus I, Bus II, and the interval voltage node group are defined as the voltage node set; Each string of circuit breakers is determined as an equivalent conductance branch, and a first equivalent network model is formed based on the series connection relationship of each circuit breaker between bus I and bus II. Based on the first equivalent network model and combined with Kirchhoff's current law, current conservation equations are written for each node in the voltage node set. Based on Ohm's law, the current conservation equation and voltage-current relationship equation are written for each of the equivalent conductance branches. By combining the preset first boundary conditions, the current conservation equation and the voltage-current relationship equation are put into a simultaneous system to construct the first sparse linear equation system.

4. The busbar split trip detection method according to claim 3, characterized in that, When the solution result of the sparse linear equation system is less than a threshold, constructing a second equivalent network model and a second sparse linear equation system specifically includes: Extract the grounding current value of bus II in the first boundary condition; When the grounding current value of the II bus is less than the preset first threshold, it is determined that the bus is in a split operation state, and a second equivalent network model and a second sparse linear equation system are constructed. If the grounding current value of bus II is greater than the preset first threshold, the bus split trip condition is not met.

5. The busbar split trip detection method according to claim 4, characterized in that, The construction of the second equivalent network model and the second sparse linear equation system specifically includes: Based on the first equivalent network model, according to the type encoding of each string connection, an equivalent grounding branch is connected to the interval voltage node of the corresponding string, and the converter valve branch current variable and the AC filter group branch current variable of the equivalent grounding branch are added accordingly to form a second equivalent network model. Based on the second equivalent network model, and in accordance with Kirchhoff's current law, the current conservation equations are rewritten for all voltage nodes, including the I bus node, the II bus node, and the interval voltage node group. Based on Ohm's law, the voltage-current relationship equations of the equivalent conductance branches are written respectively. The equivalent conductance branches include the current variables of the original circuit breaker branches, the newly added converter valve branches, and the current variables of the AC filter group branches. Pre-set second and third boundary conditions, and construct a second sparse linear equation set by combining the current conservation equation and the voltage-current relationship equation. The second sparse linear equation set includes the first linear equation set and the second linear equation set.

6. The busbar split trip detection method according to claim 5, characterized in that, The first boundary condition is that bus I is connected to a test power supply with a voltage of 1 via a preset first conductance, and bus II is grounded via a preset first conductance. The second boundary condition is that bus I is connected to a test power supply via a preset second conductance, and bus II is grounded via a preset second conductance. The third boundary condition is that bus II is connected to a test power supply via a preset second conductance, and bus I is grounded via a preset second conductance.

7. The busbar split trip detection method according to claim 5, characterized in that, The connection of an equivalent grounding branch to the interval voltage node of the corresponding string specifically includes: Determine the presence of the converter valve and AC filter group at the interval voltage node; If the interval voltage node has a converter valve, then an equivalent grounding branch connected to the ground terminal is added for the converter valve; If the interval voltage node has a large group of AC filters, then an equivalent grounding branch connected to the ground terminal is added to the large group of AC filters.

8. The busbar split trip detection method according to claim 6, characterized in that, The method for obtaining the bus split trip result based on the solution results of the second equivalent network model and the second sparse linear equation system specifically includes: Solve the first and second linear equation sets respectively to obtain the branch currents of each converter valve and each AC filter group under different boundary conditions; For the converter valve or AC filter group whose branch current is greater than the preset second threshold, the affiliation result of the equipment is determined. The affiliation result is defined as the converter valve or AC filter group being electrically connected to the bus side connected to the corresponding test power supply. The attribution result is compared with the preset operating conditions to obtain the busbar split trip result.

9. The busbar split trip detection method according to claim 8, characterized in that, After comparing the attribution result with the preset operating conditions to obtain the bus split trip result, the method further includes: Based on the bus split trip result, execute the preset trip protection strategy; The split status of bus I and bus II, equipment distribution results, and tripping action status are synchronously sent to the station monitoring backend, and operation alarms and event records are generated.

10. A busbar split trip detection system, characterized in that, The system includes: The data acquisition module is used to detect changes in the opening and closing status of circuit breakers in real time. When a change in the opening and closing status of any circuit breaker is detected, the bus parameters are acquired. The data decoding module is used to decode the bus parameters, construct a first equivalent network model and a first sparse linear equation system, and construct a second equivalent network model and a second sparse linear equation system when the solution result of the sparse linear equation system is less than a threshold. The trip detection module is used to obtain the bus split trip result based on the solution results of the second equivalent network model and the second sparse linear equation system.

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